Cost Effective Management of Confectionery Industrial Wastewater

Abstract

The goal of this study is the management of wastewater generated from a confectionery factory located at El-Obour Industrial City, Egypt. The factory produces confectionery products, chocolates, eastern and western bakery products. Laboratory analysis of raw wastewater showed high pollution load with an average COD and BOD5 of 5396 mg/L and 2526 mg/L. Most of the organic matter was present in soluble form since TSS was 908 mg/L on average. The raw wastewater showed limited nutrients concentration with average of 55 mgTKN/L and 3.3 mgTP/L. Conventional activated sludge and UASB reactors were separately investigated as treatment technologies. Aerobic sequential batch reactor (SBR) indicated hydraulic retention time (HRT) 12 hr. to produce effluent complying with the regulatory standards. Continuous activated sludge operated at 9.3kg COD/m3.d and temperature range of 20-35 ◦C showed good effluent quality with removal efficiencies of 96%, 96% and 98% for COD, BOD5 and TSS, respectively. Two-stage UASB reactor working at COD loading rate of 4.7 kg COD/m3.d and same temperature’s range, showed averages of removal of 82%, 81%, 95%, and 85% of COD, BOD, TSS and oil&grease, respectively to produce effluent complying with the regulatory standards. The activated sludge unit provided better effluent quality than the two-stage UASB reactor. However, the two-stage UASB reactor was selected as a sustainable and cost-effective technology for the treatment.