A novel pre-dilution,swirling jet diffuser to enhance effluent mixing: Hydrodynamics and dilution performance

Diffusers are widely-used to quickly dilute effluents in receiving water bodies. This study proposed a novel diffuser that pre-mixes effluent with ambient water before discharging and that uses the swirling jet to further enhance near-field dilution. The nozzle of the diffuser was examined in two ambient flow conditions: co-flow and counter-flow that are commonly-met in the environment such as oceans due to tidal effect. Physical experiments were first conducted in co-flow on its dilution performance and hydrodynamics, using heated water as the effluent. A 3-D CFD model was developed and calibrated the co-flow scenarios, and then used to investigate the diffuser in counter-flow. The results showed that the nozzle can effectively reduce the maximum temperature rise of the effluent by about 50 % before discharging. The swirling jet from the outlet has a larger shear area, half-width and entrainment rate, enabling the effluent to be rapidly diluted to a minimum of around 10 times at x/D = 6 in co-flow, whereas the dilution for conventional nozzles is about 1 because of the potential core. The flow amplification ratio (α) decreases gradually with increasing velocity ratio in co-flow but increases with increasing velocity ratio in counter-flow. The counter-flow reduces the water drawn into the device; however, the pre-dilution effect at the outlet remains stable. The near-field dilution in counter-flow was significantly enhanced than that in co-flow. Environmental regulations at outfalls and mixing zones can be more easily met using this novel diffuser.     

Effect of Dyebath Additives on Decolorization Efficiency in the Ozonation of Dyehouse Effluent

It is necessary to study the effect of dyebath additives on decolorization efficiency in order to optimize ozone-based decolorization processes as the consumption of ozone can be reduced through selecting ozone favorable additives. The effect of 5 dyebath additives viz. electrolytes (sodium chloride and sodium sulfate), chelating agent (ethylene diamine tetra acetic acid or EDTA), reducing agent (sodium dithionite), optical brightener (Uvitex BHT), and dispersing agent (Zetex DNVL) was investigated. All of the additives showed synergistic effect as addition of sodium chloride, sodium dithionite and Zetex DN-VL markedly improved decolorization efficiency, but EDTA and optical brightener showed negative effect. Sodium sulfate did not show any positive or negative effect on decolorization efficiency.     

神经网络模型在预测BAF出水水质中的应用

采用BP神经网络模型对沈阳仙女河污水处理厂曝气生物滤池出水水质进行预测,将运行数据分为训练样本和测试样本,对神经网络模型的预测值和实测值进行t检验发现两者之间无显著差异,结果表明,神经网络模型可以对BAF处理系统的出水水质预测及运行管理提供参考。     

法国洛代夫铀水冶厂工艺流程的改进——碱性浸出剂再生及溶液返回法

洛代夫铀水冶厂原采用加压碱法浸出和直接沉淀的流程从矿石中回收铀。本文叙述了作者为改进洛代夫铀水冶厂的生产，提出的碱性浸出剂再生和溶液循环的新方法。在不必更新和增加设备的条件下，改进了该厂的生产工艺流程，提高了经济效益，降低了生产成本。该方法已直接用于洛代夫厂的生产中，并为该厂节省至少每年1400万法郎的操作费用。     

Debottlenecking procedure of effluent thermal treatment system

In this study pinch technology has been improved for wastewater temperature reduction. Having considered design grouping rules on the basis of pinch technology, a new debottlenecking procedure for thermal treatment of the wastewater network, has been introduced. In the presented procedure, better thermal treatment of effluent network using the new method can be used to avoid investment in new cooling tower capacity and to improve the performance of the tower in a systematic way. Related coding in Visual Sudio.Net 2003, C++, has been developed for the illustrative example to get optimal values in the cooling water design method computations.     

解读核设施放射性流出物释放的ALARA和BAT概念

基于对核设施放射性流出物释放最优化方面的ALARA和BAT这两个重要概念的理解,结合现存核设施放射性流出物的特征和污染消减技术,本文阐述了核设施放射性流出物排放的浓度控制原则,即以流出物消减的最佳可行技术为前提,引入良好的工程实践,适当考虑厂址条件等外部因素对流出物释放进行优化。     

Comparative study of indices used in toxicity evaluation of effluents

Several toxicological indices currently proposed (inter)nationally to aid decision-making tasks in effluent control were compared. To evaluate effluent ranking differences between the indices an inversion distance as a similarity measure was proposed. The major factor influencing effluent ranking were found to be a composition of test-battery. Differences in mathematical operator of the indices such as, e.g. arithmetic mean (used in averaging indices) or maximum one (used in an approach of the most sensitive test in a battery), affect the ranking similarity noticeably lesser than the modification of the percentage effect level of the measurement endpoints. Effluent and/or river flow parameters incorporated into the indices substantially modify ranking results of the effluent set. For the analysis, the toxicological information on 23 effluents from municipal wastewater treatment plants operating in cities and small towns of Lithuania as well as test-battery data on industrial effluents published elsewhere were used. It seems that the general statements achieved in the current study can be applied to any set of effluents.     

Survey of users and providers of recycled water: quality concerns and directions for applied research

Users and providers of recycled water in Queensland, Australia, were canvassed to ascertain concerns about recycled water quality and directions for applied research. Some 79% of respondents had concerns about recycled water quality including microbiological components, such as viruses, parasites and bacteria, salinity related components, aggregate components, such as pH and solids, nutrients, organic components, including pesticides and endocrine disruptors, as well as quality variability. Relative differences in the proportion of concern for some quality characteristics were observed between the areas of different population density with those from the low population areas being more concerned than those from medium or high areas. Some users and providers observed changes in recycled water quality during distribution including nutrients, chlorine, solids, colour and odour. Some 52% of providers and 19% of current users propose to expand their usage and 30% of non-users propose to commence doing so in the next 5 years. Recycled water quality characteristics identified for applied research included microbiological components, organic components, nutrients and salinity.     

Electrocoagulation of a synthetic textile effluent powered by photovoltaic energy without batteries: Direct connection behaviour

The feasibility of the use of an electrocoagulation system (EC) directly powered by a photovoltaic (PV) array has been demonstrated. The model pollutant used was a reactive textile dye Remazol Red RB 133. It has been proved that PV array configuration is a factor of great influence on the use of the generated power. The optimum PV array configuration must be reshaped depending on the instantaneous solar irradiation. A useful and effective methodology to adjust the EC–PV system operation conditions depending on solar irradiation has been proposed. The current flow ratio, J_v, is established as the control parameter.