Appropriate technology for municipal sewerage/excreta management in developing countries, Thailand case study

Design criteria for planning urban sewerage/excreta management systems appropriate for developing countries as distinguished from affluent industrialized country practices.     

经济发达地区的生态农业发展战略--以江苏省江阴市为例

我国的经济发达地区普遍存在着人地关系紧张、环境质量恶化和农产品质量下降等问题,发展生态农业是缓解这些矛盾的重要途径。本文以江阴市为例,分析了经济发达地区农业发展中存在的主要制约因素,强调了区内发展生态农业的迫切性和优势条件,根据区域社会经济发展特点,指出该市应以为中心城市服务的都市生态农业为发展方向,借鉴发达国家生态农业建设的先进经验,将生态农业建设与农业现代化建设有机地结合起来,探索和推广适合本地特点的精准设施农业技术,达到节约水、肥资源,提高农产品产量和品质的目的。     

Modeling integrated urban water systems in developing countries: case study of Port Vila,Vanuatu

Developing countries struggle to provide adequate urban water services, failing to match infrastructure with urban expansion. Despite requiring an improved understanding of alternative infrastructure performance when considering future investments, integrated modeling of urban water systems is infrequent in developing contexts. This paper presents an integrated modeling methodology that can assist strategic planning processes, using Port Vila, Vanuatu, as a case study. 49 future model scenarios designed for the year 2050, developed through extensive stakeholder participation, were modeled with UVQ (Urban Volume and Quality). The results were contrasted with a 2015 model based on current infrastructure, climate, and water demand patterns. Analysis demonstrated that alternative water servicing approaches can reduce Port Vila’s water demand by 35 %, stormwater generation by 38 %, and nutrient release by 80 % in comparison to providing no infrastructural development. This paper demonstrates that traditional centralized infrastructure will not solve the wastewater and stormwater challenges facing rapidly growing urban cities in developing countries.     

中国城市矿产开发潜力、问题及对策研究

城市矿产以开发城市废弃物中人类所需的各类矿产资源为目的,为解决中国面临的资源和环境问题提供了一个有效的解决方案。从中国城市矿产的开发现状着手,重点分析了中国城市矿产的开发潜力,并对当前城市矿产开发过程中面临的问题进行了讨论,最终提出了未来推动中国城市矿产有效开发利用的对策建议,以期对中国城市矿产的发展起到一定的积极意义。     

Equivocating on the polluter-pays principle: The consequences for Pakistan

The polluter-pays principle has been widely implemented in OECD countries and credited for bring about a significant reduction in pollutant discharge. However, it has had only limited implementation in developing countries. The consequences of not implementing it in developing countries, to the extent they are documented, are limited to estimating the economic damages of environmental degradation. Yet there are several other but seldom documented negative consequences of the failure to implement the polluter-pays principle. These consequences are documented in the case of Pakistan. They include limited construction of effluent treatment plants, heavy dependence on the government and international donors for funding the only two operational common effluent treatment plants, significant operational issues at the two common effluent treatment plants, missed opportunities to build cost-effective common effluent treatment plants and minimal environmental improvements from isolated investments in individual effluent treatment plants in addition to the already documented significant level of environmental degradation due to uncontrolled pollutant discharge.     

Zonal management of arsenic contaminated ground water in Northwestern Bangladesh

This paper used ordinary kriging to spatially map arsenic contamination in shallow aquifers of Northwestern Bangladesh (total area  35,000 km²). The Northwestern region was selected because it represents a relatively safer source of large-scale and affordable water supply for the rest of Bangladesh currently faced with extensive arsenic contamination in drinking water (such as the Southern regions). Hence, the work appropriately explored sustainability issues by building upon a previously published study (Hossain et al., 2007; Water Resources Management, vol. 21: 1245–1261) where a more general nation-wide assessment afforded by kriging was identified. The arsenic database for reference comprised the nation-wide survey (of 3534 drinking wells) completed in 1999 by the British Geological Survey (BGS) in collaboration with the Department of Public Health Engineering (DPHE) of Bangladesh. Randomly sampled networks of zones from this reference database were used to develop an empirical variogram and develop maps of zonal arsenic concentration for the Northwestern region. The remaining non-sampled zones from the reference database were used to assess the accuracy of the kriged maps. Two additional criteria were explored: (1) the ability of geostatistical interpolators such as kriging to extrapolate information on spatial structure of arsenic contamination beyond small-scale exploratory domains; (2) the impact of a priori knowledge of anisotropic variability on the effectiveness of geostatistically based management. On the average, the kriging method was found to have a 90% probability of successful prediction of safe zones according to the WHO safe limit of 10 ppb while for the Bangladesh safe limit of 50 ppb, the safe zone prediction probability was 97%. Compared to the previous study by Hossain et al. (2007) over the rest of the contaminated country side, the probability of successful detection of safe zones in the Northwest is observed to be about 25% higher. An a priori knowledge of anisotropy was found to have inconclusive impact on the effectiveness of kriging. It was, however, hypothesized that a preferential sampling strategy that honored anisotropy could be necessary to reach a more definitive conclusion in regards to this issue.     

Decentralized approaches to wastewater treatment and management: applicability in developing countries

Providing reliable and affordable wastewater treatment in rural areas is a challenge in many parts of the world, particularly in developing countries. The problems and limitations of the centralized approaches for wastewater treatment are progressively surfacing. Centralized wastewater collection and treatment systems are costly to build and operate, especially in areas with low population densities and dispersed households. Developing countries lack both the funding to construct centralized facilities and the technical expertise to manage and operate them. Alternatively, the decentralized approach for wastewater treatment which employs a combination of onsite and/or cluster systems is gaining more attention. Such an approach allows for flexibility in management, and simple as well as complex technologies are available. The decentralized system is not only a long-term solution for small communities but is more reliable and cost effective. This paper presents a review of the various decentralized approaches to wastewater treatment and management. A discussion as to their applicability in developing countries, primarily in rural areas, and challenges faced is emphasized all through the paper. While there are many impediments and challenges towards wastewater management in developing countries, these can be overcome by suitable planning and policy implementation. Understanding the receiving environment is crucial for technology selection and should be accomplished by conducting a comprehensive site evaluation process. Centralized management of the decentralized wastewater treatment systems is essential to ensure they are inspected and maintained regularly. Management strategies should be site specific accounting for social, cultural, environmental and economic conditions in the target area.     

The weight method: a new screening method for estimating pesticide deposition from knapsack sprayers in developing countries

Investigations of occupational and environmental risk caused by the use of agrochemicals have received considerable interest over the last decades. And yet, in developing countries, the lack of staff and analytical equipment as well the costs of chemical analyses make it difficult, if not impossible, to monitor pesticide contamination and residues in humans, air, water, and soils. A new and simple method is presented here for estimation of pesticide deposition in humans and soil after application. The estimate is derived on the basis of water mass balance measured in a given number of high absorbent papers under low evaporative conditions and unsaturated atmosphere. The method is presented as a suitable, rapid, low cost screening tool, complementary to toxicological tests, to assess occupational and environmental exposure caused by knapsack sprayers, where there is a lack of analytical instruments. This new method, called the “weight method”, was tested to obtain drift deposition on the neighbouring field and the clothes of the applicator after spraying water with a knapsack sprayer in one of the largest areas of potato production in Colombia. The results were confirmed by experimental data using a tracer and the same set up used for the weight method. The weight method was able to explain 86% of the airborne drift and deposition variance.     

微生物絮凝剂的研究现状与发展趋势

相对于传统絮凝剂而言,微生物絮凝剂具有絮凝效果好、应用范围广、易生物降解、对环境安全、无二次污染的特点。文章综述了微生物絮凝剂的类型和特点,详细阐述了其絮凝机理,分析了影响微生物絮凝剂絮凝性能的因素以及微生物絮凝剂在水处理中的应用。指出了当前微生物絮凝剂研究存在的问题以及今后的发展趋势。     

中亚五国气溶胶光学厚度时空分布特征研究

气溶胶时空变化是影响气溶胶气候效应不确定性的主要因素之一.在生态环境脆弱的中亚五国(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦和塔吉克斯坦)研究气溶胶光学厚度(Aerosol Optical Depth,AOD)的时空变化对中亚地区及全球生态环境和气候变化具有重要意义.基于2002-2019年MODIS 04_...