Studies on the Use of Fortified Kaolinitic Soil-Clay in Industrial Wastewater Treatment

This study aimed to design an uncomplicated, reliable, technologically simple and low energy consuming decentralized wastewater treatment system using kaolinitic soil-clay fortified with stone pebbles to enhance the permeability to water. Soil-clay samples were obtained from different deposits in Nigeria viz: Auchi (AU), Ozanagogo (OZ) and Ubulu-Uku (UB). The geochemical analysis of the soil-clay samples was done using an atomic absorption spectrophotometer (AAS). The miner-alogical analysis, studied with an X-ray diffractometer, revealed the presence of kaolinite as the domineering clay mineral present. Illite was also found in the clay OZ and AU (6.50 % and 0.50%, respectively). Composite wastewater samples were obtained from brewery, textile and polymer industries. Performance efficiency studies were conducted to determine the best combination ratio of pebbles/soil-clay. Soil-clay fortified with pebbles in combination ratios of 1:3 (i.e., pebbles: soil-clay = 1:3 [w/w]) showed optimum water treatment while the combination 3:1 gave the least. The flow rate studies showed that the wastewater had a longer residence time in non-fortified soil-clay than in fortified soil-clay. Two modes of treatment methods were employed: single and double column treatment (SCT and DCT). The two methods gave effluents with good-quality characteristics but those from the DCT were of better quality. The quality of effluents also varied from one fortified column to another. The fortified column containing OZ exhibited the best performance while UB showed the least perfor-mance in the entire treatment processes. Results obtained from the studies on the effects of repeated use on the performance efficiency of the fortified soil-clay showed that the pH of effluents decreased with time toward acidity; the amount of TS also decreased with time; and, as the COD value increased, depletion in the DO was also recorded