Over the past 25 years, the onsite wastewater industry has developed many new treatment technologies that can achieve high-performance treatment on sites with size, soil, groundwater and landscape limitations that may preclude the installation of conventional systems. According to Stephen P. Dix, technical director for Infiltrator Systems, Inc., 37 percent of new development in the United States is utilizing onsite septic systems. (See story on page 24.) It is estimated that septic tanks currently are used by 25 to 30 percent of residences in the United States.
Onsite wastewater treatment now is being recognized as a permanent long-term solution to the wastewater infrastructure in many areas. Codes, guidelines, standards, regulations and laws are being created and updated weekly to further its use.
A conventional onsite system (septic tank and subsurface wastewater infiltration system) is capable of nearly complete removal of suspended solids, biodegradable organic compounds and fecal coliforms if properly designed, sited, installed, operated and maintained, according to the EPA (USEPA, 1980; USEPA 1997).
Am I advocating replacing the current wastewater infrastructure and having all new developments install onsite equipment? No, definitely not. However, since federal funding for centralized wastewater collection and treatment has diminished, there has been more interest from professionals and the public toward decentralized wastewater technologies that can be compatible and cost-effective.
Onsite product advances include several types of pretreatment devices, improved septic tank designs and septic tank filters. Onsite management also has prospered from this digital age. New monitoring devices can electronically measure the solids grease layer and water levels in the tank with modems and report back to solids management contractors or a management authority.
Septic tank filters trap solids particles and protect downstream components from harming a pump or the distribution system. These filters usually are designed to be replaced with the septic tank cleaning.
Ongoing maintenance is critical to any onsite wastewater system. Establishing maintenance programs that receive public support and are cost effective is a major challenge facing the industry. With the proper management, the decentralized approach can provide significant environmental and economic benefits.
If you are interested in learning more about onsite treatment, the National Onsite Wastewater Recycling Association, Inc. (NOWRA) will be hosting its 10th Annual Conference from October 10—13 in Virginia Beach, Va. (800-966-2942 or www.nowra.org). In addition, the WEF Small Community Committee along with NOWRA is sponsoring a one-day seminar titled "Small and Natural Systems and Water Reuse" on October 14 at the 2001 WEFTEC Conference (703-684-2400 or www.wef.org).