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In the present study, the treatment of tannery wastewater was performed by electrocoagulation method (EC) using aluminium and steel electrodes. Response surface methodology (RSM) with three factors; current density (I), electrolysis time (t) and pH, with each factor at five levels, was used to optimize the factors for higher chemical oxygen demand (COD) and total suspended solids (TSS) removal. Operational parameters I, t and pH were varied between 22-110 mA/cm2, 5-45 min and 3-7, respectively. For the optimal parameter values, the removal efficiency of COD and TSS attained respectively 82.2% and 85.5% for aluminium electrodes and 67.4% and 86.2% for steel electrodes. Analysis of variance (ANOVA) showed a high variance coefficient (R2) value of 0.96 and 0.81, for COD and TSS removal, respectively, thus ensuring a satisfactory adjustment of the second-order regression model with the experimental data Corresponding energy consumption was found to be 2.92 €/m3 and 8.18 €/m3, for COD removal by using aluminium and steel electrodes, respectively. [ABSTRACT FROM AUTHOR]

Since treatment of landfill leachate is quite complicated, there is a need to develop a system that is capable of providing high treatment efficiencies. In this study, the treatment performance of a jet - loop membrane bioreactor (JLMB) operated at different organic loading rates was investigated by observing the changes in Chemical Oxygen Demand (COD), Total Kjehldahl Nitrogen (TKN) and Total Ammonia (NH3) concentrations. The same COD removal rates (83%) were observed at all the studied loading rates, and it should be noted that the biodegradable part of the leachate was removed completely. It was also observed that the NH4 - N / TKN ratios, which were found to be approximately 0.9, did not change throughout the study. However, further treatment technologies, such as reverse osmosis, nanofiltration or ion - exchange, should be employed for the complete removal of inert COD and NH3 in order to meet related discharge limits. [ABSTRACT FROM AUTHOR]

A thermophilic anaerobic contact reactor for the treatment of potato-processing wastewaters was designed as a continuous-flow, completely-mixed homogeneous system. The reactor was operated at ten different organic loading rates ranging from 0.84 g COD/Ld to 7.00 g COD/Ld for a duration of approximately 250 days. The fundamental way to maintain optimum operating conditions of anaerobic digestion systems is to have a well acquaintance with the dynamic behaviours of the process. For this purpose, different types of kinetic models were used in this study, namely the substrate balance, the maximum / specific substrate utilization rate and the methane production rate models. The experimental data obtained indicated that the models used were all applicable for the description of bio-kinetic behaviour of the thermophilic anaerobic contact reactor. [ABSTRACT FROM AUTHOR]

Many countries in the Mediterranean basin are facing water shortage issues. Since water is becoming a rare resource, grey water and domestic wastewater reuse arises as a sustainable solution to reduce the overall water demand. In this study, a compact household reverse osmosis unit was used in order to determine the feasibility of pre-treated grey water and domestic wastewater reuse. The preliminary studies revealed that the compact system used was able to treat the wastewaters studied with quite high organic mater and nutrient removal efficiencies. For pre-treated grey water, the COD and BOD removal rates were around 80%. For pre-treated domestic wastewater, the organic mater removal rates were higher. In addition, soluble nutrients, such as nitrate and phosphate were also studied. The conductivity of permeate was reduced to 15 µS/cm and 55 µS/cm for grey water and domestic wastewater, respectively, within 15 min. The permeate obtained was free of suspended solids and had an excellent physical appearance. The overall results indicated that the product can be used for gardening, ire hydrants, ield irrigation, or alternatively for toilet flushing after disinfection. [ABSTRACT FROM AUTHOR]