Simulation of managed aquifer recharge by recycling treated wastewater in Nigeria.

The study evaluated the potential of recycling treated industrial effluent for groundwater quality and quantity restoration using a laboratory--scale soil aquifer treatment (SAT) simulator. SAT has the potential to reverse groundwater level decline being experienced in the North-eastern part of Nigeria and saltwater intrusion and groundwater quality deterioration in the coastal zones of the country. Soil column depth (SDC) and hydraulic loading rate (HLR) were optimized for the best treatment performance. Results show that HLR of 14.6 mm min-1 at an SCD of 1.5 m gave maximum removal efficiency for all parameters (hydrogen ion concentration (pH), temperature, electrical conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), dissolved oxygen (DO), bio-chemical oxygen demand (BOD5), total hardness (TH), chloride (Cl-), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+) and bacterial count (BC)) tested in comparison with HLR 16.98 and 20.37 mm min-1 and SCD of 0.5 and 1.0 m. This renders the wastewater adequate for aquifer storage and subsequent reuse. Further evaluation of the results indicates that surface spreading system will be best suited for the Sudan and Sahel Savannah areas of the country, while direct injection into wells is recommended for the southern and coastal areas. Given that Nigeria has a vast potential for managed aquifer recharge (MAR), the implication is that the implementation requires policy and regulatory frameworks to enable bulk wastewater producers to put their effluents to positive use and thus to enhance environmental sustainability. [ABSTRACT FROM AUTHOR]