Wednesday, November 4, 2009

'Container Farming in the Slums of Mexico' by Claire Kurtin

In the mid 1990's, half of Mexico's population fell to below the poverty line (some 40 million people). 15 million of those lived in extreme poverty, and most of them were concentrated in urban slums, such as those of Mexico City. About a decade ago, a group of some 20 NGOs attempted to create a method in which people living below the poverty line could produce their own food using "little or no land, little or no investment in infrastructure, no purchase of chemical inputs, and be light weight for rooftop cultivation"1. This development would hopefully alleviate some of the economic pressure on these slums.

The technology is relatively simple and accessible. Produce is grown in 18-20 litre containers filled most of the way to the top with grass clippings or tree leaves. A thin layer of soil is placed on top, where the seeds are then planted. There is a drainage hole 10-15 cm from the base, which allows for a water reservoir. Because the container is filled mostly with leaves and grass, it weighs a lot less than it would if it were entirely filled with soil.

The key to the whole system is the fertilization method. Chemical fertilizers can be expensive and often don't work well. The recommended fertilizer for container farming is actually urine. The decaying leaf matter in the bottom of the container breaks down the urine quickly, so that the smell is reduced and germs do not survive in urine. Also, most importantly, urine is obviously inexpensive and quite easy to produce. Due to the decomposition process happening inside the container, plants proved to be more pest resistant and resilient to disease as well.

The project has proven extremely successful in creating a form of farming which is cheap, self sustaining and accessible .

1. Willem Van Cotthem. "Mexico: Container Farming in Slums," Desertification Blog, posted on February 16, 2008, (10/04/09 10:30 am)

-Claire Kurtin

'Logistics of the Agricultural Economy' by Victor Poon

Logistics, the science dealing with “the integrated management of all the material… from supplies through transformation of input materials up to the end consumer” (Vanecek 1) is fundamentally tied to concepts of the economy. The concept of an agricultural economy can be visualized as a plane, with a system of individual supply lines linking the producer to consumer. At each point, resources such as water must be consumed to maintain the system.

The raw material that is consumed by the system (the input) has a cost – including but not limited to: the cost of water, the cost of supplies and the cost of transportation. In the United States, only 21% (see diagram source) of energy expended for food production goes into agricultural production – the rest is consumed for subsidiary activities such as processing, transport and refrigeration.

(click for larger image)

If we look at a newly industrialized country like Thailand, we can begin to better understand the new stresses placed on a developing agricultural system. Food prices will continue to escalate, for reasons including but not limited to: the diversion of food-producing fields to fields that produce biofuels, rising fuel costs or simply as a result of higher global population and demand. There are two solutions for the poorer citizens of Thailand to cope with the increased prices – first, to increase their income or second to reduce the costs of their food production system, or to develop new ones altogether. (Thepent et al.)

Looking at Thailand’s recent history we can see that the increased production of rice has not corresponded with an equal increase in price. During the years of 1955-1985, Thailand increased crop production by increasing productive area, rather than increase the productivity of the land itself. In 1976, the government began to slow down the reallocation of forested areas to become farmland, and usable agricultural fields became capped. Despite increased efficiencies, total energy costs have increased by about 22 times since 1950, while crop yield has only increased by 7 times. (Aphiphan et al.) It is clear that this new energy usage is both unaffordable and inefficient.

This is in part due to the Thai government’s push for a high-input, export-oriented system to help supplant its fast growing economy. The new agricultural systems are now heavily reliant on mechanization and chemical product use and much less so on worker labour.

Thus, economic pressures in the agricultural sector have forced resource consumption to dramatically increase (water shortage less an issue in Thailand) and for farmers to produce more product, rather than a cheaper, more efficient crop yield. In order to simplify the current logistical model, energy usage must be trimmed at each and every point in the system. The methods outlined in this blog begin to relieve the stresses imposed on the system – from sustainable water management to the creation of keyhole gardens (which serve to introduce a new self-sufficient model completely). These are not simple problems that agriculture faces today, and solutions must be both economical and innovative to be effective in addressing the issues at hand.

Image Sources

1. Vanecek, D. and Kalab, D, “Logistics in Agricultural Production,” University of South Bohemia, Kalab.pdf.

2. Thepent , Viboon and Chamsing, Anucit, “AGRICULTURAL MECHANIZATION DEVELOPMENT IN THAILAND,” Agricultural Engineering Research Institute Department of Agriculture, Chatuchak,

3. Thepent , Viboon and Chamsing, Anucit, “AGRICULTURAL MECHANIZATION DEVELOPMENT IN THAILAND,” Agricultural Engineering Research Institute Department of Agriculture, Chatuchak,

Information Sources

Pookpakdi, Aphiphan. "Sustainable Food Production in Thailand". Department of Agronomy, Kasetsart University. (accessed November 1, 2009).

Thepent , Viboon and Chamsing, Anucit. "AGRICULTURAL MECHANIZATION DEVELOPMENT IN THAILAND". Agricultural Engineering Research Institute Department of Agriculture, Chatuchak . (accessed November 1, 2009).

Setboonsarng, Sununtar and Gilman, Jonathan. "Alternative agriculture in Thailand and Japan ". Asian Institute of Technology School of Environment Resources and Development. (accessed November 1, 2009).

Vanecek, D. and Kalab, D. "Logistics in Agricultural Production". University of South Bohemia. Kalab.pdf. (accessed November 2, 2009).

- Victor Poon

Tuesday, November 3, 2009

'Urban and Rural Irrigation Water in Beijing' by Devon Holdsworth

One of the leading producers and consumers of agricultural products in the world is China. Nearly 300 million Chinese farm workers are in the industry working on virtually all of the arable land in the country. Beijing’s econmy relies greatly on its agriculture, as it is their primary industry. With a population of 13, 000, 000 their urban agriculture is greatly relied upon to be a source of inexpensive food as opposed to the alternative of importing goods. Therefore, it is not a shock to find out that their ground water resources are quickly depleted from farming and in some places the water table has become over 20 m deep making it completely impossible for farmers to tap into. For many years farmers in Beijing have compensated for this by reusing wastewater, however they have not been practicing proper wastewater management until very recently. It was not until 2000 that they started to use water from central wastewater treatment plants. The organization known as SWITCH is now projecting high hopes for the future of Beijing’s water; with the use of water treatment plants the water table is hoped to be restored to 1960s levels, rivers and lakes will meet Surface Water Quality Standards grade III and above and tap water will reach international drinking water standards.

In the 1980s Beijing’s population was discharging 2,000,000 cubic meters of sewage; half from domestic wastewater and half from industries but nearly all of it was pumped into rivers and lakes without receiving any treatment. Beijing is still recovering from their previously low standards of sanitation and the Gaobei Dian Wastewater Treatment Plant is playing a large role in this by treating 40% of Beijing’s daily untreated wastewater. Beijing’s water is treated to the secondary level by neutralizing and disposing the wastes using biological matter, which makes it suitable to be used for agriculture. Now 1,350,000,000 cubic meters of water is discharged, of this 1,000,000,000 cubic meters of water is treated and of this 230,000,000 cubic meters is used for agriculture. Not only is this plant promoting sanitary wastewater concerns, it is also restoring Beijing’s natural habitat, boosting their economy by providing water for the agricultural industry and it is providing job opportunities for the people of Beijing.

1. Gaobei Dian Wastewater Treatment Plant

Unfortunately water from wastewater treatment plants is not available to all farmers in Beijing, some are too far removed in rural areas from these plants to access it. For these farmers there is another option, which is harvesting rainwater. This technique is also used by many citizens in residential areas and has been largely promoted since the year 2000. There are multiple techniques to do this, which makes clean rainwater available to almost anybody. One technique includes water pooling in roadside gutters, storing in local deposit pools, and then being transferred to large water-saving ponds for primary treatment (sedimentation). The most common form of rainwater harvesting which has been practiced for thousands of years in rural China uses the roofs of houses and since recently greenhouses have been promoted for capturing rainwater and irrigating crops.

2. Greenhouse Rainwater Harvesting System

One greenhouse, which is specially made to incorporate rainwater harvesting, can on average collect 200-300 cubic meters of rainwater each year, which can irrigate large amounts of area with efficient (drip) irrigation. Unfortunately at this time only 1 percent of irrigation systems in government subsidized farming uses rainwater as only twenty of these greenhouses now exist, however it is expected that more will be built.

Beijing is now doing their part in order to continue farming for their economy in an environmentally friendly way. Whether its done using state of the art Wastewater Treatment Plants or simply collecting rainwater off of their roofs to feed their crops, both urban and rural parts of Beijing are adapting to water scarcity. Any country that cannot afford a Wastewater Treatment Plant could easily learn from rural Beijing’s rainwater collection techniques and there is no reason that any place should be without clean drinking water and clean water for agricultural uses.

3. Greenhouse in Beijing

Image Sources:

1. "Introduction to Beijing Drainage Group," BDC, (accessed November 4, 9:30pm)

2. Zhang Feifei, "Innovations in Greenhouse Rainwater Harvesting System in Beijing, China," UA-Magazine, December 2007, (accessed November 4, 10:00pm)

3. Sara Elliot, "How Greenhouses Work," How Stuff Works, 2008, (accessed November 5, 6:00pm)

Information Sources:

Ji Wenhua, Cai Jianming, "Adapting to Water Scarcity: Improving Water Sources and Use in Urban Agriculture in Beijing," UA-Magazine, September 2008, (accessed November 4, 8:00pm)

"Drinking Water Health Advisories," Water Quality Criteria US EPA, November 2009, (accessed November 4, 7:45pm)

"Economy of People's Republic of China," Wikipedia, November 2009, (accessed November 3 10:00pm)

Michael Levenston, "Water for Urban Agriculture," City Farmer News, October 2008, (accessed November 4 9:00pm)

- Devon Holdsworth

'The Bio-Sand Filter' By Andreea Toca

As architects, engineers, innovators, and designers, we can begin to create, build and design in such a way that we bring forthcoming positive change to the places we live in. This positive change can be extended and applied towards subsistent urbanized areas, such as slums. Since we have the power to create innovative technologies, we can help these areas attain better physical infrastructure conditions. One important part to good physical infrastructure, is the ability to get and have access to clean drinking water. The Bio-Sand Filter is one way architects and engineers can provide this access to less developed, and densely populated areas.

1. The Bio-Sand Filter

Slums have taught us that when living in densely packed, close quarters, disease can spread rather quickly. This is important to know when developing infrastructure, as to know what exactly you are designing for and the conditions that apply. The bio-sand filter is a concrete block that filters the water using sand. However, the same method can be applied if the block is to be made from plastic or metal drums. There are many reasons why it is a beneficial technological development, whether its an economic, sanitary, agricultural or architectural reasons.

2. Slums

From an economic perspective, Bio-Soil Filters (BSF) are quite simple and cost-efficient to manufacture for slum dwellers in developing countries. Part of this reason is due to the fact that they are not mass produced, but rather usually "small-scale micro-projects". These micro-projects are usually led by humanitarian groups or NGO's, that provide and pay for the implementation of the concrete filters. The costs of implementing the filters are quite reasonable when building concrete filters. The cost does go up if trying to implement a plastic filter (which is a newer innovation), but if subsidized, it is possible to implement. Aside from costs, resources are very important in the implementation. To build the filter itself, the concrete needs a metal mould, hence a metal workshop is required in order to make the moulds. As well, in preparation for the filter, sand must be acquired. It is important to note that if the site itself does not have sand readily available, it must be extracted from elsewhere, therefore raising the costs.

From a sanitary perspective, BSF is quite effective in filtering out contaminated particles that exist in the water. However the surrounding site, and the quality of the water it is set out to filter, both affect how well the BSF will function. This goes hand-in-hand with the agricultural perspective, and the proposed site has to be tested before implementing a BSF. The filter, while it will withstand short periods of heavy contamination, will not operate effectively when filtering extremely murky water, as the solids in the water settle at the top, and it slows down the flow of water. Due to this fact, BSF's are usually installed in areas that are dependent on surface water as their main source of water.

3. Left: water after BSF, Right: water before BSF

Relating back to the economic value of the BSF's, they are economic also in the way that they are designed. The traditional rectangular shape shows minimalism at its best, however the new circular design uses less material, and therefore is more economical. When BSF's are created from concrete, both rectangular and circular, they display a very industrial, minimalist look. Personally I believe, this is a very architecturally appealing look, and it fits well into any space, as concrete tends to blend into its surroundings. However, plastic and metal BSF's are not as pleasing to the eye.

4. A circular metal BSF

Image Sources:

1. "Bio Sand Filter." Photograph. (n.d.) From Borda South Asia. (accessed Nov. 3, 2009).

2. Rikka. "Slums." Photograph. 2008. From Flickr (accessed Nov. 3, 2009).

3. "After & Before." Photograph. 2008. From Flickr (accessed Nov. 3, 2009).

4. Oxfam International. "7 yr old Shanta Rame Ale using a water filter recently installed in the family home" Photograph. 2009. From Flickr Nov. 3, 2009).

Information Sources:

Eric Fwester and Adriaan Mol, " Small-Scale Micro-Projects," 2004, (accessed Nov. 3, 2009).

Eric Fwester and Adriaan Mol, " How to start a Filter Project," 2004, (accessed Nov. 3, 2009).

- Andreea Toca