Highlands WWTP 1000pxA preliminary study, schematic and final design, preparation of construction estimate, acquisition of permits and bid and construction phase services were performed by MRA for Phase 2 & 3 improvements to the existing extended aeration plant with spray irrigation system, originally constructed in 1975. MRA’s work included rehabilitation of the existing effluent holding ponds, addition of secondary clarifier, and expansion of irrigation field and holding ponds to meet upgraded Maryland Department of Environment requirements.

In 1992, the County acquired a surface water discharge permit for the treatment plant, allowing the spray irrigation system to be abandoned.

In 2013/14, MRA designed a wastewater collection/conveyance system comprised of: an influent bypass for the existing WWTP; 7,300 LF of 8, 12 & 16-inch gravity sewer; and a 1,186 gpm regional sewage pumping station with 1,600 LF of 10-inch force main discharging to the County Meadowview WWTP, which will allow the decommissioning of the 40-year-old Highlands WWTP.

Some unique challenges encountered by this project include: negotiating six easements including one from DuPont across a high security agricultural research area; the appropriate location for the sewage pumping station was within a planned residential community, so MRA worked closely with the site engineer to locate the station and align the influent sewer to serve the community and allow decommissioning of a 30-year-old pumping station.