You asked about the performance of alternative on-site sewage treatment (AT) systems.

SUMMARY

Proponents and opponents of AT systems differ about how well they perform. Generally, proponents argue that properly installed and maintained systems pose no public health or environmental harm. Opponents argue that the risk of potential failure makes AT systems a poor choice for environmentally sensitive areas.

BACKGROUND ON AT SYSTEMS

AT systems, which use a variety of technologies to treat wastewater, are often proposed for use in areas where conventional septic systems are impractical or unworkable because of the concentration of development or location (e. g. , wetlands, coastal areas or other environmentally sensitive sites).

The Department of Environmental Protection (DEP) now oversees all AT systems. However, PA 07-231 requires the Department of Public Health (DPH) commissioner, by December 31, 2008, to set and define discharge categories for AT systems with a daily capacity of 5,000 gallons or less, and gives him jurisdiction over these systems once he has done so. DEP continues to have jurisdiction over larger AT systems. The law prohibits, with certain exceptions, the installation of AT systems in drinking water supply watersheds.

HB 6402 (heard as HB 1026 at a February 26, 2007 Environment Committee public hearing), would have imposed a statewide moratorium on the permitting or construction of AT systems with a capacity of more than 5,000 gallons per day. The bill died in the House.

DEP'S POSITION

According to DEP, properly sited, installed, maintained, and operated AT systems have environmental and public health benefits. In some cases, DEP said, an AT system may be the only feasible solution to a water pollution problem. But the department acknowledged that AT systems are different enough from traditional septic and sewer systems that their use must be carefully considered.

DEP Water Permitting and Enforcement Division Director Oswald Inglese, Jr. , notes that the department has not found that AT systems have caused any adverse environmental or public health impacts despite some instances where pollutant permit levels were exceeded. Inglese points out that DEP monitors AT systems according to federal Safe Drinking Water Act standards that ensure groundwater quality is suitable for drinking without treatment. DEP does not evaluate these systems according to federal Clean Water Act standards, but Inglese says the department considers such factors as the system's location and the location's environmental sensitivity when reviewing applications.

Inglese also notes that AT systems, unlike passive septic systems, must be actively maintained and operated by qualified, trained personnel.

Public Hearing Testimony

At the February 26, 2007 public hearing, DEP stated that it did not oppose the proposed one-year moratorium and would use the year to complete its evaluation of the AT permit process, discuss possible changes with stakeholders, and put in place specific improvements.

Many people at the hearing focused on DEP's evaluation of a particular AT technology using membrane filters developed by Zenon, now a division of General Electric Co. Many of the arguments raised at the hearing occurred in response to DEP's appraisal of these systems.

DEP's Zenon Performance Appraisal

DEP evaluated 12 facilities in Connecticut that use Zenon technology for wastewater treatment or treatment and recycling. (The DEP's report can be found at this website. )

DEP found that nine of the 12 facilities did well in three tests, including those for removing pathogens and suspended solids. One facility did poorly; the results from two others were inconclusive. Other tests found four of the 12 facilities exceeded their total nitrogen permit levels and three exceeded their phosphorous levels. DEP issued violation notices to these facilities in November, 2006. In general, the department found, the violations could be attributed to: operation and maintenance, equipment failure, design, or introduction of a toxic substance. However, DEP said its groundwater monitoring consistently found nitrogen, phosphorous, and fecal coliform at levels safe for drinking water.

DEP made several recommendations as a result of its evaluation. Among other things, it recommended that:

1. plans and drawings for an AT system include a statement signed by the system supplier that it was installed in substantial compliance with the approved plans and specifications;

2. system operators state in writing that they are satisfied that the system's operation and maintenance manual ensures the facility's proper operation and maintenance;

3. a discharge monitoring report include a detailed explanation of any violations and corrective action taken; and

4. a qualified engineer conduct biennial permit compliance audits, including reviewing all pertinent records, plans, specifications and schedules; summarizing compliance with permit terms and conditions; and describing remedial actions taken or proposed to correct violations.

OPPONENTS' ARGUMENTS AND COMMENTS

There was disagreement at the hearing on how to interpret DEP's findings about the Zenon systems. Some witnesses counted each violation of a specific pollutant limit as an instance of system failure; others argued that the system's overall performance was acceptable.

Keith Ainsworth, an environmental attorney representing a Griswold group that opposes an AT project in that town, said that because AT systems are used in environmentally sensitive areas that otherwise could not be developed, their failure would be “a recipe for disaster. ”

Other proponents of the proposed moratorium pointed to a Massachusetts study of 90 AT facilities (attached) that found that only seven percent always met their total nitrogen permit limits of 10 milligrams per liter, and that 41% of them met the nitrogen permit limits between 80% and 99% of the time.

Sally Harold, project director of the Nature Conservancy's Saugatuck River Watershed Project, testified that AT systems, while not “necessarily inconsistent” with the goal of maintaining healthy watersheds, were “extremely temperamental,” require frequent monitoring, and “may not treat effluent to standards touted by manufacturers and required by DEP. ”

She agreed with DEP that the system must be properly designed, sited, and maintained. She also said municipalities are uncertain whether and how they should regulate AT systems.

The Nature Conservancy, a national environmental organization, prepared a “white paper” (attached) summarizing its position on AT systems. It notes that AT systems that meet drinking water standards of up to 10 milligrams per liter for nitrogen may still not adequately protect local wetlands and watercourses.

Among other things, it recommends that:

1. AT systems be permitted only if their reliability can be demonstrated based on objective, long-term data measuring their ability to treat effluent to DEP standards;

2. a review of AT applications consider their environmental impacts, maintenance requirements, and required level of operation, attention, and skill;

3. municipalities require financial guarantees from AT system owners to ensure money is available for inspection, repair, and replacement;

4. monitoring programs identify baseline conditions before DEP approves an AT system;

5. municipalities consider prohibiting AT systems at environmentally sensitive sites;

6. municipalities decide on AT systems based on their land use objectives, rather than what is technologically feasible; and

7. emergency shutdown plans be prepared.

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