Chemical characterization of vermicompost of sewage sludge with different proportions of diatomaceous material

Abstract

The pursuit for waste recovery has been the best way to contribute to environmental sustainability. The mix of sewage sludge (SS) from Sewage Treatment Plant with diatomaceous material containing oil (DE), used as a filter in biofuel production, can form a substrate rich in minerals and organic matter through vermicomposting. Therefore, this study aimed to produce vermicompost using worms, Eisenia foetida, from a pre-compost (PC) of sewage sludge and garden pruning residues mixed with different proportions of DE in relation to PC: 0; 7.53; 15.06; 22.59; and 30.12% v/v. The design was randomized complete blocks with five treatment replicates. The chemical characteristics of the vermicompost were analyzed after a period of four months. The proportion of up to 30.12% v/v of DE met the criteria established for agriculture uses, registration and marketing of the product as organic compost in accordance with the Normative Instructions SDA 27/2006 and 25/2009 from the Ministry of Agriculture.