Abstract:
Demand for city water supply by industrial sector is rising drastically. Hotels
consume a huge amount of water for their operational and recreational practices.
Thus, the demand for water in the hotels is difficult to achieve by the city water
supply. Hence, the reuse of treated wastewater (WW) after tertiary treatment can
reduce the fresh water demand and this treated WW can be used for non-potable
water consumption. In this study we attempted to evaluate a reverse osmosis (RO)
system for the treatment of secondary treated wastewater (after rotating biological
contactor) to reuse in boilers and cooling towers in Le Grand Hotel, Galle. Based on
the flow rate and total dissolved solids (TDS) of secondary treated water, the RO
plant was designed using Hydranautics Nitto software. Designed RO plant was
installed and evaluated the treatment efficiency for three months. Samples were
taken after RBC and RO and they were analyzed for COD and TDS. According to the
results, COD removal was 100% by the RO while TDS removal was 95%. The
statistical analysis showed that the quality of tertiary treated water (COD and TDS)
significantly lower than the reference values given by the central environmental
authority. Based on the results of this study, it can be concluded that the tertiary
treated water through reverse osmosis can easily be used for boilers and cooling
towers for steam-making and chilling processes reducing the demand for fresh
water.
