Effect of sewage sludge on ecological sustainability of agricultural landscape of reclaimed solid waste landfill

Abstract

The study shows the possibility of using sewage sludge as an alternative to topsoil in reclamation of solid waste landfills to create an agro-landscape. Sewage sludge is an effective and economical solution for biological remediation of solid waste landfills contributing to land rehabilitation and ecosystem improvement. Sewage sludge contains valuable nutrients which make it suitable for agro-landscape formation. The studies on the environmental sustainability of the agro-landscape of a reclaimed solid municipal waste landfill in the City of Barnaul were conducted on the upper part of the landfill (33.7 ha). This landfill includes an upper area which was not used since 2004, and a lower area where filling with household waste is currently ongoing. Sewage sludge was used for biological remediation of the landfill. The field study was divided into three variants concerning the formation of 0.4 m arable layer of the agro-landscape: the use of fertile soil, a 1:1 mixture of fertile soil with sewage sludge and the use of sewage sludge alone. The studies conducted at the landfill have shown that the use of sewage sludge is safe; the content of heavy metals in soils and crops does not exceed the maximum permissible concentrations. High yields of crops as triticale, festulolium and awnless bromegrass were also observed when using sewage sludge which demonstrated its potential as a fertilizer. The maximum yield of awnless bromegrass, festulolium and triticale were observed in the variant with sewage sludge with nitrogen content of 0.23%, phosphorus - 2.38%, and potassium - 0.98%. The use of sewage sludge is an environmentally safe and economically beneficial way to restore disturbed lands.