An Onsite Wastewater Treatment System Owner’s Manual
Remediation
When there are indications of a soil treatment system MALFUNCTION, it is important to analyze and correct the problems as early as possible. A few things can be relatively simple to correct, such as a leaking fixture. They should be fixed immediately and normal water use reduced as much as practical. Another corrective action would be to divert any surface water that may be running onto the soil treatment area. If there is a distribution box, check or have a wastewater professional check that trenches are receiving relatively equal volumes of wastewater and make adjustments as needed.
Contacting a Professional
If these actions do not correct the problem, a REGISTERED ONSITE WASTEWATER TREATMENT SYSTEM PROFESSIONAL or other qualified SERVICE PROVIDER should be contacted to pump out the sewage tank. The SERVICE PROVIDER is responsible for the proper treatment and disposal of all hauled wastewater by transporting to a municipal sewage treatment plant capable of receiving the waste; transporting to a sludge handling facility which possesses a current and valid permit issued for such activity; or land applying under a current and valid permit for such activity. While pumping out the tank, the SERVICE PROVIDER should be able to verify the size of the tank and whether it leaks. The professional may observe WASTEWATER returning to the tank from the dispersal system, an indication of possible overloaded system, SATURATED soil or bio-mat clogging. Further investigation may be needed.
Extensive Corrective Options
More extensive corrective options may include expansion, repair, replacement, or remediation. Expanding the OWTS would be applicable when building an addition to the home, there is an increase in the number of occupants, or if the system was originally undersized but meets other construction standards. Repairs are usually only acceptable when a trench or pipe has been damaged, for example by a heavy vehicle or during the installation of another underground utility. Replacement of the soil treatment system may be necessary if the type of system, the design, or the installation was not correct based on the soil properties. Older systems could have appeared to function while putting groundwater at risk. When a problem is observed, a replacement soil treatment system may be needed to protect public health, groundwater, and surface waters.
INSPECTIONS:
Refer to the appropriate chapters of this manual – Gravity Distribution and Soil Dispersal Trenches, Pressure Distribution, or Drip Dispersal for INSPECTION criteria, Warning Signs and Dos and Don’ts.
Soil treatment system remediation can be another option; however, it cannot be expected to correct problems in many situations, such as those noted above. Before attempting remediation of a MALFUNCTIONING system, a REGISTERED ONSITE WASTEWATER TREATMENT SYSTEM PROFESSIONAL should troubleshoot the problem to rule out causes that could not be corrected by soil treatment remediation, such as excessive water use, water leaks, root clogs, etc. Even when remediation might help, the benefit is may be for a limited time only. The OWNER should be aware of the limitations of remediation and assume the financial risk if remediation is attempted.
Generally, if a MALFUNCTION is due to long-term bio-mat buildup, remediation will provide at least temporary improvement. Common remediation methods include resting, aeration, and soil amendment as shown in the table on the following page.
| Method | Description | Typical Situation | Cautions |
|---|---|---|---|
| Resting | One or more trenches are taken out of service for 6 to 12 months to allow the trench(es) to dry out and the bio-mat to degrade naturally. Rest trenches alternately. | Most effective if used in conjunction with a soil treatment system expansion or as routine management of a serial distribution system. | In other situations, resting may require severely restricted water use for an extended time period. |
| Aeration | Replace a septic tank (primary treatment) with an NSF 40 aeration treatment unit or a bio-filter; or Add aeration to an existing septic tank (models generally do not meet NSF Standard 40) | Aerated EFFLUENT supports different bacteria and organisms that may consume a portion of the clogging bio-mat and increase wastewater movement into the soil. Somewhat reduced water use may be necessary. | Non NSF aerators can increase the amount of solids discharged to the soil treatment system. After remediation, distribution of EFFLUENT may be less even. In some permeable soils, there may be increased potential for groundwater contamination. |
| Soil Amendment | Injection of compressed air or some other method is used to open voids in the soil. Foam beads may be injected to help keep voids open. | May be most effective in compacted soils and platy soil structure. | Effect on clogging bio-mats may be short-term. Effects in high shrink/swell clays will be temporary at best. Must not apply soil amendment too deep. If a restrictive or slowly permeable horizon is breached, there may be increased potential for groundwater contamination. |
Note: except for the trench resting method, a permit may be required for remediation. Also, remediation may not be permitted when a Notice of Violation has been issued for the MALFUNCTIONING system. Check with the local onsite permit authority.