16 of 74  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 3: Plant Description  The pumping station shall be designed and constructed for wet or dry installed submersible pumps. Operation of the pumps shall be controlled by the water level controllers (by using ultrasonic level or  radar type sensor) in the pump sump. The pumps shall operate in an alternating sequence, including  the spare pump in order to minimize the wear of the pumps. The inlet pumps shall be locally  controlled and operate as autonomous units. The operation status, however, should be monitored and  controlled by the SCADA system. The proper location of the pump sump shall be made chamfered to  prevent waste accumulation and to direct the wastewater towards the pump. The pumping station shall  be designed that septic conditions are not occurred.  The pumps shall be of the centrifugal type and be rated for raw wastewater. Hence, the impellers can  be designed either as canal or screw centrifugal types with non-clogging  Guide bars and automatic couplings shall allow easy service and maintenance of the pumps. A lifting  system with overhead travelling crane shall be provided to carry out the maintenance works for  pumps.  Foul air shall be collected from the building and shall be sent to the odor treatment unit. The air of the  pumping station has to be H$_{2}$S and CH$_{4}$ monitored and warning system shall be installed.  Minimum number of pumps for Stage 2  : 3 duty + 1 stand-by  Type of pumps  : wet or dry installed submersible  Number of stand-by pump  : min. 1 no.  Control of each pump  : by frequency converter  Minimum efficiency  : 70%  From the inlet pumping station, the wastewater shall come to the fine screen channels inlet. If the  Contractor prefers, the inlet pumps can also be located after fine screens. In that case the distribution  channels shall be designed and constructed before, after and between each screen groups, i.e. between  coarse and fine screen groups. The aim of this construction is to maintain the cross operation  flexibility of all screens. In any case, coarse screen, fine screen and inlet pumps shall be in either same  building or separate buildings.  3.3.4.4 Fine Screens Fine screen channels shall be designed, constructed and equipped regarding the requirement set in  Table 2-1. The maximum flow (Q$_{WW,h}$) of the related stage requirements shall be met for the unit. There shall be electrically actuated motor controlled penstocks in accordance with the specifications  given in Section 7.8.8 and 7.8.18 at the inlet and outlet of fine screen channels in the scope of project.  The operation status of the penstocks should be monitored and controlled by the SCADA system. The fine screen shall be of the perforated plate type step screen. The unit may be provided with  integrated washing and pressing facility. The screens shall be designed for lifting/tipping out of the  channel for service with an overhead travelling crane.  The fine screenings shall be automatically removed, washed, dewatered and transferred to containers.  If separate dewatering system is offered, the screenings shall be discharged onto screenings conveyors,  which convey the screenings to a washing and pressing system. The screening press proposed by the  3_Vol3_d4.3_Section 3_Plant Description_GIR_rev08 