In this study, an integrated aerobic membrane bioreactor (MBR)-nanofiltration (NF) system has been applied for advanced treatment of Opium processing wastewaters to comply with strict discharge limits. Aerobic MBR treatment was successfully applied to high strength industrial wastewater. In aerobic MBR treatment, a non-fouling unique slot aeration system was designed using computational fluid dynamics techniques. The MBR was used to separate treated effluent from dispersed and non-settleable biomass. Respirometric modeling using MBR sludge indicated that the biomass exhibited similar kinetic parameters to that of municipal activated sludge systems. Aerobic MBR/NF treatment reduced chemical oxygen demand (COD) from 32,000 down to 2,500 and 130 mg/L, respectively. The MBR system provided complete removal of total inorganic nitrogen; however, nearly 50 mgN/L organic nitrogen remained in the permeate. Post NF treatment after MBR permeate reduced nitrogen below 20 mgN/L, providing nearly total color removal. In addition, a 90% removal in the conductivity parameter was reached with an integrated MBR/NF system. Finally, post NF application to MBR permeate was found not to be practical at higher pH due to low flux (3-4 L/m/hour) with low recovery rates (30-40%). As the permeate pH lowered to 5.5, 75% of NF recovery was achieved at a flux of 15 L/m/hour.
BACKGROUND: This study investigated the anatomy of organic carbon (as chemical oxygen demand, COD) removal from sewage through chemically assisted settling, by means of particle size distribution (PSD) analysis: it showed which size fractions were affected, aside from the particulate COD. The experiments were conducted on the effluent of the existing preliminary treatment plant before deep-sea discharge into the Bosphorus. FeCl 3 , alum and polyaluminum chloride (PAC) were used as coagulants at different doses. The performance of the coagulants on the effluent COD was interpreted with PSD.RESULTS: PAC at 25 mg L −1 , selected as the optimum coagulant, reduced COD below soluble COD level, to around 145 mg L −1 , with an overall efficiency of more than 70%. Although chemical settling was most effective on particulate COD at >450 nm, it also provided a COD removal of 28% in 220-450 nm of the colloidal range and 40% in 13-220 nm of the range, representing soluble hydrolysable COD. The lowest removal rate was observed in the soluble range, consisting of readily biodegradable (only 5%) and a part of the inert COD (<2 nm) identified as 12%twice as high as ordinary domestic wastewaters, with only 1%.CONCLUSION: PSD and COD fractionation analyses were instrumental in depicting the potential of chemically enhanced settling to reduce COD in the soluble range, identifying the distribution of remaining COD fractions in different size intervals. The results also suggested a novel treatment process with additional membrane filtration, namely membrane chemical reactor, (MCR), reflecting a potential for replacing the conventional activated sludge process.
Food industry wastewater (FIWW) streams with high organic content are among the most suitable and inexpensive candidates for polyhydroxyalkanoate (PHA) biopolymer production. Due to its high organic acid content, pickle industry wastewater (PIWW), can be considered as one of the prospective alternatives to petroleum-based polymers for PHA production. In this context, this study aimed to investigate the production of PHA with enriched microbial culture using PIWW. Two laboratory scale sequencing batch reactors (SBRs) were operated under aerobic dynamic feeding conditions at a sludge retention time of 8 days, with a total cycle duration of 24 hours. SBRs were fed with peptone mixture and PIWW. In-cycle analysis and batch respirometric tests were performed to evaluate PHA storage together with biodegradation kinetics. In-cycle analysis showed that maximum PHA content was 1,820 mgCOD/L, corresponding to 44% in the biomass (ratio of chemical oxygen demand (COD) to volatile suspended solids) for PIWW. Experimental results were also confirmed with activated sludge model simulations. As for the PHA composition, hydroxybutyrate was the major fraction. Model simulations proposed a unique conversion–degradation–storage pathway for the organic acid mixture. This paper presents a novel insight for better understanding of PHA biopolymer production using high saline FIWW.
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