Climate Change Effects and Implications for Wastewater Treatment Options in Ghana

Abstract

Climate change is a major global challenge in the 21^st Century, with Africa as one of the most vulnerable regions to its predicted impacts due to low adaptive capacity. In literature, the effects of climate change on water availability are well documented with projections indicating an increase in water stress populations due to decreasing water availability, ultimately resulting in increasing wastewater reuse for West Africa Region. Climate resilient wastewater treatment options must be identified to protect human health and environment. The aim of this paper is to assess the possible implications of climate change on wastewater treatment options in Ghana, West Africa. Temperature, rainfall and evapotranspiration trends are analyzed from meteorological data for the cities of Accra and Tema, over the last five decades stretching from years 1963 to 2013. The long-term changes in all three climatic parameters have been assessed by linear trend analysis. Mann-Kendall trend test is used to confirm the increasing trend in mean annual temperature and evapotranspiration and decreasing trend in rainfall for both cities. Mean annual temperature and evapotranspiration for Accra and Tema increased by 0.65^oC and 1.3^oC, and 11.8mm and 5.2mm respectively, with rainfall decreasing by 171.4mm and 83.4mm respectively. Projections were made for the climatic variables for the next 50 years, using 2010 as the base year. Applying multi-criteria analysis to compare the various treatment options in use in Ghana resulted in the activated sludge as the most climate resilient wastewater treatment option. Though the activated sludge process is not a first choice option for developing countries due to its high energy, capital and skills requirements, the results of this study indicate a need for its modification to make it viable and sustainable for developing countries in the face of climate change.

Keywords: Climate change, Trend analysis, Wastewater treatment options, Ghana.