Pitfalls of passive mine water treatment

Passive (wetland) treatment of waters drainingabandoned and derelict mine sites has a numberof detractions. Detailed knowledge of many ofthe fundamental processes that dictate theperformance and longevity of constructedsystems is currently very limited and thereforemore research effort is needed before passivetreatment becomes an off-the-shelf technology.     

Life cycle assessment of municipal waste water systems

Life Cycle Assessment was applied to municipal planning in a study of waste water systems in Bergsjön, a Göteborg suburb, and Hamburgsund, a coastal village. Existing waste water treatment consists of mechanical, biological and chemical treatment. The heat in the waste water from Bergsjön is recovered for the district heating system. One alternative studied encompassed pretreatment, anaerobic digestion or drying of the solid fraction and treatment of the liquid fraction in sand filter beds. In another alternative, urine, faeces and grey water would separately be conducted out of the buildings. The urine would be used as fertilizer, whereas faeces would be digested or dried, before used in agriculture. The grey water would be treated in filter beds. Changes in the waste water system would affect surrounding technical systems (drinking water production, district heating and fertilizer production). This was approached through system enlargement. For Hamburgsund, both alternatives showed lower environmental impact than the existing system, and the urine separation system the lowest. Bergsjön results were more difficult to interpret. Energy consumption was lowest for the existing system, whereas air emissions were lower for the alternatives. Water emissions increased for some parameters and decreased for others. Phosphorous recovery was high for all three alternatives, whereas there was virtually no nitrogen recovery until urine separation was introduced.     

Subsurface-flow constructed wetlands in Spain for the sanitation of small communities: A comparative study

In comparison with other European countries, constructed wetlands may still be considered a recent technology in Spain. A survey of the systems treating urban wastewater in this country revealed that over 80% of subsurface-flow constructed wetlands have been built over the last 5 years, horizontal systems (HF-CW) alone or in combination with other unit processes such as ponds being the most widespread type. Organic loads ranged from 0.8 to 23, from 22.8 to 29.8 and from 3.6 to 16.7 g BOD m⁻² day⁻¹ for HF-CW (alone), vertical systems (VF-CW) and combined systems (HF-CW with other unit processes), respectively. The performance of such systems in terms of BOD₅ removal generally ranged from 80 to 95% in all cases (HF-CW, VF-CW and combined systems), whereas COD removal was slightly lower, ranging from 50 to 95%, 80 to 95% and 50 to 90% for the HF-CW, VF-CW and combined systems, respectively. Furthermore, the TSS removal rate ranged from 70 to 95% for combined systems and from 85 to 95% for HF-CW (alone). The systems were not very efficient in terms of nutrient removal (nitrogen and phosphorus), with total average removal efficiencies around 40–50%. In general terms, the analysis of constructed wetlands in Spain shows that although they operate with higher loads than in other European systems, their performance in terms of organic matter and nutrient removal is in the range of that described in previous studies.     

Long term performance of a constructed wetland for landfill leachate treatment

The constructed wetland (CW) was developed as a pilot integrated system for the capital city's old sanitary landfill site. It consisted of three interconnected beds, two of vertical flow and one of horizontal flow stage. The CW covered 311 m² with an intermittent hydraulic load of 0.5 cm d⁻¹, filled with sand media and planted with reeds and cattails. The performance efficiency of the CW systems was evaluated for 7 years through physical and chemical parameters. Some monitored parameters varied noticeable. The efficiency for COD was 50%, BOD₅ (59%), ammonia nitrogen (51%), nitrate (negative), total phosphorus (P) (53%), sulfates (negative), sulfides (49%), chlorides (35%), and Fe (84%). The average concentrations of suspended solids, COD, BOD₅, nitrate, total P, sulfates, sulfides, and Fe were below limits after treatment. The ratio between N and P showed a limited level of P for biological processes. The performance of the system did not vary significantly with regard to temperature, however, it varied with precipitation. The results showed that the CW system, as a tertiary system or as an independent system, could be a low-cost alternative for the treatment of leachate from old landfill sites.     

Effects of penitrem A on rat's performances in passive avoidance and Morris water maze tests

Intraperitoneal administration of the mycotoxin penitrem A 30 min before a training session in passive avoidance task, impaired performance of rats subjected to a test-session 24 h after. This effect was not antagonised by pretraining administration of physostigmine or bicuculline. Administration of penitrem A 20 min before a training session or 30 min before a test-session did not impair performance. In the Morris water maze, doses of penitrem A that induces slight to moderate tremors, but not a lower dose, disrupted place learning. These results suggest that penitrem A disrupts the processes that take place at the time of acquisition, but not those just after acquisition, and does not alter the restitution of information. This effect would not be related to a decrease of cholinergic neurotransmission nor to a stimulation of GABA A receptors. Nevertheless, it could not be totally excluded that the performance impairments induced by penitrem A would be secondary to a motor disruption. This revised version was published online in June 2006 with corrections to the Cover Date.     

Arsenic exposure and cancer risk reduction with local ordinance requiring whole-house dual-tank water treatment systems

Arsenic, a known human carcinogen, occurs naturally in groundwater in New Jersey and many other states and countries. A number of municipalities in the Piedmont, Highlands, and Valley and Ridge Physiographic Provinces of New Jersey have a high proportion of wells that exceed the New Jersey maximum contaminant level (MCL) of 5 µg/L. Hopewell Township, located in Mercer County and the Piedmont Province, has a progressive local ordinance which requires the installation of dual-tank, point-of-entry treatment systems on affected wells. This provided a unique study opportunity. Of the 55 homes with dual-tank POE treatment systems recruited into this study, 51 homes (93%) had arsenic levels under the MCL at the kitchen sink, regardless of years in service and/or maintenance schedule adherence. Based on the study participants’ water consumption and arsenic concentrations, we estimate that Hopewell's arsenic water treatment ordinance, requiring POE dual-tank arsenic treatment, reduced the incidence of excess lifetime (70-year) bladder and lung cancers from 121 (1.7 cancer cases/year) to 16 (0.2 cancer cases/year) preventing 105 lifetime cancer cases (1.5 cases/year). Because the high risk of cancer from arsenic can be mitigated with effective arsenic water treatment systems, this ordinance should be considered a model for other municipalities.     

Performance of stationary and portable passive transponder detection systems for monitoring of fish movements

A stationary system for long-range detection of PIT tags in fish was efficient under high water conditions in streams. A portable system was particularly effective for detecting habitat use by fish without recapture.     

人工湿地污水处理系统研究及性能改进分析

人工湿地污水处理系统是有效的污水处理与水资源再用相结合的方法,与传统的污水处理法相比具有基建、运行费用低,操作与维护简单等优点。该系统已被广泛应用于生活污水的处理,并通过工艺创新有向工业污水、农业废水等特殊污水处理方向发展的趋势。本文总结了人工湿地系统的研究现状,预测其研究与应用发展的趋势,探讨不同类型的污水在人工湿地系统中的净化过程,分析影响人工湿地污水处理性能的因素及技术性能改进的一些措施,并探讨人工湿地污水处理系统的应用前景。     

Applying geographic information systems and remote sensing for water quality assessment of mangrove forest

The study of environmental conditions is one of the most important measures in the field of reforestation. The present study was undertaken to assess the environmental status of the mangrove forest of Alibaug, Maharashtra, India with respect to different sixteen physicochemical parameters of water using Geographical information system (GIS) for rehabilitation, conservation and development of the destructed area of the mangrove forest. The Base map of study area was prepared using topographic map and the remote sensing data of Landsat 7 ETM + for spatial analysis. The distributions of water pollutants were assigned using a GIS approach of Inverse Distance Weighted (IDW). The results showed that the amounts of EC, COD, hardness, O&G, Cl^?, Na⁺, Ca^2 +, Mg^2 +, NO₃^? and PO₄^3? are higher than the normal ranges in mangrove forest due to natural processes and human activity, industrial and domestic wastewater disposal, oil spillage and agricultural runoff which all eventually affect the water quality of mangrove forest of Alibaug. To identify the areas within the normal ranges of 16 studied parameter, suitability map of water was prepared through an integration of 16 suitability maps of the studied parameters. The suitability map of water classified the water to six classes of suitability in order of moderate > moderate to high > low to moderate > high > low suitable. The areas with classes of 1 and 2 were suitable for the protective measures. Classes 3 and 4 were suitable for replantation and restoration of native mangrove species as well as local communities' cooperation in the participatory protection measures. The areas of classes 5 and 0 need to be designed an urgent management and mitigation plan to reduce impact of human activities. The result of the study also proves the use of GIS as a powerful tool in addressing assessment and monitoring programs of the water quality in the mangrove ecosystems.     

Two‐tiered methodology for the assessment and projection of mine vegetation rehabilitation against mine closure restoration goal

Reinstatement of a ‘self‐sustaining native ecosystem’ is an increasingly common revegetation goal for open‐cut mines in Australia. This is usually applied as a regulatory requirement for mine closure, with some mines aiming for a high standard of ‘ecological restoration’. There is a growing appreciation that ecological restoration outcomes of mine rehabilitation are unachievable within the life of a mine and that assessment methodologies are subjective and inadequate to provide the high degree of confidence needed for mine closure. Here we elaborate on the integration of the BioCondition assessment and the Ecosystem Dynamics Simulator (EDS) trajectory methodologies. We also demonstrate an alternative early relinquishment assessment criteria similar to that used for early recruitment of regrowth native vegetation that exhibit structural characteristics of undisturbed native vegetation into remnant status in Queensland. We used ten age cohorts of rehabilitation ranging from three to 22 years at Meandu coal mine, south‐east Queensland. All the sites gained average BioCondition scores ranging from 19 to 44 out of possible score of 65. Growth trajectories indicated decline in species and basal area on all sites in the next three decades as the dense stock of short‐lived acacia species senesce and die. None of the sites are projected to meet self‐sustaining status by 2072, but there is evidence in some of a progression. All the sites except two (K2.3 and SW2) are projected to achieve remnant vegetation status by 2062. Applying the remnant vegetation criteria results in shorter timeframes and robustly evaluates whether sites are progressing towards the self‐sustaining ecosystem mine closure goal.     

Evaluation of methodology for detection of human adenoviruses in wastewater,drinking water,stream water and recreational waters

Aims: This study evaluates dialysis filtration and a range of PCR detection methods for identification and quantification of human adenoviruses in a range of environmental waters. Methods and Results: Adenovirus was concentrated from large volumes (50–200 l) of environmental and potable water by hollow fibre microfiltration using commercial dialysis filters. By this method, an acceptable recovery of a seeded control bacteriophage MS2 from seawater (median 95·5%, range 36–98%, n = 5), stream water (median 84·7%, range 23–94%, n = 5) and storm water (median 59·5%, range 6·3–112%, n = 5) was achieved. Adenovirus detection using integrated cell culture PCR (ICC‐PCR), direct PCR, nested PCR, real‐time quantitative PCR (qPCR) and adenovirus group F‐specific direct PCR was tested with PCR products sequenced for confirmation. Adenovirus was routinely detected from all water types by most methods, with ICC‐PCR more sensitive than direct‐nested PCR or qPCR. Group F adenovirus dominated in wastewater samples but was detected very infrequently in environmental waters. Conclusions and Implications: Human adenoviruses (HAdv) proved relatively common in environmental and potable waters when assessed using an efficient concentration method and sensitive detection method. ICC‐PCR proved most sensitive, could be used semiquantitatively and demonstrated virus infectivity but was time consuming and expensive. qPCR provided quantitative results but was c. ten‐fold less sensitive than the best methods.     

Experience with establishment and operation of reed bed treatment for small communities in the UK

The design and development of constructed reed beds for secondary, tertiary and storm outflow treatment is described from the experience of a major water utility in the Midland region of the UK. There were only two trial sites in 1987, but 125 sites by June 1995. The problems and their resolution with the establishment ofPhragmites in gravel filled beds are described.Two secondary treatment systems with horizontal subsurface flow beds arranged in terraces show that dilute sewage can be treated to a good secondary standard, but that nitrification is likely to be only partially complete. The example of four tertiary treatment applications showed that, for beds sized at 0.7 to 1.2 m²/pe, effluents consistently averaged better than 5 mg/l BOD₅ and 10 mg/l TSS. Three sites showed improved removal of ammonium nitrogen (N) after the first year, with better than 50% removal. One site, treating highly nitrified secondary effluent, showed a small net increase in ammonium-N even after 4 years. Samples taken by the regulatory authority from 79 sites confirm the ability of the system to meet tight standards for BOD₅. A comparison made of the performance of storm reed beds during three storm events showed relatively consistent removal of BOD, TSS, ammonia nitrogen and TON.     

An assessment of the presence and health risks of endocrine-disrupting chemicals in the drinking water treatment plant of Wu Chang,China

An assessment of the presence and health risks of endocrine-disrupting chemicals in the drinking water treatment plant (DWTP) of Wu Chang was performed. A recombinant yeast assay was used to assess the endocrine disrupting activity of the effluents of the DWTP. Agonistic activities of the estrogen receptor and androgen receptor were not detected in any of the effluent samples. However, anti-estrogenic and anti-androgenic activities were observed. In addition, the removal rates of the DWTP for the anti-androgenic activities were limited. A health risk assessment was performed on the basis of the results of the recombinant yeast assay, and the total daily production of hormones was used to evaluate the health risks of these types of endocrine-disrupting chemicals. The predicted effects of the anti-estrogenic and anti-androgenic disrupting activities were below 1.5%. This study suggested that the combined toxicity bioassays with health risk assessment could provide an available method to assess endocrine-disrupting chemicals and to evaluate the potential adverse effects on human health for aquatic environmental samples.     

Start-up performance and granular sludge features of an improved external circulating anaerobic reactor for algae-laden water treatment

The microbial characteristics of granular sludge during the rapid start of an enhanced external circulating anaerobic reactor were studied to improve algae-laden water treatment efficiency. Results showed that algae laden water was effectively removed after about 35 d, and the removal rates of chemical oxygen demand (COD) and algal toxin were around 85% and 92%, respectively. Simultaneously, the gas generation rate was around 380 mL/gCOD. The microbial community structure in the granular sludge of the reactor was complicated, and dominated by coccus and filamentous bacteria. Methanosphaera, Methanolinea, Thermogymnomonas, Methanoregula, Methanomethylovorans, and Methanosaeta were the major microorganisms in the granular sludge. The activities of protease and coenzyme F₄₂₀ were high in the granular sludge. The intermittent stirring device and the reverse-flow system were further found to overcome the disadvantage of the floating and crusting of cyanobacteria inside the reactor. Meanwhile, the effect of mass transfer inside the reactor can be accelerated to help give the reactor a rapid start.     

Challenges and opportunities in the use of iron in water and wastewater treatment

Even though iron salts are widely used in waterand wastewater treatment, many questionssurrounding the use of this element remain.Issues surrounding the impact of mixingconditions on floc structure and strength, theeffect of reduction of ferric iron species onanaerobic sludge properties (includingdewatering) and the possible options for choiceof ligand in the modified photo-Fenton processfor contaminant oxidation are discussed andaspects requiring further attention in theseand other areas involving iron transformationspresented.     

城市黑臭水体形成机理与评价方法研究进展

黑臭水体是水体污染的一种极端现象.造成黑臭水体的主要污染源包括有机污染物、底泥再悬浮以及水体热污染,城市水循环条件不足是引起黑臭水体的水动力学因素.从黑臭形成化学机理看,致黑物质主要包括悬浮物、Fe、S元素及其化合物FeS;致臭物质主要包括H₂S、NH₃等小分子气体以及硫醚类(VOSCs)、乔司脒和2-二甲基异莰醇等化合物.本文重点从黑臭评价指标、黑臭指数法、多元线性回归模型以及综合评价法4个方面对黑臭水体评价方法进行对比与总结,并对未来城市黑臭水体研究进行展望,旨在进一步明确城市黑臭水体判别技术,为城市水环境治理和水生态维护提供依据.     

Life cycle assessment of fuel cell vehicles a methodology example of input data treatment for future technologies

Life cycle assessment (LCA) will always involve some subjectivity and uncertainty. This reality is especially true when the analysis concerns new technologies. Dealing with uncertainty can generate richer information and minimize some of the result mismatches currently encountered in the literature. As a way of analyzing future fuel cell vehicles and their potential new fuels, the Fuel Upstream Energy and Emission Model (FUEEM) developed at the University of California—Davis, pioneered two different ways to incorporate uncertainty into the analysis. First, the model works with probabilistic curves as inputs and with Monte Carlo simulation techniques to propagate the uncertainties. Second, the project involved the interested parties in the entire process, not only in the critical review phase. The objective of this paper is to present, as a case study, the tools and the methodologies developed to acquire most of the knowledge held by interested parties and to deal with their — eventually conflicted—interests. The analysis calculation methodology, the scenarios, and all assumed probabilistic curves were derived from a consensus of an international expert network discussion, using existing data in the literature along with new information collected from companies. The main part of the expert discussion process uses a variant of the Delphi technique, focusing on the group learning process through the information feedback feature. A qualitative analysis indicates that a higher level of credibility and a higher quality of information can be achieved through a more participatory process. The FUEEM method works well within technical information and also in establishing a reasonable set of simple scenarios. However, for a complex combination of scenarios, it will require some improvement. The time spent in the process was the major drawback of the method and some alternatives to share this time cost are suggested.     

Status of water environment pollution in the Xixi Wetland and its ecological treatment countermeasures

In this paper,the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey data.Based on the status of water quality and its functional requirements as an urban wetland,biological-ecological countermeasures were suggested.The experimental use of ecological technologies,such as artificial wetlands,ecological aquiculture and artificial floating island,were done in several fish ponds in the Xixi Wetland.Water monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective.