COD fractions changes in the SBR-type reactor treating municipal wastewater with controlled percentage of dairy sewage

Abstract

Abstract. The aim of study was to investigate the influence of percentage of dairy wastewater in the municipal wastewater on the changes of COD fractions during the cycle of SBR-type reactor. The scope of the research included physicochemical analyses of municipal wastewater without dairy wastewater, dairy wastewater, mixture of municipal and dairy wastewater as well as treated sewage. Both the concentrations and the proportions between COD fractions changed in the SBR cycle. In raw municipal and dairy wastewater -XS, insoluble hardly bio-degradable fraction of COD dominated (49.6 and 64.5% respectively). In treated wastewater SI, COD for dissolved compounds that are not biologically decomposed (inert) (from 62.1 to 74.6%) dominated, while XS fraction was from 19.1 to 24.4%. The consumption rate of organic compounds depended on the type of COD fraction, SBR cycle phase and the percentage of dairy wastewater. The highest rates of organic compounds consumption were noted in the phase of mixing. In the case of fraction SI, no differences in concentration in the SBR cycle time, were found. Concentration of COD in treated wastewater was from 34.8 to 58.9 mgO2·L -1 (efficiency wastewater treatment from 96.0 to 98.6%).

Variability of dairy wastewater characteristics in Piatnica – one of the largest and most advanced milk processing plants in Poland

“…333,000,000 dm 3 •year -1 912,329 dm 3 •day -1 cottage cheese (natural, with friut, vegetables, honey), drining milk (2-3.2% fat, free of lactose, organic), cream (10-42% fat), curd (natural, with vegetables, spices), yogurt (natural, with fruit, Greek and Icelandic type), mascarpone, butter, kefir (0-2% fat), sour milk Dairy sewage generated in production processes flows into the industrial wastewater treatment plant, the extension and modernization of which ended in 2012.…”

“…Dairy industry is one of the biggest sources of industrial wastewater in Europe and the problem of dairy sewage treatment is not completely solved, especially in plants of medium and small milk processing capacity. Dairy wastewater is characterized by high load of COD and BOD5 [1][2][3]. This includes dissolved and crystallized fats (glycerol, triglycerides), sugars (lactose) and protein (casein) in colloidal form and as clots; shares of these substances can vary.…”

“…Quantity of dairy sewage is characterized by high seasonal variations (20% increase in spring and summer). Additional oscillations relate to the daily and hourly shift work dependent on the size, production profile, and shifts at milk processing plant [1][2][3][4][5][6][7][8][9][10][11][12][13]. Dairy wastewater is normally treated by physical, biological and chemical processes and the various possibilities are presented in fig.…”