Thread by @DerekSLarson

Ever wonder how dialysis units make that fancy, high-quality water? It has always interested me as a nephrologist. Here's a 🧵with photos👇 1/12

⭐️Potable water💧enters the treatment circuit and the mixing valve blends to the desired temperature
⭐️The valve is equipped with a thermometer🌡️and adjustment knob

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⭐️A backflow assembly prevents the dialysis water from entering back into the city water supply

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⭐️A booster pump helps to provide adequate/continuous water pressure for operation💪
⭐️Also includes an electric pump controller (equipped with a pressure transducer) and expansion tank
⭐️The expansion tank helps smooth out pressure changes

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⭐️ ON THE LEFT - A depth filter removes coarse particulate matter. The filter consists of coal, sand, and garnet as the filtration media
⭐️ ON THE RIGHT - A water softener reduces levels of calcium and magnesium.
⭐️Ca and Mg ions are exchanged for Na

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⭐️Softeners have a finite capacity and must be regenerated
⭐️Regeneration is completed by exposing the resin to a strong brine solution

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⭐️Carbon tanks are next in line!
⭐️They are the principal method to remove chlorine and monochloramine, substances that can degrade reverse osmosis membranes and harm patients

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⭐️ A backup carbon filter is often used in series
⭐️Carbon beds are closed monitored to detect exhaustion of their removal capacity
⭐️Frequent testing is necessary to verify that total chlorine levels remain ≤0.1 parts per million (PPM)

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⭐️Just before water reaches the Reverse Osmosis unit, a pre-filter clears out any particulate matter that may damage the membrane

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⭐️Reverse osmosis (RO) removes substances such as metal ions/salts, chemicals, and microbial elements (bacteria, endotoxins, and viruses)
⭐️Organic contaminant removal is largely based on size; those with a molecular weight >200 Da are filtered
⭐️Uses Hydrostatic pressure!

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⭐️Deionization removes ionic contaminants when the RO fails or when additional purification is necessary
⭐️H+ exchanged for➡️Cations
⭐️OH- exchanged for➡️Anions
⭐️H+ and OH- combine to become water
⭐️Followed by an endotoxin filter since DI systems promote bacterial growth

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So:
✅ Dialysis patients are exposed to ~150L of dialysis solution each treatment
✅ Providing clean water for dialysis is critical for patient safety and positive patient outcomes
✅ The components of H20 treatment need to be monitored closely to ensure optimal performance

Fin