Reza Shokoohi
1, Ghorban Asgari
2, Mostafa Leili
1, Meisam Sedighi Hemmat
1*1 Department of Environmental Health Engineering, Faculty of Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, IR Iran
2 Social Determinants of Health Research Center (SDHRC), Department of Environmental Health Engineering, School of Public Health, Hamadan University of Medical Sciences, Hamadan, IR Iran
*Corresponding Author: * Corresponding author: Meisam Sedighi Hemmat, Department of Environmental Health Engineering, Faculty of Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, IR Iran. Tel: +98-9188127738, Email:
meisam2005_r@yahoo.com
Abstract
Hospital wastewater is of great environmental concern because it contains a variety of hazardous microbial and chemical substances.
This study aims to investigate the efficiency of a moving bed biofilm reactor (MBBR) with a light expanded clay aggregate
(LECA) carrier for treating hospital wastewater. This pilot study used a Plexiglas reactor that had a volume of 100 L, a continuous up-
flow hydraulic regime, and a LECA carrier to test removal of chemical oxygen demand (COD) from wastewater in a public hospital.
To assess MBBR efficiency, the study used retention times of 8, 12, and 24 hours, filling percentages of 30% and 50%, and mixed liquor
suspended solids (MLSSs) of 1000, 3000, and 5000 mg/L. The results indicated that using a single LECA carrier in an MBBR system
was not sufficient to remove organic materials from hospital wastewater, because the carrier could not be completely suspended.
After some modifications, consisting mainly of returning activated sludge, the system was 83% efficient at removing COD using a
LECA carrier at a retention time of 24 hours, with 50% filling, and 5000 mg/L of MLSS.