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Zhao C.-Y.,CAS Research Center for Eco Environmental Sciences | Zhao C.-Y.,Capital Safety | Wei Y.-S.,CAS Research Center for Eco Environmental Sciences | Wei Y.-S.,China Institute of Technology | And 5 more authors.
Huanjing Kexue/Environmental Science | Year: 2014

There is a lack of observation data on greenhouse gas (GHG) and ammonia emissions from sewage sludge composting, though the emissions can result in environmental issue and nitrogen loss. In this study, GHG and ammonia emissions were monitored under different operating parameters during sludge composting with continuous aerated turning pile at full scale. Results illustrated that the reduction of amendment addition could result in low organic matter transformation (1.38% and 8.85% for the test group and the control group, respectively). Though low C/N ratio might slightly increase the ammonia emission (8.68% higher than the control group), it was helpful to reduce both GHG emission (1.70 g·kg-1 DC for the test group and 2.85 g·kg-1 DC for the control group, respectively) and total nitrogen loss (16.1% and 21.8% for the test and control groups, respectively). Through applying an aertion strategy in which the airflow rate was lower in the beginning and higher in the end of sludge composting, a higher GHG emission and a lower ammonia emission were observed in the test group, e.g., 55.1% higher of GHG emission than the control, and 66.86g·m-2 and 72.04g·m-2 of ammonia emission in the test and the control, respectively. And a good conversation of total nitrogen thus occurred in the test as a result of such aeration strategy, with only 51.34% of TN loss as compared to the control.


Qi L.,CAS Research Center for Eco Environmental Sciences | Qi L.,Capital Safety | Wei Y.-S.,CAS Research Center for Eco Environmental Sciences | Wei Y.-S.,China Institute of Technology | And 7 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

The data on nitrogen gas (NH3, N2O, NO) emissions during sludge bio-drying process in China is scarce, especially NO due to its unstable chemical property. In this study, effect of two aeration modes on emissions of methane and nitrogenous gas was compared during the continuous aerated turning pile sludge bio-drying process at full scale. In these two aeration strategies, the one currently used in the plant was set as the control, and the other was set as the test in which the aeration was used for oxygen supply, pile temperature control, and moisture removal in the start-up, middle and final stages, respectively. The results showed that the aeration strategy used in the test could not only obviously accelerate the rate of sludge drying (the moisture contents of the test and the control were 36.6% and 42% on day 11), but also had a better drying performance (the final moisture contents of the test and the control were 33.6% and 37.6%, respectively) and decreased the ammonia cumulative emission by 5%, (ammonia cumulative emission of the test and the control were 208 mg·m-3 and 219.8 mg·m-3, respectively). Though a lower accumulated emission (eCO2) of greenhouse gas in the test at 3.61 kg·t-1 was observed than that of the control (3.73 kg·t-1 dry weight), the cumulative emission of NO in the test at 1.9 g·m-2 was 15.9% higher than that of the control (1.6 g·m-2). © 2016, Science Press. All right reserved.


Zhang J.,CAS Research Center for Eco Environmental Sciences | Cai X.,Chinese Research Academy of Environmental Sciences | Qi L.,Capital University of Economics and Business | Shao C.,Chinese Research Academy of Environmental Sciences | And 5 more authors.
Applied Microbiology and Biotechnology | Year: 2015

Sludge bio-drying in which sludge is dried by means of the heat generated by the aerobic degradation of its own organic substances has been widely used for sludge treatment. A better understanding of the evolution of dissolved organic matter (DOM) and its degradation drivers during sludge bio-drying could facilitate its control. Aeration is one of the key factors that affect sludge bio-drying performance. In this study, two aeration strategies (pile I—the optimized and pile II—the current) were established to investigate their impacts on the evolution of DOM and the microbial community in a full-scale sludge bio-drying plant. A higher pile temperature in pile I caused pile I to enter the DOM and microbiology stable stage approximately2 days earlier than pile II. The degradation of easily degradable components in the DOM primarily occurred in the thermophilic phase; after that degradation, the DOM components changed a little. Along with the evolution of the DOM, its main degradation driver, the microbial community, changed considerably. Phyla Firmicutes and Proteobacteria were dominant in the thermophilic stage, and genus Ureibacillus, which was the primary thermophilic bacteria, was closely associated with the degradation of the DOM. In the mesophilic stage, the microbial community changed significantly at first and subsequently stabilized, and the genus Parapedobacter, which belongs to Bacteriodetes, became dominant. This study elucidates the interplay between the DOM and microbial community during sludge bio-drying. © 2015, Springer-Verlag Berlin Heidelberg.

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