A moving bed biofilm reactor coupled with an upgraded nanocomposite polyvinylidene fluoride membrane to treat an industrial estate wastewater

Abstract

Industrial wastewaters threaten the environment potentially, however by implementing effective treatment techniques, industrial wastewater could be treated aiming to water reuse for various applications. Thus, in the present study a moving bed biofilm reactor (MBBR) followed by an efficient nanocomposite polyvinilyden fluoride (PVDF) membrane was operated to obtain high-quality effluent from an industrial estate wastewater. Hydraulic retention time (HRT) of 5–15 h, air flow rate (AFR) of 1–4 l/min, and filling ratio (FR) of 30–70% have been chosen as three independent variables to analyze, model, and optimize biological treatment process. Soluble COD (sCOD) and total nitrogen (TN) removal efficiencies were found to be 93.37 and 27.61 %, respectively, at the optimum condition with HRT of 10 h, AFR of 2 l/min, and FR of 70%. To generate high-quality treated wastewater, MBBR effluent was passed through an optimal amended nanocomposite PVDF membrane. To tailor PVDF membrane, tannic acid decorated by caffeine (caffeine-TA) was incorporated in the matrix of PVDF membrane in various loadings (0.1, 0.5, and 1 wt%). 0.5 wt% of the additive was found to be the optimal loading owing to an upsurge in the pristine membrane’s pure water flux (PWF) from 32.64 to 48.98 kg/m2.h, and a drop in the pristine’s water contact angle from 68.42° to 51.73° and also a 20% rise in the pristine’s flux recovery ratio (FRR). Also, microbial test was negative and turbidity was below 1 Nephelometric Turbidity unit (NTU) after filtering the MBBR effluent. As a conclusion, the combination of the operated MBBR and the optimally ameliorated PVDF membrane could be considered as a promising suggestion to produce high-quality effluent from industrial wastewaters.