ONE out of every four American households currently treat and release wastewater on their own property. Although most people assume that on-site systems are confined to rural areas, in fact half are in suburbs and a few even remain within the confines of large cities.
Public works engineers have long dreamed of eliminating on-site systems. That has proved to be an impossible dream given the enormous expense of bringing sewers and centralized wastewater treatment to sparsely populated areas. In fact, in 1997, the federal EPA declared that the era of “sewer everything” was over. Decentralized wastewater management had to form an integral part of the nation’s means for dealing with sewage.
In recent years, the proportion of new homes not connected to sewer lines has actually risen. Nationally 37 percent of new homes are now approved with on-site sewage treatment and in Minnesota, the percentage has risen even higher, to 45 percent of new homes. The message is clear: decentralized wastewater systems are here to stay.
From March 11 to 14, 2001, the American Society for Agricultural Engineering — the nation’s oldest and most prestigious professional group specializing in rural applications — met to discuss on-site wastewater treatment. Over 500 participants from around the nation came to the Ninth Symposium on Individual and Small Community Sewage Systems in Fort Worth, Texas to learn about new developments in this rapidly changing field.
The conference was organized around three issue clusters. One dealt with the ability of soils to absorb discharge from on-site systems. Researchers reported results from numerous studies of conditions under which the receiving environment can safely handle effluent produced by decentralized systems. The second focus was on recently developed technologies that can provide more effective alternatives to the septic tank and standard drain field used almost universally for on-site systems for the past 50 years. A variety of papers described experiences with such alternatives as peat filter systems, constructed wetlands, drip irrigation and sand filters. The third major issue for conference participants concerned management of on-site systems and the policy developments that will be necessary to achieve better control over decentralized systems.
According to the Environmental Protection Agency, failing septic systems are the second leading cause of groundwater pollution in the United States. Steve Hogye, with the EPA’s Office of Wastewater Management, cited statistics showing that over half of the nation’s on-site systems are more than 30 years old. According to the Census Bureau, at least ten percent of the nation’s homeowners report that their systems are not working at all. However, as many as 25 to 30 percent of the systems may be “malfunctioning to some degree, even though this is not apparent to the average homeowner.”
The most obvious way to fix a failing system is to replace its overloaded drain field. But many older properties cannot meet standards for drainfields implemented by state or local agencies since the original systems were installed. The best (and perhaps the only) way to deal with wastewater in those circumstances may be through alternative systems which treat the effluent before it is disposed into the ground. Remember that standard systems rely on a tank to settle most of the solids in waste-water and then on the capacity of the soil to treat the wastewater. Alternative systems developed over the past two decades put another step (whether a constructed wetland, a peat or sand filter or an aerobic unit) into the treatment train before final discharge into the soil.
Several papers delivered at the on-site conference in Fort Worth dealt with the performance of alternative systems. George Loomis, a soil scientist at the University of Rhode Island, studied the performance of seven innovative wastewater treatments “installed as remedial systems”. These consisted of textile, sand and peat filters and an activated sludge system. Each system was monitored for the usual parameters: BOD (Biological Oxygen Demand), TSS (Total Suspended Solids), fecal coliform (an indicator of pathogens remaining in the wastewater) and TN (Total Nitrogen). Systems were installed in a sensitive watershed where local shellfish beds had been closed due to bacterial contamination and computer modeling estimated that over 80 percent of the nitrogen leaching to the groundwater was due to “the high density of outdated, marginally functioning and failed septic systems.” Loomis found that all the alternative systems he tested produced effluent that met state standards for BOD and TSS and that the peat filter and the sand filter reduced fecal coliform to acceptable levels. Nitrogen removal was a bit more problematic, but on the whole, alternative systems functioned to meet strict limits for groundwater pollutants.
Larry Hepner also found encouraging results from his work in Pennsylvania. Hepner, Chair of the Agronomy and Environmental Science Department at Delaware Valley College, studied six types of systems including a constructed wetland, and various types of sand filters and pressure distribution systems. He concluded that “reduction in fecal coliform bacteria numbers were significant” at various depths beneath the soil. While he and his colleagues are still evaluating the public health consequences of the data, he suggested that risk assessment techniques could help to answer the question of whether alternative technologies ought to be permitted in Pennsylvania.
CHANGING POLICY ON DISTRIBUTED SYSTEMS
Progressive states such as Wisconsin have been moving toward regulatory reform. But most other states are still mired in the era of prescriptive standards that rigidly specify details that systems must meet if they are to be allowed in their jurisdictions. These regulations make it extremely difficult to introduce new and innovative technologies. The EPA recognized this obstacle in a landmark document issued in response to a congressional inquiry in 1997. EPA identified three main barriers to improving decentralized wastewater management. According to Jim Kreissl, who was heavily involved in writing the report, regulatory reform topped the list, with better management of system performance and better training and education of local officials following closely on its heels.
EPA has developed a framework for management of decentralized systems “to meet water quality objectives, while offering communities a wider range of options, often at considerably lower cost.” According to the EPA’s Steve Hogye, the framework consists of five model programs which become more rigorous as system technologies become more complex or as the sensitivity of the environment increases. The least intensive management, for areas where “conventional on-site systems are adequate to protect water quality and public health,” consists of insuring that systems are installed properly and periodically inspected and maintained. In more sensitive areas, maintenance contracts or operating permits may be required. The most intensive level of management consists of a utility-type structure for maintaining decentralized systems which requires professional management and takes responsibility for the performance of systems.
While EPA’s guidelines are still being finalized, other reports at the conference identified elements that are necessary for any type of management system to function well. Ken Olson, extension educator with the University of Minnesota, emphasized homeowner education. After all, homeowners control the quantity of wastewater flowing through the system as well as its quality (whether it is contaminated with chemicals, grease or other materials that treatment is not designed to handle) Equally as important, homeowners control the funds necessary for proper maintenance of the system. Since “we haven’t designed a system that can handle any quantity or quality” of wastewater, says Olson, it is critical that homeowners understand the operation of their system and have incentives to properly maintain it.
A management plan that grows out of a sense of need, and protects community values is much more likely to gain acceptance and support than a plan imposed by officials from an office in the state capitol or the county seat. Karen Mancl, Professor of Biological Engineering at The Ohio State University, presented two case studies of successful on-site system management, one from Iowa and the other from Colorado. Both areas contained what were originally second homes (and are now often converted to primary residences) and were centered around a lake. The need to prevent pollution of the natural resource motivated homeowner associations to support management of residents’ on-site systems. Recognition that cost was a major factor led to reasonable rate structures. As a result, management programs for both communities are still going strong after more than 20 years.
Another aspect of the development of effective management practices lies in adoption of standards to govern treatment system performance. The National OnSite Wastewater Recycling Association’s (NOWRA) model framework for unsewered wastewater infrastructure is “based on performance; performance of the treatment system, system owner, system practitioners (site evaluators, designers, installers, pumpers, operators and regulators) and system regulatory agencies.” NOWRA concludes that the “traditional prescriptive model will not achieve the goal of sustainability” and is actually “detrimental to that goal because it largely ignores local environmental sensitivities, thwarts innovation and is unable to adequately balance human health and environmental protection with economic development pressures.”
This conference set out many of the issues involved in improving management of decentralized systems. But the biggest change may involve perceptions. Ken Olson of the University of Minnesota noted the widespread belief that homeowners don’t want to take care of systems and can’t do it while professionals invariably know how to manage systems and can do so without the homeowner’s involvement. Olson challenges those notions. On a more general level, the perception is of wastewater disposal. As keynote speaker, George Tchobanoglous of the University of California told the conference participants: “We should be dealing with collection, treatment and reuse of wastewater at or near the point of generation. Disposal indicates a problem. We need to make a paradigm shift from effluent disposal to water reuse.”
Robert Feinbaum is the founder and director of TWO (The Treatment Wetlands Organization), a project of Earth Island Institute. TWO aims to help the paradigm shift along in California by promoting innovative treatment methods for wastewater, providing education for policy makers and the public about water conservation and wastewater issues and helping to change regulations that limit new approaches to water reuse.