Poultry Slaughterhouse Wastewater Remediation Using a Bio-Delipidation Pre-Treatment Unit Coupled with an Expanded Granular Sludge Bed Reactor

Moses Basitere,Mahomet Njoya,Phumeza Akhona Dyosile,Ephraim Kaskote,Seteno Karabo Obed Ntwampe,Cebisa Thabo Mdladla

doi:10.3390/pr9111938

Abstract

The treatment of poultry slaughterhouse wastewater (PSW) with an Expanded Granular Sludge-Bed Bioreactor (EGSB) is hindered by the washout of activated sludge, and difficulties associated with the operation of the three-phase separator and the determination of the optimum up-flow velocity for sludge-bed fluidization. This results in a poor reactor functionality, and thus a poor performance due to pollutants such as fats, oil and grease (FOG) in the PSW being treated. Hydrolyzing the FOG content with a bio-delipidation, enzyme-based agent in a pre-treatment unit would significantly improve the effectiveness of the primary PSW treating system, i.e., the EGSB. In this study, PSW was pre-treated for 48 h with a biological mixture containing bioflocculants and bio-delipidation constituents. The pre-treated PSW was further treated in an EGSB. The PSW FOG, total chemical oxygen demand (tCOD) and total suspended solids (TSS) content were determined to assess the effectiveness of the pre-treatment process as well as to observe the remedial action of the combined pre-treatment-EGSB system. An increased treatment efficacy was noted for the combined PSW treatment system, whereby the tCOD, FOG and TSS removal averaged 76%, 88% and 87%, respectively. The process developed is intended for micro, small and medium poultry slaughterhouses.

Highlights

Poultry slaughterhouse wastewater (PSW) contains a high concentration of organic matter and other pollutants such as fats, oils and grease (FOG), and colloidal particles, as well as soluble proteins from the slaughtering and cleaning activities from the poultry slaughterhouses
This study evaluated how this pre-treatment process, combined with an Expanded Granular Sludge-Bed Bioreactor (EGSB), could improve the overall efficiency of poultry slaughterhouse wastewater (PSW) treatment at a high throughput, small plant footprint, and low cost
The anomaly Processes 2021, 9, x FOR PEER REVIEdWetection process was used to identify the outliers from their relevant distribution7 aonf d18to replace them by the median value of the corresponding distribution

Summary

Introduction

Poultry slaughterhouse wastewater (PSW) contains a high concentration of organic matter and other pollutants such as fats, oils and grease (FOG), and colloidal particles, as well as soluble proteins from the slaughtering and cleaning activities from the poultry slaughterhouses. Several treatment processes have been employed by the poultry industry to meet the regulatory PSW discharge standards set by regulatory bodies. These treatment processes include biological, physical, and chemical treatment processes, with anaerobic digestion (AD) being the primary treatment technology of choice. AD is noted to be suitable for effectively treating high-strength, industrial wastewater while providing energy generation, low sludge output and, when stabilized, provides an effluent with a consistent concentration of monitored parameters when compared with aerobic and physicochemical methods. Hydrolysis is noted as one of the processes that limits the stages of wastewater treatment, resulting in the slow degradation rates by the sludge in an AD [7]. The introduction of hydrolytic bacteria and their constituents in the pre-treatment step, i.e., microorganisms or biomolecules which can convert carbohydrates even partially, hydrolyzing FOG, can improve the sludge performance for the treatment of wastewaters such as PSW [9]

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