to Worton Plant

UV disinfection discharge during initial testing.

   McCrone's Public Works team is nearing successful completion of its dual discharge Worton Wastewater Treatment Plant project, which incorporates Membrane Bioreactor technology (MBR).

   MBR technology is the combination of activated sludge treatment with a separation of biological sludge via ultra-filtration membranes. The result is a high quality effluent (water) acceptable for spray irrigation or discharge to surface water.

Center pivor operation during initial testing.

   The new facility will discharge a nitrogen concentration of less than 4.8 milligrams per liter and 0.3 milligrams per liter of phosphorous. The low nitrogen and phosphorous limits help Worton meet the nutrient removal goals issued by the Maryland Department of the Environment (MDE). Initial effluent discharge from the facility shows nitrogen and phosphorous concentrations below those required by the discharge permit.

Installation of membrane cassettes.

   To integrate MBR technology into the design, our Public Works team collaborated with GE-Zenon, a Canadian-based manufacturer of ultra-filtration membranes. Together, McCrone and GE-Zenon designed a system that limits nitrogen and phosphorous loads to Maryland's surface waters, while generating effluent acceptable for discharge into a nearby creek and use in nearby agricultural farm sprayfields.

The treatment process begins with a fine screening process that removes inorganic debris from residential wastewater and septage before entering a biological treatment basin where microorganisms consume nutrients in aerated and anoxic zones. The biologically-treated wastewater then passes through the ultra-filtration membranes made up of "spaghetti-like" hollow fibers, which separate solids from treated water.

   The treated water then passes through UV disinfection equipment to deactivate bacteria before effluent is discharged to the creek or sprayfields.

The MBR system and associated structures, tanks, buildings, and equipment were all accommodated on the existing wastewater treatment plant site.

McCrone's Public Works group was able to design a sequence of construction that kept the existing lagoon treatment system in operation during the entire upgrade, as well as account for the septage received at the plant on a daily basis. The offsite site improvements for the sprayfields included 10,000 feet of 10-inch force main between the WWTP site and the sprayfield site; a 2-million gallon earthen lagoon lined with a geosynthetic clay liner; a 2,350 gallon per minute pump station used to pressurize the network of sprayfield piping between irrigation rigs; and five center-pivot irrigation units that apply treated wastewater over 75.5 acres of farmland. 

WWTP site after initial restoration. Structures visible: screen building, process tanks, and operations building.

   McCrone was awarded the design, bidding, construction services, and inspection services contract after completing a study for the Kent County Department of Water and Wastewater Services. The study originally focused on conventional wastewater treatment options, but was amended when the County requested the use of MBR technology in the new design.

   The WWTP and associated effluent land application system (ELAS) allowed the County to serve the projected growth needs for the Worton area while staying within regulatory requirements.

   Wayne Morris, Director of Kent County Public Works, comments, "The Worton WWTP and ELAS project was very important to Kent County, specifically the town of Worton. The existing lagoon system wasn't able to meet the new more stringent discharge limits and consequently, a moratorium was imposed on any new growth. With the help of McCrone's team we were able to design and build a new "state of the art" (membrane technology) treatment system."

Mr. Morris added, "The existing lagoon discharge is limited to six months from November 1 through April 30, which also hindered the ability to gain additional capacity for future growth. With the foresight and assistance from McCrone, we were able to work with a local farmer. Then, through painstaking months of working with numerous regulatory agencies, we were able to secure a site for land application which allowed the county to double the treatment capacity and accommodate planned future growth for the Worton Service Area.

   Morris concludes, "Working with the McCrone team has been a pleasure. Together we were able to complete the multi-million dollar projects within budget."

   The project is now in the warranty phase of construction after nearly six years of planning, study, design, and construction. Initial WWTP effluent discharge has met or exceeded discharge permit requirements.

   Located in Kent County, Maryland, the Worton Wastewater Treatment Plant is owned and operated by the Kent County Commissioners.

   Please contact Ryan Rangel at 410-267-6947 for more information on how McCrone may assist you with your next water or wastewater project.