Water, Sewage & Effluent July-August 2017 | Page 28

If landfills do not have a protective bottom layer, or if it is cracked, contaminants can make their way into the groundwater. Clarifying groundwater While countries such as the United States depend on groundwater by as much as 50% for their drinking water, this source, unfortunately, is susceptible to a variety of pollutants, normally of human origin. By Kim Kemp* 26 W hile South Africa has rivers and dams aplenty, our water infrastructure is buckling under decades of non-maintenance, ageing structures, and an influx of people into the cities and thus an increase in demand on the water supply. We need to source alternative supplies, including using our groundwater reserves, but also bearing in mind that not all groundwater is safe for human consumption. Groundwater pollutants include contaminants such as petrol, oil, and chemicals that cause it to become unsafe and unfit for human consumption. Also, materials such as pesticides and fertilisers can move through the soil and, in time, end up in the groundwater supply. Poisonous substances from mining sites and used motor oil may also seep into groundwater, as well as untreated waste from septic tanks, toxic chemicals from underground storage tanks, and leaky landfills. Water Sewage & Effluent July/August 2017 Unattended containers with hazardous materials can jeopardise the groundwater supply if the material leaches into the ground.