Natural Freezing, Drying, and Composting for Treatment of Septic Sludge
Publication: Journal of Cold Regions Engineering
Volume 13, Issue 4
Abstract
A full-scale experimental plant intended for local treatment of septic sludge, situated in northern Sweden, is presented in this paper. The concept investigated included natural freezing, thawing, and drying in combination with composting. The experimental plant consisted of an undrained freezing-thawing-drying bed and a heat-insulated composter. About 500 L of fresh sludge, with a dry matter (DM) content of 4–5%, collected from a septic tank employed by one family, was transferred to the freezing-thawing-drying bed in the beginning of November 1996. During the winter months, the sludge froze and then thawed in the middle of May 1997. During a drying period of three weeks, the DM content increased from 10.6–21.3 to 25–95%. The final sludge volume and weight were 180 L and 54 kg, respectively. Approximate concentrations of nitrogen, phosphorus and total organic carbon of the dried sludge were determined to be 23, 5.9, and 346 g/kg DM. From June until the end of August, the sludge was cocomposted with kitchen refuse. Within two weeks, the composting temperature exceeded 65°C. The measured composting temperature indicated a high pathogen die-off, but before this concept can be suggested as an alternative to conventional septic sludge treatment, further studies should be conducted, including direct measurements of pathogens. The concept, however, has proved to be of interest in cold regions due to its simple construction and operation.
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References
1.
Albihn, A., and Stenström, T. A. (1998). Hygiene study of sanitary systems (Systemanalys VA—Hygienstudie). Rep. 1998-16, VA-Forsk, Stockholm (in Swedish).
2.
Babbitt, H. E. (1931). “Sewage investigation at the University of Illinois.” Sewage Works J., 3(4), 580–287.
3.
Baskerville, R. C. (1971). Freezing and thawing as a technique for improving the dewaterability of aqueous suspensions. Filtration and Separation, Croydon, England, Mar./Apr., 141–144.
4.
Biddlestone, A. J., and Gray, K. R. ( 1985). “Composting.” Comprehensive biotechnology, M. Moo-Young, ed., Vol. 4, Pergamon Press, Oxford, 1059–1070.
5.
Brock, T. D., et al. (1984). Biology of microorganisms, 4th Ed., Prentice-Hall, Englewood Cliffs, N.J.
6.
Burge, W. D. (1983). “Monitoring pathogen destruction.” Bio Cycle, 24(2), 48–50.
7.
Doe, P. W., Benn, D., and Bays, L. R. (1965). “Sludge concentration by freezing.” Water and Sewage Works, 112(11), 401–406.
8.
Ezekvo, G., et al. (1980). “On the mechanism of dewatering colloidal aqueous solutions by freeze-thaw processes.” Water Res., 14, 1079–1088.
9.
Halde, R. (1980). “Concentration of impurities by progressive freezing.” Water Res., 14(6), 575–580.
10.
Hellström, D., and Kvarnström, E. (1997a). “Natural sludge dewatering. I: Combination of freezing, thawing and drying as dewatering methods.”J. Cold Regions Engrg., ASCE, 11(1), 1–13.
11.
Hellström, D., and Kvarnström, E. (1997b). “Organic matter, nitrogen and phosphorus content in sludge dewatered by natural methods.” Vatten, Lund, Sweden, 53, 253–265.
12.
Hernebring, C., and Lagesson, E. (1986). Conditioning of sludge by natural freezing—Full-scale dewatering at three WWTP in northern Sweden (in Swedish). Rep. No. 27 1986, Dept. of Envir. Engrg., Div. of Sanitary Engrg., Luleåa University of Technology, Luleåa, Sweden.
13.
Mara, D., and Cairncross, S. (1989). Guidelines for the safe use of wastewater and excreta in agriculture and aquaculture. World Health Organization, Geneva.
14.
Marklund, S. (1993). “Dewatering of drying beds—Combined biological-chemical sludge behaviour.” Water Sci. and Technol., 28(10), 65–72.
15.
Martel, C. J. (1993). “Fundamentals of sludge dewatering in freezing beds.” Water Sci. and Technol., 28(1), 29–35.
16.
Sanin, F., Vesilind, P. A., and Martel, C. J. (1994). “Pathogen reduction capabilities of freeze/thaw sludge conditioning.” Water Res., 28(11), 2393–2398.
17.
Stenström, T. A. (1996). Pathogenic micro-organisms in sewage systems. Rep. 4683, Swedish Environmental Protection Agency, Stockholm (in Swedish).
18.
Strauss, M., Larmie, S. A., and Heinss, U. (1997). “Treatment of sludges from on-site sanitation—Low-cost options.” Water Sci. and Technol., 35(6), 129–136.
19.
Vesilind, P. H., and Martel, C. J. (1990). “Freezing of water and wastewater sludges.”J. Envir. Engrg., ASCE, 116(5), 854–862.
20.
Williams, T., et al. (1991). “Septage dewatering, treatment and composting.” Biocycle, 32(4), 66–75.
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Received: Jul 8, 1998
Published online: Dec 1, 1999
Published in print: Dec 1999
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