Duffield Associates was retained by the New Castle County, Department of Special Services to upgrade the Water Farm No. 1. wastewater treatment facility, in Odessa, Delaware.  The plant serves the towns of Middletown, Odessa, and Townsend as well as unincorporated areas in southern New Castle County.   The upgraded facility has a design treatment capacity of 2.5 MGD and the capability to provide biological nutrient reduction (BNR). Treated wastewater is land applied and discharged to the Appoquinimink River.

Before design work could begin, several different BNR treatment processes were reviewed.  Ultimately, a sequencing batch reactor (SBR) system was chosen for its compact footprint and DSC_0614treatment capabilities.  Improvements included a new headworks utilizing internally fed rotary drum screens, two SBR treatment basins, a post equalization tank, an aerobic digester , and  a new tertiary treatment building housing cloth disk filters, an ultraviolet disinfection system,  chemical storage and feed equipment, blowers, and controls.

The plant upgrade was brought online in May, 2006.  Other projects completed by Duffield Associates at the facility have included improvements to the existing spray irrigation system, review of alternative discharge options and plant performance evaluations.