Dr. Prem Mohan Jha discussed the need for pure water in dialysis and the water purification system used to provide it. Two main water sources are surface and groundwater, both of which can contain various contaminants harmful for dialysis patients. The water purification system uses multiple steps including carbon filtration, softening, reverse osmosis, and sometimes deionization to remove contaminants. Strict water quality standards must be followed and the various components of the system such as softeners and filters require regular monitoring, maintenance and disinfection to ensure water purity and prevent bacterial growth.

1. Presenter – Dr Prem Mohan Jha
Moderaor -Dr. Manisha Dassi

2. Weekly Water Exposure

3. Need of Pure water
 Exposure to 120 – 200 L of dialysis solution per session
 Small molecular contaminants of raw water may
accumulate in absence of renal excretion
 Hence, dialysis solution prepared from purified water
or “product water” & electrolytes added later

4. Water Supply
 Two sources of municipal water:-
 SURFACE WATER: More contaminated with organisms
and microbes, industrial wastes, fertilizers, and sewage
 GROUND WATER: Lower in organic materials but
contains higher inorganic ions such as iron, ca, mg and
sulfate.

5. Water Contaminants
 Aluminum: Added as a flocculating agent by many
municipal water systems (aluminum sulfate used to
remove nonfilterable suspended particles)
 Chloramine: Added to prevent bacterial proliferation
 Fluoride: Added to reduce tooth decay
 Copper and zinc: These can leach from metal pipes
and fittings.

6. Water Contaminants
Bacteria and endotoxin:
 Antibacterials added to source water are removed by the
water purification system,
 Product water & the final dialysis solution are susceptible
to microbiologic contamination
 Endotoxins & other bacterial products as bacterial DNA
fragments cross dialyzer membranes and enter
bloodstream to produce pyrogenic reactions

7. Contaminant Possible effects
Aluminum Dialysis encephalopathy, renal bone disease, anemia
Calcium, Magnesium Hypertension, hypotension
Chloramine Hemolytic anemia
Copper Nausea, headache, liver damage, hemolytic anemia
Fluoride Osteomalacia, osteoporosis, pruritus, nausea, Fatal VF
Sodium Hypertension, pulmonary edema, confusion, headache,
seizures, coma
Microbial Pyrexia reactions, chills, fever, shock
Nitrate Methemoglobinemia, hypotension, nausea
High iron Hemosiderosis
Sulfate Nausea, vomiting, metabolic acidosis
Zinc Hemolytic anemia, vomiting, fever
Aromatic hydrocarbons Potential chemical carcinogens
Toxic Effects of Contaminants

8. Components of the Water Purification System
Water Supply
Temperature Blending Valve
Backflow Prevention Device
Booster Pump
Depth Filter
Carbon Tank
Water Softener with brine tank
Reverse Osmosis Device
De-Ionization System (Optional)
Distribution System
Drain System

9. What does what ??
Process Contaminant Removed
Carbon
Adsorption
Chloramine, organics
Softener Calcium, Mg
Reverse osmosis Ionic contaminants, bacteria,
endotoxin
Deionization Ionic contaminants
Ultrafilters Bacteria, endotoxin

10. Overall plan of Water Purification
System

11. The Water Treatment Plant

12. Choice of Material
 Piping, storage, and distribution systems..
 Should not interact chemically or physically with
purified water
 √ Unreactive materials (e.g., plastics) or stainless steel.
 X Copper, brass, galvanized material or aluminum.

13. Temperature blend valve
 RO systems operate efficiently at specific feed water
temperature
 Achieved by using a heater with a temperature blending
valve
 Can be set to mix hot and cold water to achieve specific
water temperature
 Incorporates a thermostat
 Output temperature should be recorded atleast once daily
 Defective valve can damage the water treatment equipment

14. Back Flow Prevention Device
 Also known as Reverse Flow Prevention Device
 Dialysis water treatment equipment should be connected
to Source water through a Backflow Prevention Device
 Purpose:
 Prevent water from water treatment equipment being pulled
backwards into the building’s water supply piping
 Prevents the backflow of disinfectants into the building water
main
 Monitoring: Increase in pressure difference between pre
and post RP device by more than 10 PSI above baseline
 Annual testing

15. Booster Pump
 In order to maintain the necessary minimum pressure
and flow to the treatment system, booster pumps are
often used on the feed water line
 What to monitor: Water pressure
 What to look for: Pump turning on and off at the
appropriate pressures or flow rates

16. Acid Feed Pump
 Purpose: Adding inorganic acidic solution to raw water
in areas where the pH of feed water is high
 Some municipalities add NaOH/CaCO3 into water
system to minimizes leaching of metals from the pipes
 Carbon filtration and Reverse Osmosis devices will not
work effectively at pH of >8.5
 What to monitor: pH post acid feed pump
 What to look for: pH should be between 7.0 and 8.0

17. Depth Filters
• Large particulates of >10
microns such as dirt, are
removed by a multimedia
depth filter.
• Contain multiple layers of
various sized rocks/sand that
trap the large particles as the
water is filtered downward.

18. Depth Filters
• Monitoring:
1. Pressure drop more than a 10 PSI from baseline
2. If so, filter should be backflushed or replaced
• Backflush timer should be set to perform the
backflush after facility operation hours.

19. Water Softener
 Used primarily for protecting and prolonging the life
of the RO membrane.
 Water softeners are used primarily to remove Ca and
Mg from water
 Softeners remove Ca and Mg by exchanging these for
Na
 Purpose: Ca build up on RO membrane can cause
decrease in RO membrane life & decrease in water
quality

20. Water Softener
Need to Monitor
Total hardness post softener
Measured in either in GPG or
PPM
AAMI RD52 recommends a
limit of 1GPG ( or 17.2 PPM)
PPM: GPG x 0.058

21. Water Softener
 The softener needs regeneration regularly with
concentrated NaCl solution (brine) before the resin
capacity is used up
 The resin is backwashed to loosen the media and clean
any particulates from the tank.
 After the backwashing step, the brine solution is
drawn into the tank

22. Water Softener
 Need to Monitor
 Pressure Drop
• The device may require back flushing if the pressure drop
changes by more than 10 PSI
• A breakdown of the resin can occur (from chlorine) which
can also cause increased pressure drops

23. Water Softener
 Need to Monitor
 Salt level in the brine tank
 Adequate amount of salt in the tank to allow the resin beads
to be regenerated by the softener.
 Monitor the brine tank for a “Salt Bridge” making it appear as
though the tank is full when it is actually empty underneath.

24. Water Softener
 Regeneration:
 Water is drawn into the softener in reverse direction
backwashing & then brine solution is introduced to
regenerate the resin, replacing the adsorbed Ca++ and Mg++
with sodium ion.
 Need to Monitor
 Regeneration Timer
 The system should be set to regenerate the resin beads.
 The timer should be set to activate when the facility is not operating
.

25. Water Softener

26. Carbon Tanks • Chlorine & chloramine are
added to municipal water
systems to kill bacteria
• Cause Hemolysis in patients
• RO system not effective at
removing chlorine and is
damaged by them
• Removed by running it through
tanks filled with Granulated
Activated Charcoal which
adsorbs it

27. Carbon Tanks
 Usually two tanks arranged in series configuration
 First tank: “worker” tank
 Second tank: “polisher” tank
 Water must be exposed to the carbon for 5 minutes in each
tank
 Chlorine Monitoring:
 Chlorine and chloramine levels by colorimeter/ color test
strips
 No separate test for chloramine
 Chloramine = Total chlorine – Free chlorine
 AAMI Limits: Chlorine 0.5 PPM, Chloramine 0.1 PPM

28. RO System

29. RO Membrane Prefilter
• Prefilters are particulate filters
position before the RO pump
and membrane
• Carbon fines, resin beads, and
other debris exiting the
pretreatment damage the pump
and RO membrane
• Prefilters range in pore size from
3-5 microns.

30. Reverse Osmosis
 RO overcomes natural osmosis by forcing feed water
under pressure through a semi-permeable membrane
leaving contaminants behind

31. Reverse Osmosis

32. RO System
 The RO membrane is the most important component
of the system
 Produces purified water by RO
 Polyamide thin membranes

33. De-iodination System (Optional)
• Does not remove nonionic contaminants, bacteria or
endotoxins
• Cationic resins contain sulfuric radicals and exchange
hydrogen radicals for other cations such as Na, Ca and
Al
• Anionic resins contain ammonium radicals which
exchange hydroxyl ions for chloride, PO4 and flouride

34. De-iodination System (Optional)

35. Bacterial Filters

36. Storage Tanks

37. Distribution System
 RO distribution systems
 DIRECT FEED: Directly delivers the product water from
the RO unit to the loop for distribution
 INDIRECT FEED: Involves a storage tank that
accumulates the product water and delivers to the
distribution loop
 Unused portions are recirculated back into the storage
tank.

38. Distribution System
 A continuous loop design is recommended by AAMI
 No dead-ends or multiple branches should exist in the
distribution system, as these are places for bacteria
biofilm to grow.

40. Monitoring the Product Water
 AAMI Chemical Standards
(Association for the Advancement of Medical
Instrumentation)
 Water should be tested atleast annually by tests
specified by AAMI
 Results interpretation:
 No contaminants exceeding AAMI standards
 Comparison of the results with past tests

41. Maximum Allowable Levels of
Contaminants in Water

42. Continuous monitoring of chemical
contamination
 Measure conductivity in RO & resistivity in DI
 Conductivity
 Indicates the level of Total Dissolved Solids (TDS) in
water in Parts per Million
 Percent rejection = {1-(output conductivity / input
conductivity)}*100
 Conductivity of raw and RO water is measured in Micro
Siemens (equivalent to PPM).

43. Continuous monitoring of chemical
contamination
 Resistivity in DI systems
 Resistance to the flow of electricity (inverse of
conductivity) is measured
 Acceptable limit of resistivity for final product water is
greater than 1 megaohm/cm resistance

44. AAMI Microbiological Standards
 AAMI recommendations:
 Product water & dialysis solution: <200 CFU/mL
bacteria and <2.0 EU/mL endotoxin
 European Pharmacopoeia
 Product water: <100 CFU/mL bacteria & <0.25 EU/mL
endotoxin
 No values for dialysis solution recommended

45. AAMI Microbiological Standards
 AAMI Action level for Bacteria: 50 CFU for bacteria
 AAMI Action level for Endotoxin: 1 Endotoxin Unit/ml
 Testing should be performed monthly. If standards are
exceeded, testing should be performed weekly until
the problem is resolved

46. AAMI Standards for Bacteria/Endotoxin
 Site 1: At the point where the water leaves the RO machine,
before it enters the holding tank (Indirect System), or
before it goes to the treatment room to provide water for
dialysis machines (Direct System).
 Site 2: If an RO water holding tank is present, a sample
should be taken at the point where the water leaves the
tank.

47. AAMI Standards
 Site 3: At the end of the return line of the RO water
distribution loop, whether it is returning to the RO or
a water holding tank. If a bacteria filter is installed
anywhere in the system, a sample is to be drawn from a
sample port both pre and post filter
 Site 4: At the point where water enters into the
dialyzer reprocessing system, whether it is a manual or
automated system
 Site 5: At a point where water enters equipment used
to prepare bicarbonate and acid concentrate

48. AAMI Standards
 Site 6: At the point where the dialysis machine is
hooked up to the product water loop
 Site 7: If the facility uses softened, de-chlorinated
water as a backup water plan, it is necessary to perform
cultures and a Limulus Amebocyte Lysate (LAL) test
on this water

49. AAMI Standards not met ??
 Isolate the potential problem:
 RO membrane
 Product water distribution system disinfection
procedures
 Examination of the distribution piping system for dead
spots that may contribute to bacterial contamination
 Contamination of bacteria filters installed in the
distribution system.

50. AAMI Standards not met ??
 Corrective Actions:
 Cleaning and disinfection of RO machine membranes
 Disinfection of the product water distribution system
 The installation of an endotoxin filter system in the
RO water distribution system and/or increasing the
frequency of disinfection of existing bacteria filters

51. Product water flow rates
 Bacteria form a layer of biofilm within the pipes.
 Risk minimized by friction of rapidly moving water
through the pipes.
 Minimum flow velocity of 3 ft/second in order to
reduce bacteriological problems
 The rate of flow and the size of the pipes determines
the flow velocity
 AAMI Standards available

52. Monitoring the drain system
 Minimum 1-inch air gap between the equipment drain
line and the building drain pipes. This prevents sewage
being drawn into the machine
 Bleach or a commercial gel product down the drains to
prevent flies

53. Water treatment system & Dialysis
machine disinfection
 Chemicals such as bleach (chlorine), peracetic
acid/hydrogen peroxide mixtures, and formaldehyde
are commonly used for this purpose.

54. Ultrapure dialysis solution
 Decreases CRP and IL-6
 Improves response to EPO
 Promotes better nutrition
 Reduces plasma levels of ß-2-microglobulin
 Slows loss of residual renal function
 Lowers cardiovascular morbidity
 AAMI: Bacteria level below 0.1 cfu/ml and
endotoxin level below 0.03 EU/ml
Susantitaphong P et al. Effect of ultrapure dialysate on markers of inflammation, oxidative
stress, nutrition and anemia parameters: a meta-analysis. NDT (2013) 28: 438-446

55. Ultrapure Water

56. Maintenance of Water Quality
 The key to maintaining water quality is the
establishment of a facility-specific quality
management program for the water treatment and
distribution system
 The quality management system should be fully
documented with clearly delineated lines of
responsibility

57. Thank you