4027 4TH ST SE 2018-01-01 MF Import

TLe plant stage exnansion elements of the Stage One ATTACIIM�3NT "A" Project Summnry � �� � �: � (� � �'' c � � �� 22 i��:;. -; 'IrY �;� �� Plan,�ina ---��LJ .o C'l'f�4 upgrade planned by the City involves a two- . The following are descriptions of the two project stages. The first stage of the pro,;ect is comprised of the tasks described below. (1) Pond Recirculation.--To more thorou�hly circulate the oxidation pond's contents, the City propose� to install recirculation channels along the w::st and east �ides of the e�cisting oxi.dation pond. (See Attachment No. 4, Sheets No. 2 and 3.) The channels will be created hy installing ne�a precast concrete tee sections para11e1 to the inboard sides of the oxidution pond dikes. The discharge channel will be 25 £cet in width, and will follow the west side of the pond; the return channel will be 5 feet in width, and will be located on the east side of tt�e pond. The typic2l elevation of the tops of the tee sections creating both channels will be 14.1 £eet, or 7.0 feet above the etisting grade (National Oceanographic Survey datum; see Attachment No. 4, Sheet No. 3 for a sectional vie�a of these channels). To regulate flows between the discharge and return channels, the�City plans to construct a recirculatio❑ pump �tation at the southern end of the pond (Attachment No. 4, Sheet No. 2). (2) Aerated Lagoon Sludge Utilizntion.--In accordance with Department of Ecology Compliance Order No. 1085-08-47- 309, the City proposes to dredge and utilize the accLmulated sludge in the aerated lagoons. The City's plan is to dredge approximately 158,000 cubic yards (11,000 dry weight tons at 8 percent solids conter.t) of sludge from the aerated lagoon, dewater and stabilize it, then transport it to various oermitted utilization and/or disposal sites. f,a part of the City's long term sludge management prograo, a temporary 9" to 10" pipeline with a capacit� of 800 to 1,600 gallons per mznute will be installed during ap�ropriate seasons to pericdically transport lagocn slud3e to an agricultural utilization site. The pipeline will extend fs'oa the aerated lagoon across Steamboat Slough to Ebey Island. Ther:: Nill be a total of 2,000 lineal feet of pipeline constructed inside the City limits uith the City ju^i.sdiction extending to the centerli.ne of Steaoboat Slough. d 200,000 gallon sur3e barge uill be placed on the north side of Steao!:oat Slough.