The city of Shahre Ghods Wastewater Treatment Plant

Location: The western part of Tehran

Capacity: : 28,650 m3 per day

Employer: West Tehran Water and Wastewater Company

Supervisor: ReyAb Consultant Company

Date of starting: 2007

The city of Shahre Ghods Wastewater Treatment Plant

Brief specification of treatment process

In the beginning of the process, the untreated sewage passes a mechanical screen to remove the suspended matters which could disturb pumping systems or otherunits in the process. Sewage is then pumped in rotary screeners with filter size of 1mm. Sewage is then led to the Biolock section which is consisted of Anaerobicunit to remove Phosphor (Bio-P), Active sludge unit, clarifier and the Polishing zone in which the treated water will be aerated again.

The Bio-P section is equipped with a mixer system which blends the untreated sewage with the returned Active Sludge of Clarifier unit. This method prepares ananaerobic medium for the organic acids to reproduce so the micro organism in aeration unit will be able to remove Phosphor.

The removal of phosphor is usually removed in Bio-P unit, and there is no need to inject Chemical Compound.

In aeration unit (ASB) a mobile aeration in depth is done blowers and fine bubble diffusers. This kind of aeration leads to an augmentation in Oxygen transfereeefficiency and maximum mixing with minimum energy.

The Aeration System BioLack is easy to repair and maintain. There is no need to interrupt the process while repairing.

In clarifying unit (sedimentation) the produced active sludge in aeration in unit is removed from treated water by centrifuges. A part of this active sludge isreturned back to the aeration unit and the rest is pumped to the dewatering unit. The excess sludge is gathered from two modules, is sent to the thickening tanksthen it is transferred to the belt filter press.

Treated water is transferred to the polishing unit after clarifying section. In this unit a short aeration is done to increase water’s soluble oxygen before leaving.After this phase the treated water is treated according the standards, flow into the exit channel.