Decentralized wastewater treatment systems, whether onsite or clustered, provide effective means to collect, treat, and disperse or reclaim wastewater from individual dwellings, businesses, or small communities or service areas. Decentralized systems are commonly referred to as septic systems, private sewage systems, individual sewage treatment systems, onsite sewage disposal systems or package plants.
Unfortunately, many of the systems in use are improperly managed and do not provide the level of treatment necessary to adequately protect public health and groundwater quality.
To help state, tribal and local governments determine the best way to protect public health and the environment, the U.S. EPA has issued a booklet that outlines their recommendations, titled Voluntary National Guidelines for Management of Onsite and Clustered (Decentralized) Wastewater Treatment Systems. These recommendations are referred to as the Management Guidelines.
Proper management of decentralized systems must involve system owners, regulators, service providers and, in some cases, third-party managers, to ensure maximum system performance before, during and after installation. EPA’s Management Guidelines strive to improve system performance by standardizing the concept of management, raising the quality of existing management programs and suggesting minimum levels of activity.
The guidelines involve five models structured to reflect an increasing need for more comprehensive management as the sensitivity of the environment or degree of technology increases. A management program’s intensity increases progressively from one level to another in order to adequately achieve water quality and public health goals.
The models only suggest a basis for a community’s program and can be customized by substituting elements of one program into another to accommodate local needs. A hybrid or combination of programs may be appropriate where environmental sensitivity and public health risks vary within the area.
Due to space considerations, this article will provide an in depth look at Management Guideline Models 1, 2 and 3.
Model 1: Homeowner Awareness Model
Model 1 is the minimum level of management recommended by the EPA and is referred to as the Homeowner Awareness Model. Model 1 can be considered the starting point for enhancing management programs because it provides communities with a good database of existing onsite wastewater treatment systems. Simply put, Model 1 requires local authorities to create an inventory of all existing systems and educate homeowners about the maintenance required to keep systems working effectively.
This model is often used in areas of low environmental sensitivity, i.e., where there are no restricting site or soil conditions, such as shallow water tables or drinking water wells within locally determined horizontal setback distances. Failures that might possibly occur and continue undetected in such areas theoretically would pose a relatively low level of risk to public health and water resources.
This model’s objectives ensure that all systems are sited, designed and constructed in compliance with the prevailing rules; the local regulatory authority documents and inventories all systems; and system owners are informed about the maintenance needs of their systems through timely reminders.
This model recommends that local authorities provide an accurate record of the types and locations of installed systems, raise homeowner awareness of basic system maintenance requirements, and ensure that the homeowners attend to those problems that threaten public health. A limitation at this level of management is lack of an identification system for noncompliance. In addition, small communities might find it difficult to finance database maintenance and homeowner education.
Model 1 suggests using trained and licensed or certified service providers. The Management Guidelines booklet provides a detailed chart that breaks down the elements of the program, the responsible parties and activities. The parties responsible for activities at this level are the local regulatory authority, the local service provider, the developer, the pumper/hauler, the site evaluator, the system designer, the installer and the homeowner.
The guidelines suggest that the local regulatory authority be responsible for the education of homeowners on the purpose, use and care of their treatment system, evaluation of the environmental impact of potential wastewater discharges, establishment of system failure criteria and site evaluation procedures.
Local officials administer the permitting of new systems; perform final inspections; administer a tracking system for residuals hauling, treatment and disposal; and perform compliance inspections at point-of-sale of properties. Regulatory authorities also are responsible for negotiating compliance schedules with owners, maintaining the database inventory, and providing the legal and financial support to sustain the management program.
The local service provider participates in advisory committees, maintains appropriate certification and licensing, and obtains training from manufacturers or vendors for proprietary equipment.
The developer is responsible for hiring planners, certified site evaluators and designers to ensure the lots of the proposed development meet requirements for onsite treatment.
The site evaluator must obtain certification to practice, describe site and soil characteristics, determine suitability of the site with respect to code requirements, and estimate the site’s hydraulic and treatment capacity according to the regulations.
The system designer must be certified and design a treatment system that is compatible with the site’s soil as determined by the site evaluator. During construction, the designer must approve any changes and submit them to the owner.
The installer must have the proper certifications or licenses to practice, construct the system according to the approved plan, prepare drawings of the completed system for the homeowner, and perform repairs, modifications and upgrades as necessary.
After construction, the system owner is responsible for submitting final drawings of the system to the regulatory authority. The owner is required to perform recommended maintenance and hire a certified pumper to periodically inspect, service and remove septage. The owner also is required to maintain approved drawings of the system, keep a maintenance log, and provide these drawings and records at the time of sale of the property.
The pumper/hauler is required to obtain certification to practice, inspect and service the system as required, and inform the owner of any noncompliant items observed during routine servicing. Pumpers must also comply with any applicable federal, state, tribal and local requirements in the pumping, hauling, treatment and disposal of system residuals and submit records of residuals handling as required.
Model 2: Maintenance Contract Model
This more advanced model is recommended where enhanced system designs are employed. Small cluster systems are typical of this level of treatment. The systems often involve more complicated engineering with mechanical parts that require routine observation and maintenance if they are to perform satisfactorily. Service contracts must be established and maintained with a certified operator.
Because of the increased potential for malfunction, the activity levels of the involved parties also increase. Benefits of this level of management are that the risk of system malfunction is reduced and homeowner investments are protected. At this level of management, it is difficult to track and enforce compliance because it relies on the owner or contractor to report a lapse in a valid service contract, and there is no mechanism provided to assess the effectiveness of the maintenance program.
As treatment options become more complex, so do the amount of activities for all responsible parties. This level of management includes the major parties and responsibilities of Model 1 as well as additional ones.
At this level, a new entity, the operator, is involved. This would be a certified and licensed party, responsible for the actual maintenance of the system according to the operation and maintenance (O&M) manual. The operator must certify to the owner that the required maintenance was performed in a timely manner and describe any system deficiencies noted. The owner submits this maintenance report to the regulatory authority immediately following the scheduled maintenance.
According to the guidelines, at this management level, the regulatory authority is required to establish minimum performance criteria and maintenance requirements for all approved systems and components. These local authorities must determine alternative site acceptance criteria for approved systems providing enhanced pretreatment and administer an evaluation program for approving components for use with pre-engineered designs. The regulatory agency oversees compliance of the maintenance contract by periodically checking that the owner holds a valid contract with a licensed operator for maintenance on the system.
System owners are required to submit a copy of the system O&M manual to the regulatory authority after installation and are responsible for keeping up the maintenance contract with the certified operator. The owner is responsible for submitting a signed maintenance report following each service visit by the operator and is expected to inform the regulatory authority of any change in maintenance contract status.
Model 3: Operating Permit Model
This management level includes renewable and/or revocable operating permits issued to the system owner. These permits stipulate specific and measurable performance criteria for the treatment system and require the system owner to submit compliance reports periodically. The performance criteria are based on risks of public health and water resources posed by wastewater dispersal.
Operating permits allow the use of clustered or onsite systems at sites with a greater range of site characteristics, but this management level is particularly appropriate in areas adjacent to estuaries or lakes where excessive nutrient concentrations may be a concern. Although, in some areas where it is appropriate to use conventional onsite system designs, the operating permit may only require that routine maintenance be performed in a timely manner and the condition of the system be inspected periodically.
The EPA recommends that Model 3 be the minimum model used where large-capacity systems or systems treating high-strength wastewater are present. This management program’s principal directive is to ensure the onsite wastewater treatment systems continuously meet their performance criteria. The operating permit provides a mechanism for continuous oversight of system performance. If compliance with the permit is not maintained, corrective actions will be taken.
As recommended by the guidelines, the regulatory authority will establish performance criteria to protect water resources for each defined receiving environment and will require the designer to certify that completed system construction is in compliance. At this level, the regulatory authority must establish defining characteristics for each receiving environment in the jurisdiction. The authority must also design a review program for engineered designs to meet stipulated performance criteria. In addition, they are responsible for overseeing the submission of routine operation and emergency contingency plans that will sustain system performance and avoid unpermitted discharges.
Administering the operating permits and tracking compliance monitoring reports also are part of the authority’s responsibilities. The owner must be notified of impending scheduled submission of compliance monitoring reports. Local authorities also perform system inspections randomly or at the time of operating permit renewal. During the construction phase, the regulatory authority will require the designer of record to certify that the completed system construction is in compliance with approved plans and specifications. After construction, the regulatory authority is required to administer a tracking system for operating permits and a database for compliance reports.
The owner or user is charged with operating and maintaining the system in accordance with the O&M manual or permit stipulations. The owner is responsible for submitting monitoring reports to the regulatory authority along with inspection reports generated by the operator. The owner also is responsible for hiring a certified contractor and for submitting a copy of the system’s O&M manual to the regulatory authority to record required maintenance. The owner must submit a signed compliance inspection report prior to applying for renewal of the permit.
The certified operator shares responsibilities with a new participant—the inspector. The inspector must be certified or appropriately licensed and is responsible for inspections for compliance with the operating permit prior to permit renewal. Either the operator or the inspector performs monitoring of the system according to the owner’s operating permit. The operator is responsible for the servicing of the system as stipulated in the O&M manual for that system.
Readers should remember that these models are only suggestions and should be considered a flexible framework for a community to work within. Activities from one model may be incorporated into another model as necessary to achieve the desired objectives and the specific needs of the community and of the watershed, regardless of environmental sensitivity.