Any facility that treats, stores or disposes of wastes faces potential liabilities from environmental exposures. While these seem apparent at landfills or hazardous waste treatment facilities, environmental exposures are less obvious at facilities such as wastewater treatment plants (also known as sewage treatment plants). Nevertheless, wastewater treatment plants do face environmental exposures from their operations, with potential resulting liabilities.

Think of wastewater treatment plants, and what often springs to mind are unpleasant odors. However, wastewater treatment plants face the potential for contamination which results from:

• discharges of contaminated effluent — i.e., outflow — due to inadequate treatment;
• cracks in wastewater treatment tanks;
• leaks or releases from storage tanks; and
• leaching of contaminants from sludge in on-site storage areas.

Effluent Exposures

The most common exposure at a wastewater treatment plant is the discharge of contaminated effluent. Effluent is typically handled in either of two ways. The treated effluent is discharged to surface water or groundwater, or the effluent is sprayed on the land. The effluent generated at the end of the treatment process is supposed to be "clean.” However, if the plant encounters any problems in the treatment process, the effluent may contain contaminants which then enter the receiving surface water, groundwater or soils. Problems that can upset the treatment process include:

• a treatment process breakdown;
• untreatable contaminants; or
• excess volume from combined sewer overflows, resulting in treatment bypass.

Subsequently, the contaminated effluent can cause surface water, groundwater, and/or soil contamination. If contaminated effluent enters a surface water body, the following effects could occur:

• fish kills;
• harm to human health if the surface water body is used for recreational purposes such as swimming, boating and fishing; or
• contamination of a drinking water supply source.

Contaminated effluent also poses harm to groundwater, which may be a drinking water source for both private and public wells. Overall, contaminated effluent can be a costly exposure for wastewater treatment plants. In the event that a stream was contaminated by effluent, local residents could sue the treatment plant for bodily injury, and also file a property damage suit for loss of stream use under the Clean Water Act. Costs for such damages could range from several hundred thousand to over $1 million.

Tank Exposures

Most wastewater treatment plants utilize concrete tanks that are often partially in the ground to process the wastewater. Over time, these tanks can develop cracks. If these cracks are not repaired promptly, tank contents can emanate from the process tank and contaminate underlying soils and groundwater. This could result initially in on-site contamination and lead eventually to third-party property damage from contaminants migrating off-site. Once again, there is also the potential for contaminating groundwater that may be a drinking water supply source. Groundwater cleanup costs can be daunting — from several hundred thousand to several million dollars.

Additionally, wastewater treatment plants generally use both underground and aboveground storage tanks to store process materials and wastes on-site. These tanks present several environmental exposures. Underground storage tanks may leak over time, and their contents have the potential to contaminate the underlying soils and groundwater. Aboveground tanks have the potential to present problems such as:

• leaks from tank bottoms;
• ruptures causing a catastrophic release of tank contents; or
• spills during the loading or unloading process.

The potential for financial loss from tank exposures can be significant, depending on the extent of contamination. For example, the discovery of contamination in private wells has the potential to incur costs for property damage, trespass of pollutants, diminution of property value, potential bodily injury for drinking contaminated water, and contingent business loss. Claims and cleanup costs could easily exceed $1 million.

Storage Exposures

One of the process materials typically stored on-site is chlorine. A deadly gas, chlorine can kill people in the vicinity of a release. Therefore, on-site chlorine storage represents a major exposure.

Another practice of many wastewater treatment plants is on-site storage of sludge that is a byproduct of the treatment process. Historically, “storage” simply meant placing the sludge on the ground or on wooden pallets. This storage method may have resulted in contamination of underlying soils and groundwater. Today, however, many plants store sludge in covered concrete areas, thus minimizing the impact of the sludge on the surrounding environment.

Odor Exposure

Getting back to the odor problem...Indeed, there is also the potential for a wastewater treatment plant to have a negative effect on the surrounding environment simply by producing foul odors. While these odors are not harmful, they are unpleasant and could result in nuisance claims against the facility. For instance, a convention taking place at a park was disrupted and forced to relocate because of the odor from a wastewater treatment plant. A suit in the amount of $23,000 was filed against the plant for loss of enjoyment and for costs to relocate the convention.