引入ISO9000标准提升环卫作业企业管理质量

根据ISO9001质量管理体系要求,结合常州市环卫事业发展要求,阐释引入ISO9001质量管理体系并运用于环卫作业企业管理质量控制中的必要性和可行性,并提出环卫作业企业质量管理策划、控制、监测和改进的方法。     

Changing Ownership Structures in the Water Supply and Sanitation Sector

Abstract

The development over time of the water supply and sanitation sectors in four countries is analyzed to reveal the changing role of the private sector. In some cases, local, small-scale private water supply and sanitation systems have been able to develop progressively into large-scale official systems, which may later be privatized. In other cases, foreign capital has been more significant in the development of modern water supply and sanitation systems, particularly where privatization has occurred much earlier in the national development process. In much of the developing world, domestic water supply and sanitation is dominated not by the official water supply and sanitation companies but by independent operators who function without subsidies but with enormous variability in terms of quality of service and prices offered. However, they are constrained generally by the absence of appropriate institutional and legal frameworks, including the lack of independent regulatory authorities. There is a need, where appropriate, to continue to encourage large-scale private sector involvement in the official water supply sectors of the developing world. At the same time though, it is only by promoting policies that also further the development (where appropriate) of the independent water supply and sanitation providers that access to water supply and sanitation services can be maximized since better use of local resources in many developing countries, both local human resources and capital, provide a key means for improving access to water supply and sanitation.     

A case study of urban water balancing in the partly sewered city of Nablus-East (Palestine) to study wastewater pollution loads and groundwater pollution

Untreated sewage can contribute a significant proportion of urban groundwater recharge, via on-site sanitation facilities and sewer exfiltration. In the West Bank of the Palestinian Territories 94% of sewage is discharged untreated to the ground or surface waters. This has contributed to increasing nitrate concentrations in groundwater, which is the critical water source. In this case study of a drainage catchment from the city of Nablus, a water balance indicates that sewage as a source of groundwater recharge is as much as 50% of total recharge from precipitation, and nitrogen pollutant loads by area are up to 60% as much as those from agriculture. Results suggest that 22% of total wastewater flow directly infiltrates the ground via cesspits and sewer exfiltration.     

Water,sanitation and hygiene and indigenous peoples: a review of the literature

The levels of sanitation and water services coverage as well as health attainment are low among indigenous peoples. This exclusion from basic service has not been sufficiently studied. The present review has analyzed 185 articles dealing with indigenous peoples and the water, sanitation and hygiene complex. The literature is dramatically skewed towards water resources, and overwhelmingly focused on conflicts, at the expense of basic sanitation and hygiene. More initiatives towards the acknowledgement of indigenous peoples’ world-views and institutions in all aspects of the water management cycle are needed. To this end, the development of effective intercultural dialogue mechanisms is crucial.     

Governance structures and their impact on tariff levels of Brazilian water and sanitation corporations

This study analyzes the effect of governance structure on the tariff levels applied by Brazilian corporations of water supply and sanitation. It aims to contribute to the traditional debate of public versus private management, and to determine the effect of regulatory structure on tariff levels. The results first show that, when jointly considered, the water supply and sanitation tariff levels are higher for privately managed corporations. Second, we have found that a corporation regulated by a local agency or a regional agency does not exhibit significantly lower tariff levels than unregulated corporations. Finally, the results indicate that the use of the rate of return and price cap/revenue cap regimes do not provide tariff levels lower than those set via negotiation with the municipality.     

Assessment of greywater reuse as a potential mitigation measure for water shortages and sanitation problems in senior high schools

The study assessed water shortages and its effects on sanitation in Senior High Schools using structured questionnaires involving water availability, water use pattern and perception of greywater reuse. Additionally, an observation of the sanitation situation was done to validate the responses. The study found that water availability was an issue as this caused students to use more than an hour round trip to access water resulting in poor sanitation and hygiene practices. Meanwhile, an average greywater generation rate of 14.5 L per person per day, is always disposed of despite its potential reuse. Greywater reuse was accepted by respondents as 59% proposed reusing it if available for non‐potable applications (94%) such as toilet cleaning and flushing. This is because, there is a significant association between cleanliness of the toilet facilities and usage (P < 0.05). Respondents who declined greywater reuse cited health risks (58%), uncomfortable feeling (37%) and cultural issue (5%).     

城市环卫专项规划的评估与保障措施

根据城市环境卫生现状及问题,结合社会经济发展特点,分析城市环境卫生专项规划的层次、目标和主要内容,提出对城市环境卫生专项规划评估、实施的保障措施。     

Assessing nutrient flows in septic tanks by eliciting expert judgement: a promising method in the context of developing countries

Simple models based on the physical and biochemical processes occurring in septic tanks, pit and urine diversion latrines were developed to determine the nutrient flows in these systems. Nitrogen and phosphorus separation in different output materials from these on-site sanitation installations were thus determined. Moreover, nutrient separation in septic tanks was also assessed through literature values and by eliciting expert judgement. Use of formal expert elicitation technique proved to be effective, particularly in the context of developing countries where data is often scarce but expert judgement readily available. In Vietnam, only 5-14% and 11-27% of the nitrogen and phosphorus input, respectively, are removed from septic tanks with the faecal sludge. The remaining fraction leaves the tank via the liquid effluent. Unlike septic tanks, urine diversion latrines allow to immobilize most of the nutrients either in form of stored urine or dehydrated faecal matter. These latrines thus contribute to reducing the nutrient load in the environment and lowering consumption of energy and non-renewable resources for fertiliser production.     

Anaerobic biodegradability and treatment of grey water in upflow anaerobic sludge blanket (UASB) reactor

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30 degrees C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52-64% was obtained at HRT between 6 and 16 h. The UASB reactor removed 22-30% and 15-21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0.18 and 0.28 kg COD/(kg VS d).     

两种稀土纳米材料对红细胞脆性的影响

为研究稀土纳米材料对红细胞脆性的影响，以豚鼠作为实验对象，将稀土纳米材料配成质量浓度分别为100g／L和500g／L的两种溶液，通过皮肤接触、口腔摄入、静脉注射和肌肉注射4种途径作用于豚鼠，采用红细胞脆性试验观察了动物血液指标之一——红细胞脆性的变化。结果发现，豚鼠接触该类稀土纳米材料后，红细胞的脆性与对照组相比升高。这说明稀土纳米材料对红细胞膜的结构产生了破坏，同时红细胞脆性的增加也表明该材料在豚鼠体内引起了遗传性球形红细胞增多症或自身免疫性溶血性贫血等疾病。