we have used. Comparing the results obtained with counters {c') and {d') with the corresponding results obtained from (c) and (d), a small increase in the coincidence rate is noted. Considering the fact that the counters (c f ) and (d f ) are more sensitive to photons of low energy, the increase in the number of coincidences observed can be explained by the hypothesis that a fraction of the coincidences are due to the association between 7-radiation and x-rays subsequent to iT-capture. A sensible increase in N is obtained only for counters with KF (A?>-A^=0.48:db0.26) and not for those with KG, This agrees with the hypothesis that the increase is actually caused by x-rays of the K a line of argon which are strongly absorbed in chlorine.The hypothesis that there is an association between iT-capture and 7-radiation justifies the magnitude of the observed effect.

Membrane distillation is getting increasing attention thanks to its advantages in terms of energy consumption and final permeate quality in addition to its resistance against highly corrosive media which forms an appealing solution for industrial wastewater treatment. Despite its advantages, one of the most challenging issues in direct contact membrane distillation (DCMD) is membrane fouling and wetting. In the present research work, saline dairy effluent discharged from hard cheese industry was pretreated by macrofiltration (MAF) and ultrafiltration (UF) and processed by DCMD to investigate the extent of the aforementioned issues. Effluents pretreated by UF have led the best process performance with stable flux values at different operating conditions. Fouling has occurred in all the experiments, though their effect on the flux behavior and membrane wetting was different from one feed to the other. Changing the flow rate and the temperature difference have affected slightly the membrane wettability for all feed qualities. In all experiments, the permeate has maintained a good quality with low electrical conductivity that did not exceed 70 μS/cm and low total organic carbon < 2 mg/L.

Abstract. In this work a combined system consisting of a CPV and thermal (CPV-T) system connected with a reverse osmosis (RO) and membrane distillation (MD) for desalination is presented. In the CPV-T electrical energy is generated. The electrical energy is partly needed to run the desalination systems (e.g. pumps). The surplus electricity can be fed into the grid or an electrical storage system. The reverse osmosis process is the most energy efficient and established way of desalting brackish water and high volumes of pure water can be reached. However, with rising salinity the specific energy consumption (SEC) of RO rises significantly. Therefore, a second desalination system is introduced, the MD. The distillation is driven by the difference in temperature and vapor pressure of two fluid cycles. Hence, in the MD the thermal energy generated in the CPV-T system is used to heat the cycle of the high temperature side. The MD process runs with low temperature heat (<100 °C) and its SEC is less sensitive to the water salinity than the RO-process. Therefore MD is suitable to achieve high brine salinity by further concentrating the brine resulting from the RO-process. The connection in series of the both desalination technologies is especially useful to treat brackish water that is often found in high DNI regions, thus match to the CPV technology very well. The scarce water resources in dry regions are of high value and should therefore be as fully used as possible. In addition, the quantity of brine that needs to be disposed of is reduced when concentrating to a high salinity.

Stricter environmental regulation policies and freshwater as an increasingly valuable resource are leading to global growth of zero liquid discharge (ZLD) processes in recent years. During this development, in addition to water, the recovery of recyclable materials, e.g. salts, from industrial wastewater and brines is considered more frequently. Within the framework of the HighCon research project, the subject of this study, a new ZLD process with the goal of pure single-salt recovery from industrial wastewater has been developed and investigated in a demonstrational setup at an industrial site. With regard to pure salts recovery, separating organic components is of great importance during the treatment of the concentrate arising from used water recycling. The removal of COD and of ions responsible for scaling worked very well using nanofiltration. The nanofiltration permeate containing the monovalent ions was pre-concentrated using electrodialysis and membrane distillation before selective crystallization for single-salt recovery was performed. An example economic case study for the newly developed ZLD process – based on demonstration results and considering optimization measures for a full-scale design – indicates that the costs are equal to those of a conventional ZLD process, which, however, does not provide inter alia the aforementioned benefit of single-salt recovery.