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For the calculation of the blower capacities, the minimum required O$_{2}$ concentration in the tanks, peak factor for carbon or nitrogen load (whichever the highest), and maximum wastewater temperature, maximum ambient temperature of 45  C at 50% relative humidity, water depth, diffuser performance, static head and dynamic friction losses and complete mixing of aerobic zone must be taken into consideration. The performance data of the blower and diffuser shall be submitted together with the tender. 

All air piping shall not be buried. All required piping from blower building up to the water level in aeration tank shall be in stainless steel and rest of air pipe shall be HDPE 100 PN 16 considering the external physical impact. 

The blower building shall be provided a proper ventilation in accordance with “Heating and Ventilation” section of this document. 

## 3.3.4.19 Primary Sludge Pumping Station 

The primary sludge pumping station shall be designed, constructed and equipped regarding the requirements set in Table 2-1. 

The settled sludge shall be pumped to the gravity sludge thickeners via primary sludge pumps. A sludge screen to be located top of the gravity sludge thickener shall be installed on discharge line of the primary sludge pump. A means of control on sludge suction from the each individual clarifier shall be provided by electrically actuated devices. 

The requirements for the drainage, foul air collection and clean water supply system stated in Section 3.3.4.34 and 3.3.4.35 should be met for the primary sludge pumping station inner area. 

The pumps for primary sludge shall be dry mounted and placed in the primary sludge pumping station. The pumps shall be positive displacement or progressive cavity pumps. The capacity of the primary sludge pumps shall be calculated according to the settleable solids amounts at the maximum flow and maximum operation of 24 hours/day. A frequency converter and dry running protection system shall be provided for each pump. 

Washing water shall be connected to both the suction and discharge lines of the sludge pumps. This washing system will engage automatically when the pumps are not operated. In addition, the service water line shall be installed to the appropriate places of the primary sludge pumping station and sufficient number of connection points shall be supplied. The treated water should be used for this purpose. 

Macerators shall be used to macerate the solid and fibrous components in the primary sludge. For each pump, one macerator shall be supplied and installed on the suction pipe of the pump. 

A permanent crane or lifting system shall be provided to carry out the maintenance works for primary sludge pumps. 

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