Treatment of Swine Wastewater Using Microalgae Book in Scopus uri icon

abstract

  • Swine production has considerably expanded worldwide resulting in a significant increase in wastewater generation. Swine wastewater (SW) contains high levels of organic matter, nitrogen, phosphorus, and other pollutants. Hence, disposal of inadequately treated SW poses serious hazards to the environment and human health. Stabilization ponds and anaerobic digestion (AD) are commonly employed systems for SW treatment, but the resulting effluents contain high nutrient concentrations and do not meet the quality standards required for discharge into water bodies. Microalgae-based wastewater treatment (MbWT) has received interest as an alternative, or complementary, treatment method that allows the recovery of nutrients and organic matter from SW while simultaneously fixing carbon in the form of valuable biomass and producing microalgal value-added products through a circular bioeconomy approach. Nevertheless, several challenges must be overcome to increase the efficiency of MbWT to treat SW. The nutrient concentration of SW is critical for enhancing microalgal biomass production and pollutant removal through MbWT. Nutrient addition or intensive dilution are typically used to achieve the desired nutrient proportions and to decrease turbidity, allowing light penetration for microalgal growth. However, these strategies may compromise the sustainability of MbWT by increasing overall costs. Hence, MbWT has been preferred as a secondary treatment for SW following primary treatments, such as AD. Yet, the anaerobically digested swine wastewater (ADSW) is often still rich in organic matter, nitrogen, and phosphorus, and displays high turbidity and microbial load, thus requiring flocculation and ultraviolet (UV) treatment before coupling with MbWT. The implementation of a complete treatment process sequentially involving AD and MbWT can help livestock producers comply with environmental regulations by lowering greenhouse gas emissions and simultaneously generating value-added products. This chapter summarizes the use of microalgae for the treatment of SW as a primary treatment and as a secondary, tertiary, or even quaternary treatment when coupled with other operation units, like AD, flocculation-coagulation, and UV treatment. © 2024 WILEY-VCH GmbH, Boschstra¿e 12, 69469 Weinheim, Germany.

publication date

  • January 1, 2024