Maintenance of Water System

7/27/2019 Maintenance of Water System

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Maintenance of Water

System


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Purified Water System


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For Existing System(WHO Technical Report Series 929 Annex 3 P.57 )

The following list identifies items and a logicalsequence for a WPU system inspection or audit:

A sampling and monitoring plan with a drawing of all samplepoints

The setting of monitoring alert and action levels

Monitoring results and evaluation of trends

Inspection of the last annual system review Review of any changes made to the system since the last audit

and check that the change control has been implemented

Review of deviations recorded and their investigation

General inspection of system for status and condition Review of maintenance, failure and repair logs

Checking calibration and standardization of critical instruments.

For an established system that is demonstrably under

control, this scope of review should prove adequate.


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Maintenance of Water

SystemMaintenance Activities

Engineering Practices


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Visual checks

Pipes and pumps

hygienic couplings

welded pipes

hygienic pumps

hygienicsampling points

acceptable floor no leaks

Maintenance of Water System

WHO Technical ReportSeries No 929, 2005. Annex 3


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Staining on

water storagetanks

Corrosion on plates of heat exchangersindicates possible contamination

Visual checks (2)

Check condition of equipment




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Visual checks (3)Maintenance records, maintenance of pump

seals and O rings




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Air filters

Integrity testing, sterilization

and replacement frequency

Check burst discs

Visual checks (4)


WHO Technical Report

Series No 929, 2005. Annex 3


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Pretreatment schematic drawing

raw water in

S trap to sewer

Water is keptcirculating

To water

softener& DI

plant

cartridgefilter

5 micrometers

activatedcarbon

filter

spray ball

break tank

air break to draincentrifugal pump

air filter

floatoperated

valve

Multimediafilter

excess water recycledfrom deioniser


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Multimedia Filter

Reduce turbidity of feed water

Remove suspended solids

Normally can remove particles with size of

10 micron

Sand (mangenese greensand) to remove iron


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Sanitization of MMF

Backwash + Use City water with additional

Chlorine 200-2000 ppm to the column andsoak it overnight +Backwash again untilchlorine level back to normal level

Hot water at 80oC for 30-60 min

Steam sanitization 120oC for 15-30 min


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Chlorine removal (Activated-carbon (AC) filtration or bisulphite)

AC removes chlorine but bacteria can then

grow AC filtration can remove organic impurities AC should be able to sanitize with Hot Water

80oC

Sodium bisulfite is added to the raw water.Bisulphite leaves sulphate residues but isantimicrobial

Bisulfite also reduces free chlorine to thechloride ion, which is then separated throughreverse osmosis together with sulphate. Theadded quantity must be adjusted.

Water for Pharmaceutical Use


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Water Softener schematic drawing

brine and salt tank

brine

"hard" waterin

zeolite water softener

-exchanges-Ca and Mg for Na

drain

"soft" water to deioniserby pass valve


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Water Softener The potable water is first coarsely filtered, then the scale

(calcium, magnesium, sulfate, carbonate) is removed in afirst stage.

Softened water is the prerequisite for the next stage in themanufacturing of purified water, as otherwise there could

be scaling of magnesium and calcium sulfates on thedownstream equipment, such as membranes of thereverse osmosis units, deionization devices, anddistillation units.

But it increase the free CO2 by shifting the bicarbonate to

carbonic acid and then to CO2 and H2O


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Sanitization of Softener

Normally do not require sanitization

Can use residual chlorine Add chlorine to the brine tank at a level of 100 ppm

and then start regenerating, leave it 2-8 hours

before fast rinse and continue the regeneratingprocess, flush to drain with clean water until thelevel of chlorine is below 1 ppm in order to avoid theshorten of resin life

Hot water sanitization at 80 oC for 30-60 min


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CO2 Elimination

By adding NaOH to convert CO2 to carbonate

and bicarbonate and then eliminate by RO Membrane degassing: The gases dissolved in

the water are diffused through a membrane

through the creation of a particle pressuredifference and are rinsed from the membraneusing air.

Degasifier (Force Draft Decarbonator)


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Degasifier

Decarbonator Forced Draft

Vacuum

Membrane Contactor Liqui-Cel

Chemical Injection Sodium hydroxide

Nitrogen Gas


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Degasifier

To eliminate free carbon dioxide

Free carbon dioxide can cause

low pH of water

Corrosion

High conductivity

The installation position are varies. Itdepends on type of degasifier


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Purification System

Conventional Deionization

Cationic Anionic

Conventional Deionization + Mixbed

Reverse Osmosis

Double RO

RO + Mixbed

RO + EDI (Electrodeionization)

Ultrafiltration + RO

Ultrafiltration + EDI


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Typical deionizer schematic

Cationic column Anionic column

Hygienic pump

Outlets or storage.

Ozone generator

UV light

HCl NaOH

Eluates toneutralization

plant

Air break to sewer

Drain line

from water softener

Watermust bekeptcirculating

1

2

345

6

1

2

345

6

Return to deionizer

Cartridgefilter 5 m

Cartridgefilter 1 m


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Branch

Branch

2nd stage buffer tank

Cartridgefilter 1 m

Second stage RO cartridge

First stage filtrate feeds second stage ROwith excess back to 1st stage buffer tank

.

1ststage

re

jectconcentrate

Air breakto sewer

Second stage reject water goes back to first stage buffer tank

Second stage RO watermeets Pharmacopoeia

standardsOutlets or storage

1st stage buffer tank

Water from softener or de-ionizer

Water returns to 1st stage buffer tank

Typical 2-stage RO schematic

Hygienic pump

First stage RO cartridge

High pressurepump


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Ion Exchange Resin Bed

Cation resin Ca Mg Na

Anion resin SO4 PO4

resin spherical beads 0.4 0.8mm resin resin 3-5% regenerate resin

resin

5


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Mix Bed Unit

Mixedbed

Conductivity

Anion & Cation resin Column mixed bed deionization

anion 60% cation 40%


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raw water

High pressure

Feedwater

underpressure

Reject

water

Semi-permeable

membrane

Permeate

water

drain or recycle

Low pressure

Purified water

Reverse osmosis (RO) theory

Water for Pharmaceutical Use


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Reverse Osmosis In order to reverse the process of osmosis, pressure

higher than the osmotic pressure must be applied tothe concentrate stream in order to push water witha low amount of solids through the membrane.

A semi-permeable membrane retains cations,

anions, colloidal systems and bacteria. The membrane lets through water that is almost

pure. With reverse osmosis, more than 98% of saltsand 90% of organic compounds are retained, as

well as bacteria and organisms, but 100% retentionis not achieved.


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Reverse Osmosis

The reverse osmosis units therefore work with a

high operating pressure of more than 15 bar(positive pressure).

Reverse osmosis units are today designed so thatfeed water flows over the membranes tangentially.

The flow of water splits into two parts, theconcentrate and the permeate. The concentratewith the high amount of solids is rejected and fed

into the wastewater system


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RO membrane should provide a 3-log

reduction (99.9%) in bacteria

If the bacteria level in the product water ishigher than feed water. It is likely that thebacteria are growth at the surface ofmembrane

Bacterial Reduction By RO


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Prevention of Bacteria in RO System

Good Design No ball valves

No threaded connections

No deadlegs or crevices/cracks

No imperfection pores in PVC piping

Non sanitary sampling valves

Reduce water stagnation

Provide continuous/intermittent chemicalcontrol

Minimize available nutrients


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membrane

(Membrane scaling Elimination) Scale RO membrane bicarbonate ion

Calcium Carbonate, Calcium bicarbonate membrane scale

1. pH feedwater2. Scale inhibitor

3. pretreatment


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Chemical Sanitization of RO System

Chemical Sanitization on a regular basis

Remove foulant first by using An acid cleaner such as citric acid to remove inorganic foulants

Then sodium hydroxide to remove organic foulants

Use Sanitizing agents to circulate 15-30 min

Formaldehyde

Hydrogen peroxide

Per-acetic acid/hydrogen peroxide

Soak the system for 20-30 min

Periodically start the system every 5-10 min Rinse with purified water


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Removal of Biofilm1. Remove inorganic by using low-pH cleaner

2. Remove organic compound by high-pH cleaner3. Use sanitizing agent such as formaldehyde,

chlorine or peracetic acid/hydrogen peroxide for

15-30 minutes4. Rinse with purified water

5. Repeat step 2-3 many times (5-10 times)


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Sanitizers


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Chemical Sanitizers


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UV Disinfection Disinfection. The most common application of UV radiation in water

treatment is disinfection.

In a typical water system, the chlorine present in the raw water(municipal water) is depleted by the carbon beds or by the additionof sodium metabisulfite, thereby rendering the water stream devoidof any microbial control mechanism and consequently invitingmicrobial growth and proliferation.

The microorganisms thrive and multiply exponentially and soonwould invade the downstream piping and equipment including thereverse osmosis (RO) system. The microbial growth, if not checked,very soon would lead to the formation of slimy biofilm on the ROmembrane. This results in the decline in ionic and salt rejections andin flux, consequently necessitating frequent sanitization of the

membrane. A UV unit installed upstream of the RO system significantly destroys

the live bio-burden on the membranes and thereby extends itslongevity.


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UV 185 VS 254 nm Two different UV wavelengths are employed in water

treatment, the 254 nm and the 185 nm.

The 254 nm UV lightalso called the germicidal lightdue to its unique ability to destroy microorganismsisemployed in disinfection and ozone destruction

applications. It penetrates the outer cell wall of themicroorganism, passes through the cell body, reachesthe deoxyribonucleic acid (DNA) and alters the geneticmaterial. The microorganisms thereby are destroyed in a

nonchemical manner. The 254 nm UV light also can destroy residual ozone

present in a water stream.


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UV 185 VS 254 nm

The 185 nm UV light, utilized in TOC

reduction application, decomposes theorganic molecules. The 185 nm light carriesmore energy than the 254 nm light. The 185

nm light generates hydroxyl (OH-) freeradicals from water molecules. It will oxidizemost organic compounds in to CO2 and H2O


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UV for Destruction Ozone destruction. Ozone commonly is utilized in the

industry to disinfect the storage tanks, vessels, piping

and auxiliary equipment such as pumps and valves, andto insure that they remain bacteria-free. The residual ozone needs to be destroyed prior to the

point-of-use so that it does not interact with the product.

UV technology is a good choice for this application dueto its nonchemical and fast mechanism. A UV unit,properly sized, can completely destroy the residualozone in the water and thereby help ensure the integrityof the process and product.

Chlorine/chloramine destruction. As an alternative tothe use of chemicals and activated carbon beds, UVtechnology can be utilized to destroy chlorine/chloramineand thereby eliminate the need for additional chemical

treatment.


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Ozone

Ozone oxidizes the organic material in bacterial

membranes, which weakens the cell wall andleads to cellular rupture. This exposes the

organism to the external environment, whichcauses almost immediate death of the cell. It'ssimilar to a knife deeply cutting skin.

Ozone reduce TOC by oxidizing organiccompounds to CO2 and H2O

Concentration for sanitization is 0.008-0.020mg/L or ~25 ppb


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Ozone Generator

1. Electrolytical process from PW

2. By forcing oxygen or ambient air to pass throughan ultraviolet light source matching the (ozoneproducing) wavelength of the suns rays (185

nanometers).3. By sending a lightning-like spark (a corona

discharge) through an oxygen or dry air flow.


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Total Organic Carbon

TOC is defined as any compound containing the

carbon atom. except CO2, and related substancessuch as carbonate, bicarbonate and the like. TOC can be found in most city water as naturally

occurring microorganisms, other organic matter and

man-made organic-based chemicals. In cases of extremely high TOC loads, (>1,000

ppm), municipal chemical treatment by coagulationand settling using alum or iron salts effectively

reduces them to a manageable level for the public.


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TOC Reduction Activated Carbon

Reverse Osmosis

Ion Exchanger Anion Bed

Mix Bed

EDI

Oxidation

Hydrogen peroxide

Ozone

UV 185 nm Ultra & Nano Filtration (0.1-0.001 micron)

Typical water storage and distribution schematic


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Water mustbe kept

circulating

Spray ball

Cartridgefilter 1 m

Air breakto drain

Outlets

Hygienic pump

Optionalin-line filter

0,2 m

UV light

Feed Waterfrom

DI or RO

Heat Exchanger

Ozone Generator

Hydrophobic air filter& burst disc

Typical water storage and distribution schematic


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Continuous turbulent flow circulation

Specified velocity proven (qualification),and monitored

Avoid dead legs ( 1.5 D)

Hygienic pattern diaphragm valves

Shortest possible length of pipe work

Pipe work of ambient temperature systems,isolated from hot pipes

Biocontamination control techniques


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There should be no dead legs

Water scours dead leg

If D=25mm & distance X is

greater than 50mm, we have

a dead leg that is too long

Dead leg section

>1.5D

Flow direction arrows

on pipes are important

Sanitary Valve

D

X


Bi i i l h i


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3. The water is contaminated as itpasses through the valve

1. Ball valves are unacceptable

2. Bacteria can grow whenthe valve is closed

Stagnant water

inside valve


Bi i i l h i


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Pressure gauges separated from systemmembranes

Pipe work laid to fall (slope) allows drainage

Maintain system at high temperature (above70 degrees Celsius)

Use UV radiation

Flow rate, life-cycle of the lamp Suitable construction material


Bi t i ti t l t h i


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Periodic sanitization with hot water Periodic sanitization with super-heated hot

water or clean steam

Reliable Monitoring temperature during cycle

Routine chemical sanitization using, e.g. ozone

Removal of agent before use of water is important


Documents

Maintenance of Water System