Comparison of Nitrification Performance between Vermifilter Using Quartz Sand and Ceramsite as Media

The nitrification performance by vermifilter with different filter media of quartz sand and ceramisite was studied to determine proper filter media for the vermifilter for treating municipal wastewater through the comparison of quartz sand and ceramisite. It was found that the nitrifying capacity was different among different positions in the quartz sand filter bed, and the nitrifying capacity of the external of the upper layer in the filter bed was the highest(0.47 mg/m³Â·h), while the nitrifying capacity of the inner of the under layer was the lowest(0.19 mg/m³Â·h) . Compared to the quartz sand filter bed (0.30 mg/m³Â·h), the ceramsite filter bed (0.48 mg/m³Â·h) had a higher nitrifying capacity. The average NH3-N removal rates of the ceramsite filter bed and the quartz sand filter bed were 68.4% and 53.4% respectively. It was mainly due to the different physical properties of the two filters. The ceramsite bed had high available oxygen capability, which favored to the survival of earthworms and microbes. The existence of plentiful earthworms and microbes was crucial to the steady nitrification performance of the vermifilter.