ECOLOGICAL AND MICROBIOLOGICAL ASSESSMENT OF SEWAGE SLUDGE OF WASTE TREATMENT PLANTS IN THE CITY OF ODESA

Abstract

Objective. Investigate the number of microorganisms – representatives of various ecological trophic groups in mechanically dewatered and naturally disinfected sewage sludge (SS) of the biological sewage treatment plants (BSTP) “Pivnichna” and “Pivdenna” of the City of Odesa to determine their suitability for microbiological parameters for use as fertilizers in agriculture.
 Methods. Microbiological, statistical.
 Results. It was established that SS of BSTP “Pivdenna” and “Pivnichna” in the City of Odesa, bacteria that consume organic and mineral nitrogen compounds, phosphate-mobilizing microorganisms, are actively developing, due to the presence of the corresponding trophic substrates. By the number of ammonifiers, microorganisms that consume mineral compounds of phosphorus and bacteria capable of hydrolyzing the organophosphates, spore microorganisms, the waste is inferior to traditional organic manure – animal manure. The functional orientation of microbiological processes in the studied substrates is determined on the basis of the obtained data, calculations of the mineralization-immobilization factors and the oligotrophic index. The parameters of the mineralization-immobilization factors (0.04-0.2) in the SS indicate the predominance of synthesis processes over the destruction of organic matter. The oligotrophic index (an indicator of the supply of substrates with easily digestible nutrients) shows insignificant content of nutrients available for microorganisms in SS from BSTP “Pivnichna” (OI = 1.0) and a high level of supply with nutrients of SS from BSTP “Pivdenna” (OI = 0.1). In general, according to microbiological parameters, investigated SS are suitable for use as fertilizing substrates in agriculture.
 Conclusion. Taking into account the obtained data and taking into account the results of previous studies on the compliance of SS with sanitary regulations, it can be considered that the use of SS as fertilizers will have a positive effect on the functioning of agrocenoses.