Using a Private Wetlands Effluent Disposal System as a Component of Alternative Septic Systems for Difficult Sites
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Designs for private wetlands for septic system effluent treatment
What are wetlands, how are they used with septic systems?
Questions & answers about the design, constrution, maintenance, diagnosis & repair of private septic wetlands systems.
Private wetlands septic systems: this document discusses use of private wetlands for residential onsite wastewater treatment. Wetlands used in this manner are natural systems for polishing or recycling septic effluent include public and private wetlands, greenhouses, and other systems.
The photograph at above left shows a constructed wetlands in San Miguel de Allende, Guanajuato Mexico. This wetlands
forms a portions of a wetlands ecosystem which treats septic effluent from a local community and provides fresh
water to botanical gardens.
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Wetland Septic Systems for Private Onsite Wastewater Disposal
Wetland Septic Systems or "natural" septic
systems use a constructed wetlands
area (or a greenhouse) to treat septic effluent. These systems are more common in Louisiana, Mississippi, Tennessee, South Dakota, and Florida
where both municipal wetland septic designs and private homeowner wetland septic system designs are in use.
"Wetlands" may include both visible water such as open ponds, and underground water located in constructed
beds which are covered with soil. Typically these systems are used as a final "polishing" step to treat effluent
which has been processed in an
aerobic treatment unit (ATU) or effluent which has been processed by a media filtration unit.
Wetlands septic effluent disposal systems usually require a large area and are not easily adjusted to accommodate variations in
the level of system usage, such as a sudden increase in the occupancy of the site. However these systems also use
less electricity or other energy source than pumping, dosing, and similar effluent handlers.
A more sophisticated (and costly) alternative to an open wetlands for treatment of effluent is the use of a
greenhouse system which encloses the wetland treatment facility and provides a more controlled environment.
A
greenhouse septic effluent system discharges effluent into the atmosphere in the form of humidity, similar to evaporation systems. Jantrania (op.cit.)
describes greenhouse systems which use UV light for final disinfection of effluent which is then recycled
to flush toilets.
At Technical Reviewers & References below we provide a bibliography of references and information sources about the design, performance, & maintenance of wetland septic systems.
Questions & Answers regarding this article
Questions & answers about the design, constrution, maintenance, diagnosis & repair of private septic wetlands systems.
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EPA. 1993. Subsurface flow constructed wetlands for wastewater treatment: A technology assessment. EPA
832-R-93-001. Environmental Protection Agency, Washington, D.C.
Steer, David, Lauchlan Fraser, James Boddy, Beth Seibert, "Efficiency of small constructed wetlands for subsurface treatment of single-family domestic effluent", Ecological Engineering, Vol 18 Iss 4, pp. 429-440, 2002/3/1 - Abstract:
Single-family constructed wetland systems in Ohio, USA, are studied to evaluate their effectiveness in improving water quality. Twenty-one, three-cell systems (septic tank with two wetlands) are found to meet US Environmental Protection Agency (EPA) effluent load guidelines in 68% of the quarterly water quality samples collected from 1994 to 2001.
These wetlands most frequently meet EPA standards for mitigation of biochemical oxygen demand (89% below 30 mg/l); total suspended solids (79% below 30 mg/l); and fecal coliform (74% below 1000 counts/100 ml). Phosphorus and ammonia discharge meet the guidelines less often (50% at 1 mg/l and 16% at 1.5 mg/l, respectively). These data also indicate that domestic treatment wetlands can reduce output of fecal coliform 88±27%, total suspended solids 56±53%, biochemical oxygen demand 70±48%, ammonia 56±31% and phosphorus 80±20%. Analysis of variance for these systems indicates that biochemical oxygen demand reduction is ∼10% less efficiently reduced during winter and ammonia was reduced ∼20% more efficiently in fall when compared with the other seasons. Phosphorus reductions display complex seasonal variations that imply that the least efficient phosphorus reduction occurs in winter and the most efficient reduction occurs in fall.
Neralla, Srinivasan, Richard W Weaver, Bruce J Lesikar, Russell A Persyn, "Improvement of domestic wastewater quality by subsurface flow constructed wetlands", Bioresource Technology, Volume 75, Issue 1, October 2000, Pages 19–25, Abstract:
A large proportion of households throughout the world and approximately 25% of the households in the US use on-site wastewater disposal systems. Subsurface flow constructed wetlands are gaining popularity as a reduced cost and low-maintenance technology for on-site treatment of septiceffluents. Constructed wetlands from residences at eight locations in Texas have been used for the past 2–4 years to determine their effectiveness in improving the quality of septiceffluent passing through them. Influent and effluent samples were collected once every month over a period of one year from each location and analyzed to determine the reduction in concentrations of biological oxygen demand (BOD5), total suspended solids (TSS), volatile suspended solids (VSS), ammonium-N (NH4+-N), phosphorus, total and fecal coliform bacteria. Results of these investigations indicate that the organic load, fecal coliform populations and the N and P concentrations of the septic water decreased considerably by passing through the wetlands. Constructed wetlands reduced BOD5 of septic water by 80–90% which provided for feasible disinfection by chlorination. Reduction in populations of fecal coliforms varied but generally, populations were reduced by 90–99%. Chlorination further reduced populations of fecal coliforms to less than 2 cfu 100 ml−1. Constructed wetlands provided an effective method for secondary treatment of on-site domestic wastewater.
Henneck, J., R. Axler, B. McCarthy, S. Monson Geerts, S. Heger Christopherson, J. Anderson, J. Crosby, "ONSITE TREATMENT OF SEPTIC TANK EFFLUENT IN MINNESOTA USING SSF CONSTRUCTED WETLANDS: PERFORMANCE, COSTS AND MAINTENANCE", ASAE symposium on individual and small community systems,
Fort Worth TX, Mar 11-14, 2001 [copy on file as Wetlands_Henneck.pdf ] - Abstract:
About 30 % of Minnesotans use on-site systems for wastewater treatment (~500,000 residences). Unfortunately,
55-70 % are failing or out of compliance with state standards. Homeowners and small businesses require
cost-effective options in locations with restrictive soil and site conditions. In particular, many sites occur near lakes
and streams creating a health hazard and deteriorating water quality. Constructed wetlands (CWs) are one option
being evaluated and this paper addresses CWs as a viable wastewater treatment option in Minnesota based on
experiences at three research sites, encompassing 5 subsurface flow wetlands from 1995-2000. These are small flow
(<1000 gpd) subsurface flow gravel beds located at the Northeast Regional Correction Center (NERCC), Grand
Lake, and Lake Washington, MN. Performance monitoring shows that CWs are a viable, year-round onsite treatment
option. The systems were generally able to achieve design criteria of 30 mg BOD5/L, 25 mg TSS/L and 200 fecal
cfu/100 mL, although the NERCC CWs required 30 cm. of unsaturated soil to achieve consistent disinfection. High
strength (~300 mg BOD/L and 100 mg TN/L) influent at NERCC probably limited system performance, particularly
N-removal which was ~40% in summer and ~20% in winter (mass-based). Declining P-removal at the oldest sites
suggest substrate saturation. Although CWs remain a viable option for homeowners in terms of performance, ease of
operation, and cost, other issues relate to inconsistent vegetation growth (affecting performance and freezing), and
meeting concentration-based regulatory standards since they may exhibit substantial variability due to rain events,
partial freezing, spring snowmelt, and summer evapotranspiration.
Henneck, J., R. Axler, D. Nordman, B. McCarthy and S. Monson Geerts.1999. Operation and maintenance
experiences with constructed wetlands in Minnesota. In Proc. National On-Site Wastewater Recycling Assoc,
NOWRA, Laurel MD. pp. 219-223
Ameel, J., E.Ruzycki and R.P.Axler. 1998 Analytical chemistry and quality assurance procedures for natural
water samples. 6th edition., NRRI Tech. Rep. NRRI/TR-98/03, Natural Resources Research Institute, University of
Minnesota, Duluth, MN.
Anderson, J. and D. Gustafson.1998. Development of alternative on-site treatment systems for wastewater: A
demonstration project for southern Minnesota. Fin. Rep. to Minnesota Pollution Control Agency/Legislative Comm.
on Minnesota Resources, St. Paul, MN
Amer. Publ. Health Assoc.,Amer.Water Works Assoc.,Wat. Environ Fed, APHA 1995. Standard Methods for the
Examination of Water and Wastewater, 19th ed, Washington, D.C.
Axler, R., J.Henneck and B. McCarthy. Submitted for publication. Residential subsurface flow treatment wetlands
in northern Minnesota. Water Science and Technology.
Axler, R.P., J. Henneck, S. Bridgham, C. Tikkanen, D. Nordman, A. Bamford, and M.E. McDonald. 1996.
Constructed wetlands in northern Minnesota for treatment of aquaculture wastes. In Proc. Constructed Wetlands in
Cold Climates, The Friends of Fort George, Niagara on the Lake, Ontario, Canada.
Axler, R.P., J. Henneck, B. McCarthy. 2000. Residential subsurface flow treatment wetlands in northern
Minnesota. 7th International conference on Wetlands for water pollution control,IWA, London, UK
Brix, H.1998. Denmark. In: Constructed wetlands for wastewater treatment in Europe, J.Vymazal, H.Brix,
P.F.Cooper, M.B.Green and R.Haberl (eds.), Backhuys Publ., Leiden, Netherlands, pp.123-152.
Cooper, P.F. and M.B.Green.1998, UK. In: Constructed wetlands for wastewater treatment in Europe, J.Vymazal,
H.Brix, P.F.Cooper, M.B.Green and R.Haberl (eds.), Backhuys Publ., Leiden, Netherlands, pp.315-335.
Crites, R. and G. Tchobanoglous.1998. Small and Decentralized Wastewater Management Systems. McGraw-Hill,
Companies, Inc., pp.1084
Kadlec, R. and R. Knight.1996. Treatment Wetlands. Lewis Publ., Boca Raton, FL.
Kadlec, R. 2000 a. The inadequacy of first-order treatment wetland models. Ecol. Eng. 15(2000):105-119.
Kadlec, R.H. 2000 b. Thermal considerations of constructed wetlands in cold climates. 7th
International conference on Wetlands for water pollution control, IWA, London, UK.
Kadlec, R.H., R. Axler, B. McCarthy and J. Henneck. 2001. Subsurface treatment wetlands in the cold climate of
Minnesota. In Advances in Ecological Sciences, U. Mander, Editor, Constructed Wetlands for Wastewater
Treatment in Cold Climates.
Maehlum, T. and P. Jenssen. (1998). Norway. In: Constructed wetlands for wastewater treatment in Europe,
J.Vymazal, H.Brix, P.F.Cooper, M.B.Green and R.Haberl (eds.), Backhuys Publ., Leiden, Netherlands, pp. 206-217.
McCarthy, B., R. Axler, S. Monson Geerts, J. Henneck, D. Nordman, J. Crosby, P. Weidman, 1998. Performance
of alternative treatment systems in Northern Minnesota. , In: Onsite Wastewater treatment, Proc. 8th Internat. Symp.
on Individual and Small Community Sewage Systems, ASAE, St. Joseph, Missouri. pp 446-457
McCarthy, B., R. Axler, S. Monson Geerts, J.Henneck, J. Crosby, D.Nordman, P.Weidman and T. Hagen. 1997.
Development of alternative on-site treatment systems for wastewater treatment: A demonstration project for
Northern Minnesota. Tech.Rep. NRRI/TR-97/10, U. of Minnesota, Duluth, MN.
Reed, S., R. Crites and E. Middlebrook. 1995. Natural Systems for Waste Management and Treatment.
McGraw-Hill Companies, Inc.
Reed, S., R. Crites and E. Middlebrook. 1995. Natural Systems for Waste Management and Treatment.
McGraw-Hill Companies, Inc.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389
(2006), Advanced Onsite Wastewater Systems Technologies.
Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going
for homeowners but is a text we recommend for professionals--DF.
Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
Design Manuals for Septic Systems
US EPA Onsite Wastewater Treatment Systems Manual [online copy, free] Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm Onsite wastewater treatment and disposal systems,
Richard J Otis, published by the US EPA. Although it's more than 20 years old, this book remains a useful reference for septic system designers.
U.S. Environmental Protection Agency, Office of Water Program Operations; Office of Research and Development, Municipal Environmental Research Laboratory; (1980)
"International Private Sewage Disposal Code," 1995, BOCA-708-799-2300, ICBO-310-699-0541, SBCCI 205-591-1853, available from those code associations.
"Manual of Policy, Procedures, and Guidelines for Onsite Sewage Systems," Ontario Reg. 374/81, Part VII of the Environmental
Protection Act (Canada), ISBN 0-7743-7303-2, Ministry of the Environment,135 St. Clair Ave. West, Toronto Ontario M4V 1P5 Canada $24. CDN.
Manual of Septic Tank Practice, US Public Health Service's 1959.
Onsite Wastewater Disposal Books
Onsite Wastewater Disposal, R. J. Perkins;
Quoting from Amazon: This practical book, co-published with the National Environmental Health Association,
describes the step-by-step procedures needed to avoid common pitfalls in septic system technology.
Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in
both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers,
consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. (DF volunteers to serve as indexer if Burks/Minnis re-publish this very useful volume.)
While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference
for both property owners and septic system designers. We refer to it often.
While Minnis says the best place to buy this book is at Amazon (our link at left), you can also see this book at Minnis' website at http://web page .pace.edu/MMinnisbook
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Planting Over Septic System Component", Daniel Friedman (author/editor, InspectAPedia.com), The Innovator, Winter/Spring 2008, BCOSSA, British Columbia OnSite Sewage Association, 201-3542 Blansard St., Victoria BC V8X 1W3 Canada
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF.
Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
Test Pit Preparation for Onsite Sewage Evaluations, State of Oregon Department of Environmental Quality, Portland OR, 800 452-4011. PDF document. We recommend this excellent document that offers detail about soil perc tests, deep hole tests, safety, and septic design. Readers should also see Soil Percolation Tests and for testing an existing septic system, also see Dye Tests
Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM;
This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices.
It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers.
Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill. Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers: * Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
The NSFC Products List has an excellent list of design manuals/modules available from their website or by telephone 800-624-8301
Submissions welcome. send us a suggested document link or request an exchange of website links
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