CTDEEP, Bureau of Water Management
|Wastewater Treatment Plants Meeting Toxicity Standards|
|Percent of CT Plants|
Aquatic organisms are exposed to effluent from wastewater treatment facilities as a test for effluent toxicity. Facilities in CT are tested annually and facilities in NY are tested every 5 years. The data in the chart above represents the percentage of facilities in Connecticut passing these tests.
The toxicity test indicates whether the effluent that is being discharged into Long Island Sound is harmful to aquatic organisms such as fish and invertebrates. If a wastewater treatment plant fails the test, it is required to make changes to its practices to clean up the effluent that is discharged.
In 2009 only one of 82 Connecticut municipal wastewater treatment plants being tested failed the toxicity test or 1.2%, compared to nearly 25% failure rate in 1989. In Connecticut, a wastewater treatment plant is designated as toxic if it fails 2 consecutive or 3 separate acute tests.
There are 14 New York State facilities discharging into Long Island Sound whose permits require whole effluent toxicity (WET) testing. The most common requirement is quarterly testing, enabling seasonal effluent characterization, once every five years. For the period 2009-2016 (currently in progress with 1 quarter remaining), all 14 facilities have conducted at least one round of WET testing, with a 100% pass rate to date.