Enhancing anaerobic digestion efficiency in dairy waste water treatment: a comprehensive review of enzyme-based pre-treatment by microorganisms in South Africa

Abstract

The escalating global demand for dairy products due to population growth has led to increased production in the dairy industry, resulting in a significant rise in wastewater generation. This wastewater, laden with contaminants such as fats, oils, and greases (FOGs), biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, and phosphorus, poses a threat to freshwater sources. Anaerobic digestion (AD) is considered the optimal treatment method for dairy wastewater, but the high-fat content poses challenges like reactor clogging. To overcome this, various authors propose and implement an enzymatic pre-treatment strategy that improves FOG and organic content removal, increases biogas production, and addresses economic and environmental concerns. Despite the proven efficacy of enzymatic pre-treatment, a significant drawback is the associated cost. However, it remains a promising strategy for enhancing the biodegradability of complex organic compounds in dairy effluents. This review delves into the crucial role of enzyme-producing microorganisms in enhancing AD efficiency for dairy wastewater treatment, emphasizing their potential benefits and addressing the economic and environmental considerations associated with this approach. HIGHLIGHTS Enzymatic pre-treatment coupled with an AD produces a high-quality effluent.; Enzymatic pre-treatment is effective in the reduction of SS, FOGs in DWW but the cost implication makes it less appealing.; Recommendations have been offered for promising research areas in enzymatic pre-treatment with the use of new enzymes.;

Keywords

• biological
• dairy
• enzymes
• fog
• pre-treatment
• wastewater