System Coefficients : Septic Systems

This is the appearance of the Septic Systems tab of the System Coefficients dialog:

Following is a description of the parameters associated with Septic Systems. Refer to the main System Coefficients page for information on other categories of coefficients. To save the changes made when closing this dialog, click OK. To ignore changes, click Cancel.

WARMF simulates three types of septic systems. Each type is generic and can be set up to represent either a standard or an advanced treatment system.

Flow is the per capita flow rate from septic systems (150 – 300 L / cap/ day)
Septic Discharge Quality are parameter concentrations of discharge from each system type (>=0 mg / L)

The following table provides literature values for the septic tank effluent quality for various types of systems. A reference list is also included below.

The following cumulative distribution plots of typical septic tank effluent flow and quality were obtained from Kirkland (2001):

Domestic Septic Tank Effluent Flow rates:

NH4-N Concentrations in Septic Tank Effluent:

Phosphorus Concentrations in Septic Tank Effluent:

First Order Nitrification Rate in Soil:

First Order Denitrification Rate in Soil:

Phosphorus Linear Isotherm Constants:

References Cited:

1. Ball, H. L. (1995). Nitrogen Reduction in an Onsite Trickling Filter/Upflow Filter System. Proceedings of the 8th Northwest On-Site Wastewater Treatment Short Course and Equipment Exhibition, University of Washington, Seattle.
2. Brooks, J. L., C. A. Rock, et al. (1984). “Use of Peat for On-Site Wastewater Treatment: II. Field Studies.” Journal of Environmental Quality 13(4).
3. Byers, M. E., K. E. Zoeller, et al. (2001). Septic Tank Effluent Filters: Monitoring and Assessment. Ninth National Symposium on Individual and Small Community Sewage Systems, Fort Worth,TX, American Society of Agricultural Engineers.
4. Christopherson, S. H., J. L. Anderson, et al. (2001). Evaluation of Recirculating Sand Filters in Minnesota. Ninth National Symposium on Individual and Small Community Sewage Systems, Fort Worth, TX, American Society of Agricultural Engineers.
5. Crites, R., C. Levken, et al. (1997). “A Decentralized Wastewater System for a Small Residential Development in California.” The Small Flows Journal 2(1).
6. Darby, J., G. Tchobanoglous, et al. (1996). “Shallow Intermittent Sand Filtration: Performance Evaluation.” The Small Flows Journal 2(1): 3-15.
7. Effert, D., J. Morand, et al. (1984). Field Performance of Three Onsite Effluent Polishing Units. 4th National Symposium on Individual and Small Community Sewage Systems, New Orleans, LA, American Society of Agricultural Engineers.
8. Henneck, J., R. Axler, et al. (2001). Onsite Treatment of Septic Tank Effluent in Minnesota Using SSF Constructed Wetlands: Performance, Costs and Maintenance. Proceedings of the Ninth National Symposium on Individual and Small Community Sewage Systems, Fort Worth, Texas, American Society of Agricultural Engineers.
9. Jowett, E. C. and M. L. McMaster (1995). “On-Site Wastewater Treatment Using Unsaturated Absorbent Biofilters.” Journal of Environmental Quality 24(1): 86-95.
10. Kirkland, S. L. (2001). “Coupling site-scale fate and transport with watershed-scale modeling to assess the cumulative effects of nutrients from decentralized onsite wastewater systems.” M.S. Thesis, Colorado School of Mines, Golden CO.
11. Lindbo, D. L. and V. L. MaConnell (2001). Evaluation of a Peat Biofilter Treatment System. Ninth National Symposium on Individual and Small Community Systems, Fort Worth, TX, American Society of Agricultural Engineers.
12. Loomis, G. W., D. B. Dow, et al. (2001). Performance Evaluation of Innovative Treatment Technologies Used to Remediate Failed Septic Systems. Ninth National Symposium on Individual and Small Community Sewage Systems, Fort Worth, TX, American Society of Agricultural Engineers.
13. Mayer, P. W., W. B. DeOreo, B. Dziegielewski, and J. O. Nelson (1999). Residential End Users of Water. Report to AWWA Research Foundation and American Water Works Association.
14. Roynayne, M. A., R. C. Paeth, et al. (1984). Oregon Onsite Experimental Systems Program. Environmental Protection Agence Office of Research and Development EPA/600/2-84-157.
15. Siegrist, R. L., E. J. Tyler, et al. (2001). Design and Performance of Onsite Wastewater Soil Absorption Systems. National Research Needs Conference: Risk-Based Decision Making for Onsite Wastewater Treatment, Palo Alto, CA.
16. USEPA (1993). Constructed Wetlands for Wastewater Treatment and Wildlife Habitat. United States Environmental Protection Agency EPA832-R-93-005.