Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  67 of 74  v. Daily operation hours of centrifuges  : required flow rate to be calculated based on  digested sludge produced at the wastewater temperature given above and the solid content  of the digested sludge. Power absorbed against  the calculated flow rate to be supported by the  supplier’s data (e.g. graph and/or document)  vi. Daily operation hours of sludge drying  facilities  : required flow rate to be calculated based on  digested sludge produced at the wastewater temperature given above and the solid content of  the digested sludge. Power absorbed against the  calculated flow rate to be supported by the  supplier’s data (e.g. graph and/or document)  Please note that dewatered sludge prior to drying  process shall be taken as 22%DS vii. Annual operation hours of CHP Units  : 8000 Hours/year viii. Daily operation hours of ventilation fans  : 24 hours/day ix. Daily operation hours of extract fans  (for foul air) and bio-filter  : 24 hours/day x. Interior and outdoor lighting and any other  small powers  : nil  xi. specific digester gas production per added kg  sludge :   250 L per added kg dry solid (if thermal  sludge hydrolysis or ultrasound process is  proposed, amount of gas production could be  more. In this case, the assumed amount of gas  production rate shall be justified with the real  data from at least three operating wastewater  anaerobic sludge digester with proposed  alternative process like thermal hydrolysis or  ultrasound disintegration).  Daily operation hours and power consumption of the remaining equipment such as penstocks, crane,  valves, etc. shall be determined by the tenderer together with supporting documentation /explanation. In the assessment of the actual unit rate for sludge load, COD load shall also be evaluated besides the  TSS load. In case of different loading rates are found (e.g. 65% for COD load and 70% for TSS load),  arithmetic mean shall be applied to define the actual load ratio for sludge.  Electricity production from anaerobic digester gas shall be calculated in accordance with the other  relevant conditions given in item Section 3.4.1.3, 3.3.4.26 and 3.3.4.29.  3_Vol3_d4.3_Section 3_Plant Description_GIR_rev08  3.4.1.4 Electricity production from anaerobic digester gas