Elimination of micropollutants and hazardous substances at the source in the chemical and pharmaceutical industry.

Industrial wastewater, especially from chemical and pharmaceutical production, often contains substances that need to be eliminated before being discharged into a biological treatment plant and following water bodies. This can be done within the production itself, in selected waste water streams or in a central treatment plant. Each of these approaches has certain advantages and disadvantages. Furthermore, a variety of wastewater treatment processes exist that can be applied at each stage, making it a challenging task to choose the best one in economic and ecological terms. In this work a general approach for that and examples from practice are discussed.     

EU demonstration project for separate discharge and treatment of urine, faeces and greywater--part I: results.

The main aim of this EU demonstration project was to test two new sanitation concepts to determine if these concepts are more sustainable, compared with the conventional sanitation system, particularly with regard to nutrient recycling. Two different sanitation concepts were tested. One concept comprised the use of gravity separation toilets, the other used vacuum separation toilets. Results from a life-cycle-assessment investigation show that the new sanitation concepts are more sustainable. A cost analysis for an existing residential area did not prove lower costs for the new sanitation concepts in this special case. The experience from this demonstration project shows that prior to a widespread use of the new sanitation concepts, several improvements have to be made. One important issue is the improvement of separation toilets. Since nutrient recycling, water saving and reuse as well energy reduction become more and more important, further research should be undertaken in this field.     

Environmental impact assessment and control of pharmaceuticals: the role of environmental agencies.

In 2005, the new legislation for pharmaceuticals came into effect. Since then environmental risk assessments are required for all new marketing authorisation applications. The German Federal Environment Agency has been assessing the environmental impact of 136 veterinary and 134 human pharmaceuticals. The authorisation of pharmaceuticals has shown that the authorisation of some groups of substances have to be combined with risk mitigation measures. Environmental risks may also arise from those pharmaceuticals which were authorised before the environmental risk assessment was added to the requirements of authorisation. Four examples of "existing" pharmaceuticals, i.e. diclofenac, ethinyl estradiol, ivermectin, and florfenicol are highlighted in this article. Risk management options for veterinary and human pharmaceuticals are discussed.     

Fate of pharmaceuticals and bacteria in stored urine during precipitation and drying of struvite

Experiments were conducted to measure the behaviour of eight pharmaceuticals during urine treatment as part of the project 'SANIRESCH - Sustainable sanitary recycling Eschborn'. Urine was collected from 200 people in a public building via waterless urinals and NoMix toilets. It was then stored at room temperature at different pH values to analyse the extent to which bacteria and pharmaceuticals are eliminated over time. Although a partial elimination of pharmaceuticals could be detected, the storage at defined pH values cannot be advised. As the persons tested used pharmaceuticals with different structures, in different amounts and at varying intervals, this method of treatment is insufficient for removing them from urine. Precipitating the urine with MgO, washing it with saturated struvite solution and drying it at 30 °C will result in a free-flowing granular powder of struvite (NH(4)MgPO(4)·6H(2)O) that is free of pharmaceuticals and pathogens and can be used as fertiliser and a source of nitrogen, magnesium and phosphorus.     

EU demonstration project for separate discharge and treatment of urine, faeces and greywater--part II: cost comparison of different sanitation systems.

The experience from the EU demonstration project was used for a cost analysis of different sanitation systems with regard to nutrient recycling. The analysis was made for an existing residential area, for which the different sanitation systems have been applied. The cost calculations were made for a lifetime of 50 years. The multiple sewer systems cause higher investment costs, mainly for the installation of the additional facilities; the investment costs for the treatment are lower. The cost analysis did not prove lower costs for the new sanitation concepts in this special case in comparison with the conventional system. Economic benefits are demonstrated for the operation costs. The result will be reinforced by the consideration of an increase of the energy costs. The revenues for the nutrient related products have only a very small impact on the result.     

承德市风沙源区特点及防治措施分析

根据风沙形成的因素及危害,分析了承德市风沙源区的分布及特点,提出了不同风沙源区的防治技术措施和政策措施。     

虎跳峡镇干沟箐泥石流成因分析与防治对策

泥石流具有突发性、流速快、物质容量大、破坏力强等特点.发生泥石流常常会冲毁交通等设施、村镇,危及人民群众生命,造成巨大财产损失,影响当地经济社会发展.通过虎跳峡镇干沟箐泥石流的形成条件分析及发展趋势,提出针对性的治理措施,防与治结合降低灾害损失.     

三峡水库支流库湾营养源解析及水体富营养化调控对策研究

支流库湾水体富营养化是三峡水库带来的主要环境问题之一,三峡水库进入常态调度运行后,支流库湾水体富营养化问题日益突出.为厘清易发生水华的支流库湾水体富营养化的驱动力因素,本文以重庆市奉节县梅溪河为典型支流,采用三维水动力与水环境模拟技术解析了支流库湾水动力的驱动机制及营养盐来源及其组成.干-支流水温差导致的密度流是梅溪河...     

Review on the fate of organic micropollutants in wastewater treatment and water reuse with membranes

A brief review of the fate of micropollutants in membrane-based wastewater treatment due to sorption, stripping, biological degradation/transformation and membrane separation is discussed, to give an overview of these technologies due to the growing importance for water reuse purposes. Compared with conventional activated sludge treatment (CAS) micropollutant removal in membrane bioreactor (MBR) is slightly improved due to complete suspended solids removal and increased sludge age. For discharge to sensitive receiving waters advanced treatment, such as post-ozonation or activated carbon adsorption, is recommended. In water reuse plants nanofiltration (NF) and reverse osmosis (RO) efficiently reject micropollutants due to size exclusions as well as electrostatic and hydrophobic effects reaching potable quality. To remove micropollutants fully, additionally post-ozone or the addition of powdered activated carbon (PAC) have to be applied, which in parallel also reduce NDMA precursors. The concentrate has to be treated if disposed to sensitive receiving waters due to its high micropollutant concentration and ecotoxicity potential. The present review summarizes principles and capabilities for the most important membrane-based applications for wastewater treatment, i.e. porous membranes in MBRs (micro- or ultrafiltration) and dense membrane applications (NF and RO) for water reuse.     

多支沟泥石流形成特征及防治

温泉县孟克沟流域由1条主沟及4条主要支沟构成,具有发育数量较多、规模较小、泥石流发生频率较多的特征.流域平面形态呈漏斗状,地势总体南西高北东低,沟槽横断面呈"V-U"字型.降水主要集中于每年的5—9月,强降水在短时间内汇聚成地表径流,并与沟谷中松散碎屑物质共同运动形成水石流.泥石流主沟侵蚀速率略大于支沟,平均侵蚀切割深...     

水源水中藻类及藻毒素控制试验研究

研究了氯、高锰酸钾、臭氧等单独预氧化及与混凝沉淀联合作用时,水源水中藻类及藻毒素含量的变化规律,发现预氧化对藻类的去除作用有限,混凝沉淀对藻毒素的去除作用也有限,而两者的联合作用可提高对藻类和藻毒素的去除效果;在合适的投加量下,藻类去除率在80%以上,藻毒素的去除率近90%,可有效减轻后续处理工艺的负荷,保障饮用水的安全。     

深圳市水源水库前置库湿地建设及净化面源污染的防治

近几年,水库水源地污染对水质保护造成了严重威胁,为保护水库水源、防治环境污染,将水资源生产潜力充分发挥出来,积极应用前置库技术,充分利用其费用低、适用于多种条件、多方受益的优点,已经成为当前水库水源防治污染的重要措施.基于此,本文主要以深圳市为例,分析深圳市水源水库存在的生态与环境方面的突出问题,在充分调查水源水库污染...     

Stability analysis of a wastewater treatment plant with saturated control.

This paper presents a saturated proportional controller that achieves depollution of wastewater in a continuous anaerobic digester. This goal is reached by defining a region of the state-space where the depollution is achieved and forcing attractivity and invariance of this region. The control variable is the dilution rate and the controlled variable is a linear combination (S(lambda)) of the substrates concentrations, that could be the chemical oxygen demand or the biological oxygen demand, depending on the value of A. No measurement of the substrates concentrations in the input flow is required: the only necessary measurement is S(lambda).     

乡村河流生态的保护途径 ——流域非点源污染防治

随着点源污染控制的加强,非点源污染逐步成为我国乡村流域污染物构成的主体。在分析乡村流域非点源污染主要类型以及非点源污染对乡村河流生态系统影响的基础上,提出建立流域层面上的农村非点源污染管理模式,着重分析了最佳管理措施BMPs相关技术并建立了在流域层面上管理乡村河流的工作步骤,该工作流程有助于建立乡村非点源污染防治规划的框架体系。     

Automatic control of external carbon source addition for nitrogen removal in sewage with low C/N ratios.

For cost-effective nitrogen removal from sewage with low C/N ratios, an automatic control system for the addition of external carbon based on oxidation-reduction potential (ORP) data in an anoxic reactor has been developed. In this study, it was carried out with a pilot-scale modified Bardenpho process. This consisted of anoxic1, aerobic1, anoxic2 and aerobic2 stages with an external recycle ratio of 150% (Q/Qinf), and a media packing ratio of 2.4%-2.9% (v/v) in the aerobic reactor. As a result of applying the automatic control system for the minimization of the external carbon source dosage, the dosage was decreased by about 20%. This estimate was based on ORP compared with a stable dosage of 75 mg/L based on the C/NOx-N ratio of the anoxic influent. It was necessary that the ORP set-value be regulated from -120 mV to -80 mV because influent NH4+-N concentration varied from 12 to 15 mg/L due to rainfall. Correspondingly, the demanded dosages were decreased. Drift of the the real-time value in control system was more stable after changing the ORP set-value from -120 mV to -80 mV.     

铁岭水文站总线程控缆道测流系统试验分析

利用总线程控缆道进行流量测验与船测水深和流量数据进行统计分析,根据统计理论,对总线程控缆道施测与统计指标计算。通过试验分析和相关验证,统计指标在允许范围内,证明利用总线程控缆道实测流量完全可行,精度可靠。     

Comparison of the behaviour of selected micropollutants in a membrane bioreactor and a conventional wastewater treatment plant.

Micropollutants as pharmaceutical active compounds (PhACs), residuals of personal care products or endocrine disrupting chemicals are of increasing interest in water pollution control. In this context the removal efficiencies of sewage treatment plants (STPs) are of importance, as their effluents are important point sources for the release of those substances into the aquatic environment. Activated sludge based wastewater treatment is the worldwide prevalently used treatment technique. In conventional plants the separation of treated wastewater and sludge occurs via sedimentation. A new development is the application of membrane technology for this separation step. The studies focus on the influence of the solids retention time (SRT) on the removal efficiency, as the SRT is the most important parameter in the design of STPs. A conventional activated sludge plant (CASP) and a membrane bioreactor (MBR) were operated at different SRTs. The substances selected are the antiepileptic carbamazepine, the analgesics diclofenac and ibuprofen, the lipid regulator bezafibrate, the polycyclic musks tonalide and galaxolide and the contraceptive 17alpha-ethinylestradiole. No significant differences in the removal efficiency were detected. Due to the absence of suspended solids in the MBR effluent, substances with high adsorption potential could be retained to slightly higher amounts.     

Numerical simulation and analysis of confined turbulent buoyant jet with variable source

In this work, experimental and numerical investigations are undertaken for confined buoyant turbulent jet with varying inlet temperatures. Results of the experimental work and numerical simulations for the problem under consideration are presented. Four cases of different variable inlet temperatures and different flow rates are considered. The realizable k-ε turbulence model is used to model the turbulent flow. Comparisons show good agreements between simulated and measured results. The average deviation of the simulated temperature by realizable k-ε turbulent model and the measured temperature is within 2%. The results indicate that temperatures along the vertical axis vary, generally, in nonlinear fashion as opposed to the approximately linear variation that was observed for the constant inlet temperature that was done in a previous work. Furthermore, thermal stratification exits, particularly closer to the entrance region. Further away from the entrance region the variation in temperatures becomes relatively smaller. The stratification is observed since the start of the experiment and continues during the whole course. Numerical experiments for constant, monotone increasing and monotone decreasing of inlet temperature are done to show its effect on the buoyancy force in terms of Richardson number.     

多个离散热源的矩形空腔内自然对流的数值研究

本文对顶部散热的矩形空腔内某一竖侧壁上存在有5个离散热源时的自然对流换热问题求出了数值解。文中讨论了Ra及空腔高宽比对换热的影响。此类问题对电子器件的散热有较大参考价值。     

泾河流域源头段山洪灾害成因分析及防治

泾河发源于宁夏回族自治区最南端,其源头段为泾源县驻地,区域内多年平均降雨量608．7mm。泾河流域源头段四面环山,沟谷交错,溪流众多。区域内降雨和地表径流较丰富,但时空分布不均,汛期多年平均降水量占全年总降水量的70％,且常常集中于几次较大降雨过程,极易形成汛期洪水,引发不同程度的山洪灾害。进入20世纪90年代后,气候异常,生态失衡、人口剧增,山洪灾害更有频发密现之势。