Standards for Water Quality in Cooling Towers

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Are there any British Standards (BSI) or ISO Standards referring to physical and micro/biological parameters for cooling towers water quality?  

This is very important since cooling towers have high risks for growing bacteria.

Legionnaires bacteria could increase population in cooling towers and contaminate the water. 

Which standards regulate the water quality in cooling towers? 

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11 Answers

  1. ASHRAE 188 | Legionellosis: Risk Management for Building Water Systems

  3. The cooling tower institute has general guidelines. Bacteria are always present. There is no such thing as sterile. Legionella is easily killed in typically treated water by any reputable chemical suppler. Shock treatment or continuous residual treatments are normally quite effective. Drift and other means of producing aerosols of the water should be looked after as well. If you are treating the tower adequately to prevent slime buildup in the fill, normally, legionella isn't an issue.

    1 Comment

    1. Hi Scott, still believing that chemical treatment is the only solution? And normally NO PROBLEM?

      See this list as only a fragment of the number of cases where legionella caused deadly diseases.

      Year   ​ Location ​    ​    ​    ​    ​    ​    ​    ​    ​    ​    ​   ​Cause   ​    ​    ​    ​   # ​Death   ​    ​ # ​Infected ​
      2014   ​ Villa ​Franca Portugal ​    ​    ​    ​    ​    ​ Cooling ​Tower   ​   10 ​    ​    ​    ​    ​  334 ​
      2014   ​  Jü​lich, Germany ​    ​    ​   ​    ​    ​    ​    ​ Cooling ​ Tower ​    ​ 1   ​    ​    ​    ​    ​  70 ​
      2013   ​ Wesely ​Ohio, USA , ​    ​    ​    ​    ​    ​    ​Cooling Tower ​    ​  6   ​    ​    ​    ​    ​ 39 ​
      2013   ​ Warstein, ​Germany   ​    ​    ​    ​    ​    ​ ​Cooling ​Tower   ​    2 ​    ​    ​    ​    ​   ​165 

      Chemicals are effective no question, disinfecting the water, but in 100% of all cases, the biofilmn or slime is not removed or only in smaller parts - openings in the slime surface allowing even faster new germ and bakteria growth. You just invent an endless spiral - of continuous chemical usage. This is named perfect management? Just focus on one effect and ignore the impact of the chemicals to the environment? The continuous costs to supply these chemicals and the costs to neutralize thsi chemicals in waste water treatment?

      What is so difficult to at least seeking for other solutions?

      We can proof in various applications the effectiveness of non chemical treatments for years.

      Interested? 

      Then contact me: gerhard0261@gmail.com

      Best Regards, Gerhard Mangold

  4. Hi Goskel

    In the UK, the risk from Legionella  in cooling towers and elsewhere is controlled by good management practice. Guidance is available, principally, through the Health and Safety Executive.

    http://www.hse.gov.uk/safetybulletins/coolingtowers.htm

    It is the responsibility of an operator to develop a plan that identifies the risk and puts in place appropriate control measures. It is important that the measures are effectively and continuously monitored and corrective action taken, where necessary, to prevent a deterioration in water quality. 

    Kind regards

    Robert

  5. Hello Vatan,

    If you have any requirements about cooling tower fills, welcome to contact with me.

    Rita

    Answered on by

    1 Comment

    1. Thank you Rita Du

      1 Comment reply

      1. Hi Goksel, probably i should´nt post my answer as a comment to Mr. Baboo but directly to you - to clearify some facts:

        Gerhard Mangold 14 hours ago

        Hi Baboo,

        I value your ​answer, as you ​tried to ​explain ​standard water ​disinfection ​treatment. But ​I have to ​remind you ​about the ​original ​question wheter ​there are ​regulations for ​water treatment ​in cooling ​towers. See ​Muhammads reply:​ There are no ​existing ​regulations, ​only recommendations ​and standards ​invented by the ​industry. Due ​to the fact ​that legionella ​pneumophila ​evaporated from ​cooling towers ​caused world ​wide serious ​epidemic ​infections with ​high mortality ​rates, ​officials are ​seeking for ​existing ​regulations or ​regulations in ​similar ​appliacations. ​Currently in ​Germany the ​parliament ​passes a new ​regulation, to ​list all ​cooling towers ​by the land ​registry office ​and to enforce ​regular cooling ​tower water ​quality, ​according to ​standards ​defined by the ​German federal ​environmental ​office. The ​standards will ​be the ​same as ​drinking water ​specs and ​limited to 1000 ​KBE or Germ ​Developing ​Entities per ​1000 ml water. ​The regulation ​also froces all ​responsible ​operators to ​control and ​test the water ​quality on a ​regular base, ​to test the ​water through ​certifies labs ​and to document ​the test ​reports. ​Preventive ​meassurements ​or corrective ​meassurements ​taken so far ​are as you ​mentioned ​chemical ​treatments with ​negtive effects ​on the ​equipment or ​environment. ​All the ​standard ​treatments will ​not erradicate ​the biofilms - ​breeding ground ​for bakteries ​and germs. To ​disinfect ​cooling towers, ​you have to use ​(chorine or ​chlorine dioxid)​ continuously, ​treating ​symptoms, but ​never solve the ​problem. Please ​see my previous ​answer. I have ​listed cooling ​tower ​appliactions ​where we ​installed our ​chemical free ​treatment ​system. It ​works permanent ​and we can ​proof that we ​eliminated all ​biofilm and all ​tests over ​years show ​perfect results ​of the tested ​water. ​

        Dont you ​agree that we ​have: ​

        1. Regulations ​and standards ​in drinking ​water ​applications ​which can be ​easily ​applied to ​cooling tower ​appliactions ​

        2. Due to the ​high risk of ​epedemic ​infections ​there is a ​world wide need ​for water ​quality ​regualtions in ​cooling towers ​systems ​

        3. Due to ​futher negative ​impact chemical ​disinfection of ​cooling towers ​should be ​replaced by non ​chemical ​treatment ​processes. ​

        I would be ​happy to give ​you further ​information ​uppon request. ​

        Best, Dipl. ​Ing. Gerhard ​Mangold ​gerhard0261@gmail.com 

  6. When high temperature (over 40℃) ; generally, using corrosive steel, materials which have no protective coating against water, anticorrosive measure shall be done such as adding corrosion prevention material, Zinc degasser and etc.

    To control corrosion and scale, maintain the water chemistry of the recirculating water within the parameters listed in following

    The specific measures required vary from system to system and are dependent on the chemistry of the make-up water, the metallurgy of the piping and heat transfer devices exposed to the recirculating water, and the

    temperatures at which the system will be operating. Bleed/blowdown, the continuous flow of a small portion of the recirculating water to a drain, is used to control the concentration of dissolved solids. On rare occasions, this may be adequate to control scale and corrosion. More often, chemical scale and corrosion inhibitors are necessary, which raise the allowable level of dissolved solids without the risk of scale and corrosion.

    Chemical treatment programs must meet the following requirements:

    • The chemicals must be compatible with the unit materials of construction as well as other materials used in the system(pipe, heat exchanger, etc.).

    • BAC discourages acid dosing as means of scale control except for open circuit cooling towers with remote sump

    applications or towers constructed from stainless steel. This should be done at a point in the system where total mixing and dilution occur before reaching the evaporative cooling equipment. The preferred injection point for chemical

    scale and corrosion inhibitors is on the discharge side of the system circulating pump(s). These chemicals should not be batch fed directly into the unit’s cold water basin or water distribution system, as this can severely damage areas directly contacted.

    • When chlorine is added to the system, free residual chlorine should not exceed 1 ppm, except as noted in start-up and

    shutdown section. Exceeding this limit may accelerate corrosion.

    Generally PH-6.8-7.2

    FRC-0.1-.3 ppm

    Ortho phosphate 4.5-6.5

    Turbidity-5-10 NTU

    Conductivity(mho/cm)-1500-2000

    M. Alk-40-60 ppm

    TH- 600-700 ppm

    Ca H-500-600

    Mg. H-200-350

    SiO2-90-115

    Chloride as Cl-70-115

    Total Iron-0.1 0.3

    COC 6-7.7

    Chemical treatment programs must meet the following requirements:

    • The chemicals must be compatible with the unit materials of construction as well as other materials used in the system

    (pipe, heat exchanger, etc.).

    • BAC discourages acid dosing as means of scale control except for open circuit cooling towers with remote sump

    applications or towers constructed from stainless steel. This should be done at a point in the system where total mixing

    and dilution occur before reaching the evaporative cooling equipment. The preferred injection point for chemical

    scale and corrosion inhibitors is on the discharge side of the system circulating pump(s). These chemicals should not

    be batch fed directly into the unit’s cold water basin or water distribution system, as this can severely damage areas

    directly contacted.

    • When chlorine is added to the system, free residual chlorine should not exceed 1 ppm, except as noted in start-up and

    shutdown section. Exceeding this limit may accelerate corrosion.

    1 Comment

    1. Hi Baboo,

      I value your answer, as you tried to explain standard water disinfection treatment. But I have to remind you about the original question wheter there are regulations for water treatment in cooling towers. See Muhammads reply: There are no existing regulations, only recommendations and standards invented by the industry. Due to the fact that legionella pneumophila evaporated from cooling towers caused world wide serious epidemic infections with high mortality rates, officials are seeking for existing regulations or regulations in similar appliacations. Currently in Germany the parliament passes a new regulation, to list all cooling towers by the land registry office and to enforce regular cooling tower water quality, according to standards defined by the German federal environmental office. The standards will be the same as drinking water specs and limited to 1000 KBE or Germ Developing Entities per 1000 ml water. The regulation also froces all responsible operators to control and test the water quality on a regular base, to test the water through certifies labs and to document the test reports. Preventive meassurements or corrective meassurements taken so far are as you mentioned chemical treatments with negtive effects on the equipment or environment. All the standard treatments will not erradicate the biofilms - breeding ground for bakteries and germs. To disinfect cooling towers, you have to use (chorine or chlorine dioxid) continuously, treating symptoms, but never solve the problem. Please see my previous answer. I have listed cooling tower appliactions where we installed our chemical free treatment system. It works permanent and we can proof that we eliminated all biofilm and all tests over years show perfect results of the tested water.

      Dont you agree that we have:

      1. Regulations and standards in drinking water applications which can be easily applied to cooling tower appliactions

      2. Due to the high risk of epedemic infections there is a world wide need for water quality regualtions in cooling towers systems

      3. Due to futher negative impact chemical disinfection of cooling towers should be replaced by non chemical treatment processes.

      I would be happy to give you further information uppon request.

      Best, Dipl. Ing. Gerhard Mangold gerhard0261@gmail.com

  8. Hi Goksel,

    there are no standards in reg. to bacteria population in cooling towers yet. But in Germany government is just releasing a new regulation that all cooling towers must be listed and min. 1 time per year tested through certified labs. The standard limit is 100 KBE (Germ developing entities) per 100 ml tested water. You are absolutly right, there are many cases world wide where legionella have been spread from cooling towers and caused diseases and fatal casualties (approx. 10% mortality rate) see following list (only few of all known cases)

    Year    Location                                            Cause                  # Death        # Infected
    2014    Villa Franca Portugal                      Cooling Tower      10                   334
    2014     Jülich, Germany                             Cooling  Tower      1                     70
    2013    Wesely Ohio, USA ,                         Cooling Tower       6                    39
    2013    Warstein, Germany                        Cooling Tower       2                    165
     

    We have installed our chemical free disinfection system in following cooling tower apploications:

    Air Washer Washer  EADS Munic 2008
    Air Washer Ministery of Interieur Vienna  2005 
    Air Washer Washer State Opera Vienna  2006
    Air Washer Washer German National 2008 
    Cooling Tower Technical University Vienna 2006
    Cooling Tower MPI Garching 2012

    Since then we tested the water quality continuously and never reached any critical KBE levels.

    If you need detailed information about the system or you may have any other question reg. disinfection systems or regulations, please contact me any time.

    Best regards, Gerhard

     

    1 Comment

  9. Cooling towers and other sources should be continuously disinfected and periodically cleaned. There are ASHRAE and other Guidelines:

    Useful Resources from ASHRAE and Allied Associations on Reducing the Risk of Legionellosis

    ASHRAE Standard 188-2015, Legionellosis: Risk Management for Building Water Systems

    ASHRAE Guideline 12-2000, Minimizing the Risk of Legionellosis Associated with Building Water Systems

    ASHRAE Journal article - Risk Management for Legionellosis

    Articles and papers addressing legionella available in ASHRAE Bookstore

    Guidance from the Centers for Disease Control

    Proposed Standard from NSF and ASHRAE