Water and Wastewater Treatment in AfricaCurrent Practices and ChallengesSustainable access to safe drinking water and basic sanitation is an important part of the millennium development goals (MDGs). For most African countries, an extensive effort is needed for the last three remaining years for the achievement of the MDGs, especially in Sub-Saharan Africa. Current practices for water and wastewater treatment in Africa are insufficient to ensure safe water and basic sanitation. To address this challenge, joint efforts are needed, including transforming to green economy, innovating technologies, improving operation and maintenance, harvesting energy, improving governance and management, promoting public participation, and establishing water quality standards. IntroductionAfrica is often characterized by its clean water and abundant biodiversity [1]. It is no doubt that water quantity and quality is of vital importance for the ecosystem [2,3]. Unfortunately, as the world's second-driest continent after Australia, Africa has only 9% of global renewable water resources to support 15% of the global population [1]. The lack of water in Africa is further aggravated by insufficient treatment of water and wastewater, particularly with rapid population growth and urbanization [2].At present, however, the efforts to improve drinking water quality and wastewater treatment are not keeping pace with population growth and urbanization [4,5]. The growing population and rising economy has resulted in increasing consumption of water and discharge of wastewater, which cause heavy pollution [6]. Water pollution not only reduces available freshwater, but also affects human health and ecosystem [3,7,8]. According to the millennium development goals (MDGs), the proportion of people without sustainable access to safe drinking water and basic sanitation should be reduced in half by 2015 [9,10]. In fact, water and wastewater treatment is significant for the realization of the MDGs [11,12]. For example, goal 1 (to eradicate extreme poverty and hunger) is related to water treatment because the access to safe drinking water can save the time and cost to collect daily water, thus people may have more time to work and to get food [1]. Goal 2 is to achieve universal primary education. Some kids cannot go to school due to the fact that they have to collect drinking water, or they have to quit schools due to water-borne diseases [1]. Goal 3 (to promote gender equality and empowering women) is related to water treatment because the burden of water collection in Africa falls disproportionately on girls and women [1]. Goal 4 (to reduce child mortality rates) is related to water treatment because improving water quality can reduce child mortality [1]. Goal 5 (to improve maternal health) is closely related to water treatment [13]. Goal 6 is to combat HIV/AIDS, malaria, and other diseases. It was shown that some diseases including malaria are related with water treatment [14,15]. Goal 7 is to ensure environmental sustainability. One essential part (t...

T here is a significant lack of proper wastewater treatment in most African countries, especially in sub-Saharan Africa. Untreated sewage effluent is one of the most common types of pollution found around urban rivers and in groundwater sources in many African cities. By 2020, 75−250 million people in Africa may be exposed to increased water stress due to climate change and pollution will only exacerbate the situation. 1 In Kenya, for example, most municipal wastewater treatment plants (WWTPs) discharge partially treated or untreated wastewater containing high levels of organic matter with mean effluent TSS, COD cr , and BOD 5 being 246 mg/L, 253 mg/L and 98 mg/L, respectively, (as of 2004) against a discharge requirement of 30, 50, and 30 mg/L, respectively. This situation replicates itself across most cities in the developing world. Dar es Salaam, Accra, Khartoum, Harare, Maputo, and Kampala, to name but a few, discharge treated and untreated sewage into their water bodies. In 2004, only about 14% of sewage was collected and treated in Dakar, and the rest was discharged into the sea without treatment. 2 The story is the same in Latin America, where less than 15% of the wastewaters collected in sewered cities and towns is treated prior to discharge. 3 The inadequacy in treatment stems from a number of reasons that include poor operation and maintenance of existing systems or complete breakdown of the same, overloading, and lack of tertiary systems for extended