Detoxification of formaldehyde from hospital wastewaters

M. Sc. Thesis DETOXIFICATION OF FORMALDEHYDE FROM HOSPITAL WASTEWATERS Emre YİĞİT İnönü University Graduate School of Natural and Applied Sciences Department of Chemical Engineering 68 + ix pages 2019 Supervisor: Prof. Dr. Ahmet BAYSAR The purpose of this work is to eliminate formaldehyde from hospital wastewaters by converting it to nontoxic substances. The concentration of formaldehyde used in medical laboratories may be as high as 40 g/L. This is much higher form biodegradable level of 225 mg/L. Since formaldehyde has carcinogenic and mutagenic effect on living organisms, it should be converted to innoxious material before it is discharged to the environment. The reaction of sodium metabisulfite with formaldehyde gives sodium metabisulfite formaldehyde which is a material that is biodegradable. The reacting solution is acidic. The pH of the solution may be adjusted by buffered solutions such as phosphate (NaH2PO4/Na2HPO4) solutions. By adding this buffer to the reacting solution the pH may be kept between 7.0-7.5. Formaldehyde elimination reaction is fast and 70% of formaldehyde may react in 20 minutes and in 30 minutes the reaction is completed and the remaining formaldehyde is in ppb levels. KEYWORDS: Formaldehyde, formalin, hospital wastewater, detoxification