Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting

Abstract

Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A-the control, B-natural zeolite addition, and C-3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6 % and 23.1 %, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH 3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

Gross Ammonification and Nitrification Rates in Soil Amended with Natural and NH4-Enriched Chabazite Zeolite and Nitrification Inhibitor DMPP

“…In both treatments, the processes associated with the consumption of NH 4 + -N (e.g., volatilization, immobilization, and oxidation) exceeded those responsible for NH 4 + -N production (e.g., mineralization of organic N, DNRA). The observed lack of significant differences in functional genes between CNTR and NZ agrees with the study of [74], which reported no differences in the abundance of functional genes involved in nitrification (amoA and nxrA) and denitrification (narG, nirK, nirS, and nosZ) after natural zeolite addition to sludge composting in aerated reactors.…”

A regulating method for reducing nitrogen loss based on enriched ammonia-oxidizing bacteria during composting

“…The contents of NO 2 À -N and NO 3 À -N increased at the thermophilic phase, especially for TM, suggesting that some ammonia oxidation microorganisms could survive in high temperature condition. This was supported by the reports that some nitrifiers could resist high temperature and high temperature might favor high potential ability of ammonia oxidation (Jiang et al, 2015;Zhang et al, 2016), although inconsistent with the universally accepted points that nitrification could not occur above 40°C. These results of different nitrogen fractions indicated that inoculation with the enriched AOB might favorably affect the diversity and succession of bacterial community, which led to the changes of the physicochemical parameters during composting.…”

Effect of red mud addition on tetracycline and copper resistance genes and microbial community during the full scale swine manure composting

“…A bootstrap cutoff of 50% suggested by the RDP was used to assign the sequences to different taxonomy levels. Rarefaction curves, H 0 , E, varH, and Chao1 richness indices were calculated using the relevant RDP modules, including Rarefaction and Chao1 Estimator, as described previously (Zhang et al, 2016).…”