A sustainable approach to reuse of treated domestic wastewater in construction incorporating admixtures

In this research, the effectiveness of treated domestic wastewater in the production of plain cement concrete with the addition of commonly used admixtures, was the main aspect under consideration. For this purpose, three different samples: bore water along with treated wastewater and polished wastewater, were collected and prepared from domestic wastewater treatment plant. These were then individually used in the production of plain cement concrete for observing and analysing the variations in the strength properties of concrete. Furthermore, this research focuses on finding suitable alternatives which satisfy all required quality checks for mixing water. An in-depth analysis reflects upon the cost and energy efficiency of using treated wastewater for construction purposes. Fresh and hardened properties of concrete were evaluated as per standards. To study the effectiveness of admixtures while using treated domestic wastewater as mixing water, the amount and type of admixtures to be added in concrete produced; were varied using three different water/wastewater samples, keeping all other variables constant; including the type of materials used, environmental conditions, production and testing methodologies etc. For this purpose, CaCl2 and Chemrite 520 BA were used in this research as admixtures. The research exposed that plain cement concrete produced using treated wastewater was as good as concrete made with fresh water in terms of desired strength (compressive, tensile and flexure). Treated wastewater showed better tensile and compressive strength results as compared to bore water. Using a super-plasticizer like Chemrite 520 BA, the strength achieved by all water/wastewater samples, with or without admixtures, is approximately the same without any negative impact on mechanical properties of concrete. Results reinforce that treated/filtered wastewater tested in this research qualifies to be used as a viable alternative to fresh water in concrete production, with or without use of admixtures which of course play their potential role enhancing the strength of concrete.