Assessing utilization potential of waste concrete as a biofilm media and evaluating NH3 removal performance

In this study, waste cellular concrete (WCC) ranging in particle size from 20 mm to 40 mm was utilized as the media and packing bed for activated sludge. Lab-scale experiments were conducted using an acrylic column with an internal diameter of 60 mm, filled with 0.7 L of WCC inoculated with activated sludge. Contaminated air containing NH3 from artificial wastewater (with a concentration of 300 mg NH4-N/L) was introduced into each column at varying empty bed residence times (EBRT) of 2, 4, 8, 12, and 18 seconds. The results revealed that the biofilm formed by activated sludge on WCC media effectively removed NH3 from the contaminated air. Under humidified conditions with an NH3 concentration of 516.0 ppm, the NH3 removal rates for columns with EBRT of 2, 4, 8, 12, and 18 seconds were found to be 48.7%, 59.8%, 71.0%, 84.4%, and 97.6%, respectively. Therefore, a biofilter utilizing WCC as biofilm media can effectively mitigate odors in livestock facilities emitting high concentrations of NH3. Furthermore, since inorganic WCC exhibits limited biodegradability, its long-term use as a biofilm media can be ensured.