Combined slaughterhouse wastewater treatment via pilot plant chemical coagulation followed by 4th generation downflow hanging sponge (DHS-4G)

The article aimed to investigate performance and evaluation of combining chemical coagulation pretreatment unit with a pilot-scale fourth generation downflow hanging sponge (DHS-4G) for slaughterhouse wastewater (SWW) treatment. This combination of compact treatment technique was tested as a novel system for the treatment of SWW. A DHS-4G reactor with a capacity of about 100 liters was installed after a 1 m3 chemical treatment unit and operated under two different hydraulic retention times (HRT) namely 12 h and 8 h. The integrated treatment system gave reasonable organic and nitrogen removal efficiencies and the removal efficiency was 91%, and 87% for COD, 92%, and 88% for BOD and 94%, and 84% for TSS at HRT 12 h, and 8 h respectively. Profile analysis showed that most of solids and organic matter particles were entrapped in the top segments of the reactor, while in the middle part residual and soluble organic matter were biologically degraded and the bottom segment slightly removes small residuals and nitrogen compounds. Also, analysis of retained biomass indicated that sludge retention time (SRT) was 27 days, which indicated low sludge amount produced from the reactor. Accordingly, the use of the studied integrated treatment system is very effective in terms of treatment cost and quality as it achieved required treatment in shorter time and minimum requirements for construction and operation.