DOUGLAS — On April 3, 2012, the City of Douglas Southeast Water Pollution Control Plant
experienced solids short-circuiting from one of its secondary clarifiers. The resultant loss of solids subsequently fouled the sand filter causing it to bypass the solids and discharge them in the plants effluent discharge. Upon discovering the solids discharge, city forces instituted immediate actions to remedy the situation including corrective work to the affected secondary clarifier and sand filter. The corrective measures were able to return the plant to normal operations within approximately 7 hours.
The total suspended solids from the effluent composite 24-hour sample for April 4 (which represents the 24-hour period from 7:00 a.m. April 3rd to 7:00 a.m. April 4th) was 190 mg/l. This is greater than 1.5 times the seven day maximum allowed by the facility’s NPDES permit, constituting a major spill. All reporting and sampling requirements are being followed. The volume of the major spill is the 24-hour flow for that reporting day: 3.9 million gallons. The receiving stream is an un-named tributary to Seventeen Mile River which flows from the plant through a city-owned restricted-access pond and then crosses under Wendell Sears Road and then Clyde Kirkland Road before its convergence with the Seventeen Mile River.
Water quality sampling of the receiving stream has been initiated at a location upstream of the convergence with Seventeen Mile River (at General Coffee State Park) and a location downstream of the plant (Clyde Kirkland Road). Sampling crews involved in stream quality sampling will also observe conditions at the spill site, the sampling sites, and the downstream public access points to determine what, if any, environmental impacts have occurred.
Suspected possible causes of the loss of solids are higher than normal influent flows, higher than normal influent pollutant loadings, and a rapid transition to unseasonably summer-like temperatures. Further possible causes are being investigated.
Signs warning of the spill will be placed at the spill site and at downstream points of public access at Wendell Sears Road and Clyde Kirkland Road. The public is advised to refrain from any contact with this un-named tributary at the Wendell Sears Road Crossing and the Clyde Kirkland Road Crossing for the next seven days due to the possibility of high levels of bacteria in this stream. This is only a precaution.
For more information concerning this report, please contact Assistant Director of Wastewater Treatment Kevin Davis at (912) 389-3452 or kdavis@cityofdouglas.com.
