Ella Kot Lar

7/29/2019 Ella Kot Lar

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Blow Down cooling water systemIs ZLD the optimal process?

Ella kotlar (M.Sc.)

Environmental Licensing & Protection Unit

Israel Electric Corp.

THE ISRAEL ELECTRIC CORP. Ltd.

Environmental licensing and protection unit


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Content

Background - IECs project

Available Solutions for power stations cooling towersBlow down

Environmental aspects

and cross media effects of ZLD

Summary

Gezer power station ZLD system,IlanMalester PhdGezer power station ZLD system,IlanMalester Phd


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Background

IECs project included three Combined Cycle Electric

Power generation units of 370MW (Gezer & Alon TavorPower stations)

The combined cycle units are cooled by industrial

induced draft wet cooling towersThe water source for the cooling has been set asreclaimed municipal waste water and raw water asbackup.


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Background

IEC's project was the first major project using municipaltreated wastewater in induced draft wet cooling towersin the Israeli industry.

In order to achieve the demanded water quality for thecooling towers, IEC built a tertiary treatment plantincluding nitrification, softening and filtration.

Blow down of cooling water must be preformed due toevaporation and rising salts concentration in the coolingtowers.

The project raised the challenge of determining the bestsolution for the disposal of the cooling tower Blow down.

The cooling tower Blow down treatment plant must

operate at varies feed water composition.


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nitrificationnitrification

softenersoftener

filtrationfiltration

Dovrat - Tertiary and ZLD treatment plant Dovrat - Tertiary and ZLD treatment plant

ZLD treatment plantZLD treatment plant

Blow down

tank

Blow down

tank


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systemwaterBlow down cooling

50 - 150 m3/hr per unit

Approximately 50 container trucks per day per unit


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Solutions for cooling tower Blow down

Discharging Blow down to the sea using tankers (50 tankersper day per unit)

Discharging Blow down to the sea by a brine dischargepipeline from the inland site to the sea

Operating the cooling towers on a low number of cycles and

discharging the Blow down to the Ayalon River

Operating the cooling towers on a low number of cycles anddischarging the Blow down to wastewater reservoirs

Treating the Blow down in a Zero Liquid Discharge (ZLD)plantTreating the Blow down in a Zero Liquid Discharge (ZLD)plant


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ZLD and near ZLD

Blow down treatment alternative technologies

1. Full Thermal technology - Evaporator system(brine

concentrator) followed by a Crystallizer + filter press2. Semi Thermal technology - Brine Concentrator +

Concentrated brine truck disposal

GE Seeded sl urry brine concentrator

GE Crystallizer


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ZLD and near ZLD

Blow down treatment alternative technologies

3. Combination of membrane and Thermal

technologies - Chemical Pretreatment + RO systems +Brine Concentrator + Crystallizer + filter press

4. Combination of membrane and Thermal

technologies - Chemical Pretreatment + RO systems +

Brine Concentrator + Concentrated brine truck disposal

5. Full membrane Filtration technologies - Concentratedbrine truck disposal

Recovery is in the range of 92%-98%Recovery is in the range of 92%-98%


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ZLD treatment plant

Blow down treatment technologyMost ZLD facilities in the world that treat Blow downfrompower plant cooling towers use thermal

technologies (with/without RO as a pretreatment forreducing the blow down capacity).

Evaporator system

(brine concentrator)followed by a crystallizer

HPD Seeded slurry brine concentrator

ZLD treatment plant - Gezer power station (IlanMalester, Phd)ZLD treatment plant - Gezer power station (IlanMalester, Phd)


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Main reasons for adopting ZLD process

Environmental compliance

High operating cost (blow down disposal)


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Environmental aspects and cross

media effects

High energy consumption (electric and steam)

Solid waste / Concentrated Brine disposal

Usage of chemicals (pretreatment processes)

Main environmental Cross media effects

Prevention of water body pollution disposal of the

waste (ground water, sea, river)

Water reuse (recovered water is returned to the coolingtower or to the deminerlized water production system)

Air pollution (from electricity/steam generation,transportation)

Chemicals (Hazardous chemicals)

Land use


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Estimated Environmental parameters*

Semi Thermal

technologies

Full Thermal

technologies

Outlet:

2,5003,000Energy

consumption (kWh)

30Brine disposal

(m3/hr)

01,000 Salt cake disposal

(kg/hr)97%98%% Recovery

* for two 375MW Units, According to RFI answers* for two 375MW Units, According to RFI answers

Inlet (Blow down): 100-200 m3/hr


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Solid waste (Salt)

Gezer power station (Ilan Malester, Phd)Gezer power station (IlanMalester, Phd)

Concentrated brineConcentrated brine

Disposal


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Disposal of the waste

Concentrated brine:

- discharged to a near water body, when available- discharged to the waste water area treatment system- evaporating in evaporation ponds

Solid waste ("salt") from the crystallizer:Usually dumped in landfills, local abandoned quarry sitesetc.


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Liquid and solid residual disposal

in Israel

Because of unique environmental conditions regarding

land and groundwater salinity, land filling of the solidwaste and discharging the brine into the river or to wastewater reservoirs is prohibited.

According to Israel environmental authorities, the solidwaste and the concentrated brine must be discharged

to the sea.


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Estimated air Emissions

(Ton/year)*

Unit 21 (148MW)

Gezer PS(2011)

Semi

Thermal

technologies

Full Thermal

technologies

140,00015,00018,000CO2

1143744NOX

4.71.11.3PM

includes emissions from: Electricity generation, steam generation andtransportation

includes emissions from: Electricity generation, steam generation andtransportation


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Summary

Solutions for treatment of cooling tower Blow down

depends essentially on;- Local conditions

- Local regulatory demands

Due to the local conditions, treating the Blow down

up to a concentrated brine may be the optimal

solution.

Alon Tavor power station, Ilan Malester, Phd Alon Tavor power station, Ilan Malester, Phd


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Thank you

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