Biological treatment of slaughterhouse wastewater using Up Flow Anaerobic Sludge Blanket (UASB) - anoxic-aerobic system

Abstract

Slaughterhouse wastewater (SWW) is heavily polluted wastewater. It contains high concentration of organic matters, suspended solids, nitrogen, phosphorus, oil and grease. Discharging of SWW without a proper treatment may cause many problems for the sewage network and municipal treatment plants. Thus, this study aims to investigate the treatability of SWW using a new treatment method consists of: Up-flow anaerobic sludge blanket (UASB) reactor, Anaerobic Anoxic and Oxic (A2/O), and Virginia Initiative Plant Method (VIP). The integrated process consists of UASB reactor, anoxic tank, aeration tank (UASBAA), and final settling tank, respectively.The value of the mixed liquor suspended solids (MLSS),and return activated sludge (RAS) flows from the final settling tank to the anoxic tank were 300% and 100% of the SWW inflow respectively. During the research the influence of HRT values in UASB, anoxic tank, and the aeration tank has been investigated on the efficiencies of pollutants removal that exist in SWW. The experiments proved that the suggested method achieved high removal efficiency of COD, BOD5, TS, TDS, TSS, NH4+, PO43−, and NO3−, respectively: 97.31%, 96.91%, 57.61%, 47.91%, 96.3%, 73.11%, 83.61%, 93.01%, at HRTs value of 24 h for UASB reactor; 12 h for anoxic tank: 24 h for aeration tank, and 3 h for final settling tank. The treated wastewater could be reused it in washing processes in the slaughterhouse or for the irrigation of industrial crops.