Известия Томского политехнического университета: Инжиниринг георесурсов (Jun 2023)
SEWAGE SLUDGE FORMATION CHARACTERISTICS AND ENVIRONMENTAL STATUS OF THE INDUSTRIAL WASTEWATER CHANNEL
Abstract
Link for citation: Ushakova E.S., Belkin P.A., Drobinina E.V. Sewage sludge formation characteristics and environmental status of the industrial wastewater channel. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 6, рр.75-91. In Rus. The relevance of the research is determined by the need to obtain baseline data for the safe handling of sewage sludge produced resulting the sedimentation of the suspended solids from wastewater of industrial channel. The main aim of the research is to characterize the chemistry of wastewater and sewage sludge in an industrial channel, and to determine the environmental status and possible options for handling sewage sludge. The object of the study is the industrial channel or sewage transport channel of the city Berezniki (Perm Krai, Russia). This channel is an artificial waterway with a total length of 8,9 km. It was formed in the middle of the last century with the aim of protecting the industrial area of the city Berezniki from waterlogging and the organization of unified urban industrial canalization. At present, the channel accepts industrial wastewater from a number of plants, as well as wastewater from the city treatment facilities and storm water runoff. A treatment plant operates at the mouth of the channel, after which the treated water enters the Kama reservoir. The research methods included determination of major ions and trace element of wastewater and sewage sludge of industrial channel using capillary electrophoresis together with inductively coupled plasma mass spectrometry (ICP-MS). Additionally, microbiological and radiological parameters of the sewage sludge were determined using the methods established by the environmental legislation of the Russian Federation. In this study the contamination degree of wastewater and sewage sludge was assessed using quality guidelines, geochemical and environmental indices. To understand environmental status and geochemical assessment of sewage sludge of the industrial channel the major ions and trace element contamination of the samples were assessed based on potential ecological risk index, geoaccumulation index, sediment quality coefficient. Results. The sewage sludge samples are characterized by a moderate content of toxic elements, are safe in terms of radiation and show no signs of bacterial contamination. However, the contamination degree of sewage sludge increases significantly to the lower part of the industrial channel. Sewage sludge in the lower part of the industrial channel (in before treatment plant) is significantly enriched in all studied trace elements in comparison with the upper continental crust. It was found that the degree of contamination by Igeo in the industrial channel ranged from heavily contaminated to extremely contaminated. The highest values of the index of geoaccumulation (Igeo>1000) were found in the lower part of the industrial channel. The values of the index of potential ecological risk in the industrial channel changed from low to moderate. The average value of the sludge quality factor shown highly contamination of sludge in the downstream, while in the middle stream the sewage sludge belongs to uncontaminated. A comparative analysis of international standards for acceptable limits of heavy metals in sewage sludge for agricultural use was carried out. The possible uses of sewage sludge accumulated in the industrial channel in the city of Berezniki were assessed. The presence of extremely high concentrations of chlorides and trace elements in sewage sludge limits its recycling. This determines the need to further search for environmentally disposal and recycling routes for the accumulated sewage sludge. The most promising trend of recycling the accumulated sludge from the Berezniki industrial channel may be the development of technologies for the production of construction materials.
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