Abandoning Sewage Tanks Properly Saves Lives

Follow these decommissioning tips to prevent dangerous collapses, ongoing pollution issues and unnecessary underground obstacles in a customer’s yard

Abandoning Sewage Tanks Properly Saves Lives

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Every year there are news accounts of adults, children or pets falling into a collapsed septic tank, cesspool or seepage pit, causing serious injury, long-term health problems and even death. This past year has been no exception with multiple reports from different parts of the country. 

Aside from these types of catastrophic incidents, there are other problems caused by not properly abandoning onsite sewage treatment systems. They include instances of flooded basements or businesses due to water following old piping back to buildings from a flooded septic tank; health problems due to contact with pathogens; and all sorts of minor scrapes and broken bones. 

When a system is decommissioned in the process of upgrading and improving an onsite system or when the house switches to a municipal sewer, it is important to abandon the system in a way that protects the health and safety of the homeowner and others.

Even though cesspools and seepage pits are technically not tanks, they should be abandoned consistent with the procedures for any other sewage tank. The same is true for abandonment of vault privies or composting toilets. Access for future discharge to the tank and the rest of the system should be permanently denied. This means removing or permanently disconnecting any piping from the residence or business to the tank. 

Remove contents

To properly abandon a sewage tank, all solids and liquids should be removed. All electrical devices, pumps and floats should be removed. The tanks should either be removed or left in place, crushed and the void spaces filled with soil or rock material. If a tank left in place and crushed, this should be done in a manner that prevents it from holding water. The soil material should be sand or a granular material. The material should be compacted and slightly mounded to allow for settling. Proper grade should be established and vegetative cover provided.

Septage or mixed waste removed from the tank should be disposed of in accordance with all state, federal and local regulations. If it meets regulatory requirements, it can be land applied, taken to a landfill or to a septage or sewage treatment facility. Most treatment facilities will require some type of written agreement providing assurance the material being delivered does not contain hazardous material. This is for your protection, as the service provider, and the facility’s protection. So documentation showing the material was handled properly is important.

Power to the system should be disconnected at the source. All controls and panels should be removed. All electrical lines should be removed unless they are used for other purposes. Pumps and floats may be recycled for future use or disposed of according to local solid waste regulations. Of particular importance in older systems is some of the controls may be operated by mercury switches. This is a hazardous waste and cannot just be deposited in the garbage; but taken for proper recycling.

Many systems have additional pretreatment components that need to be abandoned. These include ATUs and media filters. Since many are proprietary products, the manufacturer may have specific requirements for abandonment. So manufacturers should be consulted before the components are disposed. Many pumps, blowers, panel boxes and alarms will be reusable, so they should be recycled or salvaged.

Soil treatment areas

Any modular containers should be removed; the distribution network should be removed along with the distribution and treatment media. Any materials that cannot be reused should be disposed of according to state and local regulations. Some may go to a treatment facility and some to a landfill. If the unit involves a tank, it can be treated like any other sewage tank, crushed and filled, with the site properly graded and with vegetative cover established.

For soil treatment areas, there are several options; it may be left in place if there are no other plans for use of the area, after resting the area can be reused, the components removed.

If abandoning the soil treatment area due to hydraulic or organic overload and the system meets all setback and separation requirements, the designer, installer and owner may decide to provide a switching option where the old system can be used as a backup or fit into planned switching back and forth between areas. Obviously, this can only be done if approved by the permitting authority and absolutely should not be done with seepage pits.

If the soil treatment component is left in place and there was no effluent surfacing, the area can be maintained with current vegetative cover. If effluent was surfacing, those areas can be treated with hydrated lime, the area backfilled, and vegetative cover established.

If the soil treatment area is removed, all piping and media will be removed and should be disposed of and handled to prevent contact with the public. All distribution and other boxes should be pumped and the field allowed to dry out. When the materials are removed the area should be backfilled, graded, topsoil applied and a vegetative cover reestablished.

If these procedures are followed during abandonment, public health and the environment will be protected, which aligns with our industry goals. 


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