ASSESSMENT AND REMOVAL OF SUSPENDED SOLIDS IN HOSPITAL WASTEWATER USING CLAY IN SRI LANKA

Abstract

Direct discharge of untreated hospital wastewater (HWW) can create severe environmental impacts. Hence, the study focuses on assessing the performance of an existing treatment plant, while determining the most suitable filter material from five different alluvial clays to remove total suspended solids (TSS) and total dissolved solids (TSS) in HWW and investigate a hospital that does not have a treatment plant to elaborate the requirement of a treatment plant. Wastewaters from Provincial General Hospital (PGH, n=5) and Base Hospital (BHTB, n=4) were collected weekly over three weeks (total n=27) where physical (n=4), chemical (n=12) and biological (n=1) parameters were measured. The clays were treated with HWW, and the adsorption of TSS and TDS to clay was determined. The water quality after the trickling filter in PGH shows a clear drop for BOD5, TSS, and pH. Maximum values for BOD5, COD, TSS, and PO4 3- of the waters were 108, 290, 904, and 16.39 mg/L, respectively, and are much higher than the National Environmental Act (CEA) standards. In BHTB, all discharged water outlets are open to the environment, and the BOD5, PO4 3- and NO3 - of discharged water varies within 8 - 98, 3.77 - 8.16, and 0.80 - 14.60 mg/L and are higher than CEA standards. The treatment plant at PGH is unsatisfactory to meet the increasing capacity requirements, thus needs improvements, and a treatment plant is required for BHTB. The highest removal of TSS was achieved using illite clay within two weeks, and the removal percentage is 96% while it was showing removal of Benzidine dihydrochloride (C12H12N2.2HCl), Neodymium titanium oxide (Nd2Ti2O7), Bismuth selenide (Bi2Se3) and Iron fluoride (FeF3) which are found to be in HWW.