Title : Enzymatic pre-treatment of red meat abattoir effluent to reduce fat, oil, and grease while enhancing biogas generation
Abstract:
The discharge of untreated abattoir effluent significantly endangers the environment due to its organic load and concentrations of fats, oils, and grease (FOG). This study examined the impact of enzymatic pre-treatment, leveraging a commercial biological product (Eco-flush™), on the hydrolysis of FOG in red meat abattoir effluent. This procedure aims to enhance effluent quality and increase bioenergy output during anaerobic digestion (AD). Characterisation of the raw effluent revealed a chemical oxygen demand of 1818 mg/L, FOG at 2593 mg/L, turbidity measuring 592 FAU, ammonia concentrations of 155 mg/L, and a low concentration of dissolved oxygen of 1.78 mg/L. The enzymatic treatment of the wastewater significantly influenced the pollutant levels of the effluent by effectively hydrolysing FOG. Maximum levels of hydrolysed FOG and maximum soluble chemical oxygen demand (sCOD) were established using enzyme dosages varying from 0.25% to 1.00% (v/v). Our investigation demonstrated that the optimal hydrolysis of FOG occurred at an enzyme concentration of 0.5% (v/v), resulting in the extraction of 17174 mg/L from the effluent solution as compared to the initial 1818 mg/L, which was readily extracted prior to pre-treatment. Exceeding the optimum enzyme concentrations to 0.75% and 1.00% (v/v) resulted in decreased process efficacy, presumably owing to enzyme saturation and process inhibition. The enzyme-assisted pre-treatment adversely affected ammonia and turbidity levels in the effluent, leading to an increase; however, the pre-treated effluent yielded improved biogas and biomethane production during AD, with biogas increases of up to 159% and methane purity of 70%.
