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UPW from Municipal Wastewater


UPW from municipal wastewater Mexico


The Client

UPW Key Figures
Flow rates: MBBR + DAF: 60 m3/h - UF: 75 m3/h (3 modules of 25 m3/h) - 1st pass RO: 35 m3/h - 2nd pass RO + CEDI: 17 m3/h

Mexico – A Combined Cycle Power plant in Mexico uses pretreated Municipal Wastewater as source for feeding the Ultra-pure water (UPW) services such as steam generators, cooling towers make-up and potable water.
 

The Client’s Needs

Due to the proper functioning of the thermoelectric plant, different water flows with different qualities are required to supply the different areas and processes carried out in the plant.

Wastewater reuse for several applications, including ultra pure water for turbines.

Veolia Water Technologies Mexico has been awarded in the start-up phase of the water treatment plant, to produce the volume of water required with the quality that each process needs.
 

The Solution

In order to supply the water services Veolia Water Technologies Mexico fabricated and installed a fully equipped system as a turnkey project.

The system consists of biological polishing with an AnoxKaldnes® Mobile Bed Bio Reactor (MBBR), an Idraflot® Dissolved Air Flotation system (DAF), a hollow fiber Ultra filtration system (UF), two-pass Reverse Osmosis (RO) systems and a Continuous Electro De-Ionization System (CEDI).

The scope of supply also included the sludge handling and some potable water systems as well.
 

Process Description

The plant therefore receives the pretreated municipal wastewater with 70 mg BOD/l and 77 mg TSS/l at the MBBR inlet. After the biological stage the water reaches 10 mg BOD/l and 10 mg TSS/l, from this point the Total Dissolved Solids content (TDS) is 470 mg/l that must be treated by RO and CEDI.

The overall system can be divided into two sections depending on the main quality goal. In one hand it is the pretreatment where Chemical Oxygen Demand (COD) and Total Suspended Solids (TSS) are mostly removed, on the other hand there is the Demineralization where the dissolved solids content in the water is targeted in order to achieve the service requirements.
UPW Process Description
 

Results

AnoxKaldnes® MBBR + Idraflot® DAF:
  • Biochemical Oxigen Demand (BOD): < 10 ppm
  • TSS: < 10 ppm
UF:
  • 99% of the suspended particles above 0.025μm are removed along with the remaining particulate COD and Oil&Grease.     
               
1st pass RO:
  • Conductivity: < 50 µS/cm
  • The polishing section has a nominal recovery of 74% and delivers permeate water quality suitable for cooling tower make up operations as well as other services since the water reaches less than 10 mg/l of TDS.
2nd pass RO + CEDI:
  • Conductivity: < 0.1 µS/cm
  • Silica: < 10 ppm
The recovery of the 2nd pass RO is 81% while the CEDI has 93% recovery, the polishing section is delivering demineralized water suitable for steam generation.