|
|
|
Nitrogen-retaining property of compost in an
aerobic thermophilic composting reactor for the sanitary disposal
of human feces |
| Fan BAI1,Xiaochang WANG2, |
| 1.Key Lab of Northwest
Water Resource, Environment and Ecology, Ministry of Education of
China, Xi’an University of Architecture and Technology, Xi’an
710055, China；Department of Geo-science
and Environmental Engineering, Baoji University of Arts & Sciences,
Baoji 721007, China; 2.Key Lab of Northwest
Water Resource, Environment and Ecology, Ministry of Education of
China, Xi’an University of Architecture and Technology, Xi’an
710055, China; |
|
|
|
|
Abstract Aerobic composting is a method for the sanitary disposal of human feces as is used in bio-toilet systems. As the products of composting can be utilized as a fertilizer, it would be beneficial if the composting conditions could be more precisely controlled for the retention of fecal nitrogen as long as possible in the compost. In this study, batch experiments were conducted using a closed aerobic thermophilic composting reactor with sawdust as the bulk matrix to simulate the condition of a bio-toilet for the sanitary disposal of human feces. Attention was paid to the characteristics of nitrogen transformation. Under the controlled conditions of temperature at 60°C, moisture content at 60%, and a continuous air supply, more than 70% fecal organic removal was obtained, while merely 17% fecal nitrogen loss was observed over a two-week composting period. The nitrogen loss was found to occur mainly in the first 24 h with the rapid depletion of inorganic nitrogen but with an almost unchanged organic nitrogen content. The fecal NH4–N which was the main component of the inorganic nitrogen (>90%) decreased rapidly in the first day, decreased at a slower rate over the following days, and finally disappeared entirely. The depletion of NH4–N was accompanied by the accumulation of NH3 gas in the ammonia absorber connected to the reactor. A mass balance between the exhausted NH3 gas and the fecal NH4–N content in the first 24 hours indicated that the conversion of ammonium into gaseous ammonia was the main reason for nitrogen loss. Thermophilic composting could be considered as a way to keep a high organic nitrogen content in the compost for better utilization as a fertilizer.
|
| Keywords
nitrogen retention
composting reactor
human feces
aerobic
thermophilic
fertilizer
|
|
Issue Date: 05 June 2010
|
|
|
Zavala M A L, Funamizu N. Designand operation of the bio-toilet system. Water Science and Technology, 2006, 53(9): 55―61
doi: 10.2166/wst.2006.277
|
|
Wang X C, Jin P K. Water shortageand needs for wastewater re-use in the north China. Water Science and Technology, 2006, 53(9): 35―44
doi: 10.2166/wst.2006.267
|
|
Kitsui T, Terazawa M. Bio-toilet,Environmentally friendly toilets for the 21st century.In: Proceedings of the 10th International Symposiumon Wood and Pulping Chemistry (ISWPC) 1999, Yokohama, Japan. 1999, 120―121
|
|
Zavala M A L, Funamizu N, Takakuwa T. Temperature effect on aerobicbiodegradation of feces using sawdust as a matrix. Water Research, 2004, 38(9): 2406―2416
doi: 10.1016/j.watres.2004.02.026
|
|
Hanajima D, Kuroda K, Fukumoto Y, Haga K. Effect of addition of organic waste on reduction of Escherichia coli during cattle feces compostingunder high-moisture condition. BioresourceTechnology, 2006, 97(14): 1626―1630
doi: 10.1016/j.biortech.2005.07.034
|
|
Vinnerås B. Comparison of composting, storage andurea treatment for sanitising of faecal matter and manure. Bioresource Technology, 2007, 98(17): 3317―3321
doi: 10.1016/j.biortech.2006.07.011
|
|
Wang H B, Wang X C. Evaluationon the effect of human feces composting in new type composting reactor. Chinese Journal of Environmental Engineering, 2008, 2(1): 97―100 (in Chinese)
|
|
Eklind Y, Kirchmann H. Compostingand storage of organic household waste with different litter amendmentsI: carbon turnover. Bioresource Technology, 2000, 74(2): 115―124
doi: 10.1016/S0960-8524(00)00004-3
|
|
Eklind Y, Kirchmann H. Compostingand storage of organic household waste with different litter amendments.II: nitrogen turnover and losses. BioresourceTechnology, 2000, 74(2): 125―133
doi: 10.1016/S0960-8524(00)00005-5
|
|
Sánchez-Monedero M A, Roig A, Paredes C, Bernal M P. Nitrogen transformation duringorganic waste composting by the Rutgers system and its effects onpH, EC and maturity of the composting mixtures. Bioresource Technology, 2001, 78(3): 301―308
doi: 10.1016/S0960-8524(01)00031-1
|
|
Wang H B, Wang X C. Variationcharacteristics of sawdust as matrix in human feces composting reactorand its effect on microorganisms. EnvironmentalScience & Technology, 2009, 32(3): 122―125 (in Chinese)
|
|
Zavala M A, Funamizu N, Takakuwa T. Biological activity in thecomposting reactor of the bio-toilet system. Bioresource Technology, 2005, 96(7): 805―812
doi: 10.1016/j.biortech.2004.07.009
|
|
Hotta S, Noguchi T, Funamizu N. Experimental study on nitrogencomponents during composting process of feces. Water Science and Technology, 2007, 55(7): 181―186
doi: 10.2166/wst.2007.143
|
|
Hotta S, Funamizu N. Biodegradabilityof fecal nitrogen in composting process. Bioresource Technology, 2007, 98(17): 3412―3414
doi: 10.1016/j.biortech.2006.10.045
|
|
Huang G F, Wong J W, Wu Q T, Nagar B B. Effect of C/N on composting of pig manure with sawdust. Waste Management (New York, NY.), 2004, 24(8): 805―813
doi: 10.1016/j.wasman.2004.03.011
|
|
Zhu N W. Effect of low initial C/N ratio on aerobic compostingof swine manure with rice straw. BioresourceTechnology, 2007, 98(1): 9―13
doi: 10.1016/j.biortech.2005.12.003
|
|
Wang H B, Sun Y, Wang X B. A study on the characteristic featuresof feces decomposition by using sawdust as microbial carrier for anaerobic compositing reactor. Journal ofSafety and Environment, 2008, 8(2): 43―46 (in Chinese)
|
|
Tiquia S M, Tam N F, Hodgkiss I J. Effects of composting onphytotoxicity of spent pig-manure sawdust litter. Environmental Pollution, 1996, 93(3): 249―256
doi: 10.1016/S0269-7491(96)00052-8
|
|
National General Administrationof Environmental Protection, Standard Method for the Examination ofWater and Wastewater Editing Board. Methodsfor Monitoring and Analysis of Water and Wastewater, Standard Methodfor the Examination of Water and Wastewater. 4th ed. Beijing: Environmental Science Press of China, 2002 (in Chinese)
|
|
National General Administrationof Environmental Protection. Water quality—Determinationof the chemical oxygen demand—Fast digestion-spectrophotometricmethod (HT/J 399―2007). Beijing: Environmental Science Press of China, 2007 (in Chinese)
|
|
Chen J, Wu Y H. Alkalinepotassium persulfate digestion determination of total nitrogen inmunicipal sludge. The Administration andTechnique of Environmental Monitoring, 2005, 17(1): 35―37 (in Chinese)
|
|
Vitousek P M, Aber J D, Howarth R W, Likens G E, Matson P A, Schindler D W, Schlesinger H W, Tilman D G. Human alteration of the globalnitrogen cycle: sources and consequences. Ecological Applications, 1997, 7(3): 737―750
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
