THE OPPORTUNITY

The Warren Township Sewerage Authority operates three wastewater treatment plants.  The 0.8 MGD Stage IV treatment plant, situated between the Dead River and I-78 in Warren Township, needed process and structural improvements due to age.

THE CHALLENGE

The Stage IV plant required replacement of process equipment in the existing Oxidation Ditches, Final Clarifiers and Ultra-Violet Disinfection (UV) Facility.  All work had to be carried out while continuing treatment under the usual flow variations and meeting NJPDES permit conditions.

THE PS&S SOLUTION

Two circular process tanks, each containing an outer Oxidation Ditch surrounding an inner Final Clarifier, are undergoing complete process equipment replacement.  The equipment includes rotors, covers, clarifier mechanisms, drives and accessories, waste pumps, bridge extensions, bridge decking and handrails.  During the construction and until final testing and acceptance of the work, all flows must be handled by only one of the two process tanks.

The aged UV Facility is situated within a converted chlorine contact tank that extends six feet above grade.  The project includes replacement of the UV lamp racks and support equipment in the extremely restricted three-channel facility.  Adding to the challenge is construction of a cantilevered floor slab on top of the tank walls to support a new prefabricated superstructure to house the equipment.  At least two channels must maintain UV disinfection operation at all times during the construction.  The WTSA Plant Operators play a vital role in flow transfers and process control to assist the Contractor in maintaining a permit-complying effluent during the construction.