Conventional onsite sewage disposal systems – septic systems – have long been the only available method for wastewater treatment in areas not served by municipal sewer.

The technology is sound and proven as a reliable means of treatment and disposal of residential wastes. In fact, the US EPA in its 1997 report to Congress declared managed, onsite systems to be a long-term viable option.

While these conventional systems serve a vital role in our nation’s infrastructure, there are other options that provide greater benefits to many of the stakeholders in the land development arena.

“Decentralized Cluster Wastewater System” is a big name for a relatively simply concept. It incorporates many of the same features and benefits found in conventional septic systems only on a larger scale.

Individual home sites are connected via a pump to small-diameter, pressure sewer pipes buried parallel to streets. The effluent from each home is pumped through the force main to a centralized collection/recirculation tank. The effluent is then typically pumped to a fixed-film system where it undergoes aerobic treatment. The effluent is then pumped to small-diameter, drip irrigation tubing installed below ground in open areas of the development.

A decentralized cluster system is more a concept than a technology, it goes beyond what is usual and customary, it provides benefits to many and is ultimately a win/win scenario. To fully embrace the decentralized cluster system concept you must understand how each stakeholder in land development benefits from its introduction into an area.

Local officials complain that the single biggest problem they face when dealing with conventional septic systems is the lack of cost-effective, routine maintenance. Homeowners usually wait until the system is irreparably damaged before they ask service providers to assess their systems.

Adopting the decentralized cluster concept removes the homeowner from deciding when system maintenance is needed. The system ultimately is overseen by a Responsible Management Entity (RME) that charges the homeowner to manage and operate the entire system. The RME is typically a public or private utility that possesses the knowledge and experience to successfully manage a decentralized system. The RME’s involvement provides the regulatory authority with assurances that the system receives proper attention throughout its life cycle.

Traditional rural developments areas follow typical land use patterns. Acreage is divided into equal sized parcels connected by streets. The individual parcels of land must be large enough to support the proposed homes and a conventional septic system, with allowances made for repair/expansion area should the septic system fail in the future. This layout creates a very uniform distribution of homes and usage of the entire land area.

Utilizing this system can allow planners to achieve the same number, if not more individual home sites, while preserving and enhancing the overall aesthetics of the property. They can also allow planners and developers to reduce individual lot sizes and increase lot density while retaining larger areas of open green space.

The green space within the development can remain in its natural state or be utilized for community areas, parks, greenways and other enhanced land use projects. Increasing lot density means that planners can allow growth in total numbers of home sites while reducing overall land use, loss of agricultural lands, etc.

Earlier this year in central Kentucky, representatives from local agencies in Hardin County began meeting to evaluate the use of the decentralized cluster concept for new development.

Due to its proximity to Fort Knox, and the establishment of a 1, 500-acre industrial site, the rural area of Hardin County is experiencing growth in residential developments. The local Health Department approved 640 on-site septic systems in one year.

“The decentralized cluster concept will allow us to continue approving growth while minimizing the impact this growth has on our rural character,” said Chris Hunsinger, Director of the Hardin County Planning Commission. “The ability to actually increase lot density while preserving more open green space is a great tool for proper land use and adds to the quality of life in the community as a whole.”

Developing an unsewered rural property in the traditional manner requires that each individual home site stand on its own in terms of its viability to support a conventional system. Often there is a percentage of individual lots that must be left vacant due to individual site constraints.

This concept assures that every proposed lot will become a buildable lot and allows the developer the ability to accurately forecast and plan the total investment return.

Creating green space and common-use areas in a planned development can contribute significantly to the overall property value. While the developer must spend dollars upfront to install the required infrastructure, the benefits of increased lot prices and higher lot density can result in a higher return on the developers overall investment.

A decentralized infrastructure can be phased more easily than centralized wastewater systems.

The cluster concept can allow developers to turn unusable land into profitable home sites. Properties with steep slopes, shallow bedrock, poor soils and other restrictions can be utilized for home sites while reserving areas with less problematic conditions for the installation of the decentralized technology.

The Tennessee tourist destination of Gatlinburg has long been known for its beautiful mountainous terrain. Unfortunately, this type of terrain makes installing individual onsite septic systems almost impossible.

Wastewater from the cabins flows via small-diameter pressure sewers to a central point where it undergoes treatment by a Quanics AeroCell treatment system. Final treatment and disposal of the wastewater occurs using drip irrigation fields located on the most suitable areas throughout the development.

System oversight, maintenance, and operation are achieved through utility management, with each homeowner paying a monthly utility bill just as if they were connected to public sewer.

By employing this system the developers of Sterling Springs were able to turn previously unusable land into a multi-million dollar development.

Many potential homeowners are seeking to build in rural areas away from the hustle and bustle of larger communities. The mass exodus to the suburbs has proliferated the development of rural subdivisions served by individual septic systems.

The homes in these developments are getting larger and are incorporating many other land-requiring features such as additional garages and swimming pools.

Traditional septic systems on these lots restrict the homeowners’ ability to build and enhance their property. There is also the fear of what will happen if the septic system were to fail. Can it be repaired? How much additional land would the repair require? Will the failure reduce the property value?

The decentralized concept alleviates these concerns. It allows the homeowner to purchase a lot and utilize as much space as needed; such as they would with a municipal sewer system.

The addition of green space can provide the homeowner with a more attractive and usable “community” development in which to live. While there are costs associated with the RME management of the system, it is very much inline with the fees associated with a municipal sewer connection.