A dual membrane UF/RO process for reclamation of spent rinses from a nickel-plating operation--a case study

The objective of this work was to conduct treatability studies on rinse wastewater from process lines of a typical nickel-plating plant for reuse. The study comprised of three steps: (1) a plant process review and the treatability of different combinations of simulated spent rinses in the laboratory; (2) a variability monitoring of a combined rinse at the plant and a treatability study on a combined rinse in the laboratory; (3) a pilot study for reclamation of the combined rinse on site. The study established an optimum dual membrane ultrafiltration (UF)/reverse osmosis (RO) process for treating a combined liquor of spent alkaline, acidic and nickel-plating rinses which resulted in a treated water of a quality suitable for reuse as substitute for town water for the purpose of rinsing. The results of this study provided a good guide to the selection of a UF pretreatment combined with an RO membrane unit as the treatment system. The pilot plant had successfully operated for 6 months, consistently producing a high quality product water (< 95 microS cm-1) at an overall water recovery of 67.5%. The quality of reclaimed water was better than town water used at the factory. The product water from the pilot plant has been used as substitute of town water for in-process rinsing at the factory with no detrimental effects for 3 months.     

Uncertainties of stormwater characteristics and removal rates of stormwater treatment facilities: Implications for stormwater handling

Stormwater runoff is a major contributor to the pollution of receiving waters. This study focuses at characterising stormwater in order to be able to determine the impact of stormwater on receiving waters and to be able to select the most appropriate stormwater handling strategy. The stormwater characterisation is based on determining site mean concentrations (SMCs) and their uncertainties as well as the treatability of stormwater by monitoring specific pollutants concentration levels (TSS, COD, BOD, TKN, TP, Pb, Cu, Zn, E.coli) at three full scale stormwater treatment facilities in Arnhem, the Netherlands. This has resulted in 106 storm events being monitored at the lamella settler, 59 at the high rate sand filter and 132 at the soil filter during the 2 year monitoring period.The stormwater characteristics in Arnhem in terms of SMCs for main pollutants TSS and COD and settling velocities differ from international data. This implies that decisions for stormwater handling made on international literature data will very likely be wrong due to assuming too high concentrations of pollutants and misjudgement of the treatability of stormwater. The removal rates monitored at the full scale treatment facilities are within the expected range, with the soil filter and the sand filter having higher removal rates than the lamella settler. The full scale pilots revealed the importance of incorporating gross solids removal in the design of stormwater treatment facilities, as the gross solids determine operation and maintenance requirements.     

漪汾桥改造监控中无线监测系统的应用

近年来,桥梁监测理论和技术有了长足的发展,监控系统在桥梁中的应用也越来越广,以往的桥梁监测系统多为有线监控,已经无法满足桥梁监控发展的需要,一种新的监测系统-—无线监测系统也被应用到桥梁监测中。结合漪汾桥的改造施工监控,介绍了一种新型的WDAS分布式无线监测系统,并就监测数据与理论计算数据做对比分析,验证了本次监测的良好效果。最后展望了无线监测在未来大型桥梁以及大型建筑中的应用前景。     

Disinfection by-product formation of natural organic matter surrogates and treatment by coagulation, MIEX and nanofiltration

Potentially the most effective means of controlling disinfection by-products (DBPs) is to remove precursors before disinfection. To understand relationships between physical properties, treatability and DBP formation, nine natural organic matter (NOM) surrogates were studied. Their DBP formation and removal by coagulation, MIEX^® anion exchange resin and two nanofiltration membranes was measured. Whereas treatability of NOM surrogates was explained in terms of their physicochemical properties, the same was not true of DBP formation. Hence it was not possible to selectively remove compounds which generate high amounts of DBPs. Instead, precursor removal strategies based upon empirical DBP formation potential testing are more apt. Under conditions simulating full-scale performance, MIEX^® did not offer improved performance over coagulation. A hydrophobic nanofiltration membrane proved successful for removing neutral, hydrophilic surrogates, and hence is also suitable for DBP precursors of this character.     

Characterisation and removal of recalcitrants in reverse osmosis concentrates from water reclamation plants

Water reclamation plants frequently utilise reverse osmosis (RO), generating a concentrated reject stream as a by-product. The concentrate stream contains salts, and dissolved organic compounds, which are recalcitrant to biological treatment, and may have an environmental impact due to colour and embedded nitrogen. In this study, we characterise organic compounds in RO concentrates (ROC) and treated ROC (by coagulation, adsorption, and advanced oxidation) from two full-scale plants, assessing the diversity and treatability of colour and organic compounds containing nitrogen. One of the plants was from a coastal catchment, while the other was inland. Stirred cell membrane fractionation was applied to fractionate the treated ROC, and untreated ROC along with chemical analysis (DOC, DON, COD), colour, and fluorescence excitation-emission matrix (EEM) scans to characterise changes within each fraction. In both streams, the largest fraction contained <1 kDa molecules which were small humic substances, fulvic acids and soluble microbial products (SMPs), as indicated by EEM. Under optimal treatment conditions, alum preferentially removed >10 kDa molecules, with 17-34% of organic compounds as COD. Iron coagulation affected a wider size range, with better removal of organics (41-49% as COD) at the same molar dosage. As with iron, adsorption reduced organics of a broader size range, including organic nitrogen (26-47%). Advanced oxidation (UV/H₂O₂) was superior for complete decolourisation and provided superior organics removal (50-55% as COD).     

Characterization and treatability of aerobic bacterial thermophilically treated wastewater by a conventional activated sludge and granular activated carbon

An industrial wastewater that was pretreated by an aerobic thermophilic bacterial consortium (THE) was subjected to additional treatability studies by granular activated carbon (GAC) and a conventional activated sludge (CAS). The removal of dissolved organic carbon (DOC) in both systems was generally found to be similar. While GAC was able to attain better effluent concentrations of toluene and methyl isobutyl ketone (MIBK), the CAS was much more efficient at removing acetone. Furthermore, unlike the GAC, the performance of the CAS was not influenced by the high degree of variability in the influent wastewater. Characterization of the influent thermophilic wastewater using gas chromatography-mass spectroscopy (GC/MS) was performed to quantify the micropollutants as well as to evaluate removal efficiencies from the GAC and CAS systems.     

Organic markers in the lipidic fraction of sewage sludges

The lipidic organic fraction of 48 sewage sludges that originated from food-processing, paper-mill and domestic (urban, small urban, and rural) wastewater-treatment plants of the Lorraine region (Northeast of France) was characterised by gas chromatography coupled with mass spectrometer (GC-MS). This study enables us to define an average organic composition typical of each group of sewage sludges. Linear alkyl benzenes (LABs) are only present in domestic sludges, sterols in food-processing and domestic sludges. Paper-mill sludges are characterised by the specific distribution of n-alkanes. Besides, all the domestic sludges, whatever the size of the wastewater catchment, are characterised by the same distribution of polar compounds. Differences can be evidenced in the distribution of the aliphatic compounds of some domestic sewage sludges and are attributed to the important contribution of petroleum products in their sewer system. Moreover, this study highlights the correlation between abundance of polycyclic aromatic hydrocarbons (PAHs) in the aromatic fraction of some sewage sludges and a distribution of n-alkanes characteristic of heavy petroleum products into the corresponding aliphatic fraction. This might be a clue for the determination of punctual sources of PAHs.     

智能建筑供配电系统监测研究

介绍了供配电系统监测的现状、原理和功能实现，并对该研究的应用前景进行了展望，即监测技术的应用可以有效地提高供配电系统的可靠性，从而实现供配电系统管理的现代化。     

Electrochemical treatment of cigarette industry wastewater: feasibility study

The electrochemical treatability of wastewater from the cigarette industry has been investigated in this paper using cast iron electrode. The treatment efficiency was monitored in terms of COD, BOD and suspended solids concentration. The cast iron anode was found effective in treatment of the above-mentioned wastewater. About 56% of COD and 84% of BOD removal was observed at 3.5 A current for 5 h of electrolysis. The effect of increase in surface area of anode reduces electrolysis time and also energy consumption per kg of COD removal. The treated effluent was subjected to chemical coagulation studies using Ca(OH)2 as coagulant. The final treated effluent was found to confirm the stipulated standards for safe disposal into surface water bodies (Indian Standards). It was concluded that the electrochemical treatment followed by chemical coagulation could be opted as an alternate treatment scheme for the present industry.     

Synthetic reactive dye wastewater treatment by narrow-leaved cattails (Typha angustifolia Linn.): effects of dye, salinity and metals

Narrow-leaved cattails were studied in synthetic reactive dye wastewater (SRDW) under caustic conditions. The effects of the toxic dye were expressed in terms of relative plant growth rate and the appearance of symptoms such as necrosis, and chronic or acute wilting. The dye toxicity was 25.33 mg l(-1) which was close to approximate the concentration of dye residue from the textile effluent in the public stream. The system pH and % color removal were decreased, indicating that narrow-leaved cattail can treat wastewater. The average system pH decreased from 9 to 7. The maximum color removal was approximately 60% when cultured under soil conditions. The SEM image of narrow-leaved cattail root after treatment with SRDW indicated that the root cortex was damaged and the crystalline sodium salts deposited in the root cells which caused evaporation and transpiration decreased in SRDW. The salinity under caustic conditions also affects the growth of the plants. The maximum sodium removal was approximately 44% and was found in the SRDW under soil conditions within 14 days. A small amount of sodium could enhance the relative growth rate. However, the sodium removal of the plants was limited after the third week of treatment. It should be noted that narrow-leaved cattails are known to avoid the textile dye and salt stress conditions during SRDW treatment through special mechanisms such as salt accumulation in the roots or shedding of older leaves. In addition, elements such as silicon, calcium and iron in plants might help the plant to detoxify by forming complexes with dye molecules.     

Treatability of organic fractions derived from secondary effluent by reverse osmosis membrane

Dissolved organic matters (DOMs) from two batches of secondary effluent collected from a local water reclamation plant were fractionated using column chromatographic method with non-ionic resins XAD-8, AG MP-50 and IRA-96. Seven isolated fractions were obtained from the fractionation study and these fractions were quantified using DOC, UV(254) and SUVA values. The fractionation study revealed that the secondary effluent samples comprised about 47.3-60.6% of hydrophobic and 39.4-52.7% of hydrophilic solutes. The treatability of each isolated fraction was investigated by subjecting each fraction to reverse osmosis (RO) treatment individually. It was noted that RO process could achieve high DOC rejections for acid and neutral fractions (ranging from 80% to 98% removal) probably due to the negative charge of RO membrane. The results obtained also indicated that hydrophobicity of DOMs is significant in determining treatability of organic species by RO process. The performance of RO in terms of DOC rejection of un-fractionated secondary effluent was also investigated to assess possible effects of interactions among organic fractions on their treatability by RO process. It was noted that DOC rejection associated with the un-fractionated secondary effluent was generally higher (ranging from 2% to 45%) than the corresponding rejection obtained from each individual fraction isolated from the secondary effluent. This finding suggested there is a beneficial interaction among the fractions that in turn has contributed towards a better overall DOC rejection performance by RO treatment.     

Effective partial nitrification to nitrite by down-flow hanging sponge reactor under limited oxygen condition

Combining the processes of partial nitrification and anaerobic ammonium oxidation (ANAMMOX) is an attractive wastewater-treatment technology for nitrogen removal. In this study we investigated partial nitrification by implementing a closed down-flow hanging sponge (DHS) reactor operated at controlled oxygen concentrations. Basic concept of DHS process is similar to that of trickling filter, in which oxygen concentration can be easily manipulated by controlling airflow to the reactor. The closed reactor was fed with artificial wastewater containing NH(4)Cl and operated with an HRT of 1.5h at 30 degrees C. Oxygen inside the reactor was maintained below 3% (1.2mgDO x L(-1)) (DO-dissolved oxygen) except during the startup periods. Five months of continuous operation showed that there was a strong relationship between oxygen concentration and nitrite production. The ratio of nitrite produced relative to ammonium oxidized increased by decreasing oxygen concentration. Partial nitrification was satisfactorily accomplished under oxygen limitation at around 0.5% in the gas phase (0.2mgDOL(-1)). The system showed a high ammonium-removal rate, at a maximum of 1.46kg NH(4)(+)-Nm(-3)day(-1), even at limited oxygen concentration. We also found that oxygen concentration played an important role in the production of nitrous oxide, which increased with decreasing oxygen concentration.     

深井矿山地压灾害微震监测技术应用研究

 会泽矿区深部8号矿体埋藏深度达1 000 m,矿体赋存于十余条断层所控制的破碎带中,开采条件十分复杂。根据矿山实际情况,建立一套具有地震学定量分析和可视化解释功能的数字化24通道微震监测系统。详细介绍微震监测系统的组成和性能,采用人工爆破震源对微震监测系统的定位精度进行3次测试,监测范围内的震源定位误差为3.16～6.78 m,达到预期目的,证明该监测系统可满足矿山地压监测要求。该系统于2007年8月正式投入使用,在半年监测数据的基础上,通过对井下采集的多种振动波形特征、微震事件b值时序特征及震源应力降等参数进行分析,初步总结深部8号矿体开采过程中的地压活动规律。     

Simultaneous colour and DON removal from sewage treatment plant effluent: Alum coagulation of melanoidin

The aim of this study was to detect and characterise melanoidin in sewage treatment plant (STP) effluent, and to study the ability of alum coagulation to remove the colour and dissolved organic nitrogen (DON) associated with melanoidin. The melanoidin is non-biodegradable due to the complex cyclic based structure and thus it directly contributes to effluent nitrogen concentrations from the sewage treatment plant (STP). Lowering of effluent total nitrogen limits and the link between colour and chlorinated disinfection by-products have therefore driven a need to understand the structure, properties and treatability of DON species found in STP effluent.The focus of this paper is the refractory coloured, organic nitrogen compound melanoidin. Wetalla STP effluent has relatively high colour (170 mg-PtCo L⁻¹) and DON (2.5 mg L⁻¹) for a biological nutrient removal STP, owing to an industrial supply of melanoidin containing molasses fermentation wastewater. Alum coagulation jar tests were performed on synthetic melanoidin solution, STP effluent containing melanoidin (Wetalla, Toowoomba, Australia) and STP effluent free of melanoidin (Merrimac, Gold Coast, Australia) to examine the treatability of melanoidin and its associated colour and DON content when present in STP effluent.The removal of melanoidin from STP effluent resulted in significant colour and DON reduction. An alum dose of 30 mg L⁻¹ as aluminium was sufficient to reach maximum removal of colour (75%), DON (42%) and dissolved organic carbon (DOC) (30%) present in melanoidin containing STP effluent. Alum was shown to preferentially remove DON with a molecular weight >10 kDa over small molecular weight DON. Fluorescence excitation-emission matrix examination of the humic compounds present in the STP effluent indicated that melanoidin type humic compounds were more readily removed by alum coagulation than other humic compounds.     

建立高含硫气田生态监测体系分析

针对西南某气田投产运行后,净化厂尾气、集气站火炬等正常生产和事故性放空等会排放大量二氧化硫的问题,及其对周边生态环境产生影响的现实,研究建立气田生态环境监测体系。通过现场踏勘、资料收集等手段,提出建立气田生态监测的布点网络、生态监测方法体系,重点探讨生物多样性及典型植物监测方法。通过在该气田实际监测得出该生态监测体系具有科学性、完整性、有效性等特点。     

Preliminary engineering application of microseismic monitoring technique to rockburst prediction in tunneling of Jinping Ⅱ project

Monitoring and prediction of rockburst remain to be worldwide challenges in geotechnical engineering.In hydropower,transportation and other engineering fields in China,more deep,long and large tunnels have been under construction in recent years and underground caverns are more evidently featured by ＂long,large,deep and in group＂,which bring in many problems associated with rock mechanics problems at great depth,especially rockburst.Rockbursts lead to damages to not only underground structures and equipments but also personnel safety.It has been a major technical bottleneck in future deep underground engineering in China.In this paper,compared with earthquake prediction,the feasibility in principle of monitoring and prediction of rockbursts is discussed,considering the source zones,development cycle and scale.The authors think the feasibility of rockburst prediction can be understood in three aspects：（1） the heterogeneity of rock is the main reason for the existence of rockburst precursors;（2） deformation localization is the intrinsic cause of rockburst;and（3） the interaction between target rock mass and its surrounding rock mass is the external cause of rockburst.As an engineering practice,the application of microseismic monitoring techniques during tunnel construction of Jinping II Hydropower Station was reported.It is found that precursory microcracking exists prior to most rockbursts,which could be captured by the microseismic monitoring system.The stress concentration is evident near structural discontinuities（such as faults or joints）,which shall be the focus of rockburst monitoring.It is concluded that,by integrating the microseismic monitoring and the rock failure process simulation,the feasibility of rockburst prediction is expected to be enhanced.     

Toxicity Measurements and Their Use in Treatment Strategies

The use of measured toxicity for evaluating the effects of a chemical or effluent on the environment, or monitoring the performance of an effluent treatment plant, is becoming increasingly important to complement the analytical techniques which are conventionally used. Although many consents on effluent discharges refer to specific chemical components, regulatory authorities are increasingly realizing the value of toxicity measurements to evaluate a combined effluent effect, particularly in the case of complex effluent streams.
This paper (a) describes the basic principles of conventional methods of measuring toxicity, (b) highlights the benefits and shortcomings of these methods, and (c) outlines some promising methodologies which are being developed. The use of these measurements is then discussed in evaluating treatment alternatives, modifying existing treatment plants and conducting treatment evaluations. Several case studies are outlined to illustrate the use of toxicological measurements in assessing industrial wastewater treatment processes.     

黄山世界遗产监测信息系统建设研究

监测和评估反馈是世界遗产保护管理的重要手段。随着科学技术的更新迭代,如何更有效地利用数字信息技术统筹各类监测活动,以及如何更充分地利用监测数据实现适应性管理,是各个世界遗产地普遍面临的挑战。黄山是世界自然文化双遗产,在生态环境保护、防灾减灾、游客管理等方面实施了一系列监测管理措施,但在监测项目统筹、数据管理和数据利用等方面还需进一步优化提升。通过构建适用于不同类型保护地管理目标的保护管理监测指标体系,统筹整合不同监测管理部门之间的监测需求,建立了监测数据定期收集、整理和分析的数字系统,形成了一套有效的监测信息集中管理和共享机制,为黄山世界遗产的保护管理决策提供了技术支持和制度保障,也为其他遗产地构建监测信息系统提供了案例借鉴。     

Enhancement of 2,4-dichlorophenol degradation in conventional activated sludge systems bioaugmented with mixed special culture

Efficient and reliable removal of recalcitrant compounds, which are present in wastewater intermittently, is critically important to prevent toxicity discharge and system upset, especially for those biotreatment systems with poor anti-shock loading capacity such as conventional activated sludge (CAS) systems. In this study, 2,4-dichlorophenol (2,4-DCP) was chosen as a model recalcitrant substance. 2,4-DCP degrading mixed culture was bioaugmented to a CAS system in terms of enhancing 2,4-DCP removal and maintaining system stability under shock loading conditions. The effects of bioaugmentation on the performance of CAS systems after single inoculation were investigated under long-term continuous operation, during which four times shock loading occurred. Results showed that the two bioaugmented CAS systems, which were inoculated with 5% and 15% 2,4-DCP degrading mixed culture, respectively, demonstrated and maintained stronger ability to degrade 2,4-DCP than the non-supplemented control one during the first three shock loading periods within the first month after the first inoculation. For the fourth 2,4-DCP shock loading which occurred 100 days after inoculation, the advantages demonstrated by the bioaugmented systems were greatly reduced compared to those of the previous three runs. In addition, ribosomal intergenic spacer analysis method was used to track the supplemented special culture and assay the effect of bioaugmentation on the changes of microbial community structure.     

Microbial interactions with tributyltin compounds: detoxification, accumulation, and environmental fate

While inorganic forms of tin are of relatively low toxicity towards microorganisms, the more lipid-soluble organotins can be highly toxic. Generally, trisubstituted (R3SnX) organotins are more toxic than di- (R2SnX2) and monosubstituted (RSnX3) compounds; the anion (X) apparently having little influence on toxicity. However, many microorganisms exhibit resistance to organotins, a phenomenon of relevance to the environmental cycling of organotins and also to novel biological methods of treatment. Organotin degradation can involve the sequential removal of organic moieties to yield less toxic derivatives, e.g. debutylation of tributyltin compounds to di- and monobutylins. Such degradation is known to take place in bacteria, algae and fungi, and this provides one route for detoxification. In addition, microorganisms are capable of accumulating tributyltin compounds, and this is another mechanism of removal from solution. The high lipid solubility of organotins ensures cell penetration and association with intracellular sites, while cell wall components also play an important role. Of the fungal wall components, melanin pigments are capable of TBT binding, and the addition of melanin to growing cultures can remove toxicity; melanised strains are also more sensitive than albino strains of the same species. To date, little attention has been paid to the biotechnological exploitation of these interactions for the degradation of tributyltin or its removal from solution. This paper describes some interactions of microorganisms (bacteria, cyanobacteria, microalgae, and fungi) with tributyltin compounds, with particular reference to toxicity, bioaccumulation and detoxification. Such processes should receive due consideration in any environmental management programme.