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This paper assesses the performance of an integrated multistage laboratory-scale plant, for the treatment of poultry slaughterhouse wastewater (PSW). The system was comprised of an eco-flush dosed bio-physico pre-treatment unit for fats, oil, and grease (FOG) hydrolysis prior to the PSW being fed to a down-flow expanded granular bed reactor (DEGBR), coupled to a membrane bioreactor (DEGBR-MBR). The system’s configuration strategy was developed to achieve optimal PSW treatment by introducing the enzymatic pre-treatment unit for the lipid-rich influent (PSW) in order to treat FOG including odour causing constituents such as H2S known to sour anaerobic digestion (AD) such that the PSW pollutant load is alleviated prior to AD treatment. This was conducted to aid the reduction in clogging and sludge washout in the DEGBR-MBR systems and to achieve the optimum reactor and membrane system performance. A performance for the treatment of PSW after lipid reduction was conducted through a qualitative analysis by assessing the pre- and post-pre-treatment units’ chemical oxygen demand (COD), total suspended solids (TSS), and FOG concentrations across all other units and, in particular, the membrane units. Furthermore, a similar set-up and operating conditions in a comparative study was also performed. The pre-treatment unit’s biodelipidation abilities were characterised by a mean FOG removal of 80% and the TSS and COD removal reached 38 and 56%, respectively. The final acquired removal results on the DEGBR, at an OLR of ~18–45 g COD/L.d, was 87, 93, and 90% for COD, TSS, and FOG, respectively. The total removal efficiency across the pre-treatment-DEGBR-MBR units was 99% for COD, TSS, and FOG. Even at a high OLR, the pre-treatment-DEGBR-MBR train seemed a robust treatment strategy and achieved the effluent quality set requirements for effluent discharge in most countries.

Poultry slaughterhouse wastewater contains high concentrations of chemical oxygen demand (COD), total suspended solids (TSSs), fats, oil and grease (FOG), proteins and carbohydrates. It is important that the wastewater is treated to acceptable environmental discharge standards. In this study, the poultry slaughterhouse wastewater (PSW) was treated using two-stage processes consisting of a biological pre-treatment using a biodegrading agent (Eco-flushTM) coupled with a down-flow expanded granular bed reactor (DEGBR). The results showed that the biological pre-treatment was observed to be highly effective for removal of FOG, COD and TSS with a removal efficiency of 80 ± 6.3%, 38 ± 8.4% and 56 ± 7.2%, respectively. The DEGBR showed a stable performance in terms FOG, COD and, TSS removal, with average removal efficiencies of 89 ± 2.8%, 87 ± 9.5%, and 94 ± 3.7%, respectively. The overall removal rate performance of the integrated system of pre-treatment and DEGBR in terms FOG, COD and TSS, was 97 ± 0.8%, 92 ± 6.3% and 97 ± 1.2%. Furthermore, the average volatile fatty acid/alkalinity (VFA/Alkalinity) ratio of 0.2 was reported, which indicated that the DEGBR was stable throughout the operation.