Mathematical modeling to size anaerobic stabilization ponds intended for slaughterhouse wastewater treatment – the role of temperature and hydraulic retention time

Abstract

Slaughterhouse wastewater treatment is mainly performed using anaerobic stabilization pond systems. Despite some mathematical models for facultative ponds provided in the literature, no guidelines or mathematical equations exist to specifically size anaerobic ponds for this particular type of wastewater. In most cases, empirical knowledge or domestic wastewater treatment criteria are adapted for this purpose. This study proposes a mathematical model based on Bartha and Pramer's classical respirometry adapted to anaerobic conditions. Raw slaughterhouse wastewater was analyzed for biochemical oxygen demand (BOD) removal under steady-state conditions at varying temperatures and contact times. Results showed compatibility between the experimental conditions and data from anaerobic pond systems in operation, enabling the development of a mathematical model capable of correlating hydraulic retention time for BOD removal as a function of temperature. The model was validated using literature and field data, with a standard deviation of up to 7%, and can be used to design anaerobic stabilization pond systems over a wide temperature range (from 10 °C to 35 °C).