Recyclable Potential of Car Wash Effluent for Concrete Production

Abstract

The need to find sustainable ways to reuse water to ensure its continued supplies has been in the forefront of water conservation discuss globally. Increasing population and high standard of living as evidenced in the increased purchase of cars by the middle class leading to more water being utilised for washing and cleaning of the exterior and interior compartments of cars. This study investigates the potential of car wash effluent to be employed for concrete production thereby reducing the burden of water extraction for construction purpose. Car wash effluent was collected from selected car wash enterprises in the Ugbowo area of Benin City. The first and second wash effluent were subjected to physicochemical, setting time tests, slump tests and compressive strength tests. The results showed that the first wash effluent understandably contains alkaline compounds with high concentration of most of the anions and cations. The highest setting time value of 248mins was notice for the first wash while the second wash effluent had a final setting time of 208mins less than even the control setting prepared with cement and potable water. All the slump values meet the minimum criteria for concrete even as the first wash effluent gave the highest setting time. The compressive strength of the first and second wash effluents were 65.38% and 44.74% respectively of the control concrete compressive strength produced with potable water. This fell short of its adoption for concrete production as stipulated in ASTM C1602. Consequently, it is recommended that car wash effluent, particularly the first wash effluent that has high concentration of soap or detergent should not be used for concrete production in its untreated state