Urbanisation Without Development: Environmental and Health Implications in African Cities

Sustainable development advocates for a balance between socio-economic development and the environment in the pursuit of human advancement. In Africa, high population growth and inadequate infrastructure in urban areas exert pressure on the environment and this threatens the health and wellbeing of urban residents. The population of the African continent until the 1960s was predominantly rural. This scenario has taken a swift turn and some of the major shifts in the global urbanisation process are taking place on the continent. Factors including natural increase in the population, rural–urban migration, strife and hunger leading to the internal displacement of populations have exacerbated the urbanisation process in Africa. The situation has been worsened by the imposition of Western development policies, including structural adjustment programmes on African nations, which has eroded the subsistence base of rural agricultural communities and further ignited rural urban migration. The failure of industry to absorb the increasing labour force has created massive unemployment and deepening poverty crisis in urban centres. Inadequate provision of infrastructure and services to meet the growth in urban populations has resulted in inefficient spatial development of urban centres, the proliferation of squatter settlements, inadequate basic amenities including potable water, sanitation and waste disposal. Poor environmental sanitation has resulted in the upsurge of infectious diseases and deteriorating urban health. Urban populations in Africa are also the worst affected by newly emerging diseases, particularly HIV/AIDS. The poor bear a disproportionately large share of the problems due to their particular vulnerability to environmental and health risks. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

WATER RESOURCES MANAGEMENT: INTERNATIONAL CHALLENGE AND OPPORTUNITIES1

The entire water resources field is not contemplated, although reference thereto will be registered. Water supply for potable and hygienic purposes will be presented as symbolic of the global issues confronting 4.8 billion people. Some two billion of these live in the so-called developing or less favored countries. They are either underserved or not served at all by utility systems of whatever grade. Targets for meeting their needs were exemplified by the international agencies in the International Water and Sanitation Decade of 1980-1990. Some successes are apparent, but, in general, hopes are not fulfilled. The pace of accomplishment is very slow. Constraints will be reviewed in some detail. Challenges for reducing these and increasing pace of installations are presented. The potential for a global public works program unprecedented in history is reviewed. Several issues will not be discussed in this paper. Their omission rests primarily upon the fact that their resolution is improbable for decades ahead, if ever. Economists have categorized water as any other economic commodity - and should always be subject to benefit-cost scrutiny. I do not share that view. People could well live without the telephone or the automobile, a destroyer. Without water, their survival is a matter of days. Cost-benefit seems unreal and singularly inappropriate under such circumstances. Secondly, the search for quantifying the health impact of safe water goes on forever. My view is that the results speak for themselves - while sturdy souls continue to seek out the exact correlation figure. Thirdly, the population explosion, although softened a bit, proceeds apace while I write. Lastly, the exposition herein is restricted to potable water and its associated sanitation aspects. Other major uses of water, obviously highly important, are not addressed.     

Climate and Water Conflicts Coevolution from Tropical Development and Hydro‐Climatic Perspectives: A Case Study of Costa Rica

Costa Rica is a nation with a vast wealth of water resources; however, recently the country has faced water conflicts (WC) due to social, economic, legal, and political impediments in response to limited water availability during El Niño events and inefficient use of its water resources. This study presents a spatial distribution and temporal analysis of WC in Costa Rica from 2005 to 2015. In total, 719 WC were analyzed of which 54% were among private individuals and government. The largest urban areas and the Grande de Tárcoles Basin were identified as the main “hot spot” for the conflicts. WC were mainly caused by spills of wastewater, water pollution, water shortage, infrastructure damage, and flooding, and can be predicted using a multiple linear model including the population size and the number of hydro‐meteorological events (HME) (R² = 0.77). The identified HME also coevolved significantly with the changes in precipitation regimes (r = 0.67, p = 0.021). Our results suggest that there is a need to recognize that water infrastructure longevity across the country concatenates and amplifies WC, mainly in the most populated area located in the Central Valley. Implications of our findings include the need for truly integrated water resources management plans that include, for example, WC as indicators of hydro‐climatic changing conditions and water supply and sanitation infrastructure status.     

试论农村居民点的环境优化

作者从现今农村居民点存在的主要环境问题入手，分析了广大农村居住环境脏、乱、差的客观及主观原因，并就此提出了8条切合实际的整改措施。     

20世纪末至21世纪初欧洲21国国民的健康、劳动卫生与安全状况

重点介绍了英国、法国、德国、意大利、芬兰、瑞典、挪威、西班牙、瑞士和俄联邦等21个欧洲国家的国民健康水平，以及职业病和劳动安全状况。     

垃圾卫生填埋技术

介绍我国第一座现代化城市生活垃圾卫生填埋场－深圳市下坪固体废弃物填埋场的卫生填埋技术设施,如防渗设施、垃圾渗沥液导流设施、场外排水设施和场内清污分流设施等;垃圾卫生填埋工艺技术及作业方法,如分区分层填埋法、单元作业法和高效作业法;垃圾填埋场的环境监测项目及监测成果。     

Field survey of a sustainable sanitation system in a residential house

Sustainable sanitation is an approach for more ecological and sustainable water resources management. In this paper, we proposed one of the new integrated waste treatment systems： an ＂sustainable sanitation system＂ that includes separation of the black water from water system by a non-flushing toilet （bio-toilet）, and a gray water treatment based on a biological and ecological concept. Sustainable sanitation system also converts the domestic waste to soil conditioners and fertilizers, for farmland use. As one of the case studies, Environmentally Symbiotic Housing in which people actually live using the bio-toilet for the black water treatment and the household wastewater treatment facility for the gray water was introduced. The availability of this system was investigated by analyzing the sawdust used in the bio-toilet and the quality of the effluent in the household wastewater treatment facility. As the result, the water content of the sawdust did not exceed 60% in any of the sampling points and the BOD and COD of the effluent of the household wastewater treatment facility were below 10 and 20 mg/L respectively, due to the low loading. Compared to the pollution load on the water environment created by the conventional system, it was found that the effluent of the house has a lower load than the tertiary treatment and the volume of the water consumption is 75% of the conventional system.     

新疆农村饮水工程卫生状况调查

对全疆 2 1 0 4个农村饮水工程进行了水源类型、工程类型、水质处理、卫生防护设施、饮水消毒措施及卫生管理情况进行了调查。结果表明 :全疆农村大部分地区在水源类型选择、工程类型选择、卫生防护设施及卫生管理上均有较大的改善和提高 ,但水质处理、饮水消毒率均较低 ,分别为 1 8.54 %和 1 8.73% ,尚需加强和改善。     

Composting toilets as a sustainable alternative to urban sanitation – A review

In today’s flush based urban sanitation systems, toilets are connected to both the centralized water and wastewater infrastructures. This approach is not a sustainable use of our water and energy resources. In addition, in the U.S., there is a shortfall in funding for maintenance and upgrade of the water and wastewater infrastructures. The goal of this paper was to review the current knowledge on composting toilets since this technology is decentralized, requires no water, creates a value product (fertilizer) and can possibly reduce the burden on the current infrastructure as a sustainable sanitation approach. We found a large variety of composting toilet designs and categorized the different types of toilets as being self contained or central; single or multi chamber; waterless or with water/foam flush, electric or non-electric, and no-mix or combined collection. Factors reported as affecting the composting process and their optimum values were identified as; aeration, moisture content (50–60%), temperature (40–65 °C), carbon to nitrogen ratio (25–35), pH (5.5–8.0), and porosity (35–50%). Mass and energy balance models have been created for the composting process. However there is a literature gap in the use of this knowledge in design and operation of composting toilets. To evaluate the stability and safety of compost for use as fertilizer, various methods are available and the temperature–time criterion approach is the most common one used. There are many barriers to the use of composting toilets in urban settings including public acceptance, regulations, and lack of knowledge and experience in composting toilet design and operation and program operation.     

中国环境卫生标准体系设计研究

我国现有的环境卫生标准体系与环境保护目标相脱节、体系定位模糊、体系框架未体现专业化,且对流程管理和质量管理重视不足、体系结构不合理。所以重新设计中国环境卫生标准体系应遵循的原则包括以环境保护为最终目标、应用生命周期管理原则、区分强制性与推荐性标准、标准在体系框架内分布合理。据此设计了"专业—流程—质量"三维体系框架及各专业分体系。建议以新框架指导标准制(修)订;推进环境卫生法律法规与强制性标准统一管理,推荐性标准自愿执行;并实现标准查询和管理的信息化。