Abstract
This research study investigated the anthropogenic contamination of water sources (surface, groundwater and tap water) in Kaduna metropolis, Nigeria. The water sources were identified and delineated on the basis of land use; domestic, commercial, agricultural, industrial and refinery areas. The water sampling programme was undertaken from 2009 to 2011 in accordance with the Standard Methods (APHA, 2005) covering hand dug wells, streams and rivers. Water samples were analysed for various water quality parameters, including pH, temperature, electrical conductivity, total dissolved solids, dissolved oxygen, biochemical oxygen demand and faecal coliforms. Also analysed were trace element levels by inductively coupled plasma mass spectrometry (ICP-MS). The results were compared with drinking water guideline legislations of relevant agencies and governments. Groundwater samples were found to be most contaminated with microbiological coliforms from the improper disposal of domestic sewage and the proximity of these water wells to the sewage points. Surface water (streams and rivers) were found to be more chemically contaminated than groundwater due to urban run-off and the discharge of solid wastes. In general, trace elements (As, Mo, Se, Cd, Sb & Pb) levels were found to be generally below the guideline limits of the regulatory bodies with the exception of Mn near textile industries; Ni near vehicle assembly plant and Cu & Zn were higher in tap water. The determination of anthropogenic water contamination led to the selection and design of a multi stage filtration system to treat water at point of use for residents without access to potable water. Experiments at pilot scale were undertaken using raw and chemically modified lake water. The results showed that this basic filtration system was capable of reducing the turbidity and faecal colifoim levels of the lake water. Furthermore, Al, Mn and Fe levels were reduced. The pilot filtration system was scaled-up for field application in Kaduna, Nigeria (December 2012 to March 2013). Five filtration plants were established to treat raw water from domestic and commercial ground/surface waters, and industrial surface water of the Nigerian study area. The results showed that it is not capable of providing water that is completely potable but can produce water that is, to a great extent treated for turbidity and bacterial contamination better than the water available for domestic use by people in low income bracket and those in emergency situations such as aftermath of natural disasters e. g. Typhoon Haiyan.