Biological treatment of dairy wastewater by a sequencing batch flexible fibre biofilm reactor

Abstract

Biological treatment of dairy wastewater was investigated using a laboratoryscale aerobic sequencing batch flexible fibre biofilm reactor (SBFFBR). The SBFFBR system was modified from a typical sequencing batch reactor (SBR) system by using eight simple flexible fibre bundles with a very high specific surface area, which served as a support for bacteria. The 8 litre Perspex flexible fibre reactor was developed for efficient and cost effective treatment of milk industry effluent. A fine bubble air diffuser supplied oxygen in the reactor. Raw dairy wastewater was fed to the reactor under different dilutions. The reactor was operated under different influent COD concentrations (610, 2041 and 4382 mg/l) and constant hydraulic retention times (HRT) of 1.6 days. The results have shown successful applicability of the SBFFBR system, indicating high COD removal efficiencies between 89. 7% and 97% at average organic loading rates of 0.42 kg COD/m3. d and 2.74 kg COD/m3.d, respectively. Easy operation, low cost and minimal sludge production were some of advantageous of the process.