June 1997 2 1 17 No. 17 Agriculture ¢4 Technology Notes 4 The Agricultural and Forestiy Systems Division (AGRAF) The World Bank Urban Waste and Rural Soil Management Making the Connection As urban communities face increasing congestion, more and more fresh water and a range of solid materials are required to satisfy the daily needs of people and industry. This trend is especially true in developing Using Urban Waste A well designed and cost-effective waste countries, where urban populations are Expanding populations require more food. management system, based on resource expected to triple by 2025. Management Until recently, use of higher yielding crops recovery and recycling teclhnologies as well of municipal wastes poses many problems and livestock and expanded agricultural as reuse of wastewater, can produce sub- in these growing urban centers. Waste areas provided most of the necessary in- stantial social and economic benefits. management is a labor- and capital-inten- creases, but now most productive land is Processors of raw materials are reusing dis- sive function that often consumes 20 to 50 already in use. Higher yielding crop vari- carded products made from metals, glass, percent of a municipal operating budget. eties require good soils, but many farmers plastics, and paper, an approach that needs Financing waste management is a major are forced to use mediocre land without to be expanded. In addition, large quanti- problem for municipalities that are faced the means to purchase inputs to maintain ties of organic materials can be composted with chronic resource shortages and com- soil fertility. In many areas livestock make instead of polluting rivers and lakes or end- peting demands. As a consequence, waste management in many cities fails to meet Wastewater treatment is always expensive minimum acceptable standards, with grave adverse effects on the urban environment, Total cost ($/household) Biological public health, and the quality of life for 900 Chemically-enhanced secondary large numbers of city dwellers, especially 0 primary poorer people living in these highly con- Conventional high dose gested areas. (see graph below) 600 primary Indiscriminate dumping of liquid and _ solid wastes pollutes soil and water and 450 _ damages the economy and public health. 300 Costs increase as treatment levels increase 150 I l l l I 0 20% 40% 60% 80% 100% Per capita waste generated Percent BOD removal in selected cities S I the major contribution to soil fertility, but ing up in landfills. The same principle ap- some areas are not able to sustain livestock plies to wastewater. Rather than paying Bangkok:321 in numbers that would significantly ben- for secondary or tertiary treatment, efit soil fertility. the water can be used for irrigation or I] IQuito: 281 Linking waste to soil. One solution is to aquaculture. The economics of these use urban waste to improve rural soils, es- alternative approaches is a necessary Abidjan: 200 pecially in peri-urban areas. The benefits part of the decisionmaking process, of such programs can be demonstrated, ei- but when total costs are considered- I I I ther as a free-standing intervention, or in health, pollution, landfill, and incinerator 0 200 400 conjunction with other soil improving ef- costs -these options begin to make sense (Kg/year) forts such as the use of fertilizer and various (see graph above). land conservation techniques. AGRAF Technology Notes Managing waste. Liquid wastes from widely used in horticulture, seedling pro- a city sewer system that are destined for The Dutch VAM example duction, and general agriculture, while reuse are usually processed in a wastewa- lower quality material is used in city parks ter plant, while solids are composted. In the 19th century, the Dutch and to stabilize land. Sludge and compost These processes produce water, sludge dried their swamps and harvested add nutrients and organic matter to the (which can be dried or composted), and the peat for fuel, leaving sandy bot- soil, improve water retention and transmis- compost. As concerns about water quality tom land. They then developed a sion, and improve soil structure. increase, more sewage waste products are scheme to improve these sandy ar- Public health concerns. Disposal of applied to agricultural lands (see graph, eas, dalgironden, by mixing in municipal waste by land application has below). urban waste that was transported been a popular option for centuries from Composting is the controlled, biological by train from western Holland 100 northern Nigeria to China and beyond. decomposition of organic materials into a miles away. This system worked While generally successful, there is evi- stable humus-like product that can be wellintheearly20thcenturywhen dence that irrigation with untreated handled, stored, and applied to land with- city waste was mainly organic, but municipal and industrial waste can harm out adversely affecting the environment. more complex handling became crops as well as humans, either those Compost is an excellent organic soil necessary in the second part of the living in the area or those who consume amendment that improves soil moisture century as more and more inor- the products. These risks can be resolved retention and increases biological activity, ganic waste and plastics were by preventing pollutants from accumulat- thereby improving soil productivity. mixed in. The parastatal company ing in the soil, taking advantage of the soil's Recycling experience. Recycling VAM now has a sophisticated capacity to assimilate and detoxify pollut- waste for agriculture is by no means new. waste handling, sorting, and ants, and determining optimal levels of Well-known examples include use of city composting facility, and sells its safe application. Specific attention needs waste in peanut growing systems on the products (such as high quality to be given to the risks associated with Kano plains of Nigeria, use of nightsoil in compost) on the open market. transfer of human pathogens. China, and 'sewage farms' around Euro- Standards. A mature waste manage- pean cities during the 19th century. More Technology. The current, limited use nment industry will develop overall quality recently, city waste improves soil in the of waste in agriculture lhas been niostly standards for both processes and products. Netherlands (see box, right); urban waste- beneficial, but there are some potential Process standards often relate to odor con- water is used in many parts of the U.S., detrimental effects, usually closely related trol and prevention of air and groundwater Israel, and Jordan; and abattoir waste pro- to either the quality of the raw material, contamination, while quality standards are duces methane and compost in Senegal its processing, or both. The level and type necessary to control pathogens and toxic (see small box, page 3). The Calcutta sew- of treatment varies, as does cost (see box materials and produce a homogeneous age fisheries system is the largest single page 4 left). Composting technologies product that maintains its value. To real- wastewater system involving aquaculture, have improved greatly in recent years and ize the full benefits of compost in the soil, \vith 4,600 hectares of sewage-fed fish ponds provide better quality compost with in- it is crucial to use a proven method. As employing 4,000 families (Pescod 1992). creased acceptability. In California, with commercial fertilizers, the compost creaed aceptbilty. n Caiforia, must be of high quality to he effective. growers add compost to build up soil or- Issues and Policies ganic matter -high quality compost is Methodologies for quality indicators for Widespread adoption of recycling tech- nologies has been hindered by undeveloped markets, transportation cs,eaelthp d culetu es, tandp . rad Quantity of municipal sludge disposed in U.S. costs, lhealth and cultural issues, and inad-(mlints/er equate regulations. But the primary barrier is that the potential benefits are not 1993 adequately taken into account by urban 1972 planners, sanitary engineers and farmers. Waste handling has focused on landfills ' - and incinerators, while inorganic fertilizer / - 086 / 1.79 and fresh water are the primary inputs : . used to meet the needs for soil nutrients \. 0.64 _ 1 07 \ Q 34 and irrigation water. Both sides could ben- 0.64 0.34 efit from closer cooperation, and urban and agricultural policies can significantly affect the acceptance of urban waste in ag- * Landfill D Land application U Incineration D Ocean disposal riculture (see large box, page 3). Source: Lue-hing et al. 1994 page 2 June 1997 Implementation in Bank cultural technical staff, while agricultural New income stream for Projects planners may benefit from the expertise Senegal abattoirs At the policy level, Bank staff and coun- of urban waste maniagers. Essential in this terparts should evaluate wlhether effort is the integration of the private sec- Since 1990, a project in agricultural, environmental, and urban tor in the collection and recycling of waste, Thies supported by French policies are conducive to recycling in gen- and marketing the final product. and Senegalese government eral, as well as to recycling waste for Most experience in the Bank involves agencies has demonstrated agriculture. This approach will likely re- use of wastewater based on long-term ex- significant economic and envi- quire building bridges between sectors and perience of the UNDP/World Bank Water ronmental benefits from fostering complementarity. Modern agri- and Sanitation Group. Innovative, smaller- chanineling slaughterhouse culture is still associated with extensive scale interventions (such as the Senegal wastes into continuious meth- fertilizer use rather thani withl a mix of com- example) could be suggested for agricul- ane- and compost-generation. inercial fertilizer and organics, and there tural as well as urban projects, either as Despite the project's nearly is little appreciation for the benefits of us- pilots or as an integral project component. 25% annual return on a ing such a combination. Based on experience in both developed $250,000 investment, creating the public/private partnership necessaiy to operate on a com- Policies that may influence the use of waste in agriculture mercial basis faces institutional Multisector policies and management constraints. * Integrated, mnultisectoral policies and framework for waste and water The key challenge is coordina- managemenit bon of the slaughterlhouse * WVell defined r euse priorities and strategies recognizing the need to protect production of compost with human health companies skilled in growing * Link urban waste management to agriculture, especially to fertilizer and high-value crops such as toma- other input suipplers toes and melons from compost Urban policies - limiting Rutral and agricultural policies- ball seedlings. Another current * Subsidized landfills and incinieration li7niting challenge is to apply the lessons * Lack of or below-cost water charges * Subsidized chemiiical fertilizers learned in the pilot project in * Lack of (cleani) water laws and r-egu- * Subsidized agricultural water Thies to larger abattoirs. lation of sewage treatmenit and * Regulations restricting processing, disposal use, or transportation of waste- water, sludge. or compost (odor Urban policies - stinmulating restrictions, for example) * Promotional and support activities Rural and agricultural policies- compost are now being developed - public education, voluntary or stiunanlating (Bidlingmaier and Maile 1996). manidatomy recyclinig targets, liaison C Direct or indirect economic Marketing. A key step in the develop- with private sector benefits of the isec of wastewate ment of sustainable waste management is * Incentives for engaging in resource sludge, or compost marketing the final product. Products can recovety technical assistance, tax * Incentives to use urban waste be compost, treated sludge, or more ad- credits, surcharges on land fills, provided by cities, off-setting vance proucts uch s alklinestabiizedsound environ mlental regulationls vanced products suclh as alkaline-stabilized * Incentives to stimulate marketing of duumping costs sludge in the U.K., compost enriched with recovered material - info ation * Research and extension policies fertilizer in Haiti, and seedlings grown on tax credits that embrace the concept of waste compost in Senegal. There are a number use in agricultuire and support in- of companies specializing in treatment and creasing potential, user awareness. sale of (urban) waste for agricultural uses such as N-viro and Ecosci (U.K.) or Milorganite (U.S.). In some other coun- tries, waste is directly marketed by Success in fostering such appreciation and developing countries, the best oppor- municipal waste management facilities. canl lead to project level initiatives that rec- tunities to use compost exist in peri-urban (see box, page 4, right). ognize the environmlental and economic areas where higher value vegetable and benefits of using urban waste in agricul- horticulture crops are grown - transpor- ture. Greater collaboration among Bank tation costs are lower and enhanced staff in different sectors is necessary to productivity has been demonstrated. identify these projects - urban waste The time is right to make these practices project planners may need to consult agri- universal: page 3 AGRAF Technology Notes Nutrient content and value of sludge and compost Keys to market development Nitr-ogeni Phiospliorus Potash * Product must be clean (no Slidge pathogens, glass, plastics, heavy Nutrient content (%) 1.0-6.0 0.8-6.1 0.5-5.0 metals, etc.) Compost * Strict quality control to ensure Nutrient contenit (%) 1.0-2.0 1.0-2.0 2.0-4.0 product consistency Average ntitrient content (kg/ton) 17.0 15.5 25.0 * Properties and quality of the Approx. value of nutrient (US$/ton) 10.00 6.50 7.50 product must be understood by producer and user, and where possible, should be tailored to Based on NRC (1996) anid World Bank commoditv price data, 1997. the users * Regular supply of raxv product . cultural considerations are shifting . use of organics to sustain soil produc- A sliift in policies and technologies from a 'throw xviay' to a 'recycling' tivity is experiencing a resurgence; and to make better use of urban waste wvill approach; . planners and politicians are being benefit the environment, economy, agri- . land for conventional waste disposal is pressured to make better use of culture, and rural and social develop- becoming scarce; fresh water. ment. New partnerships must be forged . conventional disposal methods are ex- among local governments, private indus- pensive and/or socially or environimen- try, farmers, and development insti- tally unacceptable; * L tutions to champion this effort. References and Readings Bidlingnmaier, W and AMaie, A. 1996. "Restults of a Parallel Logsdon, G. 1993. "Using Compostfor Plant Disease Control." Interlaboratory Test ofthe Analy/sis of Compost. " Compost Science Bio Cycle. October & Utilization 4:18-37. Lue-hing et al. 1994. Cited in NRC 1996 Chang, A.C., Albert L. Page, and TakashiAsano. 1995. "Developing NRC (National Research Couincil). 1996. Use of Reclaimed Water Human HeLltli-Related Cliemiical Guidelinies for Reclaimiied and Sludge in Food Crop Production. Washington, D.C.: WVastewater and Sewage Sludge Applications in Agriculture." National Academy Press. Genetva: World Health Organization. Pescod, M. B. 1992. -Wastewater Treatment and Use in Ernst, A.A. 1990. "A Review of Solid Waste Management by Agricul ture. " FAO Irrigationi and Drainage Paper 47. Rome: Composting in Enrope. Resource Conservation and Recycling Food andAgriculture Organization of the United Nations. 4:135-149. Obeng, L. A. and Frederick W Wright. 1987. "Integrated Resou rce Khlouri, N.,John Al. Kalbermatten, and CarlR. Bartone. 1994. "Thle Recoveny: The Co-composting of Domestic Solid and Human Reutseof Wastewaterin AgricIlture: A GuideforPlanners." Water Wastes." World Bank Technical Paper Number 57 and UNDP andSanitation Report 6. UNDP-Worid Bank Waterand Saniitation Project Management Report Numilber 7. Washington, D.C.: Program. Washington, D.C.: World Bank. World Bank. Agriculture T.,lm."l'. ' Notes provide up-to-date mtif-.-r-, a,:'i on selected topics to World Bank i':. f. S.,k7l: This Note was prepared by Tjaart .-hzll, S hrr 1'n . tt,n .2nd Paul F O'Connell ofthe World B.rik Toi. 'fbt.ri, ,pi.; ..fthisorother A.te.wi orto enquire about the series, plu-.: tall i202) 4 .:.: 14il6 Notes in this series include: Sustainable Agiculture National Seed Systems Reform of Seed Regulations Participatory Rural Assessment lIrl,;;,nl.flic.: l.-.-:lnQ.7lc .. iRural Development . . Irs. "'.,. l dZ I .S. l -j, I;.1,jf .. r,>., Simple Animal Health Techniques or . - Z l r t. r i Competitive Research Grant Systems Livestock Production and Sustainable Resource UTse Provson of Mineral Supplements Promoting Sustainable Agriculture Integrated Pest Management Tree Planting Technologies to Inprove Forestry Investments ['l / .Ttr.ra et .Atinial Health Services Cotton Production and Marketing Fundamentals World Fisheries Edited by Seth Beckerman, Business and Technical Communications, Pittsburgh, PA. Layout by Tony Condeflo, Condello Design, Pittsburgh. PA. page 4