41 of 74  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 3: Plant Description  including all coordination and technical clarification and permits with the responsible power supply  companies.  The CHP units shall be provided with complete heat exchange cabinets, including low temperature  heat exchangers for lubricating oil and cooling water, charge cooling, complete exhaust heat  exchangers, exhaust pipe with exhaust flaps and by-pass of the waste heat exchanger, as well as the  pre and post exhaust mufflers, measurement, drive and control boxes. The proposed CHP shall be  capable of work with both natural and biogas. The CHP units shall be located in digester operation/control building. This room shall have three  sections for the installation of the CHP with auxiliary equipment and local control panels, the local  power sub-distribution and operator’s control office. The operation room shall be designed in such a  way that fulfills the requirements for noise/odor control and working security. Access to the machines  and components shall be secure and unhindered. With regard to the ambient conditions in the  operation room sufficient ventilation and natural lighting shall be made.  Moreover, an underground technical gallery shall be built to connect this room to transformer building  and emergency diesel generator building for relevant cabling and piping.  Heat from the CHP unit shall be used for heating the sludge in the digester. Furthermore, it shall be  possible to use the gas in a boiler station, which also can provide energy for heating the sludge in case  of insufficient heating from the biogas engine or due to operational problems. The capacity of the  boiler system shall be able to heat all the digesters in the plant. The burner in the boiler shall be a dual  fuel burner to use either biogas or natural gas.  All heat supply pipes and return pipes shall be of 1.4404 and provided with thermal insulation.  The desulphurization plant shall be designed for biogas volume production for Stage 2 needs and for a  sufficient reduction of hydrogen sulphide to meet the demands of the combined heat and power (CHP)  units. Biological scrubber type desulphurization unit shall be used.  A gas flare with a capacity suitable for burning the maximum amount of produced gas at Stage 2 from  the digesters shall be installed. The gas flare shall be equipped with automatic ignition, valves and  safety equipment. In the case of necessity in manual use, by-pass line shall be built to gas flare.  Minimum number of gas holding tank : 2 units  Minimum retention time  : 12 hours @ Stage 2 max. gas production  Minimum number of CHP  : 2 units  Minimum capacity of CHP  :   100% of the power consumed at %100 load case on 24 h/d basis and max 8000 hours/year  Operation time  : max 8,000 hours/year Electrical efficiency  :   35 %  Heating efficiency  :  40 %  Minimum number of boiler  : 1 unit  The dewatering building shall include mechanical thickeners, centrifuges, polymer preparation units,  thickened excess sludge pumps and other auxiliary equipment used for dewatering and thickening. A  3.3.4.30 Dewatering building  3_Vol3_d4.3_Section 3_Plant Description_GIR_rev08 