Effect of nitrogen source and spray conditions on the integral biotrickling filter operation for hydrophobic volatile organic compounds

Abstract

A nutrient solution containing major and trace elements plays a crucial role in biotrickling filter (BTF) operation in practical applications. This study conducted a series of experiments on the BTF packed with integral filters using two types of nitrogen sources under different spray conditions. The rapid start-up was observed in the BTF feeding with ammonium tartrate-N (AT-N) nutrient solution. Heterotrophic nitrification and denitrification were observed by monitoring the concentration of ammonia-N, nitrite-N, nitrate-N, PO43− and SO42− in the nutrient solution. The BTF performance under two different types of the nutrient solutions were detected up to ∼90% at the inlet toluene concentration of 300–700 mg∙m−3. The BTF packed with integral filters exhibited the stable performance with the change of nitrogen source and could be steadily operated at a wide pH range of 5.5–8.5. To illustrate the effect of the two types of nitrogen sources on the biofilm, metagenomic sequencing was used to assess the microbial diversity and functional genes of biofilm on the integral filters. The results showed that the application of AT-N nutrient solution increased the functional genes of denitrification in the microorganisms on the filters. Furthermore, the more stable performance of BTF was achieved by using the AT-N nutrient solutions, which might be beneficial to the long-term operation of BTF packed with honeycomb integral packing.