REUSE OF SECONDARY & TERTIARY TREATED WASTE WATER IN CONSTRUCTION MATERIALS IN EGYPT

Concrete is the most widely used construction material in the world. Shortage of water is perhaps the most critical environmental problem in several countries. Fresh water accounts for only (2.5%) of the Earth's water. The concrete industry alone uses over one trillion gallons of water each year worldwide. In addition, the use of water for industrial purposes increases. Therefore, it is essential to conduct research of substitution of potable water by reclaimed water partially or totally to produce concrete. Works included intensive laboratory experiments, preparing concrete cubes with sewage treatment plant water from different stages of the treatment process and different percentage in the formulation of concrete mixtures. The plan is to test reclaimed water samples in different blending with potable water 20%, 50%, and 100% sewage treatment water. Compressive strength, for concrete cubes. Compressive strength for cylinders and flexural strength for beams were casted for 3, 7, 21, 28, 56 and 92 days. Results showed that the treated water tested in this study qualifies to be used in mixing concrete. Hence results suggested the secondary treated waste, and the tertiary treated waste water are appropriate for using in construction industry. For making concrete, the suggested wastewater treatment unit processes secondary treatment and disinfection, are (Biochemical Oxygen Demand) (BOD5 ≤ 30mg/l), (Total Suspended Solids) (TSS≤30mg/l), fecal coliforms (≤200 CFU/100ml), and Cl2 residual (1mg/l Cl2 residual (minimum). Briefly, the results showed that, Tertiary treated waste water (TTWW) produced from waste water treatment plants in Egypt, is found to be suitable for mixing concrete to use in construction material with no adverse effects.