Laserfiche WebLink
<br />SECTION 1 <br />PURPOSE OF SUPPLEMENT <br /> <br />The purpose of this Supplement is to provide for Engineering Services, more <br />specifically itemized herein, in the preparation of plans for the addition of a 3,400 gallon <br />per minute (gpm) forced draft aeration system with hydrogen sulfide removal, electrical <br />and controls, piping and site improvements. <br /> <br />SECTION 2 <br />SCOPE OF SERVICES <br /> <br />2.0 General <br /> <br />The forced draft aeration water treatment system shall be designed as a packed <br />tower scrubber system for hydrogen sulfide removal from raw water and will include <br />a forced effluent air pumping system to a biofilter treatment system. An aerated <br />water clearwell with transfer pumps will be designed to transfer the treated water to <br />the existing ground storage tanks. The system shall be designed to treat a peak <br />flow rate equal to the capacity of the largest well pump (2,400 gallons per minute <br />(gpm)) plus one of the smaller well pumps (1,000 gpm), for a total minimum capacity <br />of 3,400 gpm. Controls for the system shall be linked to the existing SCADA <br />system. An evaluation of the existing and proposed total electrical loading shall be <br />performed. See electrical discussion below. <br /> <br />2.1 Packed Tower Aeration <br /> <br />The packed tower aeration design will be a dual system consisting of two identical <br />towers, each sized at 50% of the peak flow rate of 3,400 gpm. Because the <br />hydrogen sulfide removal is not agency-mandated, this will allow for one unit to be <br />removed from service for routine maintenance. A Biofilter unit will be designed to <br />remove the hydrogen sulfide from the exhaust air from the packed towers. <br /> <br />2.2 Transfer Pumpina System <br /> <br />A Transfer Pump Station (vertical turbine pumps mounted over the clearwell) shall <br />be designed to pump the treated/aerated water to the ground storage tanks. Similar <br />to the packed towers, the design will be for two pumps to provide the design flow of <br />3,400 gpm. A sloUposition will be provided to allow the installation of a third back-up <br />in the future if needed or required. Pumps shall be equipped with Variable <br />Frequency Drives (VFDs) and activated/controlled by pressure level controls. <br /> <br />2 <br />