Evaluation of the optimum conditions of an anaerobic Down-flow Stationary Fixed Film reactor for swine wastewater treatment

Abstract

The Down-flow Stationary Fixed Film (DSFF) reactor is a downstream anaerobic reactor combined with a fixed layer of adhesive media that is capable of handling large organic loads, has cheap investment costs, and has a shorter treatment time than other conventional anaerobic technologies. In this study, the DSFF reactor was used to investigate its potential to remove contaminants from swine wastewater. The optimal operating conditions of the DSFF reactor including hydraulic retention time (HRT), organic concentration, and nutrient ratio were investigated. The obtained results showed that the COD removal efficiency increased from 50% to 79.721% when the influent COD enhanced from 500 to 3000 mg/L. The COD removal efficiency was 85.66%, 61.71% and 50.81% at three different nutritional ratios of C/N/P:250/1.5/1, C/N/P:250/7.5/1, and C/N/P:250/7.5/0.2, respectively. The overall results revealed that the optimal HRT is 12 hours, the optimal COD concentration is between 2000 mg/L and 3000 mg/L, and the optimal nutrient ratio is C/N/P:250/1.5/1. The DSFF reactor effectively manages BOD and phosphorus removal while handling a range of contamination levels in swine wastewater. Furthermore, there is no significant sludge loss and the operation mode is simple. This reactor is potentially appropriate for implementation in pig farming households.