MISCELLANEOUS WATER MISCELLANEOUS WATER SYSTEMSSYSTEMS

Jonathan BeresfordJonathan BeresfordAKVO LtdAKVO LtdJune 2013June 2013

TYPES OF SYSTEMSTYPES OF SYSTEMS

Vehicle washVehicle wash Chilled water systemsChilled water systems Heating, low, medium or high temperatureHeating, low, medium or high temperature Closed loops in generalClosed loops in general Air handling unitsAir handling units Fume scrubbersFume scrubbers Cutting machinesCutting machines Spa poolsSpa pools

LEGIONELLA/BACTERIA LEGIONELLA/BACTERIA CONSIDERATIONSCONSIDERATIONS

If it creates an aerosol you have to consider the If it creates an aerosol you have to consider the legionella possibilities. possibilities.

Temp, nutrients, environment, spray, peopleTemp, nutrients, environment, spray, people

Bacterial/fungal growth can be an issue with Bacterial/fungal growth can be an issue with process systems.process systems.

Fungal slime growth can block and reduce cooling. Similar Fungal slime growth can block and reduce cooling. Similar to what scale and iron deposits can do. Bacteria can to what scale and iron deposits can do. Bacteria can corrode metals too. Even stainless steel.corrode metals too. Even stainless steel.

SCALE/CORROSIONSCALE/CORROSION

Any system that is supplied with hard water Any system that is supplied with hard water and cools process systems can deposit and cools process systems can deposit scale at the hotter areas – heat exchangers.scale at the hotter areas – heat exchangers.

The heat exchangers themselves can be The heat exchangers themselves can be made of brass, aluminium, copper, iron. made of brass, aluminium, copper, iron. – Different metals in a system can also add to the Different metals in a system can also add to the

corrosion potential by adding to the electrolytic potential by adding to the electrolytic effect.effect.

SYSTEM DESIGNSSYSTEM DESIGNS Fume scrubbers, AHU’s, Vehicle washers spray Fume scrubbers, AHU’s, Vehicle washers spray

water that is typically dirty. They can thus lead to water that is typically dirty. They can thus lead to legionella growth.legionella growth.

Metal cutting machinery if often a source of bacterial Metal cutting machinery if often a source of bacterial infection, including legionella.infection, including legionella.

Closed systems have slime, scale and corrosion Closed systems have slime, scale and corrosion issues. issues.

Heating systems can be either low, medium or high Heating systems can be either low, medium or high pressure systems, the higher the pressure the pressure systems, the higher the pressure the higher the temperaturehigher the temperature

Chilled water systems cool water that is pumped Chilled water systems cool water that is pumped around jacketed vessels or heat exchangers and around jacketed vessels or heat exchangers and frequently involve a holding tank(s).frequently involve a holding tank(s).

DOSING AND CONTROLDOSING AND CONTROL

Dosing pots provide a means to add chemical and Dosing pots provide a means to add chemical and also allow for sampling the water. also allow for sampling the water.

Inhibitor considerations need to take into account Inhibitor considerations need to take into account what could be the bigger issues. Could be lack of what could be the bigger issues. Could be lack of cooling from scale or corrosion may be a greater cooling from scale or corrosion may be a greater issue. issue.

Bacterial control is invariably by non-oxidising is invariably by non-oxidising biocidesbiocides

Dosing can be manual, water meter pulsed, or Dosing can be manual, water meter pulsed, or timer controlled pumps. timer controlled pumps.

CORROSION CONTROL CORROSION CONTROL

Nitrite is the most common inhibitor for closed Nitrite is the most common inhibitor for closed systems, coats metals protecting against systems, coats metals protecting against corrosion, nitrite is an anodic inhibitor. corrosion, nitrite is an anodic inhibitor.

Has the potential to foam if overdosed. Has the potential to foam if overdosed. Typically dosed to systems with little water losses Typically dosed to systems with little water losses

like chilled and heating systems.like chilled and heating systems. Has to be dosed at >1200 ppm if Chlorides >100. Has to be dosed at >1200 ppm if Chlorides >100.

>600ppm otherwise. >600ppm otherwise. Makes pH of system water high at roughly 10-11 – Makes pH of system water high at roughly 10-11 –

aluminium corrosion pH levelaluminium corrosion pH level If not enough is dosed it adds to the problem by If not enough is dosed it adds to the problem by

localising the corrosion attack to the remaining localising the corrosion attack to the remaining areas not protected.areas not protected.

CORROSION POTENTIALCORROSION POTENTIALGALVANIC SERIESGALVANIC SERIES

Most cathodic or resistant to corrosionMost cathodic or resistant to corrosion Platinum Platinum Gold Gold Graphite Graphite Titanium Titanium SilverSilver Chlorimet 3 Chlorimet 3 Hastelloy C Hastelloy C 18-8 Mo stainless steel (passive) 18-8 Mo stainless steel (passive) 18-8 stainless steel (passive) 18-8 stainless steel (passive) Chromium steel >11 % Cr (passive) Chromium steel >11 % Cr (passive) Inconel (passive) Inconel (passive) Nickel (passive) Nickel (passive) Silver solder Silver solder Monel Monel Bronzes Bronzes Copper Copper Brasses Brasses Chlorimet 2 Chlorimet 2 Hastelloy B Hastelloy B Inconel (active) Inconel (active) Nickel (active) Nickel (active) TinTin Lead Lead Lead-tin solders Lead-tin solders 18-8 Mo stainless steel (active) 18-8 Mo stainless steel (active) 18-8 stainless steel (active) 18-8 stainless steel (active) Ni-resist Ni-resist Chromium steel >11 % Cr (active) Chromium steel >11 % Cr (active) Cast iron Cast iron Steel or iron Steel or iron 2024 aluminum 2024 aluminum Cadmium Cadmium Commercially pure aluminium Commercially pure aluminium Zinc Zinc Magnesium and its alloys Magnesium and its alloys Most anodic or easy to corrodeMost anodic or easy to corrode

BACTERIAL CORROSIONBACTERIAL CORROSION

Gallionella bacterium corrode stainless steelGallionella bacterium corrode stainless steel There are organisms that accumulate iron or manganese. The accumulation There are organisms that accumulate iron or manganese. The accumulation

of manganese in biofilms is blamed for several cases of corrosion of stainless of manganese in biofilms is blamed for several cases of corrosion of stainless steels and other ferrous alloys in water systems treated with chlorine or steels and other ferrous alloys in water systems treated with chlorine or chlorine/bromine compounds.chlorine/bromine compounds.

Certain fungi are also capable of producing organic acids and have been Certain fungi are also capable of producing organic acids and have been blamed for corrosion of steel and aluminium. i.e. Aircraft fuel tanks, sulphate blamed for corrosion of steel and aluminium. i.e. Aircraft fuel tanks, sulphate reducing bacteria will produce sulphuric acid and nitrite reducers will product reducing bacteria will produce sulphuric acid and nitrite reducers will product nitric acid.nitric acid.

Aerobic slime formers can inadvertently produce enzymes that are capable of Aerobic slime formers can inadvertently produce enzymes that are capable of intercepting and breaking down toxic substances (such as biocides) and intercepting and breaking down toxic substances (such as biocides) and converting them to nutrients for the cellsconverting them to nutrients for the cells

Various anaerobic bacteria such as Clostridium are capable of producing Various anaerobic bacteria such as Clostridium are capable of producing organic acids. Could be a problem in closed water systems that become organic acids. Could be a problem in closed water systems that become anaerobic. In addition anaerobic bacteria produce foul smells.anaerobic. In addition anaerobic bacteria produce foul smells.

COPPER AND BRASSCOPPER AND BRASS Brass is an alloy of copper with zinc present (10-15%). The zinc component is Brass is an alloy of copper with zinc present (10-15%). The zinc component is

susceptible to corrosion resulting in a weakened metal that can fracture under susceptible to corrosion resulting in a weakened metal that can fracture under stress.stress.

Pitting corrosion occurred only in low dissolved inorganic carbon (DIC) (5 and Pitting corrosion occurred only in low dissolved inorganic carbon (DIC) (5 and 10 mg C/L) and high-pH (9) water in the presence of chloride (20 mg/L) and 10 mg C/L) and high-pH (9) water in the presence of chloride (20 mg/L) and was not observed at pH 7 or 8. Sulphate was not necessary to develop pitting was not observed at pH 7 or 8. Sulphate was not necessary to develop pitting corrosion; however, it did affect the composition of the corrosion by-products corrosion; however, it did affect the composition of the corrosion by-products associated with pitting corrosion. Increasing the DIC from 10 to 50 mg C/L or associated with pitting corrosion. Increasing the DIC from 10 to 50 mg C/L or adding 3 mg POadding 3 mg PO44/L prevented pitting corrosion at pH 9. A conceptual model /L prevented pitting corrosion at pH 9. A conceptual model was established that attributed pit initiation to the deposition of copper chloride was established that attributed pit initiation to the deposition of copper chloride or sulphate compounds on the pipe at the anode. or sulphate compounds on the pipe at the anode.

In other words if the pH is less than 7 raise it to between 7 & 9, ensure enough In other words if the pH is less than 7 raise it to between 7 & 9, ensure enough phosphate is present and the conductivity is high enough. Keep an eye on phosphate is present and the conductivity is high enough. Keep an eye on chloride levels as they seem to pit just about anything when high enough. chloride levels as they seem to pit just about anything when high enough. (>200 stainless steel etc)(>200 stainless steel etc)

If the water is soft, the corrosion potential is much greater. TTA is a good If the water is soft, the corrosion potential is much greater. TTA is a good copper inhibitor, but protecting the zinc present in brass is difficult – filming copper inhibitor, but protecting the zinc present in brass is difficult – filming amine is an option.amine is an option.

ALUMINIUMALUMINIUM

Aluminium readily forms a protective layer of aluminium Aluminium readily forms a protective layer of aluminium oxide assuming oxygen is present.oxide assuming oxygen is present.

Aluminium readily corrodes usually as a result of the Aluminium readily corrodes usually as a result of the breakdown in the oxide layer from mechanically being breakdown in the oxide layer from mechanically being removed. Also corrosion occurs greatly when iron/copper removed. Also corrosion occurs greatly when iron/copper deposits on the metal. (electrolytic/battery effect)deposits on the metal. (electrolytic/battery effect)

At a high pH aluminium is corroded At a high pH aluminium is corroded Protection is via pH control, blended hardness levels and Protection is via pH control, blended hardness levels and

chemical protection should be at high levels to ensure chemical protection should be at high levels to ensure sufficient coating / removal of any electrolytic effects.sufficient coating / removal of any electrolytic effects.

In soft/softened water systems molybdate treatment, is In soft/softened water systems molybdate treatment, is the only option at high concentrations, at least 800ppm the only option at high concentrations, at least 800ppm product.product.

Vehicle wash systemsVehicle wash systems

VEHICLE WASH SYSTEMSVEHICLE WASH SYSTEMS

Produce substantial aerosol.Produce substantial aerosol. Can be contaminated with all manner of road Can be contaminated with all manner of road

soiling.soiling. Can be contaminated with surface run off.Can be contaminated with surface run off. Can be contaminated with drift from cooling towersCan be contaminated with drift from cooling towers Have lots of organic matter for food sources.Have lots of organic matter for food sources. Should be treated with biocides if a recirculating Should be treated with biocides if a recirculating

system.system. Have been implicated in legionellosis outbreaks.Have been implicated in legionellosis outbreaks. Biocide treatment is usually with OxycareBiocide treatment is usually with Oxycare

METAL CUTTING SYSTEMSMETAL CUTTING SYSTEMS

CNC lathe

METAL CUTTING SYSTEMSMETAL CUTTING SYSTEMS

Often have central Often have central solution storage tanks.solution storage tanks.

Sometimes applied by Sometimes applied by spray, ie aerosol.spray, ie aerosol.

Prone to biological Prone to biological contaminationcontamination– Including legionellaIncluding legionella

Have been implicated Have been implicated in legionellosis.in legionellosis.

Treat with non-oxidising Treat with non-oxidising biocidebiocide

Legionnaires’ bug hit 115 people at spa Legionnaires’ bug hit 115 people at spa clubclub Jul 13 2007Jul 13 2007

by Graeme Whitfieldby Graeme Whitfield The Journal.The Journal.  ONE hundred and fifteen people are believed to have ONE hundred and fifteen people are believed to have

been affected by the Legionnaires’ disease bug in an outbreak at been affected by the Legionnaires’ disease bug in an outbreak at a Sunderland leisure club, a report said yesterday.a Sunderland leisure club, a report said yesterday.

The Health Protection Agency traced the outbreak last year to The Health Protection Agency traced the outbreak last year to faults in the water treatment system at the Springs health club, faults in the water treatment system at the Springs health club, which led to the legionella pneumophila bug colonising the spa which led to the legionella pneumophila bug colonising the spa pool system.pool system.

It is now known that the 115 people became ill after visiting the It is now known that the 115 people became ill after visiting the leisure club from August 11 to 25 last year. Of these, two have leisure club from August 11 to 25 last year. Of these, two have been confirmed as having Legionnaires’ disease and five of been confirmed as having Legionnaires’ disease and five of having Pontiac Fever, a milder version caused by the same having Pontiac Fever, a milder version caused by the same legionella organism. Three people needed hospital treatment after legionella organism. Three people needed hospital treatment after the outbreak, which led Springs to shut the health club earlier this the outbreak, which led Springs to shut the health club earlier this year.year.

Typical Spa Pool System

Dosing and controlDosing and control

Normally two stagesNormally two stages– FiltrationFiltration– DisinfectionDisinfection

Control system will Control system will maintain control over maintain control over pH pH

Control system will Control system will maintain control over maintain control over chlorine/bromine via /bromine via redoxredox

Complex pipe workComplex pipe work

Makes full draining Makes full draining difficult.difficult.

Potential dead legsPotential dead legs Areas for bacteria to Areas for bacteria to

“hide”.“hide”. Corrugated pipes Corrugated pipes

should be avoidedshould be avoided..

Bacterial infectionsBacterial infections

Legionella speciesLegionella species can give rise to both Legionnaires can give rise to both Legionnaires Disease and/or Pontiac Fever.Disease and/or Pontiac Fever.

Pseudomonas aeruginosa Pseudomonas aeruginosa can give rise to folliculitis can give rise to folliculitis which is an infection of the hair follicles, children and young which is an infection of the hair follicles, children and young adults are most at risk.adults are most at risk.

Mycobacterium avium Mycobacterium avium has been associated with has been associated with respiratory infections.respiratory infections.

Amoeba Amoeba such as Naegleria fowleri is a rare cause of fatal such as Naegleria fowleri is a rare cause of fatal meningitis which has been associated with natural spas. meningitis which has been associated with natural spas. Acanthamoeba species are common in water systems and Acanthamoeba species are common in water systems and can cause eye infections especially in wearers of contact can cause eye infections especially in wearers of contact lenses. This amoeba can also cause encephalitis of the lenses. This amoeba can also cause encephalitis of the brain.brain.

FOR FURTHER INFORMATIONFOR FURTHER INFORMATION

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