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Could We Dredge the Netherlands Without Fossil Fuels?

Sun, 05 Aug 2018 00:00:00 +0000

1699 scale model of a scratcher rigged with sails. Image: [Maritiem Digitaal](http://www.maritiemdigitaal.nl/index.cfm?event=page.home)

The dredging industry has been the backbone of the Dutch economy for centuries. If canals, harbours and rivers would not be maintained for a few years, the whole country would literally grind to a halt.

Today, dredging happens with oil powered ships, which burn up to 3,000 litres of fuel per hour. However, in earlier times, the Dutch waterways were dredged mostly by hand, using simple but ingenious tools.

Manual dredging was heavy labour, especially when waterways became deeper. Therefore, it was supplemented by animal power, wind power and tidal power. However, in some parts of the Netherlands, people chose a different strategy: they designed a new type of cargo ship that could sail in shallow waterways.

35 million m³ of mud

Siltation is a serious problem in the Netherlands, which lies in the delta area of various rivers that supply large amounts of silt and clay particles. At the same time, navigable waterways are essential to maintain transportation and trade — the country is home to the largest port in Europe, Rotterdam.

Each year, some 30 to 35 million m³ of mud are dredged out for the maintenance of the Dutch waterways. Approximately 75% comes from salty waters. In the port of Rotterdam alone, 20 million m³ of mud is collected each year.

The demand for dredging continues to increase. Both inland ships and seagoing vessels continue to get bigger, requiring ever deeper and wider waterways. A “modal shift” policy, in which cargo transport moves from the road to the water in order to improve sustainability and reduce congestion, also leads to more and larger ships, and thus to more dredging.

Dredging by hand in Delft, the Netherlands. Image: [Maritiem Digitaal](http://www.maritiemdigitaal.nl).

Although most of the mud is dumped into the sea, each year 3.5 to 5 million m³ of contaminated sediments must be landfilled. Then there is the dependency on fossil fuels. A typical suction hopper dredger has a pumping power of 2,500 kW and removes 100 m³ of sediments per minute. The largest dredgers have 30,000 kW engines and 6,000 kW of pumping power. At full power, these ships consume 3,000 litres of oil per hour.

Dredging a Country by Hand

Silting is a very old problem in the Netherlands, so how did this job happen before the arrival of fossil fuel powered dredging machines and boats?

For centuries, the Netherlands were mainly dredged by hand. Dredgers stood on a small boat and scraped mud from the bottom with their “dredge bag” (“baggerbeugel”). In an alternative configuration, the dredger stood on a wooden board that was supported by the river bank on one side, and by a floating container on the other side.

A dredging bag. Image: [Maritiem Digitaal](http://www.maritiemdigitaal.nl/index.cfm?event=page.home)

Dredging by hand, standing on a boat. [Image](https://www.yumpu.com/nl/document/view/18609381/pre-industrial-dredging-rosmolens-en-krabbelaars-baggeren-vssd/2).

Handling a dredge bag.

The dredge bag, a tool that was also used for peat cutting, was a long stick (up to 6 metres long) with an annular metal scraper and a net at the end. There were different types of nets and bags, depending on the composition of the sediment. Working with the dredge bag, the handle was rested against the shoulder, so that the net could be dragged over the bottom with two hands.

For large dredging works, thousands of workers with dredging bags were deployed.

The mud was pulled ashore or deposited in a flat barge. For large dredging works, such as the construction of the Northern Holland Canal in 1822-1825, thousands of workers with dredging bags were deployed. Until about 1960, contractors of dredging works employed men with dredging bags for the maintenance of shallow ditches and canals. The tool is still for sale.

Dredge Mills

Manual dredging is heavy and time-consuming work, so people designed technology that could ease and speed up the task. Furthermore, ships became ever larger. In the last quarter of the sixteenth century, the “dredge mill” was introduced, which worked up to a depth of two metres. It was still based on human power, but now people were merely the power source for a machine.

On a dredge mill, a group of people worked large treadmills or capstans, which drove a paddle wheel that scooped the mud from the bottom and threw it into a barge that was moored across. The dredge mill was usually made up of two flat barges with the rotating wheel in between. These machines were often operated by prisoners.

Dredge mill operated by prisoners. Image: [Beeldarchief Rijkswaterstaat](https://beeldbank.rws.nl/MediaObject/Details/331290).

However, one century later, the depth of a merchant ship had increased to between 3.5 and 5 metres — and this was too deep for the human powered dredge mill. In 1622, the first horse-powered dredge mill was built. Three to six horses ran a pivot which set in motion a bucket chain. The horses had to be changed every hour because of the heavy labour involved.

In 1829, horse powered dredge mills could be used to dredge up to a depth of 5-7 metres. If working at a depth of 3.2 metres, with three to six horses, approximately 20 m³ of mud could be collected each hour. By comparison, the average modern suction dredger — which removes 100 m³ of mud per minute — is as powerful as 300 horse powered dredge mills.

Mechanical dredge bags on a pontoon. [Image](https://www.yumpu.com/nl/document/view/18609381/pre-industrial-dredging-rosmolens-en-krabbelaars-baggeren-vssd/2).

The original dredging techniques were also improved. Mechanical dredge bags emerged in the sixteenth century, when someone got the idea to pull the dredging bag with a rope over a winch. Mechanical dredge bags could be mounted on ships, but several dredge bags and winches could also work side by side on a pontoon.

During the first half of the nineteenth century the valve barge was invented. The bottom of this small boat could be opened without causing it to sink. In this way, it took less time to remove the mud. The technique is still used in some modern dredgers.

Valve barge with dredge bag. Image: [Maritiem Digitaal](http://www.maritiemdigitaal.nl/index.cfm?event=page.home).

Scratchers

The Dutch also took advantage of renewable energy sources to lighten the work — in particular wind and tidal power. From the fifteenth century onwards, the “scratcher” (“krabbelaar”) was used, a scraper that could dredge gullies if there was enough current.

With a strong current, dredging becomes easier, because the mud only needs to be loosened. The tide ensures the discharge of the material to the sea.

Human powered scratcher. Source: [Maritiem Digitaal](http://www.maritiemdigitaal.nl/index.cfm?event=page.home).

Human powered scratcher. Source unknown.

Simple scratchers were a kind of large rakes that were dragged across the bed of the water body. These were pulled by horses or people — some were pulled by a rowing boat.

Wind Powered Dredgers

In harbours with strong winds and tides, scratchers were rigged with sails. These triangular sailing ships had a broad stern and a flat bottom. Attached to the bottom was a harrow with iron spikes. At mid tide, the scratcher was placed just before the lock gates of a scouring basin, which was filled during high tide.

At low tide, the sluice gates of the basin were opened and the scratcher was pushed through the harbour with great force as the iron teeth scraped across the bottom. The ship gathered extra speed through the wide stern and, if the wind was good, the use of sails. Horses could also be used, pulling the ship in the absence of good winds.

At low tide, the sluice gates of the basin were opened and the scratcher was pushed through the harbour with great force as the iron teeth scraped across the bottom.

Wind powered scratchers were in use at least since 1435 in the southeastern part of the Netherlands. The flat bottom of the scratcher hinged and could sink with the help of cables to improve the draft. Two revolving doors, which could make a sharp angle of about 45 degrees with the ship, increased the reach of the barge.

Backside of a wind powered scratcher.

Nevertheless, manpower was still needed. Five to six men kept the monster in the right lane, while two to three men kept the harrow at the desired depth through pulleys and hoist blocks.

Alternatives to Dredging

Dredging was not the only answer to the siltation of waterways. Until the nineteenth century, the choice was also made to increase the height of river banks and dikes, so that the water level was allowed to rise. This was especially true for large rivers.

In a report from 1825, the dredging of large rivers was not considered a possibility because they were too deep and too wide for the technology of those days. It was only with steam power that dredging was also done on major rivers.

A Frisian Skûtsje. Image: [Skûtsje Langwar](http://skutsjelangwar.nl)

The province of Friesland, in the north of the country, reveals yet another alternative to dredging. The Frisians never used dredge mills, horse mills or other tools than dredge bags. They continued to dredge by hand until the arrival of the steam engine.

However, they innovated in a different way: from 1889 to 1933, they built 1,200 large cargo ships with a very limited draft — the so-called “skûtjes”. Obviously, boats with a smaller draft meant less dredging. The strategy reminds of the medieval Chinese wheelbarrow, which allowed transportation to keep functioning at a time when the road infrastructure was crumbling.

How many people do we need?

In a more sustainable future, could we dredge the Netherlands without fossil fuels? Sustainability is all about cars and smart appliances, but what about large infrastructure and maintenance works? Powering today’s dredgers with solar or wind power sounds unrealistic: those ships would require enormous chemical batteries, which is not practical or sustainable.

Therefore, as part of the Human Power Plant, we investigated how many people would be needed if we were to dredge the Netherlands by hand again. To answer this question, we organised a workshop in which we dredged a piece of Frisian waterway by hand and measured how long it takes to collect 1 m³ of mud. The results are discussed in the video below.

For English substitles, click CC:

Sources:

Interviews and documentation Nationaal Baggermuseum, Sliedrecht, Rotterdam.

Canon van de geschiedenis van Smallingerland, Smelne’s Erfskip 2010; Drachtstervaart, Smelne’s Erfskip 2015, ISBN 978-94-90543-08-02.

Geschiedenis van de Techniek in Nederland. De wording van een moderne samenleving (1800-1890). H.W. Lintsen, 1992.

Rosmolens en krabbelaars: baggeren in pre-industriële tijd

Maritiem Digitaal.

Groot onderhoudsplan Baggeren 2015 tot 2020. Hoogheemraadschap de Stichtse Rijnlanden.

Uitvoeringsplan 2010 Meerjarenbaggerprogramma Waterschap Rivierenland

Scheepsmodel Krabbelaar, Katie Heyning, Zeeuwse Ankers, juli 2015.

Evaluatie van het Friese Merenproject, 2000-2010, Provincie Fryslân.

Baggeruitvoeringsplan 2007-2015. Wetterskip Fryslân

Baggerproblematiek in Nederland, Compendium voor de leefomgeving.

Meerjarenbaggerplan 2012-2018, Waterschap Hollandse Delta.

Baggerschepen: van baggermolen tot sleephopperzuiger Maritiem Nederland.

Medieval Smokestacks: Fossil Fuels in Pre-industrial Times

Thu, 29 Sep 2011 00:00:00 +0000

Image: peat fuelled glass manufacturing in the Netherlands, 1700s.

The history of energy use in human civilisation is generally summarised as follows: from Antiquity until the start of the Industrial Revolution, people made use of the manual labour of both animals and humans, as well as biomass, sun, water and wind. Next, all these renewable energy sources were replaced by fossil fuels: first coal, and later oil and gas. Uranium completed the picture in the second half of the twentieth century.

While this historical summary is basically correct, there were some - rather important - exceptions. Almost all of the leading economies in Western Europe during the last millenium relied on a large-scale use of fossil fuels such as peat and coal.

Thermal energy

Before we delve into the pre-industrial history of fossil fuels, it is important to note the difference between thermal energy (heat) and kinetic energy (motion). For the greater part of history, wind, water and muscle power could provide only kinetic energy. This was the kind of energy required to grind grain, saw wood, or set boats in motion.

For centuries, wood (including charcoal made of wood) was the only source of thermal energy in Europe, apart from the use of direct solar energy for low-temperature processes like the drying of mud bricks and food crops.

Wood or charcoal were required for activities such as heating buildings, cooking food, producing building materials (such as bricks, tile, cement, lime and plaster), manufacturing glass and paper, forging iron or producing dyes and soaps. At the same time, wood was the main construction material for buildings, ships, bridges, mills, piers, wharves, cranes, winches, mine shafts, vehicles, barrels, furniture and tools.

Image: A furnace.

The invention of the steam engine in the 18th century meant that thermal energy could be converted into kinetic energy: the heat generated by the burning of coal was used to power machines and vehicles. Likewise, the arrival of electricity in the 19th century allowed kinetic energy to be converted into thermal energy: a windmill, for instance, could be used to drive a generator that delivers energy to an electric oven, or heater. (Kinetic energy could produce heat by friction, for example in windmill gears, but this was mostly wasted).

These days, it is self-evident that both types of energy can be converted to one another (with considerable efficiency losses), but for most of human history that wa not possible. Then, just as now, thermal energy was much more important than kinetic energy.

Urban revival

The Romans - who fuelled practically all their mechanical activities with slave labour - deforested large parts of Europe in their hunger for thermal energy and construction materials. When their empire collapsed, forests recovered during the half millenium that is termed the Dark Ages.

At the beginning of the second millenium AD, Europe became the setting of an urban revival. Between 500 and 1000 AD, some important agricultural innovations occurred, including improved ploughs, the triennal rotation of crops, the horse collar, and the horse shoe.

Image: Walzwerk Neustadt-Eberswalde, a painting by Carl Blechen, circa 1830.

These technologies enabled a larger population and higher food surplus: more food could be supplied with less labour, which further aided the growth of cities in which people could do things other than working the land. The invention of the printing press, for example, further increased the demand for wood. Similarly, building gothic cathedrals required tonnes of materials, raising thermal energy use.

Urbanisation thus went hand in hand with increased industrial activity. Also, medieval industrial processes were less efficient than similar processes today. For example: up to 20 kg of charcoal (with an energy content of 600 MJ) was used to produce 1 kg of iron (compared to 20-25 MJ/kg today). Urbanisation and industrialisation increased rapidly between 1100 and 1300, which again resulted in widespread deforestation.

Not a paradise

Our romantic image of the Middle Ages and Renaissance as a paradise of renewable technologies results largely because of our failure to distinguish between thermal and kinetic energy. The Dutch and the Flemish, who dominated the Western European economy from about 1100 to 1700, are famous for their impressive use of wind technology, which took off in the 1100s.

Our romantic image of the Middle Ages and Renaissance as a paradise of renewable technologies results largely because of our failure to distinguish between thermal and kinetic energy.

The most spectacular use of windmills appeared in Holland from the late 1500s (16th century) onwards. There, the Dutch applied wind power to a wide range of industrial processes, including paper production, wood sawing, glass polishing and cement production. (See the article: “Wind powered factories: the history and future of the industrial windmill”).

Image: a furnace.

The industrial windmill was a marvel of pre-industrial technology, but it explains only partly why Holland became the most important economic power in the world during the 17th century. While sustainable providers of power, windmills could only deliver kinetic energy. For example, you can use wind power to polish glass, but you can’t make glass using a windmill. For that, you need thermal energy. And in pre-industrial times, as the history books tell us, the only way to reach high temperatures was to burn wood.

One problem, though: virtually all forests in the region had long vanished by the 1600s. Yet, during the Golden Age of the Netherlands, the Dutch not only made glass, they also produced bricks, tiles, ceramics and clay pipes, they refined salt and sugar, bleached linen, boiled soap, brewed beer, distilled spirits and baked bread. All these processes were based on a massive input of thermal energy.

While peat is classified by the IPCC as a renewable fuel, this is highly debatable. It takes at least 3000 years for a peat layer of 3 m to return to its original size.

Moreover, the Dutch produced much more than needed for domestic consumption. They became the largest European exporters of many of the above-mentioned industrially manufactured products. On a more modest scale, a similar production boom had happened in Flanders a few centuries earlier, in which an energy-intensive industry appeared in the near total absence of wood reserves. So how did the Dutch and the Flemish achieve this? By mining peat on a truly massive scale.

What is peat?

An intermediate step in the formation of coal, peat forms when plant material, usually in marshy areas, does not decay fully because of a lack of oxygen. This semicarbonised fuel can be found near the earth’s surface in layers of up to 5 metres thick.

Image: peat diggers in the Netherlands.

The energy density of dried and pressed peat - known as “turf” - is about 15 to 17 MJ per kg, which is similar to the energy density of dried wood (15 to 18 MJ/kg) but lower than that of coal (24 MJ/kg) or charcoal (up to 29 MJ/kg). However, it is a bulkier fuel than wood: 1m3 of coal provides 6 times as much heat as 1m3 of turf, for instance.

Turf is still used today in some countries, notably in Ireland, Finland and Russia, where it is burned in power plants and used for domestic heating. While peat is classified by the IPCC as a renewable fuel, this is highly debatable. Peat is renewed at a rate of about 1 mm per year at most, and so it takes at least 3000 years for a peat layer of 3 m to return to its original size - and only if the land is not disturbed in that time.

In addition, the mining of peat has a very large impact on the landscape, as we shall see, while the burning of turf produces slightly more CO2-emissions than coal for the same energy content. The only advantage it has over coal is that it produces less smoke and has a lower sulfur content, and thus produces less air pollution.

How to dig peat

In pre-industrial times, peat was dug out using very simple tools. Before being cut, the peat was often partially dehydrated by digging drainage trenches on its surface. Next, the land was stripped of its vegetation and the peat sods were cut up vertically to the required size.

Image: peat digging in the netherlands.

The following step was to cut out the peat sods horizontally, after which they were loaded onto wheelbarrows and transported to a nearby field. There, they were laid out or stacked up vertically in a formation for drying. It took six to eight weeks for the peat sods to become dry enough to be used as fuel, after which they were beaten or trodden to make them more compact. During the drying process in the field, the peat sods were turned regularly. Finally, the peat (now called turf) was loaded in baskets and carried to the farm or the market.

Mining peat was a seasonal activity that took about 3 months per year, from late spring to early summer. Starting production earlier than April was risky because frost could damage the drying peat. Digging peat in summer was equally risky because there was a chance that it would not be dry enough following a cold and wet season. Likewise, a very hot summer could make the peat useless if it was not taken away from the drying field quickly enough - it would then be dispersed by the wind.

Image: drying peat sods.

You could thus argue that peat has the disadvantages of both a fossil fuel and a renewable fuel, without any of the benefits. Like other better known fossil fuels, it is a non-renewable energy source that produces large amounts of CO2, yet it has an energy density that is much lower than other fossil fuels. On the other hand, peat digging is a seasonal activity with a “harvest” that may fail because of the weather. And yet, because they had no other choice, the Dutch and the Flemish built their entire economy around it.

The Low Countries

The evolution of peat production was eerily similar to the mining of fossil fuels today. When the easiest accessible reserves were exhausted, the peat diggers developed new technologies and methods to mine harder-to-reach resources at an ever increasing financial and environmental cost. We do not have much detailed knowledge about peat production in Flanders and Brabant, because few written records from the late Middle Ages remain. However, the history of peat production in the present-day Netherlands is relatively well documented.

The urban revival of the late Middle Ages started in Northern Italy, where the dominating merchant cities were Venice, Milan, Genoa and Florence. However, around 1100 a second urban core developed east of the North Sea, a region that would become known as the “Low Countries” from the 15th century onwards. This area would soon rival the economic power of the Italian cities, and become the leading economic and industrial centre in Europe from about 1500 to 1700.

The cities of Bruges, Ghent and Ypres in the province of Flanders (today a portion of Belgium) were the first to develop. Bruges, in particular, became an economic powerhouse due to its position in international trade, finance and cloth production. In 1350, Bruges and Ghent boasted a population of 90,000 and 57,000 inhabitants respectively.

Image: The town hall in Bruges, built in 1376. Photo credit: [Pantchoa](http://www.flickr.com/photos/francois-2/5395519921/).

Around 1500, economic power shifted to the cities of Antwerp, Brussels and Leuven (today all in Belgium) in the province of Brabant. Antwerp became the economic centre of the Western world, a position it would maintain until the end of the 1500s (16th century). By 1550, Antwerp had 90,000 inhabitants, up from 40,000 in 1500, which made it the second largest city in Europe, North of the Alps, after Paris.

In 1580, the Low Countries, then under Spanish rule, were divided into two. The seven provinces in the South North revolted against the Spanish and formed a new state, the Dutch Republic (the present-day Netherlands). As a result of the subsequent chaos in the Southern provinces (present-day Belgium), the city of Antwerp lost its leading role and power shifted rapidly to the Dutch province of Holland, where the capital of Amsterdam now became the European centre of economic and industrial activity. It would remain so until the end of the 17th century.

Peat mining from 1100 to 1500

Large-scale peat digging started in the coastal area of Flanders and northeast of Antwerp in the 1100s and 1200s respectively. The activity was largely aimed at supplying the fuel for the fast-growing cities of Bruges, Ghent and Ypres. The reserves in the coastal peat bogs of Flanders were exhausted by the end of the 1300s or 1400s, while peat production in Brabant diminished sharply during the course of the fifteenth century.

When the easiest accessible reserves were exhausted, the peat diggers developed new technologies and methods to mine harder-to-reach resources at an ever increasing financial and environmental cost.

By the time Antwerp came to dominate the world economy, its peat reserves had already been dug out to satisfy the energy needs of Flanders in the course of the preceding two centuries. As a result, peat digging shifted to the neighbouring province of Holland, from where the turf was exported to Antwerp.

Image: peat digging above the water table.

At the time, Holland was still largely an agrarian region with relatively few energy needs. During this period, it is estimated that between 220 and 440 hectares of peat bogs were mined every year in Holland and Utrecht. Around 1530, the then accessible reserves in both provinces became exhausted, while demand continued to grow. As a result, peat prices skyrocketed.

Peat mining intensifies: peat mining below the water table

In response to this, peat diggers developed a new tool, the “baggerbeugel” (a dredging net on a long pole, there seems to be no English translation for the term). Standing on a small boat or at the waterside, this tool allowed them to cut peat below water level and haul it up. This technique, called “slagturven” (again, no English translation available), greatly enlarged mineable peat reserves.

The peat bogs in Holland and Utrecht were up to 4.5 metres thick, but because of the high water table in the region (why we call these the “Low Countries”), only the top layer could be stripped away using conventional techniques. Digging deeper would have flooded the land and made the fuel inaccessible.

Image: peat digging below the water table.

However, now that it was possible to cut peat far below the water level, the complete peat bogs could be mined. There is evidence that the “baggerbeugel” was already in use in Flanders two centuries earlier, and that the knowledge of the technique was transferred to the North.

The intensification of peat production came at a cost, though. To start, mining peat from below the water table introduced extra steps in the processing of the fuel. Due to its increased water content, the muddy peat had to be spread out on narrow and elongated strips of land which were not stripped of their peat. There, the water was pressed out by people trodding on it with boards tied beneath their clogs. Only when this was done, could the peat be cut up in blocks and stacked to dry.

Image: peat digging clogs. Credit: [MOT](http://www.mot.be)

Environmental costs: land turned into water

Worse, however, was the destruction of the landscape and the loss of agricultural land. Wherever the peat was mined below the water table, land disappeared into the waves. This was a rather ironic consequence for a country that spent so much effort reclaiming land on the sea elsewhere on its territory through the use of windmills. Every year, about 115 to 230 hectares of land was lost as a result of peat production below the water table. The exhausted peat bogs formed lakes that expanded to cover vast areas throughout Holland and Utrecht.

In total, peat digging would turn more than 60,000 hectares (600 km2) of land into water in Holland and Utrecht - almost 10 percent of their total surface area.

Only the elongated strips of land used to dehydrate the muddy peat remained. Historian Jan de Vries (see references) notes that the area between Amsterdam, Rotterdam and Utrecht “took on the appearance of a veritable Swiss cheese, with dozens of water-filled, exhausted peat bogs often separated from each other by nothing more than narrow vulnerable strips of land on which were scattered the structures of what once had been farms”.

Image: The consequences of peat digging can still be seen in the Dutch landscape today.

Some of these typical lakes still remain. The picture above shows the “Nieuwkoopse Plassen” in Holland, today a nature reserve of 1,400 hectares. Other remaining examples are the “Loosdrechtse plassen” and “Vinkeveense plassen” in the province of Utrecht. Often, even the narrow ridges of land used for drying the peat were eventually mined or simply washed away by the waves during storms.

Things got out of hand when entire villages disappeared. Historian J.W. De Zeeuw (see references): “Around 1600, these lakes occupied most of the area between the rivers Oude Rijn, Gouwe and Hollandse Ijssel and threatened the villages of Zevenhuizen, Moerkapelle and Waddinxveen. In 1630, the church of Jacobswoude, North of the Oude Rijn, was pulled down because by then the rest of the village had been swallowed by the waves of encircling man-made lakes.”

Image: peat digging created an inland lake of 17,000 hectares which destroyed several villages.

In the course of the centuries, peat digging caused the fusion of two large lakes (the Haarlemmermeer and the Leidsemeer) and several smaller ones in Holland, forming an inland sea of 17,000 hectares which destroyed several villages (Nieuwerkerk, Rijk, Vijfhuizen, and a part of Aalsmeer - see the map above. The water body - popularly known as the “water wolf” - threatened the surrounding cities of Haarlem, Leiden and Amsterdam in the 1800s, after which it was (largely) impoldered.

The authorities, horrified by the loss of agricultural land - and the associated tax income - tried to stop the peat diggers during the sixteenth century by placing export prohibitions and restrictions on peat mining below the water table, but they failed. Digging out peat was more lucrative than cultivating crops. In total, peat digging would turn more than 60,000 hectares (600 km2) of land into water in Holland and Utrecht - almost 10 percent of their total surface area.

Peat production moves to the North: canal digging

Again, energy demand rose significantly from the late 16th century onwards, when economic power shifted from Flanders and Brabant to Holland. In spite of the environmental damage, peat production in the low peat bogs of Holland and Utrecht continued on a casual basis during the 1600s, with an average production of 200 hectares per year. However, this was not enough to satisfy the growing demand for the fuel, and turf prices started rising again.

Image: peat digging in the northern provinces.

In response, from the 1580s onwards, attention shifted to the somewhat higher lying peat bogs in the northern provinces of Friesland, Groningen and Drenthe - 200 to 250 kilometres away (see the map above). There, total production during the seventeenth century would rise to an average of almost 400 hectares per year. Most of the turf was exported to Holland.

However, mining these reserves was a totally different matter because there were few waterways. Transporting the turf all the way to the Zuiderzee, from where it could be shipped to Holland and Utrecht, would have been inordinately expensive given the transport options of the day. In order to exploit the high peat bogs in the Northern provinces, ditches and canals had to be dug, which required a large capital investment.

Image: drying peat.

Historian Jan de Vries: “The result was that, instead of the numerous individual peat diggers each working small parcels of ’laagveen’ [low bogs], the peat in the ‘hoogveen’ [high bogs] was mined by consortia of investors (urban capitalists from the western cities) who judged market conditions sufficiently attractive to buy up vast tracts of uninhabited bog, dig lengthy canals into the bogs, and hire armies of laborers to dig the peat”.

The peat was mined by urban capitalists from the western cities who judged market conditions sufficiently attractive to buy up vast tracts of uninhabited bog, dig lengthy canals into the bogs, and hire armies of labourers to dig the peat

The maps shown below illustrate the extensive canal infrastructure that was built in the Northern provinces of the present-day Netherlands from the 1580s onwards. In the high peat regions of Groningen and Eastern Drenthe, canal building continued uninterrupted from 1580 to 1650, which opened up the main body of the peat deposit. This made some 30,000 hectares of peat available for shipping.

In the high peat region of Western Drenthe, Friesland and Overijssel, canals were dug between 1600 and 1670 to reach some 30,000 hectares of peat. In total, it is estimated that some 700 km of canals were built in the northern provinces, specifically aimed at turf transport. A substantial amount of them remain, with sometimes surprising results, such as towns without roads.

Image: Map of canal system built for peat digging in the nothern Netherlands.

Canal building had happened before in Flanders and Brabant, where the monasteries seem to have been the driving force behind large-scale, organized peat production, buying up land and hiring peat diggers. In the peat bogs in Brabant, Northeast of Antwerp, from about 1300 onwards some 20 turf canals were dug up to 16 m above sea level, each reaching lengths of 10 to 20 km.

The main canals, which connected the export harbours with the peat areas, attained a total length of more than 320 km. Aqueducts were built to help the canals cross the brooks. In the Northern provinces of the Netherlands, the total length of the canals reached at least 700 km.

Peat production and agriculture

The exploitation of the high peat bogs in the North did not always result in the loss of agricultural land, as it did in the South. Firstly, because the peat mining companies converted some peat bogs into permanently agricultural land after the peat had been dug out.

J.W. De Vries: “Once the peat was stripped away, these enterprises had a further interest in making use of the newly exposed underlying soils. Since this soil lay above the water table, the cost of converting it into productive agricultural land consisted primarily of taking the trouble to conserve the surface soil (which was in the case of high peat bogs in any event poor quality peat) so that it could be re-spread over the land, and heavily manuring the new soil. This occurred most systematically in Groningen, where the capital city encouraged agricultural development of the hoogveen by subsidizing the distribution of night soil.”

Image: More detailed view of canals built for peat production.

The new canal network created to move the turf to Holland’s industry in the South also provided low-cost transport for agriculture which, by itself, could never have afforded such an investment. However, the efforts to reclaim agricultural land in some parts of the country did not make up for the much larger losses elsewhere on the territory.

Few peat bogs in Groningen were brought under cultivation during the Golden Age - it was only with the arrival of artificial fertilizers at the end of the nineteenth century that large-scale recultivation could begin. In the province of Friesland, the underlying soil was not suited for agriculture and peat digging resulted in large lakes which still exist today. And as we have seen, vast tracts of (potential) agricultural land disappeared in the waves in the Southern part of the country.

The result is that the Dutch became, unlike other European countries at that time, highly dependent on food imports. They produced vegetables, meat and dairy products, but they had to import about half of their grain (the staple food) from the Baltic regions - a very costly affair.

Energy consumption per capita

Until the twentieth century, the Dutch stripped an estimated 283,500 hectares (2,835 square km) of peat, close to 10 percent of the total surface of the Netherlands. However, only two thirds of this was mined in pre-industrial times. Peat digging in the Netherlands continued until 1950 using mechanical peat diggers powered by coal, as it happened in many other countries from the end of the nineteenth century.

If we take 1850 as the start of the “modern” peat mining era (the Netherlands were late to enter the Industrial Revolution), the pre-industrial use of peat in the country amounts to just over 190,000 hectares from about 1300 to 1850. Of this, some 70,000 hectares were mined from 1600 to 1700, which roughly corresponds with the “Golden Age” of the Netherlands.

All these figures are deduced from a 1978 paper by .W. de Zeeuw, “Peat and the Dutch Golden Age” (see references). Other authors (like Jan de Vries) give higher estimates in more recent studies, with about 275,000 hectares of peat stripped after 1600. Either way, almost all peat that existed in the Netherlands has been mined.

Image: peat production in the Netherlands.

De Zeeuw also calculated the heat content of the extracted peat, taking into account the average thickness of the mined peat layers after dehydration. He concluded that in an average year in the seventeenth century, the Dutch consumed 25,120,800 GJ of turf. With an average population of 1.5 million this amounts to 16.75 GJ per capita per year.

Other authors have come to similar figures, ranging from 13.4 to 19.3 GJ per capita per year. This is similar to dozens of poor countries today, some of which do not even reach 10 GJ per capita. Average energy consumption per capita worldwide was 76.6 GJ in 2008, only 4.5 times higher than in the seventeenth century Netherlands (though the Dutch themselves now consume much more, with 210 GJ/capita in 2003). It should be noted that the figure of 16.75 GJ/capita only includes turf consumption, not other energy sources like wind, animal labour, firewood, charcoal and coal (see further).

Urbanization and industrialisation in 17th century Holland

The high energy consumption of the Dutch was an anomaly in seventeenth century Europe. The same goes for their prosperity, and for the level of urbanization and industrialisation in the country.

More than 60 percent of Dutch people lived in cities, compared to about 10 percent in most other European countries at the end of the 17th century. The level of urbanisation in seventeenth century Netherlands was only attained in other European countries at the turn of the twentieth century.

A similar development happened in Flanders and Brabant in the 1500s, where over 30 percent of the population lived in cities with more than 10,000 inhabitants. From about 1600 to 1720, the Dutch had the highest per capita income in the world - at least double that of neighbouring countries at the time and about five times higher than that of the poorest countries today.

Image: Amsterdam in 1662.

The opening of the peat bogs in the northern provinces from the 1580s onwards meant that the Dutch had a cheap energy source that was widely available, while most other countries in Europe were entirely dependent on wood - which had become ever more expensive as deforestation advanced. The Netherlands’ ample fuel reserves stimulated the development of various fuel-intensive and export-oriented industries.

More than 60 percent of Dutch people lived in cities, compared to about 10 percent in most other European countries at the end of the 17th century.

In several cases, the presence of these industries was solely based on the abundant and cheap supply of thermal energy. This was the case for sugar refinement, for example, which is a purely thermal process. Sugar became the world’s most important commodity in the seventeenth century, and Amsterdam was Europe’s largest sugar refiner by 1650. In 1662, more than half of Europe’s one hundred sugar refineries were located in the Netherlands, all of which processed imported sugar from South America and the Carribean.

Salt refinement too was based solely on a massive input of thermal energy. Salt was indispensable as a preserver of meat, fish and dairy products before electrical refrigeration was available. The Netherlands had 293 salt refineries in 1674, most of them concentrated in Holland and each consuming about 800 tonnes of turf per year.

About sixty of these refineries were used for packing herring barrels, another important export. In addition, the city of Haarlem became the bleacher of German linen, another industrial process that was purely built on thermal energy. For all these industries, the iconic Dutch windmills did not offer any direct advantage.

Image: brick manufacturing based using peat as a fuel.

The succes of other industries, however, was based on the combination of turf and wind power. The best example of this lies in the shipping industry. Holland became the leading builder of ships in Europe in the course of the seventeenth century.

From 1625 to 1700, the Dutch shipyards produced as many as 500 seafaring vessels per year, many of them commissioned by foreign powers. The wood used to build the ships was sawn using sophisticated wind powered saw mills invented in 1596, while peat provided thermal energy for many shipbuilding processes, such as bending planks, melting tar and forging iron fittings.

Apart from that, peat offered an important indirect advantage. While a large-scale use of peat did not prevent the Dutch from importing large amounts of wood, peat catered to their thermal energy needs, and so all imported wood was almost exclusively used as a construction material.

This generated a much higher return on investment than its use as firewood, and made the Dutch less vulnerable to high wood prices. Turf was also the fuel of choice for heating homes and public buildings, and for cooking. Only the very rich used firewood, which was much more expensive but produced less pollution.

Why was peat only used in the Low Countries?

The Low Countries were not the only region that suffered from a severe shortage of wood reserves between 1100 and 1700. In addition, peat was found over large parts of Europe, most notably north of the Alps. Why, then, did other countries not resolve their energy shortages by mining peat?

For these pre-industrial countries, the value of energy deposits depended on the cost of transportation rather than the cost of gathering the fuel itself. There exists no period in history when a global, continental or even national shortage of wood occurred. The problem was always local, caused by deforestation around urban (and industrial) centers. Land-based transport—which amounted to carts on bad roads - was extremely slow, labour-intensive and expensive, limiting the practical distance between energy deposits and consumption centres to 20 to 25 km at most.

Image: transporting peat.

One look at the map of the Low Countries immediately reveals why the region could afford to transport turf over large distances: it is criss-crossed by lakes and rivers. From Groningen and Friesland in the outermost northern part of the present-day Netherlands, one can sail (almost literally) straight to Amsterdam, Utrecht, Rotterdam, and then Antwerp, Brussels, Ghent and Bruges in present-day Belgium. No other region in Europe has such a dense water transport network.

To boot, the region is windy and flat, offering great conditions for sailing - and deforestation only improved these conditions. Importantly, the Low Countries are located near the water table - as were their peat reserves. The digging of navigable canals in the peat areas, and the linking of these canals to the already existing, extensive network of natural waterways was relatively easy. Because these natural waterways gave access to all major cities, the turf could be transported by ship directly from the peat fields to the doorstep of the consumer. Hardly any land-based transportation was involved, and this kept costs low.

Land-based transport was extremely slow, labour-intensive and expensive, limiting the practical distance between energy deposits and consumption centres to 20 to 25 km at most.

In most other countries, peat reserves were located too far above the water table, making the construction of canals much more expensive. Often, cities were too far from potential peat reserves or did not have access to navigable rivers. This explains why large-scale peat digging in other European countries and the US only started at the end of the nineteenth century, when peat could be hauled by steam trains or locally converted to electricity (which is easier to transport).

Coal and the end of the Dutch Golden Age

Peat was not the only fossil fuel used during the second millenium AD in Europe. Coal mining started in the thirteenth century in England, Wales and what is now the French speaking part of Belgium. All over Europe, coal quickly became a wanted fuel for specific industrial processes, particularly for blacksmithing and lime manufacturing.

Large-scale coal mining started in the 1400s. In 1430, between 1,600 and 2,000 people worked in the coal industry in Liège (present-day Belgium). From the 1500s onwards, coal was used on an ever increasing scale in London, which was then one of the most populated cities in Europe. There, coal was used industrially, but more often in households for heating and cooking.

Image: A furnace.

At the beginning of the 1600s, when the Dutch Golden Age began, coal accounted for three quarters of fuel consumption in London, which caused extensive air pollution. Coal burns much dirtier than wood, which is the reason why it was previously forbidden in England. However, the acute shortage of firewood from the 1500s onwards left the English little other choice than to switch to the abundant fuel. Peat was not an option for the English for many of the reasons mentioned above.

Initially, coal offered significant drawbacks compared to peat, which meant that England’s early use of fossil fuels did not provide a commercial advantage during the seventeenth century. In most production processes, coal could not be used because it came into direct contact with the product, which was then ruined by coal’s impurities - notably sulfur. Only in processes where the product could be separated from the fuel did the substitution of coal for wood cause no problems.

At the beginning of the 1600s, coal accounted for three quarters of fuel consumption in London, which caused extensive air pollution.

Because of its lower sulfur content, peat did not have these limitations. The Dutch could use it for almost all thermal processes in their industries. Over time, however, the English managed to adapt their industrial processes for the use of coal instead of wood and charcoal. With every step they took, the English slowly caught up to the Dutch. A turning point came at the dawn of the eighteenth century when the last - and most important - industrial process was converted to coal: the production of iron.

Image: a furnace.

This last step, made possible by the introduction of ‘cokes’ or purified coal, marked the start of the Industrial Revolution in the Western world. From then on, the use of iron as a construction material was no longer limited by the supply of wood.

Turf, on the other hand, could not deliver the intense heat produced by coal, and hence was not used in iron production, nor to power steam engines. (The Dutch never produced iron, they imported it). Moreover, the caloric value of coal is four times higher than that of turf for a given volume, making it much easier to transport and store than peat. The combination of steam power and iron brought the English the rail system, solving the problem of transporting their fuel supply. The railway also proved faster and more flexible than the canal system.

Exhaustion of the accessible peat reserves

Around the same time, the most accessible Dutch peat reserves became exhausted. In addition, there was a growing problem with the silting of the shallow harbours and waterways, increasing the costs of turf transport. More and more sandbanks appeared, over which vessels had to be dragged.

A similar thing happened in Bruges a few centuries earlier. The unique geographical conditions of the Low Countries, which made the early large-scale use of fossil fuels possible, eventually became a disadvantage. The depletion of the peat reserves and the difficulties in turf transport led to rising turf prices, until the point at which imported coal became cheaper.

Image: peat mining in Rotterdam, 1918.

To combat this, Dutch industries switched from peat to coal, whenever they could adapt their production to use the cheaper fuel. English export of coal to Holland rose from 35,200 tonnes in 1700 to 117,900 tonnes in around 1750.

The import of coal put Dutch industries at a disadvantage, because the English added tax duties. From the 1700s on, Dutch prosperity began to decline. The import of grain became too expensive, and de-urbanisation set in as more people returned to farming. By 1815, the level of urbanization had fallen back from 60 to 38 percent.

Can we power a prosperous society on renewable energy?

Pre-industrial use of coal and peat occured successively in those parts of Europe that dominated industrial production from the 1100s to the start of the Industrial Revolution. The Flemish, the Dutch and the English, consecutively, became the most prosperous regions in Europe at the very moments when they used the largest amounts of fossil fuels.

In other words, all economic success stories of the past millenium are based on an ample supply of fossil fuels - accompanied by serious ecological damage. Moreover, these regions produced many exports, so that countries that did not use fossil fuels also benefitted from their application.

All economic success stories of the past millenium are based on an ample supply of fossil fuels - accompanied by serious ecological damage.

All this does not mean that a prosperous society cannot be built on 100 percent renewables. We can now transport biomass over larger distances, due to good roads and cost-effective transport options. And I am not referring to motorways and diesel trucks, but to trains, strip roads, trolleytrucks, cargo bicycles and light electric vehicles in flat areas, and aerial ropeways and cable trains in mountainous regions.

Furthermore, we now have an additional renewable energy source that could deliver vast amounts of thermal energy: solar thermal power (see article “The bright future of solar powered factories”). The merits of solar thermal heat and concentrated solar power have been known for centuries, but the materials and industrial processes for large-scale deployment only became available at the end of the nineteenth century. The same applies to geothermal power, the potential use of which was previously limited because of a lack of materials and technology.

It is obvious that a prosperous future for seven billion people cannot be based on pre-industrial technology. The key to our success, however, lies in choosing the best of industrial technology and discarding the rest.

Sources:

“Energiemarkten en energiehandel in Holland in de late middeleeuwen”, Charles Cornelisse, 2008.
“Peat and the Dutch golden age” (.pdf), J.W. de Zeeuw, 1978.
“The First Modern Economy: Success, Failure, and Perseverance of the Dutch Economy, 1500-1815”, Jan de Vries, 1997.
“The Economy of Europe in an Age of Crisis, 1600-1750”, Jan De Vries, 1976
“Verdwenen venen. Een onderzoek naar de ligging en exploitatie van thans verdwenen venen in het gebied tussen Antwerpen, Turnhout, Geertruidenberg en Willemstad. 1250-1750”, K.A.H.W. Leenders, 1989 (English summary).
“Peat and Canals” (.pdf), Michiel A.W. Gerding
“Meeten, boren en besien: turfwinning in de buitenrijnse ambachten van het Hoogheemraadschap van Rijnland 1680-1800”, A.J.J. van’t Riet, 2005
“Delfstoffen, machine- en scheepsbouw”, in “Geschiedenis van de techniek in Nederland”, H.W. Lintsen, 1993.
“Het verloren technisch paradijs”, in “Geschiedenis van de techniek in Nederland”. H.W. Lintsen, 1993.
“Vervening”, “Turfsteken”, “Veen”, “Slagturven”, “Baggerbeugel”, Dutch Wikipedia.
“Canals and energy. The relationship between canals and the extraction of peat in the Netherlands 1500-1950” (.pdf), Michiel A.W. Gerding, in “Peatlands”, February 2010.
“The Rise of Commercial Empires: England and the Netherlands in the Age of Mercantilism, 1650-1770!, David Ormrod, 2003
“A Forest Journey: The Story of Wood and Civilization”, second edition, John Perlin, 2005
“The Making of Urban Europe, 1000-1994!”, Paul M. Hohenberg & Lynn Hollen Lees, 1985
“Urban World History: an Economic and Geographical Perspective.: An article from: Canadian Journal of Regional Science!”, Luc-Normand Tellier, 2009
“Peatlands and climate change” (pdf), International Peat Society, 2008
“The Dutch Republic in the Seventeenth Century: The Golden Age!”, Maarten Roy Prak, Diane Webb, 2005.
“The Rise of the Amsterdam Market And Information Exchange: Merchants, Commercial Expansion And Change in the Spatial Economy of the Low Countries, C.1550-1630”, Clé Lesger, 2006.
“Turf fires -burning peat”. Old and Interesting.
“The Mother of All Trades: The Baltic Grain Trade in Amsterdam from the Late 16th to the Early 19th Century!”, Milja van Tielhof, 2002.
“Energy transitions: history, requirements, prospects”, Vaclac Smil, 2010.

Recycling Animal and Human Dung is the Key to Sustainable Farming

Wed, 15 Sep 2010 00:00:00 +0000

Flushing the water closet is handy, but it wreaks ecological havoc, deprives agricultural soils of essential nutrients and makes food production dependent on fossil fuels.

For 4,000 years, human excrements and urine were considered extremely valuable trade products in China, Korea and Japan. Human dung was transported over specially designed canal networks by boats.

Thanks to the application of human “waste” products as fertilizers to agricultural fields, the East managed to feed a large population without polluting their drinking water. Meanwhile, cities in medieval Europe turned into open sewers. The concept was modernized in late 19th century Holland, with Charles Liernur’s sophisticated vacuum sewer system.

Broken Cycle

The innocent looking water closet breaks up a natural cycle in our food supply. Basically, it turns extremely valuable resources into waste products. When we grow crops, we withdraw essential nutrients from the soil: potassium, nitrogen and phosphate, to name but the most important. During the greater part of human history, we recycled these nutrients through our bodies and returned them to the soil, via excreta, food trimmings and the burial of dead. Today, we flush them mostly into the sea (see the infographic below),

The nutrient cycle. Source: [Humanure Handbook](http://humanurehandbook.com/contents.html)

This is problematic and unsustainable, for three main reasons. To start, dumping sewage in rivers, lakes and seas kills fish and makes fresh water undrinkable. This can only be avoided by extending the water closet and the already very costly sewerage network with an equally expensive infrastructure of sewage stations (which does not completely eliminate the detrimental effect on water life).

Secondly, we need artificial fertilizers to keep our soil fertile. In 2008, almost 160 million tonnes of inorganic fertilizers were used worldwide (Source & Source). Without these, our agricultural soils would lose their fertility in just a few years time, followed by an inevitable collapse of food production and human population. A third problem is that the water closet logically consumes large quantities of fresh water to flush everything “away”.

Water closets are energy-intensive

Fresh water production, the construction and maintenance of sewers, the treatment of sewage (and sewage sludge), and the production of inorganic fertilizers are all energy-intensive processes. Nitrogen (which makes up more than half of total fertilizer consumption) is abundantly available in air, but to convert it to a useful form the gas has to be heated and pressurized. The energy for this (polluting) process is delivered by natural gas or (in China) by coal plants.

Potassium and phosphate have to be mined (up to depths of several thousands of feet) and transported. It takes more than 150 million tonnes of phosphate rock to produce our current yearly supply of 37 million tonnes of phosphate fertilizer, and 45 million tonnes of potash ore to produce 25 million tonnes of potassium fertilizer. Both operations are energy intensive and pollute the environment.

A medieval closet in a castle.

Moreover, while potassium is widely distributed and abundantly available (we have enough economically obtainable reserves to last 700 years at our current consumption rate), phosphorus is not. Ninety percent of global phosphate reserves are only found in a handful of countries, and economically recoverable reserves large enough to meet agricultural demand are estimated to last for only 30 to 100 years. Reserves are much larger if mining phosphates from the seabed is included, but this would be extremely energy-intensive, further deterioriating the sustainability of the food and sanitation system.

The only way to get nutrients from sea to land is via marine bird droppings - which is of course in very short supply - or by eating fish or seafood. However, once we have digested our fish and chips, the nutrients filter down to the sea via the sewer network.

A sign of civilization

The existence of the water closet and the accompanying sewer system is seldom questioned. It is viewed as an obvious technology and generally regarded as a sign of civilization - countries that do not have such a system today are considered retarded or backward. The reason for this is because we have been conditioned to believe that the water closet and the sewer system are the only alternatives to stench and disease.

We have been conditioned to believe that the water closet and the sewer system are the only alternatives to stench and disease

Following the demise of the Roman Empire (with its early sewers and water closets) and right up to the end of the nineteenth century, the concentrated and unorganised distribution of human excrements in groundwater, city canals and rivers brought recurrent deadly epidemics of cholera and typhoid fever throughout the western world. These were caused by drinking water contaminated with faeces.

People answered nature’s call on the streets or emptied their honey buckets in backyards, open courtyards, badly sealed cesspools or surface waters - methods that were not conducive to healthy living in densely populated cities. Water closet and sewer system have solved this, at least in the rich world, and nobody wants to go back to the miserable hygienic conditions of those times.

Chinese agriculture

However, as obvious as it seems to us today, the water closet is not the only possible answer to the problem of sanitation. There are other, much more sustainable methods to separate human waste from drink water supplies. To start with, the grim sanitary conditions of the Middle Ages and the early Industrial Revolution were a purely western phenomenon. At the turn of the twentieth century in the East, the water in Chinese rivers was safe to drink.

The Chinese were as numerous as the Americans and Europeans at the time, and they had large, densely populated cities, too. The difference was that they maintained an agricultural system that was based on human “waste” as a fertilizer. Stools and urine were collected with care and discipline, and transported over sometimes considerable distances. They were mixed with other organic waste, composted and then spread across the fields (illustration below).

Image: In China, stools and urine were mixed with other organic waste, composted and then spread across the fields.

That’s killing two birds with one stone: no pollution of drinking water, and an agricultural system that could have lasted forever. In fact, it did last 4,000 years, which is considerably longer than even our most abundant resource - potassium, with 700 years of reserves - will allow.

The Chinese agricultural system, which was also applied in Korea and Japan, is extensively described in “Farmers of Forty Centuries”, a report of a study trip by the American soil scientist F.H. King. The book was published in 1911, around the time of the discovery of the Haber-Bosch process that would lead to the breakthrough of cheap artificial nitrogen fertilizer.

King devoted an entire chapter to the collection and use of human fertilizer by the Asians. Joseph Needham also gives an account of the method, in volume VI:2 of “Science and civilization in China”, citing various earlier sources. More recently, Duncan Brown talks about the Chinese system in his book “Feed or Feedback: Agriculture, Population Dynamics and the State of the Planet”!

Dung traders

When King visited China, the population was estimated at about 400 million adult inhabitants, compared to some 400 million inhabitants in Europe and 100 million inhabitants in the US. The stools and urine of those 400 million people were collected in terracotta jars, with air-tight seals. The matter was gathered from every home, from the tiny country villages to the great cities.

In some cities, special canal networks and boats were constructed for this purpose (picture below). This was the case in Hankow-Wuchang-Hanyang, for example, a city with almost 1.8 million inhabitants living in an area of only 6.5 square kilometres. You could thus argue that the Chinese did have a water carriage sewer network, though the difference to ours is stark.

Boats transporting Dung

Around the time of King’s visit, every year in China more than 182,000,000 tonnes of human manure was collected in cities and villages – 450 kilogram (900 pounds) per person per year. This was good for a total of 1,160,000 tonnes of nitrogen, 376,000 tonnes of potassium and 150,000 tonnes of phosphate which was returned to the soil. In 1908 Japan, 23,850,295 tonnes of “humanure” was collected and given back to the soil.

Shanghai traded and distributed the yield of its inhabitants over a specially designed canal network using hundreds of boats (see map below), a trade that brought in 100,000s of dollars every year. Human manure was considered a valuable commodity. In 1908, a Chinese business man paid the city 31,000 dollar (this would be more than 700,000 dollars today) to obtain the right to remove 78,000 tonnes of humanure per year from a region of the city to sell it to the farmers on the countryside.

Canal network for dung transportation in Shanghai.

In Japan, which was much more urbanized than China, people paid less rent when they left their landlord better quality excrements. King describes loads of human dung taken from Tokyo and Yokahama “carried on the shoulders of men and on the backs of animals, but most commonly on strong carts drawn by men, bearing six to ten tightly covered wooden containers holding forty, sixty or more pounds each”. On the Japanese countryside, it was not unusual to see signs that invited passers-by to please answer nature’s call on site. The farmers used the product to manure their fields.

The practice of recycling human dung in Asian countries repelled some foreign visitors. The Portuguese explorer Fernam Mendez Pinto wrote in 1583:

“You must know that in this country there are many of such as make a trade of buying and selling mens Excrements, which is not so mean a commerce among them, but that there are many of them grow rich by it, and are held in good account. They which make a trade of buying it go up and down the streets with certain Clappers, like our Spittle men, whereby they give to understand what they desire without publishing of it otherwise to people, in regard the thing is filthy of itself; whereunto I will adde thus much, that this commodity is so much esteemed among them, and so great a trade driven of it, that into one sea port, sometimes there comes in one tyde two or three hundred Sayls laden with it.” (sic)

The 4,000 year old closed-loop system vanished with the arrival of artificial fertilizers, which were imported from the West during the first decades of the twentieth century. Today, China is the largest consumer of inorganic fertilizers with 28 percent of total world consumption. Asia as a whole now uses more than half of the world’s artificial fertilizer.

Night soil collection in Europe

The collection of human “waste” also occured in Europe, be it for a much shorter time and on a much smaller scale. The second half of the nineteenth century marked the end of a predominantly agricultural period in Europe; migration to the cities accelerated and the problem of sewage disposal got much worse.

Collecting night soil in Amsterdam. [Source](http://www.bronnenuitamsterdam.nl/weergave.asp?ID=6).

At the same time, health experts started to realize that cholera and typhoid fever were the consequences of drinking contaminated water. Since agriculture was increasingly short of animal manure, it appeared that both problems could be solved at the same time. The first system, which was set up in several countries and cities, is generally known as “night soil” collection and reminds of the Asian method.

Dung and urine were accumulated in movable wooden receptacles beneath the privy seat and mixed with earth, ashes or charcoal to prevent offensive odours. Night soil collectors came by at more or less regular intervals (mostly at night, hence the name) to pick up the merchandise.

Night soil collection in the Netherlands. [Source](http://www.jenneken.nl/bekijk/1900afvoervanmestenhuisvuil.htm).

This happened either by emptying the full tubs into a cart and giving them back immediately (which meant the cleansing had to be done by the users), or by placing the full tubs in a wagon, switching them for fresh ones (which meant the cleansing had to be done by the scavengers). The empty tubs were replaced under the privy seat, and the cargo was transported via horse and cart to a collection point outside the city. There it was converted into compost for use in agriculture.

Unfortunately, the collection and transport of the waste was not as reliable, efficient and sanitary as was the case in China, Korea or Japan. All was good when air-tight containers were used, but this was not always done. When open carts were applied, the transport caused waste and foul smell (see the 19th century cartoon below, Sewage was spilled while carrying the tubs down the stairs and while emptying them into the carts. Moreover, the collection did not always happen that frequently, especially in poorer neighbourhoods.

Cartoon of a night soil cart. [Source](http://www.bronnenuitamsterdam.nl/weergave.asp?ID=17)

Nevertheless, the wooden tub system was an improvement over the comparitive disorder of nightsoil collection in Europe. Throughout the Middle Ages, so-called dung farmers gathered human and animal excrements from streets, backyards and cesspools and sold these to farmers who applied them to their fields. The problem was that these scavengers needed to collect enough dung before they could sell a cartload. Duncan Brown cites Cipolla, who describes the situation concisely:

“The most pathetically tragic aspect of this business was that of the people, whose poverty was so abject that they collected the manure they found in the streets where they kept it [at their homes] until they had accumulated a sufficient quantity to sell.”

There were exceptions, notably in Flanders, where an organized nightsoil collecting system that reminds of the Chinese method was set up as early as the Middle Ages. Around the town of Antwerp, the management of organic wastes (human excrements, dung of city horses, pigeon dung, canal mud and food scraps) had become a significant industry by the 16th century. By the 18th century there were great stores along the river the Schelde where the excrements from Dutch towns were transported by barge.

The vacuum sewers of Charles Liernur

A second collection method was pioneered by Dutch engineer Charles Liernur in 1866 (patent - pdf). His vacuum sewer system combined the comfort of today’s water carriage sewer network with the ecological and manurial advantages of the earlier scavenging methods. A closet inside every home was connected to an underground small diameter pipeline infrastructure, and the stools and urine immediately left the house following deposition.

The Liernur system combined the comfort of today’s water carriage sewer network with the ecological and manurial advantages of the earlier scavenging methods

The crucial difference with today’s technology, however, was that the Liernur system did not use water but atmospheric pressure as a transport medium. This meant that it avoided the dilution of the manure by the admixture of water, thus preserving its value as a fertilizer - which was Liernur’s explicit intention. On the other hand, the vacuum sewer system did away with the need for scavengers to visit every house, lugging around buckets of poo and pee, and disturbing everyone’s sleep. It was a clear improvement on the night soil systems, including the one used in Asia.

Dutch cities were equipped with the Liernur system: Leiden in 1871, Amsterdam in 1872 and Dordrecht in 1874. Initially, only a couple of thousand homes were connected to the vacuum sewer network, but in Amsterdam the system was expanded substantially. At the end of the nineteenth century, about 90,000 Amsterdam inhabitants were linked to the Liernur sewer network, some 20 percent of the population.

The Liernur system for sewage removal.

In Amsterdam and Leiden, the system remained in operation for almost 40 years. The Liernur system was also introduced on a smaller scale in Prague (Czech republic), Trouville sur Mer (France), Hanau (Germany) and Stansed (England). The system in Trouville, installed in 1892, was operated until 1987 (source, pdf). Today, the method is still being used in ships, trains and airplanes.

The French designed their own version of the Liernur system - the Berlier system. It was introduced in 1880 for a trial period in Lyon, where it successfully removed sewage over a distance of four kilometres (2.5 miles). In 1881, a five kilometre network was introduced for trial in a Paris neighbourhood. The French took the trials very seriously: the sewage was observed by placing glass pipes at various points. The Berlier system, which was technically superior to the Liernur system, worked flawlessly: the thousand soldiers in the barracks of Pépinière, where it was in operation, were the only troops in Paris that were not affected by a serious typhoid epidemic.

The arrival of the water closet

In spite of the technical success, the Berlier system never ascended beyond the experimental stage. The Dutch Health Advisory Board advised a general, national introduction of the Liernur system in 1873, following the successful operation in Amsterdam, but this did not happen either. Liernur designed plans for other cities in Europe (Paris, Berlin, Stockholm, Munchen, Stuttgart and Zurich) and in the US (Baltimore), but these were never realised.

There were several reasons why the pneumatic systems did not became the standard sewerage systems of today. Firstly, there was the arrival of the water closet and the waterworks. In the Netherlands, a growing number of people connected a water closet to the Liernur system, diluting the stools and urine in such a matter that their agricultural value declined considerably.

Even before this happened, the sale of the sewage for use as manure did not give the profits that were expected. Health experts advanced that profits should not be the first aim of a sanitary system, but the problem was that Liernur himself had stressed financial profits as an important advantage of his system. This had attracted investors, and they promptly left the technology behind when they started to lose money.

The installation of a vacuum sewer system is twice as cheap as the construction of a traditional sewer system

An important problem, not only in the Netherlands but throughout the western world, was the growing size of cities. Both the night soil system and the more sophisticated methods were eventually beaten by the logistics of maintaining the practice in huge cities supported by far away farms. The last blow for the vacuum sewer system was the appearance of inorganic fertilizers after a cheap production method was found in 1910. The shortage of fertilizers in agriculture was “solved”.

Because cities had started building water carriage systems for the discharge of storm drain water, the next logical step was to allow the discharge of sewage via the same network. Basically, this was a step backwards: excrements were again drained on surface waters, not necessarily in the immediate surroundings but a few miles further downstream. It took another 70 years before sewage stations became (relatively) common in the rich world.

Only three future possibilities

If we want to restore the natural cycle of our food supply, there are only three technological possibilities. We could develop a modern variant of the scavenging method using composting toilets, in which the stools are collected from individual homes together with other organic waste products. Urine could go to a separate tank that is emptied once a year by a tanker (this method exists in some Dutch and Swedish residential areas where people use so-called urine separation closets). Or, we could develop a modern variant of the Liernur or Berlier system, in which the sewage is collected automatically, but without the use of water.

Illustration by Diego Marmolejo.

Vacuum sewer systems have found a limited application in some new housing estates since the 1960s and 1970s. A few hundred systems are in operation in the US, the UK, Australia, Germany, the Maledives, Southern Africa and the Middle East (overview). The installation of a vacuum sewer system is twice as cheap as the construction of a traditional sewer system. A vacuum system is also faster to construct and easier to maintain: it consists of much smaller diameter tubes that have to be laid less deep into the ground - a narrow trench in the road-surface suffices.

There is a third techno-fix, but it is many times more expensive than the other two: using the diluted sewage from our water carriage system as a fertilizer. Basically, this adds another layer of costly infrastructure and complexity on top of an already very costly and complex system. Diluted sewage not only has to be dried, but also purified. This is because sewage sludge does not only contain human waste but also many other (including toxic) waste resources, both from households and factories.

Interestingly, when we remove urine and excrements from the sewer system, we might as well eliminate the water carriage sewer system altogether, further obtaining substantial cost and energy savings. There are workable alternatives for the removal of storm water (basically reducing paved surface) and for the local treatment and re-use of grey water.

Composting

Human faeces and urine can only be used as a fertilizer following further treatment. This was an already known fact by early Chinese agricultural writers, who warned that untreated humanure could “burn and kill plants, rot the shoots and harm human hands and feet”. Today we know it also carries more severe health risks. F.H. King and Joseph Needham praise the composting efforts of the early Chinese, who often combined their privy with the family pigsty. However, Duncan Brown is more critical of their composting techniques. The health advantages that the Chinese gained by keeping their drinking water supplies clean, were partly offset by the transmission of diseases via food crops:

“Gastro-intestinal diseases were endemic throughout the region. In Korea and Japan, fluke diseases were common because of the practice of eating raw fish grown in ponds fertilized with human excrement. But those diseases could have been largely avoided with a better understanding of their nature and modes of transmission. If properly used, devices like the relatively modern sceptic tank, the more modern oxidation tank or the so-called composting toilet can avoid the danger of gastro-intestinal diseases previously associated with the use of human excrement as manure.”

A process of composting should always come first, and this can happen in two ways. The first - slow composting - is a a-do-it-ourselves-guide technique that is explained in the “Humanure Handbook”, an online practical guide by Joseph Jenkins (who coined the term ‘humanure’). Slow composting happens at low temperatures and takes about one year in a moderate climate. To be secure, most say the resulting (odourless) compost should only be used for growing crops where there is no direct contact between food and fertilizer (like fruit trees) and for inedible plants (flowers, houseplants).

Image: F.H. King and Joseph Needham praised the composting efforts of the early Chinese, who often combined their privy with the family pigsty.

The second method is composting at high temperatures, which goes much faster and results in a fertilizer that can be applied to any kind of food crop. It is an industrial process, which is being applied successfully in several countries for a number of years. Interestingly, the first step of this process also generates electricity, further improving the sustainability of the whole system. Since 2005, a factory of the Dutch company Orgaworld composts diapers (from babies and elderly) together with many other kinds of organic waste. It is a high-tech process that takes about 6 weeks and results in a high-quality compost, free from pathogens, medicines and hormones. The company has also built two factories in Canada and is building plants in the UK.

Can we feed the world using humanure?

Can we produce enough natural fertilizer to substitute for synthetic nitrogen and mined potassium and phosphates? According to the figures collected by F.H. King, an adult person produces on average 1,135 grams of dung and urine each day. How much nitrogen, potassium and phosphates does this contain? That all depends on the diet.

From the China of 100 years ago, King cites different research results, ranging from 2.9 to 6 kilogram (5.8 to 12 pounds) of nitrogen per person per year, 0.9 to 2 kilogram (1.8 to 4 pounds) of potassium per person per year, and 0.4 to 1.5 kilogram (0.8 to 3 pounds) of phosphates per person per year.

If we recycle our own waste products, fertilizer production would automatically keep up with population growth

At present, the world population is estimated at 6,800,000,000 people. Let’s assume they all have a similar diet as the early 20th century Chinese and that the highest figures given by King more closely resemble today’s diets (reliable present-day figures are hard to find). This would mean that the total world population could produce 40.8 million tonnes of nitrogen, 14 million tonnes of potassium and 10.4 million of phosphates. Is that enough to eliminate the need for artificial fertilizers? At first sight, no. Today’s artificial fertilizer production is:

99.9 million tonnes of nitrogen, or more than double the amount that all people could possibly produce (40.8 million tonnes)
37 million tonnes of phosphates, almost 4 times the amount that all people could produce (14 million tonnes)
25.8 million tonnes of potassium, or more than 1.8 times the amount that all people could produce (10.4 million tonnes)

Livestock

However, we humans have “outsourced” a considerable amount of dung production to farm animals. A large amount of artificial fertilizer is used to produce livestock feed. These animals produce much more manure than all the people on the planet. Livestock excreta in 2004 were estimated to contain 125 million tonnes of nitrogen and 58 million tonnes of phosphates (there are no figures for potassium, which we will further ignore). That’s 3 times more nitrogen and 6 times more phosphates than can be found in humanure.

Animals played a minor role in the Chinese humanure-based agricultural economy, but the European farmers in the Middle Ages relied heavily upon livestock for manure, which was their main fertilizer. Animal manure was never wasted. Joseph Needham cites Fussell:

“European farmers of the 15th to 17th centuries, both high and low, had one main worry, manure. They dared not neglect any source of supply, however minute, for the success of every crop they grew depended largely on the amount they could accumulate for use. They were willing to undertake the labours of Hercules to build a sufficient dunghill”.

There are many good reasons to cut back on meat consumption, both for our health and for the environment - livestock production is also the main driver of deforestation (in its turn a major driver of soil degradation). However, if we don’t want to give up our high meat consumption, the least we should do is “to undertake the labours of Hercules to build a sufficient dunghill”.

A mechanical manure spreader.

It would not only save us the effort to produce an ever increasing amount of artificial fertilizers, but it would also stop the devastating ecological consequences of dumping 91 million tonnes of nitrogen and 49 million tonnes of phosphates into the environment every year. Most of this is discharged without any treatment, illegally, or legally by overdosing it on fields near cities as a cost-effective waste management practice.

Food scraps & management techniques

There is another source of natural fertilizer material that is being wasted - food scraps. In this case, too, we turn a valuable resource into a waste product. Food scraps could be fed to animals like pigs, greatly improving the sustainability of meat production. But, instead, we feed them grain. Of all the food scraps produced in the US, only 3 percent is currently being recycled. The rest ends up in landfills, producing large amounts of greenhouse gases.

There is also a large potential to lower demand - one of the main problems with today’s fertilizer use is overconsumption. Artificial fertilizers are cheap and as a result farmers prefer to dose their crops with too much fertilizer, instead of risking not using enough and lowering their yields. This means that more nutrients are lost through soil erosion, runoff and leaching - which also pollutes groundwater, rivers and seas, because these nutrients do not pass through sewage stations.

The main problem is not that we produce inorganic fertilizers it’s that we don’t recycle them

Things were very different in the early Chinese agricultural system and during the European Middle Ages. There was never a surplus of fertilizer, so farmers applied it thoughtfully. With more careful techniques, today’s farmers could get the same yields with the use of much less fertilizer. The use of crop rotation, intercropping and green manure, all historically important techniques which are still being applied in today’s organic agriculture, could further reduce the demand for fertilizers.

Nutrient balance

Let’s digest all this information for a second. On the one hand, we have livestock and people, who together produce 166 million tonnes of nitrogen and 72 million tonnes of phosphates. Almost all of this is wasted, wreaking ecological havoc.

At the same time, our factories produce 99.9 million tonnes of artificial nitrogen fertilizer and 37 million tonnes of phosphates. A completely superfluous operation that further increases pollution and consumes vast amounts of energy. With the expected human (and livestock) population growth, not to mention the rise of energy crops to make biofuels, both biological and artificial production will rise even further, making everything only worse.

Illustration by Diego Marmolejo.

We have more than likely already passed the stage where humanity could be sustained without inorganic fertilizers. It is, after all, artificial fertilizers that caused the population boom of the 20th century. However, this should not be a problem. The large amounts of human and animal dung include nutrients which originate from inorganic fertilizers, since we all eat food that is largely grown by means of inorganic fertilizers. It is estimated that humans have already doubled the amount of nutrients in the global ecosystem. Thus, the main problem is not that we produce inorganic fertilizers it’s that we don’t recycle them.

Logistic challenge

Even if we only consider livestock manure, there is enough natural fertilizer available to sustain almost 7 billion people. There is also no taboo when it comes to utilising animal manure, so why don’t we use it? Nutrients recovered as animal manure and applied to agricultural lands were estimated globally at a mere 34 million tonnes of nitrogen (28 percent of total) and 8.8 million tonnes of phosphates (15 percent) in 1996. The amount wasted thus equals (for nitrogen) or surpasses (for phosphates) artificial fertilizer production.

This is the consequence of an industrial and intensive meat and dairy production system that is operating on a global scale. In many countries cattle eats fodder that is produced on the other side of the world. So, in order to close the loop, we would have to ship the manure back to where the fodder comes from. The FAO writes (pdf):

“Even if livestock is raised on the same continent as where its feed is grown, the scale and geographical concentration of industrial feedstock production causes gross imbalances that hamper manure recycling options. High labour and transport costs often limit the use of manure as organic fertilizer to the direct vicinity of the production facilities.”

If we recycle our own waste products, we have to ship them back from the place of food consumption to the place of food production

Of course, the same can be said of human manure. Just like livstock, humans are geographically concentrated in large cities with no farmland in sight. Just like livestock, we eat food that is often produced far away from where we live. This means that if we choose to collect humanure, we have to ship it back from the place of food consumption to the place of food production. Consequently, recycling nutrient elements would bring along a massive logistic system consisting of trucks, trains and ships transporting dung (or pipelines transporting sewage) all over the world.

Illustration by Diego Marmolejo.

We are not saying that every ounce of dung should be sent back to the place where the food was grown—this is impossible and ridiculous. What counts is that there is a balance between import and export of nutrients. Countries that export food should also choose to import (other) food, instead of dung, yielding the same result and increasing the dietary variety. All we would essentially need is a sophisticated nutrient accounting system.

Decentralisation of the human population

The fundamental solution, of course, is to produce food more locally. This would not only do away with the shipping of manure, but also with the shipping of food. If livestock production would be geographically more diversified and mixed with cropland, all the animal manure could be used and artificial fertilizers would not be needed.

If cities were smaller and distributed more uniformly throughout farming country, the logistics of returning humanure to farmland would be greatly simplified. Of course, this ‘decentralisation’ of the human population goes against the notion that densely populated cities are more sustainable than a more uniformly distributed population. The challenge may not be to abandon Suburbia, but to make it more self-sufficient.

Many Thanks to Sietz Leeflang, inventor of the Nonolet (an urban composting toilet - building plans), who spent two years convincing me to write this epos on shit, and referred me to most documents listed below. Sietz also inspired me to write about oven stoves (which took considerably less effort).

Sources

“Farmers of Forty Centuries”, F.H. King (1911)—dung recycling in china, korea and japan
“Science and civilization in China”, Vol VI:2, Joseph Needham (1984)—idem
“De geschiedenis van de techniek in Nederland - de wording van een moderne samenleving 1800 - 1890, deel 2”, H.W. Lindsen (1993)—the liernur system (in Dutch)
“Feed or Feedback: Agriculture, Population Dynamics and the State of the Planet”, Duncan Brown, 2003—the nutrient cycle and how to restore it (great book!)
“The history of sanitary sewers” (website)—the liernur system and other early sewer systems
“Proposed plan for a sewerage system, and for the disposal of sewage”, PDF, Samuel M. Gray (1884)—the technical options at the end of the 19th century
“Humanure Handbook”, Joseph Jenkins (2005 - third edition)—diy
“The nitrogen dilemma: is America fertilizing disaster?”, Tom Philpott, Grist (2010) - inorganic fertilizers
“Livestock’s long shadow”, PDF, Food and Agriculture Organisation (2006) - figures of livestock dung production
“Production and use of potassium”, PDF (1998)
“Inorganic phosphorus and potassium production and reserves”, PDF, T.L. Roberts and W.M. Stewart, in “Better Crops” (2002)
“Environmental aspects of phosphate and potash mining”, PDF, UNEP (2001)
“Peak Phosphorus”, James Elser & Stuart White, Foreign Policy (2010)
“Scientists warn of lack of vita phosphorus as biofuels raise demand”, Times Online, June 23, 2008
“The voyages and adventures of Ferdinand Mendez Pinto, a Portugal, during his travels for the space of one and 20 years in the kingdom of Ethiopia, China, Tartaria, etcetera”, Ferdinand Mendez Pinto (1583).