Effects of Sludge Dry Solid Content and Residual Bulking Agents on Volatile Solids Reduction Using Eisenia foetida

Document Type : Research Paper


1 Prof., Dept. of Environmental Engineering, University of Tehran

2 Assist. Prof., Dept. of Environmental Engineering, University of Tehran

3 Assoc. Prof., Faculty of Health, Medical Science University of Tehran

4 Assoc. Prof., Dept. of Agronomy and plant Breeding of Abureihan, University of Tehran

5 Ph.D. Graduate, Dept. of Environmental, University of Tehran


In the first stage of this study, the compound effects of sludge dry solid content and residual bulking agent type (paper, saw dust, straw) mixed with activated sludge (10, 15, and 20% dry solids) on volatile solids (V.S.) reduction were investigated using Eisenia foetida in pilot scale experiments with batches of fifty earthworms in each of the 10 experimental treatments over a period of 10 weeks. The maximum V.S. reduction was attained in the mixture of sludge and paper, with a D.S. of 15% (0.42 ± 0.03 % day-1) while the minimum V.S. reduction was achieved in the mixture of sludge and straw, with a D.S. of 10% (0.26 ± 0.01 % day-1). In the second stage, the survival of Eisenia foetida in the anaerobic sewage sludge was investigated. In the unmixed raw anaerobic sludge, all the earthworms died during the first 9 weeks of the study period due to acute toxicity. From week 10, however, their survival rate improved so that by week 12 when toxicity reduced to 25.40%, they completely survived. This is while in the mixture of anaerobic sludge with paper (D.S. 15%), 100% of the earthworms survived from week 8 after the volatile solids reduced to 20.42% and 17.40%.


1- USEPA. (1994). Sludge handling and disposal, composting, 18th Ed., Federal Regulation, Washington.
2- Elvira, C., Goicoechea, M., Sampedro, L., Mato, S., and Nogales, R. (1996). “Bioconversion of solid paper-pulp mill sludge by earthworms.” J. of Bioresource Technology, 57, 173-177.
3- Hartenstein, R. (1978). The most important problem in sludge management as seen by a biologist, In: R. Hartenstein(ed.) Utilization of Soil Organisms in Sludge Management. Natl. Tech. Info. Serv. PB 286 932, Springfield, Virginia.
4- Hartenstein, R., and Hartenstein, F. (1981). “Physicochemical changes effected in activated sludge by the earthworm Eisenia. Foetida.” J. of Environmental Quality, 10 (13), 377-382.
5- Atiyeh, R. M., Dominguez, J., Subler, S., and Edwards, C. (2000).“Changes in biochemical properties of cow manure during processing by earthworms (Eisenia ander Bauche) and the effects on seedling growth.” J. of Pedobiologia, 44, 709-724.
6- Dominguez, J., Briones, M. J. I. (1997). “Effects of diet on growth and reproduction of Eisenia Andrei (Oligochaeta, Lumbericidae).” Pedobiologia, 41, 566-576.
7- Fair, G.M. and Geyer, J.C. (2002). Water and wastewater engineering, 3rd Ed., Wiley and sons, New York.
8- Edwards, C.A., and Bohlen, P.J. (1996). Biology and ecology of earthworms, Chapman and Hall, London.
9- Edwards, C.A. (1988). Breakdown of animal, vegetable and industrial organic wastes by earthworms, In: Earthworms in waste and environmental management, 1st Ed., SPB Acad. Pub, the Netherlands.
10- Ndegwa, P. M., and Thompson, S. A. (2001). “Integrating composting and vermicomposting in the treatment and bioconcentration of biosolids.” J. of Bioresource Technology, 76, 107-112.
11- Dominguez, J., and Edwards, C. A. (2004). Soil zoology sustainable development in the 21st Century: A review, 17th Ed., Research pub. Cairo.
12- Dominguez, J., Edwards, C.A., and Webster, M. (2000). “Vermicomposting of sewage sludge: Effects of bulking materials on the growth and reproduction of the earthworm Eisenia Andrei.” Pedobiologia, 44, 24-32.
13- Frederickson, J., Butt, K.R., Morris, R.M., and Daniel, C. (1997). “Combining uermiculture with traditional Green Waste composting systems.” Soil Biology and Biochemistry, 29 (3-4), 725-730.
14- Ndegwa, P. M., and Thompson, S. A. (2000). “Effects of C to N ratio on vermicomposting of biosolids.” J. of Bioresource Techonology, 75, 7-12.
15- Neuhauser, E.F., Loehr, R.C., Malecki, M.R. (1988). The potential of earthworms for managing sewage sludge, In: Edwards, C. A. and Neuhauser, E. F. (eds.), Earthworms in waste and environmental management. SPB Academic Publishing BV, Hague.
16- Loehr, R. C., martin, J. H., Neuhauser, E. F., and Malecki, M. R.(1984). Waste management using earthworms, engineering and scientific relationships, Final report, Project ISP-8016764, National Science Foundation.
17- Ndegwa, P. M., Thompson, S. A., and Das, K. C. (2000). “Effects of stocking density and feeding rate on vermicopomsting of biosolids.” J. of Bioresource Technology, 71, 5-12.
18- Parvaresh, A., Movahedian, H., and Hamidian, L.(2004). “Vermistabilization of municipal wastewater sludge with Eisenia Foetida.” Iranian J. Env. Health Sci. Eng, 1(2), 43-50.
19- Alidadi, H., Parvaresh, A.R., Shahmansouri, M.R., Pourmoghadas, H., and Najafpoor, A.A.(2007). “Combined composting and vermicomposting process in the treatment and bioconversion of sludge.” Pakistan J. of Biological Sciences,10(21), 3944-3947.
20- Naddafi, K., Zamanzade, M., Azimi, A.A., Omrani, G.A., Mesdaghinia, A.R., and Mobedi, E. (2004). “Effect of temperature, dry solids and C/N ratio on vermicomposting of waste activated sludge.” Pakistan J. of Biological Sciences, 7 (7), 1217-1220.