Poultry slaughterhouse wastewater, which represents one of the most important pollutants in Turkey, is generally treated with conventional biological processes in Turkey and around the world. In this study, poultry slaughterhouse wastewater was treated using laboratory-scale membrane processes, which were substituted for conventional processes. The performances of the membrane processes were investigated in terms of chemical oxygen demand (COD), conductivity, and membrane fluxes. Economic analyses were conducted for several membrane system alternatives. In addition, the alternatives were compared with each other and with conventional economic analysis of the data obtained in this study and data from several previous studies. The membranes used for the membrane processes were AG for reverse osmosis (RO), DK for nanofiltration (NF), and ER for ultrafiltration (UF). The highest COD removal efficiencies were 90% for NF and 97.4% for RO, and the conductivities decreased by 51.7% for NF and 96.6% for RO. When the (UF) was not used, the long-term membrane fluxes of the RO and (NF) sharply decreased, which increased the operation costs of these processes. Therefore, RO and NF without pre-treatment and with UF were not effective for this wastewater. According to the economic analysis results, the operational costs of the RO and NF after UF, the UF alone, and the conventional treatment process were 0.66, 0.70, 0.79, and 1.66 $/m³, respectively. Because the operational cost of the conventional treatment process was 2.5 times greater than RO after pre-treatment with UF, it was deduced that this membrane process combination was a suitable treatment alternative for treating poultry slaughterhouse wastewater.

In this study, the electrocoagulation process was evaluated as a pretreatment process for olive mill wastewaters. Aluminium (Al) and iron (Fe) electrodes, several contact times and 0.5, 1 and 2 A currents were used to compare chemical oxygen demand (COD) removal efficiencies for each case. The optimum contact time and current were 45 minutes and 1 A, respectively, which resulted in a COD removal of 58.7% with an Al electrode. Experimental data from distinct operational conditions were used to fit a model for COD removal efficiencies. Energy consumption was also predicted. Under optimum operational conditions, the treatment cost was approximately €0.13 kg⁻¹ COD_removed and €4.41 m⁻³. The results showed that the electrocoagulation process was a cost-effective method for the pretreatment of olive mill wastewaters.

Although conventional biological treatment plants can remove basic pollutants, they are ineffective at removing recalcitrant pollutants. Membrane bioreactors contain promising technology and have the advantages of better effluent quality and lower sludge production compared to those of conventional biological treatment processes. In this study, the removal of pharmaceutical compounds by membrane bioreactors under different solid retention times (SRTs) was investigated. To study the effect of SRT on the removal of emerging pharmaceuticals, the levels of pharmaceuticals were measured over 96 days for the following retention times: 20, 30, and 40-day SRT. It was found that the 40-day SRT had the optimum performance in terms of the pharmaceuticals’ elimination. The removal efficiencies of the chemical oxygen demand (COD) for each selected SRT were higher than 96% at steady-state conditions. The highest degradation efficiency was observed for paracetamol. Paracetamol was the most removed compound followed by ranitidine, atenolol, bezafibrate, diclofenac, and carbamazepine. The microbial community at the phylum level was also analyzed to understand the biodegradability of pharmaceuticals. It was noticed that the Proteobacteria phylum increased from 46.8% to 60.0% after 96 days with the pharmaceuticals. The Actinobacteria class, which can metabolize paracetamol, carbamazepine, and atenolol, was also increased from 9.1% to 17.9% after adding pharmaceuticals. The by-products of diclofenac, bezafibrate, and carbamazepine were observed in the effluent samples.