Production of vermicompost from agricultural wastes and sewage sludge

Abstract

At the beginning of the 21st century, the problems of soil fertility restoration and utilization of production and consumption wastes have become particularly topical ones. Failure to solve at least one of the problems puts mankind on the brink of survival. The reason is sharply increased natural-climatic and technogenic load, potentiation of their negative effects which led to significant soil degradation and threat to environmental safety. At the same time, production and life activity wastes contain millions of tons of organic matter and trace elements excluded from the natural cycle. The research goal was to develop an environmentally friendly and low-cost technology for the utilization of organic wastes of animal, vegetable and municipal origin in order to obtain complex organomineral fertilizers. Vermicomposting of animal (cattle manure) and vegetable (winter wheat straw) wastes as well as sewage sludge from municipal wastewater treatment plants by using worms of the Lumbricidae family allowed not only utilizing toxic wastes but also obtaining an environmentally friendly organomineral fertilizer - biohumus which use showed the ability to improve crop growth. The biohumus obtained by vermicomposting of animal and plant wastes contained the following: organic matter weight percentage - 85%; total nitrogen - 0.23%; phosphorus (gross content) - 0.14%; manganese - 37.87 mg kg; copper - 11.45 mg kg; zinc - 31.45 mg kg; lead - 2.24 mg kg; arsenic - 1.22 mg kg; cadmium - 0.01 mg kg. Vermicomposting of sewage sludge: organic matter weight percentage - 21.35%, total nitrogen - 0.30%; phosphorus (gross content) - 4.36%; manganese - 5.4 mg kg; copper - 47.0 mg kg; zinc - 504.0 mg kg; lead - 70.0 mg kg; arsenic - 2.6 mg kg; cadmium - 2.9 mg kg; chromium - 1.75 mg kg. The use of low-cost vermicomposting technology makes it possible not only to process production and life waste, but also to obtain complex organomineral fertilizers suitable for agricultural production at various levels.