Development of a single-stage mainstream anammox process using a sponge-bed trickling filter

Area of Science:

• Environmental Science
• Microbiology
• Wastewater Treatment Engineering

Background:

• The anaerobic ammonia oxidation (anammox) process offers a cost-effective solution for nitrogen removal.
• Anammox requires nitrite as an electron acceptor and is often employed after anaerobic pre-treatment.
• Developing efficient reactor configurations for anammox processes is crucial for practical applications.

Purpose of the Study:

• To develop a single-stage partial nitritation-anammox process in a sponge-based trickling filter (STF) reactor.
• To simulate the treatment of anaerobically pretreated concentrated domestic sewage.
• To evaluate the performance of the STF reactor without mechanical oxygen control.

Main Methods:

• Laboratory-scale experiment using a sponge-based trickling filter (STF) reactor.
• Inoculation with anammox sludge.
• Simulation of anaerobically pretreated concentrated domestic sewage influent (100 mg-N·L^-1 ammonia).
• Measurement of ammonia and total nitrogen removal efficiencies.
• Calculation of nitrogen loading rate based on sponge volume.
• Microbial community analysis of retained sludge.

Main Results:

• The STF reactor demonstrated high ammonia (89.8 ± 8.2%) and total nitrogen (42.7 ± 16.9%) removal efficiencies.
• The nitrogen loading rate was 0.55 ± 0.20 kg-N·m^-3·day^-1 (based on sponge volume).
• The STF reactor exhibited a higher K_La compared to conventional activated sludge processes.
• Microbial analysis confirmed the presence of both autotrophic and heterotrophic nitrogen removal pathways.

Conclusions:

• A single-stage partial nitritation-anammox process in an STF reactor is feasible for treating concentrated domestic sewage.
• The STF reactor configuration provides efficient nitrogen removal without the need for mechanical oxygen control.
• The study highlights the potential of STF reactors for cost-effective nitrogen removal in wastewater treatment.