Characteristics of Wastewater from Animal Rendering Plant

Abstract

In this study, wastewater originating from a post-slaughter waste management plant, the main activity of which is the recovery of other than hazardous wastes of animal origin and wastes from the agri-food processing, were analyzed. The main substrates processed in the installation include post-slaughter wastes and wastes from the agri-food processing, like e.g.: waste animal tissue, raw materials and products unsuitable for consumption and processing originating from the food, dairy, bakery and confectionery industries, sludge from the onsite wastewater treatment plant, unusable dietary fats, cooking oils and fats, and biodegradable kitchen waste. The above-mentioned wastes are recovered and processed into meat-bone meal, blood meal, feather meal as well as technical fat. The wastewater was characterized by a high concentration of organic matter (COD from 20 345 to 66 260 mg O2/dm 3 ), total suspended solids (from 1068 to 4336 mg/dm 3 ), and fats (from 1186 to 2244 mg/dm 3 ). Phosphorus concentration in raw wastewater ranged from 75 to 230 mg P/dm 3 , that of total nitrogen from 496 to 910 mg N/dm 3 , and that of ammonia nitrogen from 450 to 846 mg N/dm 3 . The process line of the onsite wastewater treatment plant included: rotary screen, floatation--flocculation station (agents and procedures aiding the process: PIX coagulant, pH adjustment with soda lye, polyelectrolyte), aerobic bioreactor, and ultrafiltration station. The excess sludge from the bioreactor is dewatered on a filtration press and collected by an external company as a waste product. Removal effectiveness reached 99.7% for organic matter, 98.5% for total phosphorus, 95.2% for total nitrogen, 98.5% for ammonia nitrogen, and 98.9% for suspended solids. The total effectiveness of the first two stages of the treatment process (screening on rotary screens and wastewater treatment via floatation and flocculation) exceeded 50% in the case of most of the contaminants (except for total nitrogen with effectiveness accounting for 46%). The highest total effectiveness of the first two stages of the treatment process, reaching over 90%, was noted in the case of fats. Concentrations of contaminants in the treated wastewater did not exceed the permissible values, stipulated in the integrated permit.Keywords: slaughterhouse waste, rendering plant, wastewater quality, wastewater treatment WprowadzenieSektor mięsny wytwarza duże ilości ścieków w związku z ubojem zwierząt i czyszczeniem obiektów rzeźni i przetwórstwa mięsnego. Przemysł mięsny wykorzystuje 24% wody zużywanej przez przemysł spożywczy i aż do 29% wody

Evaluating Potential for Using Municipal Sewage Sludge in the Rehabilitation of Ground Degraded by the Sodium Processing Industry

“…3.5%. Therefore, the content found in the present study can be considered low, and, surprisingly, is more similar to values found in sludge from meat processing wastewater (Rodziewicz et al 2017 ). When analyzing the content of selected metals in the studied sewage sludge, the following mean values were found (in mg/kg dry weight): Cd 6, Cr 75, Cu 220, Ni 17, Pb 173, and Zn 1086 (Table 1 ).…”