Marshall Street WRF Sand Filter Rehabilitation

Scope

Rehabilitate twelve (12) existing sand filters, associated equipment, remove and replace seven (7) pneumatic actuators on 20-inch Butterfly Valves (Filter Cells 1, 2, 7, 8, 11, and 12), flange bolts on 20-inch Backwash Inlet Butterfly Valve (Filter Cell 7, will only be necessary if Contractor confirms the valve is not functioning), two (2) 18-inch backwash pump discharge Check Valves (will only be necessary if Contractor tests and confirms the backwash flow rate is compromised), sodium hypochlorite pumps and associated piping. Other improvements include replacement of the touch screen for the main filter control panel with improved graphics and functionality, and upgrading the SCADA interface in the filter control room to facilitate total local control of the filtration system at the Marshall Street WRF. Sequence Constraints The facility is an active wastewater treatment plant and the work must be performed in such a manner and phased to minimize the operational impact on the plant and the plant staff. The work shall be scheduled and performed such that a minimum of ten (10) filters cells (existing and rehabilitated) remain in service, including the ability to backwash the operational cells, throughout the duration of construction and the Contract Period listed at the end of this section. Contractor shall submit a sequencing plan for review and approval prior to commencement of construction. Contractor shall coordinate any changes to the treatment process such as shutdowns with the Owner at least forty-eight (48) hours in advance. The plant Lead Operator or a representative of the Lead Operator shall be present for operation of all process valves. The Contractor shall not operate any process valves or equipment. Contractor shall schedule Initial Filter Inspections with...