Breakthrough Curve of Escherichia Coli Released from Organic Manures as Influenced by Soil Properties
Organic manures are the source of many pathogenic bacteria which could be dangerous for human health. In this study, the effects of soil texture and structure on transmitting and filtering of manure-borne Escherichia Coli were investigated. The intact soil samples (25 cm in height and 16 cm in diame...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Water and Wastewater Consulting Engineers Research Development
2006-09-01
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| Series: | آب و فاضلاب |
| Subjects: | |
| Online Access: | http://www.wwjournal.ir/article_2292_e9687a0e72b97956c307d6c49bb7b992.pdf |
| Summary: | Organic manures are the source of many pathogenic bacteria which could be dangerous for human health. In this study, the effects of soil texture and structure on transmitting and filtering of manure-borne Escherichia Coli were investigated. The intact soil samples (25 cm in height and 16 cm in diameter) were taken from a sandy clay loam soil and a loamy sand soil. Three manures including: cow manure, poultry manure and sewage sludge were applied on the surface of the soil cores at the rate of 10 Mg ha-1 on dry basis. With controlled steady-state unsaturated water flow, the influent and effluent concentration of Escherichia Coli were determined vs. time up to four pore volumes (PV). In spite of greater adsorptive sites of sandy clay loam soil, more bacteria have been transmitted and polluted the effluent of the soil. The loamy sand soil filtered more Escherichia Coli compared with the sandy clay loam soil. The effluent contamination of poultry manure-treated columns was greater than the cow manure and that of treated sewage sludge. In the majority of the columns, the difference between cow manure and sewage sludge was negligible. The filtration of Escherichia Coli in loamy sand soil was greater due to weaker structure and discontinuity of pores which are responsible for physical filtering. In sandy clay loam soil, the stable structure and preferential pathways are believed to cause funneling of the bacteria towards the bottom of the columns and the early appearance of Escherichia Coli in the drain water. The results demonstrated the importance of soil structure and preferential (macroporous) flow in bacteria transport which could diminish the impacts of soil texture and adsorptive sites on the transmission mechanisms. |
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| ISSN: | 1024-5936 2383-0905 |