Mike Hoover

Soil Science Department, NCSU, Raleigh, NC

There’s great news for rural communities in North Carolina faced with the challenge of developing wastewater management infrastructure. Today more options for wastewater management exist than ever before, an these options provide rural communities with environmental protection, needed flexibility to plan for future economic growth and lower installation costs than traditional centralized wastewater management systems.

In fact, in a 1997 report to the U.S. Congress, the Environmental Protection Agency (EPA) found that the “decentralized approach” to wastewater management favors rural communities and frequently will be more cost-effective than centralized sewering.

The combined use of conventional septic systems, advanced designs of on-site systems and cluster or other land-based systems to serve a community’s wastewater management needs has been termed “decentralized wastewater treatment.” According to the EPA’s study findings, decentralized systems:

• Protect public health and the environment
• Are appropriate for low density communities
• Are appropriate for varying site conditions
• Provide additional benefits for ecologically sensitive areas, and
• Can provide significant cost savings while recharging local aquifers and providing other water reuse opportunities close to the points of wastewater generation.

Many rural communities in North Carolina lack a wastewater management system that can effectively protect public health, environmental quality, accommodate future housing needs and facilitate growth. Decentralized wastewater treatment should be at the top of their list. However, North Carolina does not have at this time a comprehensive, statewide strategy that provides for the cost-effective treatment of municiple wastewater in rural areas.

Thanks t major federal funding during the 1970s and 1980s, most urban communities across North Carolina installed centralized wastewater systems to meet their citizens’ needs. The federal money, combined with the failure of communities to adequately maintain traditional septic systems, provided justification for construction of sewers and a wastewater treatment plant. Usually, larger communities were favored over smaller communities to receive the majority of the federal funds.

During the ’70s and ’80s, most rural N.C. communities considered only two options to meet their wastewater management needs:

• Continue using poorly maintained traditional septic systems, or
• Install an extensive pipe network that collects wastewater to a centralized, highly maintained wastewater treatment plant.

These centralized systems have been termed the “big pipe” approach. They involve installing an extensive network of large sewer pipes throughout a community to collect wastewater and bring it to a central treatment plant, followed by disposal in a stream or body of water.

Today, however, major federal funding for wastewater management projects has been eliminated, and N.C. communities must bear the full cost in installation, operation and maintenance. The price tag to construct a centralized sewerage system has become prohibitive for less densely developed rural communities. And, increasing environmental requirements pose significant challenges for wastewater systems that discharge treated wastewater into surface water such as rivers, streams and coastal waters.

Today, there are multiple alternatives to centralized sewering. Conventional septic systems are dependable options where soil conditions are favorable and the systems are properly maintained. Advance on-site systems (sand filters, peat filters, pressure distribution systems, drip-irrigation system, disinfection systems) and community lagoon/spray irrigation systems can be used over a much broader range of site and soil conditions than the conventional septic systems. Cluster systems use small collection networks to bring wastewater from a limited number of houses (usually 5 to 100) to a common treatment and disposal area. Cluster systems use small-diameter gravity sewers and pressure sewer systems that are less expensive to install than the large pipes used in the centralized approach.

While these land-based, alternative wastewater systems are recognized as viable options, the treatment strategies are relatively new or not often recommended by some in the private sector. And in times past, these treatment techniques were not considered to be mainstream options that communities could depend on.

Yet, land-based system have been judged to be the most cost- effective and environmentally sound wastewater treatment options for rural communities, now and in the future. Because these systems post minimal environmental impacts on streams and rivers, the regulatory community requires assessment of land-based alternatives. Land-based system require extensive planning and stepwise implementation depending on the area to be served.

The success of the decentralized approach depends on the establishment of a management program assuring the systems are regularly inspected and maintained. And trained and certified system operators will ensure that systems function effectively. While decentralized wastewater technologies work best for rural communities, a centralized management network to oversee them provides the most effective management and the best implementation for rural areas. The centralized management can be provided on a community, county or multiple county area.

In summary, establishment of wastewater infrastructure in rural areas should include a systematic evaluation of all options, beginning with consideration of on-site systems, cluster systems and finally, the centralized treatment option. When community leaders in rural North Carolina begin reviewing their wastewater management options, they should put decentralized wastewater systems at the top of their list to ensure public health and environmental protection, lower installation costs and the flexibility to plan for future growth.

Additional copies of “Choices for communities” Wastewater Management Options for Rural Areas” can be obtained form the Office of Research, Extension and Outreach and NC State University.

Prepared by Mike Hoover, Soil Science Professor and Extension Specialist; Bob Rubin, Biological and Agricultural Engineering Professor and Extension Specialist; and Frank Humenik, Coordinator of Waste Management Programs.

Please address any questions to Dr. David Lindbo.