Baker Heights Wastewater Treatment Plant  Upgrade

In response to increased demand on the treatment facility, the District is planning to upgrade capacity at the wastewater treatment plant.  The Baker Heights Wastewater Treatment Plant is rapidly approaching 90% of its design capacity.  The WWTP serves areas where heavy housing development is underway.  With the heavy growth planned within the service area, the District is acting now to prevent shortages of treatment capacity in the near future.  Construction is planned to begin Fall/Winter 2006 with a one-year construction period.  The upgraded plant is planned to begin operation by Winter 2007. 

 

Treatment Process

An SBR system receives the raw wastewater directly into the treatment basins similar to other aerobic extended aeration processes except that the flow is not a continuous flow through, but is handled in a batch process typically cycled between multiple basins.  One basin will fill with influent wastewater, a separate basin will aerate accumulated sewage for biological treatment.  Following the aeration cycle, the aerated basin is then allowed to settle for predetermined period of time and then clear water is decanted from the top level of water within the basin.  BOD removal, nitrification, denitrification, and solids reduction are all accomplished within a single treatment unit.  This eliminates the need for a separate clarifier, sludge return equipment and scum removal devices resulting in a more compact unit size and reduced energy requirements.  The SBR process is also able to handle variations in inflow rates due to the batch sequence allowing diversion of flows between basins without increase in flow through velocities, which would result in carryover of solids. 

 

Primary treatment will consist of mechanical fine screening and grit removal units.  Secondary or biological treatment will occur in the SBR unit as previously described.  The waste stream will then be processed through an ultraviolet light disinfection system, followed by mechanical post aeration prior to effluent discharge into the receiving stream.  The solids wasted from the SBR process will be digested in an aerated sludge digestion tank with solids dewatered through a belt filter press.  The sludge cake is then hauled to a landfill for disposal or land applied. 

 

Plant Details

The Baker Heights Wastewater Treatment Plant was last upgraded in 1995.  At that time, it was converted from a trickling filter plant to a sequential batch reactor (SBR) plant.  Since the completion of the construction, the plant has been operated by the District in accordance with its permit.  The Baker Heights Wastewater Treatment Plant upgrade will be done in two phases.  The first phase of the project will increase the plant capacity from 0.9 MGD to 1.8 MGD and will include: 

 

·       The pretreatment works will be replaced during the first phase of the project with pretreatment equipment sized for a 3.0 MGD normal flow and 9.0 MGD peak flow.   

·       Four SBR treatment basins and one digester basin will be installed.  Two of the basins will be left unequipped until the Phase II upgrade becomes necessary.   

·       A new blower building will be constructed.  

·       An additional belt press building with belt press will be installed.  

·       The plant controls and SCADA system will be replaced.  

·       The disinfection system will be changed to an ultraviolet system from chlorine. 

·       Allowances will be made during the design process for the potential of chemical addition and effluent filtration for compliance with the proposed Chesapeake Bay requirements.

 

The second phase of the project will increase the plant capacity from 1.8 to 2.7 MGD and will include: 

·       Equipment for the extra basins provided in Phase I.

 

The total estimated cost for the Phase I construction is $8,929,902.

 

To view the Baker Heights Wastewater Treatment Plants site plans click here.