Investigation of a basic nitrification–denitrification biofiltration system for primary wastewater treatment

Abstract The study aimed to eliminate the nitrogen and its main residual forms from municipal wastewater by using a biofilter system adapted for small community. biological nitrification/denitrification used involved two successive polyvinyl chloride (PVC) columns; first gravel column (C1) loaded with primary followed second sandy (C2). A complex biofilm development on sand materials has been confirmed scanning electron microscope. efficiency of chemical oxygen demand (COD), BOD5, TSS, NH4+-N removal reached 75.3, 88.4, 83.5, 88.1%, respectively, at exit Inoculation activated sludge as an external carbon source allowed improvement in nitrate removal, 80 28 mg/L N-NO3. However, inoculation showed non-significant fecal coliforms Streptococcus contamination, appeared effective total bacterial abatement over 3.2 U-log10. average seemed directly related applied load about 50 cm/day tertiary disinfection treatment, such UV-C254 irradiation, is needed preventive step ensure pathogens.