Efficiency of a natural wetland for effluent polishing of a septic tank

Z. Yousefi, S. Jowhari, Sh. Nasiri


Wetlands now days apply as a polishing system for the classical wastewater treatment, in addition of different usages. Usually wetland systems are inexpensive methods vs. expensive high technology treatment systems. Objective of this study is an evaluation of natural wetland treatment in polishing of a septic effluent. Research duration works extended for 10 months on a natural wetland system in Pardis of Mazandaran University of medical sciences and eastern north of health faculty. Wastewater quality index such as pH, EC, BOD, COD, TSS, Nitrate, Phosphorus, Ammonia and Temperature performed on the samples of influent and effluent of the system. The study showed the system works as a buffering system for flow and pH. Results indicated that average of BOD5 and TSS efficiency were 67.70and 83%, respectively. Efficiency of COD was 65.26 and 80 % for a Low and moderate strength influent respectively. Average of phosphorus, NH3 and Nitrate in effluent were 0.032 mg/L, 7.18 and 0.036 mg/L, respectively. Efficiency of ammonia and Phosphorus were slightly increased in best condition. Based on this study result, natural wetland can be success in BOD, COD, and TSS removal of the classical septic tank, but for nitrogen and Phosphorus removal do not have considerable effects.


Natural wetland; septic tank effluent; efficiency

Full Text:



Vymazal J. Algae and nutrient cycling in wetlands. Florida: CRC Press/Lewis Publishers: Boca Raton, 1995

Brix H. Denmark. In: Constructed Wetlands for Wastewater Treatment in Europe, Vymazal J., Brix H., Cooper P.F., Green M.B., Haberl R. (eds.) Backhuys Publishers: Leiden, The Netherlands; pp. 123–152;1998

Cowardin LM, Carter V., Golet F C, Laroe E T. Classification of wetlands and deep water habitats of the united states, , Us. Department of the interior, Washington D.C. 1979

Mitsoh WJ, Gosselink JG. wetlands, New York, Ny, USA: VanNostremd Reinhold; 1993

Brix, H. Constructed wetlands for municipal wastewater treatment in Europe. In: Mitsch, W.J, Elsevier Science B.V; 1994

Brown, M T. Evaluating constructed wetlands through comparisons with natural wetlands: Corvallis, Oreg, U.S. Environmental Protection Agency, Environmental Research Laboratory, EPA/600/3-EPA91/058, p. 37; 1991

Kadlec R, Knight RL. Treatment wetlands., New York: CRC, Lewis Publishers. Boca Raton ; 1996

Garbisoch E W, High ways and wetlands compensating wetland losses, US. DOT, FHWA report No. FHWA-IP-22: Washington, DC; 1986

Hruby T, Brower C. Guidelines for developing freshwater wetlands mitigation plans and proposals, ecology publication #94-29. Washington State Department of Ecology: Washington; 1994

Keddy P A. Wetland ecology: principles and conservation. Cambridge: Cambridge University Press , p. 614; 2000

Sorrell BK, Boon PI. Biogeochemistry of billabong sediments II. Seasonal variations in methane production. Freshwater Biology, 1992; 27(3): 435–445

Armstrong W. Aeration in higher plants, Advances in Botanical Research, 1979; 7: 225–331.

Armstrong J, Armstrong W, Beckett PM. Measurement and modeling of oxygen release from roots of Phragmites australis. In: Constructed Wetlands in Water Pollution Control, Cooper PF, Findlater BC. eds. Oxford, United Kingdom: Pergamon Press; pp. 41–52; 1990

Lawson GJ. Cultivating reeds (phragmites australls) for root zone treatment of sewage, Contract report ITE, Water research centre, Gumbria, UK; 1985

Brix H. Gas exchange through the soil-atmosphere interphase and through dead culms of Phragmites australis in a constructed reed bed receiving domestic sewage. Water Research, 1990; 24(2): 259–66.

Brix H. Gas exchange through dead culms of reed, Phragmites australis (Cav.) Trin. ex Steudel. Aquat. Bot. 1989; 35: 81–98.

Gries CL, Kappen L, Lِsch R. Mechanism of flood tolerance in reed, Phragmites australis (Cav.) Trin. ex Strudel. New Phytologist, 1990; 144: 589–93.

Armstrong J, Armstrong W. Pathways and mechanisms of oxygen transport in Phragmites australis. In: Constructed Wetlands in Water Pollution Control, Cooper PF, Findlater BC eds. Oxford, United Kingdom: Pergamon Press; 1990b, pp. 529–34

Lamers LPM, Tomassen HBM, Roelofs JGM. Sulfateinduced eutrophication and phytotoxicity in freshwater wetlands. Environmental Science and Technology, 1998; 32(2): 199–05.

Kentula M. Restoration, creation, and recovery of wetlands, United States Geological Survey Water Supply: Paper 2425. E; 2003

Wetzel R G. Limnology, third edition, Lake and river ecosystems, California: Elsevier academic press, USA; 2001

Richardson CJ, Nichols DS. Ecological analysis of wastewater management criteria in wetland ecosystems. In: Ecological Considerations in Wetlands Treatment of Municipal Wastewaters, Godfrey PJ ed. New York: Van Nostrand Reinhold Company; 1985, pp. 351–91.

Wolverton BC. Aquatic plants for wastewater treatment: An Overview. In: Aquatic Plants for Water Treatment and Resource Recovery, Reddy KR, Smith WH. eds. Orlando, Florida: Magnolia Publishing; 1987a, pp. 3–15

Kusler J A, Kentula M E. Wetland creation and restoration: the status of science. Washington: Island Press; 1990, p. 591

Smith EL. Evaluation of Agricultural Constructed Wetlands in Cold Climates. M.Sc. Thesis, Dalhousie University, Nova Scotia Agricultural College (Nova Scotia); 2003 [26] Miklas S, Byoung – HWALEE, Constructed Wetlands / International Journal of Environmental Studies , 2005;62(4): 421-28

Nivala J, Wallace S, Headley T, Kassa K, Brix H, Afferden MV, Müller R. Oxygen transfer and consumption in subsurface flow treatment wetlands, Ecological Engineering, 2013.; 61, part B, pp. 544-54

APHA-AWWA-WPCF, Standard Methods For The Examination Of Water and Waste water ,20th Ed.,American Public Health Association , NW Washington , DC; 1999

Iran department of environment, Iranian effluent discharge standards, 2002, Tehran, Iran

Kaseva M E. Performance Of Sub-Surface Flow Constructed Wetland In Polishing Pre-Treated Wastewater- A Tropical Case Study. Water Research, 2004; 38(3): 681-87.

Smith EL. Evaluation of agricultural contracted wetlands in cold climates, Msc. Thesis, Dolhousie university, Nova Scotta agricultural college, 2003

Iranian Journal of Health, Safety and Environment e-ISSN: :2345-5535 Iran university of Medical sciences, Tehran, Iran