Treatment of sewage using an aged-refuse-based bioreactor

Area of Science:

• Environmental Engineering
• Microbiology
• Waste Management

Background:

• Landfill refuse stabilizes over time into "aged refuse," rich in microorganisms with potent decomposition capabilities.
• Aged refuse can treat both biodegradable and refractory organic matter in wastewater.

Purpose of the Study:

• To evaluate the efficacy of aged refuse as a biofiltration substrate for treating municipal sewage.
• To investigate the treatment mechanism and cost-effectiveness of this biofiltration process.

Main Methods:

• Excavated aged refuse from a 10-year-old landfill was used as biofiltration material in a custom-built bioreactor.
• Sewage with high COD, BOD, and NH3-N concentrations was introduced into the bioreactor at controlled hydraulic loads.
• The impact of NaClO disinfection on pollutant removal efficiency was assessed to determine the treatment mechanism.

Main Results:

• The biofiltration process significantly reduced influent COD (400-500 mg/L), BOD (240-300 mg/L), and NH3-N (45-50 mg/L) to effluent levels below 80-100, 10-20, and 10-15 mg/L, respectively.
• Treatment efficiencies decreased with increasing hydraulic load.
• Pollutant removal was primarily biological, as indicated by a sharp decrease in efficiency after NaClO disinfection.

Conclusions:

• Aged refuse is a viable and cost-effective substrate for the biological treatment of sewage.
• The microbial communities within aged refuse are responsible for the effective removal of organic pollutants and ammonia nitrogen.
• This method offers a sustainable approach to wastewater treatment by repurposing landfill waste.