World Commission on Environment and Development in "Our Common Future"(Brundtland, 1987) defines the sustainable development as "a strategy that meets theneeds of the present without compromising the ability of future generation to achievetheir own requirements". Developing countries have to face double challenge forsustainable agriculture, firstly to increase food production and secondly to maintain ifnot to improve resource and environmental quality. EI Bassam (1998) reported thatper capita land required for food, oxygen and water security are 15-20 m2, 6-10 m2and 3-6 m2, respectively under controlled conditions. This could be achieved ifinnovative technical means and efficient material recycling systems are implemented.One of the biggest problems that agriculture will face in the years to come will be ofavailability of good quality water for irrigation purpose. The water available and theultimate irrigation potential do not level up. Under ground water contributes to morethan 70% of the total ultimate potential through minor irrigation. To cater to thedepletion of good quality water alternate sources are being looked into.Domestic effluent or waste water generated from urban areas is generally beingdisposed off into the existing natural streams or water bodies. Rivers passing from thebig cities have become heavily polluted and need immediate attention. Huge quantityof waste water is being generated in cities every day. Domestic waste water may beused as an alternate resource for irrigation. Only a fraction of this is being treated atpresent and reused for various purposes. Waste water reuse may have one orcombination of several objectives such as: 1. Use of a reliable water source forirrigation, 2. Fertilization of infertile lands; 3. Re-use of scarce water resources; 4.Safe disposal of waste water to avoid contamination; and 5. Ground water recharge.The population of the countries and size of the cities are growing rapidly. Accordingto a survey, more than 50% of the population will be in urban areas by 2050 againstpresent level of 30%. Domestic and industrial sectors use 15% of the present waterresources which will grow to 30% by the year 2050. Waste water generated fromconcentrated population will increase in similar proportion. Waste water may be usedas water resource for agriculture and aquaculture. Domestic waste water need to bediverted for irrigation purposes. Typical waste water is composed of 99.5% to 99.9%of water and remaining percentage is composed of inorganic and organic solids, colloids and dissolved solids, which contain major nutrients and trace elements.Average annual application of waste water may correspond to about 300 kg/ha.N and50 kg/ha P. Waste water irrigation in over-exploited ground water areas may arrestthe decline of ground water table. Growing pressure on available fresh qualityirrigation water resources and increasing awareness to environmental issues amonghuman masses will force researchers and planners to design waste water disposalsystem in such a way that it could be safely made available to its users. This is theright time to give a rational thought in this direction to make the waste water a safewater resource for irrigation and make agriculture sustainable for the future.
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