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Municipal Case Studies

Alanya - Turkey


Wastewater Treatment Plant

Flow capacity

Daily average influent flow : 28.976m3/d
Population Equivalent : 144.880 p.e.

Pollution Load Capacities

Daily average :
BOD5: 8.200 kg/d
SS: 9.560 kg/d
TKN: 1.360 kg/d
TP: 260 kg/d

Treatment Targets

BOD5: 20 mg/l
SS: 30 mg/l
TKN: 10 mg/l
TP: 2 mg/l


The plant laboratory was given responsibility of the analytical measurement of waste water and sludge quality during every phase of the treatment.

A command-control system that is based on automated operations is linked to a central command post and provides complete 24-hour control of the treatment facility.
Each phase of the treatment is thus remotely controlled and optimized.

Wastewater Treatment

Pretreatment

Screening

The waste water passes through bar-screens which capture the solid wastes larger than 10mm in size to protect the following stages of the treatment.

Grit and grease removal

The influent then flows into the grit and grease removal tanks.
Settled grit is scraped and removed by pumping from the grit hoppers. Subsequently, grit separated from waste water into a classifier is discharged.
Simultaneously, in the same tanks, air is injected to emulsify the grease and oil which floats to the surface, where it is skimmed off. After concentration in a separate tank, grease is discharged to the dumping area.

Biological treatment

Activated sludge aeration tank

The physically pretreated influent is then diverted to a high-loaded plug-flow activated sludge aeration tank where a high portion of the organic material (BOD) is removed.
Also the dosing of ferric chloride in the last phase of plug-flow reactor provokes the formation and subsequently precipitation of ferric phosphates in the following sedimentation units, resulting in chemical phosphorus removal from the waste water.

Lamellar settling process

The flow is directed to lamella type sedimentation tanks.
Sludge settles on the inclined lamella surfaces and slides to the bottom, while the supernatant is collected into the weir troughs on the top and let into the next treatment unit.
The lamella configuration offers significant space-saving features ; it requires about eight times less space than the conventional settlers.

Biofiltration by Biostyr process

After settling, the supernatant is treated through 6 Biostyr filters.
The Biostyr process, developed by Veolia Water Solutions & Technologies, is an upflow submerged biofilter bed and utilizes an ascending filtration system using granular media made up of expanded polystyrene spherical beads.
These beads provide a medium to which microorganisms can attach and thrive, hence enabling the elimination of organic matter and Kjeldahl nitrogen pollutants through microbiological activities.
Additionally, the polystyrene beads allow the treated effluent to flow freely while retaining suspended solids and ensuing biological sludge.
The retained suspended solids, sludge and biofilms on beads are removed by periodical backwash, which involves alternating water-phase/airscour phase and wash cycles.
Backwash water is directed to a special sedimentation tank.

Disinfection

Treated water is finally subjected to chlorination for disinfection before discharging into the Mediterranean sea in order to prevent any nuisance condition for the swimmers and for the other recreational uses.

Sludge Treatment

Thickening

A portion of the sludge from the sludge sump is recirculated to the inlet of the activated sludge, while the''excess sludge'' is introduced to the thickeners where sludge concentrates up to 40-100 g/l of dry solid.

Dewatering and stabilization

Concentrated sludge from the thickeners is then directed to the centrifuge for mechanical dewatering. Dewatered sludge is mixed with lime for chemical stabilization.
Subsequently dry sludge with a dry solid content of about 25% is transported to a sludge dumping area. 

Odour Treatment

The entire plant is an enclosed, ventilated construction.
Polluted air is extracted and treated in three scrubber towers (Aquilair  process, total capacity : 65.000m3/h) through a physico-chemical process (liquid-gaz absorption).

Aquilair process

  • 1st Tower :
    Acid scrubber which eliminates nitrogen-based compounds.
  • 2nd Tower :
    Base oxidizing scrubber which eliminates sulfur-based compounds.
  • 3rd Tower :
    Base oxidizing scrubber which eliminates aldehyde acids and acetones.​


Diagram

Alanya diagram