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waste utilisation
waste water collection system and waste water treatment plant
waste water treatment by living machines
wastewater
the spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter.
zero-waste agriculture (ZWA)

zero waste agriculture is a type of sustainable agriculture which optimizes use of the plants, animals, bacteria, fungi and algae, to produce biodiverse-food, energy and nutrients in a synergistic integrated cycle of profit making processes where the waste of each process becomes the feedstock for another process.

The biogas digester is the heart of most zero waste agriculture (ZWA) systems. It is a 3000 year old anaerobic digestion process, where all organic waste can be converted into biogas, which is used for heating. The residue of anaerobic digestion is utilised for algae production, and agae for growing fish. Microalgae can alternatively be utilised for biodiesel-production. In sunny climates, a one hectare zero waste farm can produce over 1000 litres of oil in a year from the chlorella microalgae grown on biogas digester effluent in a 500 squermeter shallow pond. The nutritive high protein waste from the oil extraction process can be used as animal feed.

The water recycling can also be made complete in such an agricultural system: all the used waters can be naturally treated and reused.

Zero waste agriculture combines ecological or organic farming practices with a complete waste utilisation system.

Zero waste agriculture is optimally practiced on small 1−5 ha sized family owned and managed farms and it complements traditional farming & animal husbandry as practiced in most third world communities. Zero Waste Agriculture also preserves local indigenous systems and existing agrarian cultural values and practices.

Zero waste agriculture presents a balance of economically, socially and ecologically benefits as it:

  1. optimizes food production in an ecological sound manner
  2. reduces water consumption through and recycling and reduced evaporation
  3. provides energy security through the harvesting of biomethane (biogas) and the extraction of biodiesel from micro-algae all of which from as a by-products of food production
  4. provides climate change relief through the substantial reduction in greenhouse gas emissions from both traditional agriculture practices and fossil fuel usage
  5. reduces the use of pesticides through biodiverse farming.

ZWA is a target of the agrarpolitics in many third countries, such as Brazil, India, China, Columbia and South Africa.

Source: http://en.wikipedia.org/wiki/Zero_waste_agriculture