Bioconversion of organic waste by the year 2010: to recycle elements and save energy

The needs and problems existing in the field of cultivation systems and waste management concerning elements and energy, as well as pollution, health, environment, and economy are described. The lack of reproducible biofertilisers of high quality calls for an efficient use of organic waste as a renewable raw material. Each 100,000 inhabitants in Sweden generate organic waste with considerable economic values in terms of nitrogen, phosphorus, and potassium: US$ 600,000 from the organic fraction of municipal solid waste and US$ 900,000 from human excreta as liquid organic waste, meanwhile only US$ 160,000 is recovered from the sewage sludge after the wastewater has passed the wastewater treatment plants. Most of the existing systems for handling solid and liquid waste are of old-fashioned design and cause large losses of nutrient elements. Therefore, pollution of air, water, soil, and vegetation, mainly by emissions from organic uaste, continues. Bioconversion is microbial transformation and upgrading of various organic wastes to products of high value. The elements can be efficiently recycled in completely closed local bioconversion systems with subsystems for collection, pre-processing, processing, and application of end-products. Solid and liquid organic waste from the municipality can provide renewable raw material for manufacturing of reproducible biofertilisers and of biogas. Suggestions are made on how to improve the present situation by the re-orientation of technology. A scenario for bioconversion by the year 2010 is presented. (C) 1998 Elsevier Science B.V. All rights reserved.