نفيسه جامي الاحمدي

   In the first stage of this study, high-rate simultaneous carbon, nitrogen, phosphorus (CNP) removal from soft drink wastewater (SDW) in a jet loop-air lift membrane bioreactor was modeled and optimized. For this purpose, the effect of four independent factors including hydraulic retention time (HRT) (8-16 h), anaerobic volume to total working volume ratio (VAn/VT) (0.04-0.12), air flow rate (AFR) (3.5-5.5 l/min), and influent nitrogen concentration (150-300 mg/l) on the bioprocess performance were evaluated. Chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies were 97%, 63%, and 81%, respectively, at optimum conditions (HRT: 14h, VAn/VT: 0.06, AFR: 5.5 l/min, influent nitrogen: 225 mg/l). As a result in this step, it can be noted that HRT and AFR had direct positive effect on biological CNP removal while VAn/VT had direct negative effect. Influent nitrogen concentration had no direct effect on COD and TP removal efficiencies but had direct negative effect on TN removal efficienciy. In the second stage, for water reuse with a high quality from SDW, jet loop-air lift bioreactor was coupled with membrane dead-end set up. For this purpose, reactor effluent at optimum condition was post treated by an optimal ultrafiltration membrane modified by boehmite-tannic acid-graphene quantum dot (BM-TA-GQD) as a hydrophilic nanoparticle. The modified mixed matrix membrane (MMM) showed an improvement in hydrophilicity (contact angle reduction from 75.45 to 59.38) and antifouling properties (reversible resistance (Rr) from 8.8 to 41.78 % and flux recovery ratio (FRR) from 44.58 to 71.35 %) in comparison to bare membrane. As a conclusion, the combination of the jet loop-air lift bioreactor and selected membrane (0.5% wt. of BM-TA-GQD) can be considered as an effective and low-cost approach for water reuse with a high quality.