Wastewater discharge findings presented
By Bob Lassahn

During the November 8 meeting of the Worcester County Commissioners Mr. Bob Wimmer of Johnson, Mirmiran and Thompson (JMT), the engineering consultant hired by the county to assist in the evaluation of the Perdue/Showell Sanitary Service Area presented a draft report on progress to date. The first portion of their evaluation focuses on assessment of impacts of the proposed sanitary service area on the Northern Coastal Bays (NCB) and Total Maximum Daily Load (TMDL), a measure of nitrogen and phosphorous in the wastewater discharge.

A developer, ADC, is seeking to construct 1,000 new homes in the Showell area utilizing the existing Perdue wastewater treatment plant. The plant previously served as a chicken processing plant and would be retrofitted to treat human waste. An existing discharge permit allows direct discharge into a tributary of the Saint Martin River.

The plant capacity is expected to produce a total of about 4,000 Equivalent Dwelling Units (EDU) capacity, with the unused EDUs going to the county for replacement of failing septic systems. The commissioners have been reluctant regarding the direct discharge of wastewater and expressed interest in exploring spray irrigation.

JMT evaluated six potential alternatives for effluent disposal including direct discharge to the Shingle Landing Prong as existed under the permit held by Perdue, spray irrigation and combinations of the two methods. As a portion of their presentation they provided statistical data showing a significant improvement in the dissolved oxygen levels ( a measure of a water body's health) in the Saint Martin River after the Perdue plant ceased discharge into the waters.

Mr. Wimmer provided advantages and disadvantages for each alternative, including the need for storage lagoons to hold the discharge during periods when spray irrigation was not a viable alternative. One scenario referred to as "purple pipe" would make the discharge available for use in landscaping and commercial applications requiring a large volume of non-potable water. He summarized that the time to consider this type of application is during the planning phase, so that the infrastructure could go into the ground with other pipe runs.

The presentation was informative in nature and required no action from the commissioners at the present time. It remains to explore the viability and cost issues involved in each alternative before arriving at a final decision. JMT is also tasked to review the potential for retrofitting the existing Perdue facility.

ADC originally planned to utilize the existing discharge permit to dispose of the effluent into the water but the commissioners preferred the option of spray irrigation, citing protection of the NCB as a priority.

The commissioners required input from a consultant other than contracted by the developer to assist in reaching their decision on best practices to be applied regarding the Showell development wastewater issue. The developer is paying for one half of the total cost for the consultant.