Rappahannock League for Environmental Protection

Wastewater treatment goes high tech

by Don Audette, Fall 2005

Due in great part to development sprawl, the lowly septic system is going high tech along with everything else.

Virginia's Department of Health and the Department of Environmental Quality are responsible for monitoring the health and safety of wastewater treatment systems in the commonwealth. Virginia is considering requiring those who evaluate new wastewater treatment systems to have certification as an Authorized Onsite Soil Evaluator. To get certification, an individual would have to demonstrate knowledge, skills, and abilities in the practice of siting and designing onsite systems.

With housing and businesses spreading all over the landscape, it has become too expensive to build large-scale, centralized sewage treatment plants with collection systems that involve hundreds and even thousands of miles of sewer pipe. About 80 percent of the cost of a centralized wastewater treatment facility is tied up in the laying of pipe, which makes it unaffordable for small communities. In addition, excessive amounts of energy and water are involved in pumping sewage from far-flung homes and businesses to central points for treatment.

About 25 years ago Congress started funding studies on the idea of treating wastewater at the source, or very near to the source, of sewage. Thus the term "onsite/decentralized wastewater treatment" came into use. Large homebuilders and utilities opposed the idea-builders because they would have to provide such systems, and utilities because it would cut into their profits.

About ten years ago, interest in these systems was renewed as suburban and rural septic systems were becoming the second major source of pollution of groundwater. The Environmental Protection Agency funded a series of programs in a number of small communities demonstrating the use of alternative or innovative septic systems. Later aspects of the program have concentrated on how to "manage" onsite/decentralized wastewater treatment systems. It is here that things have become bogged down, so to speak.

The alternative system shown is used where the water table is too high to allow proper cleansing of the wastewater, which would pollute the groundwater. The mound is just a septic drainage system above ground, with wastewater pumped up to its top area so its can filter downward and be cleansed by the mound of soil. The site is in North Eastham, Massachusetts, on Cape Cod. Photo courtesy of Bob and Pat McMahon.

Basically, alternative septic systems are designed to reduce pathogens, nitrogen, and other pollutants by special treatment and dispersal units. Some use aerobic treatment units injecting air into sludge in septic chambers to aid in the breakdown of solid waste, while others use above ground or below ground filtering or dispersal systems to further mitigate the harmful effect of wastewater. These technologies make use of pumps, filters, alarms, air injectors, disinfectors, remote-monitoring devices, stirrers, and other mechanical, electrical, or hydraulic components.

A July 17 Washington Post article, "An Odorous Matter in Loudoun County," detailed failures of advanced/ innovative septic systems in that county. The region around Atlanta, Georgia, has 400,000 septic systems, many of which are advanced/ innovative types that are in trouble.

As the complexity of these new systems increases, they will require more expert evaluation at the state level. For example, an old-fashioned percolation test may not be adequate to determine the safety of an alternative system, since the soil itself in many cases is the reason an alternative system is contemplated. Virginia has upgraded this simple procedure to the application of specific soil evaluation procedures and is in the process of creating a new certification requirement for individuals who would perform these procedures.

The complexity of alternative systems and the use of specially trained individuals both involve more expense for the homeowner and for Virginia's monitoring agencies. It appears that the use of alternative systems requires more development and study before a homeowner may feel comfortable using them.