Optimization of waste stabilization pond performance for piggery waste treatment using response surface methodology

Benjamin Ugochukwu Okoro,Nkiruka E Nwaiwu

doi:10.5755/j01.erem.73.2.17696

Abstract

The treatment of piggery wastewater using the waste stabilisation pond was studied in a semi- continuous process. Optimization of Chemical Oxygen Demand (COD) removal was conducted using response surface methodology where pH, temperature and retention time were independent variables. The Box-Behnken design approach, an experimental design was used for creating set of experimental runs needed for optimizing COD removal. An attempt was also made to optimize COD removal by reducing hydraulic retention time while maintaining pH and temperature of a defined range. Analysis of variance (ANOVA) was conducted on model terms and the results revealed that the coefficient of determination value (R2) of % COD removal was 0.86, 0.88, and 0.86 for the anaerobic, facultative and maturation pond respectively. Highest desirability was obtained for optimum COD % removal and this was 0.89, 0.89 and 1.0 for ponds.The waste stabilisation pond treatment process can effectively be improved on for piggery wastewater treatment.DOI: http://dx.doi.org/10.5755/j01.erem.73.2.17696

Highlights

Wastewater is basically water supply that has been fouled by various users, and it is potable water that contains pollutants (Canter and Negid, 2000)
Further analysis was carried out to determine the most optimum range of variables; the optimum range for the detention time was gotten as 15 days for the anaerobic pond and 20 days for the facultative and the maturation ponds, pH as 7.1, and temperature as 30°C and 31°C, respectively
Optimum values of model variables utilised for maximum COD removal efficiency in the anaerobic, the facultative and the maturation ponds

Summary

Introduction

Wastewater is basically water supply that has been fouled by various users, and it is potable water that contains pollutants (Canter and Negid, 2000). This study investigated the removal of COD from piggery wastewater in a waste stabilisation pond by employing the use of the Box-Behnken design of response surface methodology. This study evaluates the various influences of pH, temperature and detention time (independent variables) on COD of piggery wastewater (dependent variable). A field scale prototype of a WSP was designed and evaluate relationships and optimise the removal of rescaled to a laboratory-scale model using Frou- COD from piggery wastewater using a semi-contide number and dimensional analysis. Significant lack of fit value of 0.0006, 0.0001 and 0.0002 for the anaerobic, the facultative and the maturation pond, respectively, may be attributed to variations in the waste stabilisation ponds hypothesised model (Virkutyte et al, 2010). ANOVA test for the COD removal efficiency for the anaerobic, the facultative and the maturation ponds

Model term

Optimisation analysis

Conclusions