Golnaz Ezzati
Alireza Asghari

Biofiltration has gained popularity as a cheap green technology in processing wastewater over recent years. The inexpensive installment, lower energy consumption and less maintenance requirements make implementing it applicable for people in rural areas as well. The current study tried to compare treatment efficiency of two natural filter-media known to be good nutrient absorber. The objective was to investigate either peat or biochar can enhance the ability of a laboratory scale biofilter to consistently and cost-effectively reduce concentration of ammonia which is toxic to human health and aquatic life. BOD5, COD, TSS, and concentration of different composition of nitrogen were measured on a frequent basis.Peat showed better reduction ratio of 87% and 65% in BOD5 and COD respectively comparing to biochar with +6% increase in BOD5 and 7% decrease in COD by the end of the experiment. Although biochar showed characteristic of a time-limited median and there were 25% decreases of BOD5 and 40% decrease in COD values until a certain time. Both median were efficient in TSS removal with 79% and 45% reduction ratio.Peat outperformed biochar from the first day of the experiment with 94.4% ammonia removal ratio comparing to 27.8% increase of ammonia concentration in the effluent treated with biochar.Although treated wastewater with biochar had less odor-nuisance than peat, a low retention time might have resulted in a partial nitrification in biochar biofilter. Thus it is recommended to increase retention time and decrease the volume of biochar to have more void and thus more effective presence of oxygen

wastewater, biofilter, peat, biochar, ammonia