+Filter

Criteria

  • Filtered water storage
    • capacity
    • Material
  • Certifications
    • ISI, WQA or NSF
  • Quality of service and maintenance

Water quality

  • Hardness
  • salinity
  • TDS (Total dissolved solids).
    • TDS principally includes calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates, and small amounts of organic matter
    • Higher in borewell water
    • TDS levels greater than 1000 mg/litre make drinking-water increasingly unpalatable and unhealthy.

Water quality record

  • vAruNI nilaya, sahakAranagara 2021-03

    • kAverI water, filter reject - TDS 170
    • kAverI water, filtered - TDS 160
    • borewell water, filter reject - TDS 430
    • borewell water, filtered - TDS 360

  • अन्तर्वेदीय-गुरुकुलम्

    • 450 TDS + water turns yellow if kept for few hours

  • हर्याणा-गुरुकुलम्

    • bore 1 - TDS of 750+
    • bore 2 TDS of 1131+
प्रिया-प्रयोगाः
  • Tap water - TDS 864, ph 7.5
  • Himalaya Bottled water - TDS 210, ph 7.25
  • Himalaya Bottled water boiled to half - TDS 225, ph 9.5
  • RO water - TDS 186, ph 6.25
  • RO water, single boil - TDS 204, ph 7.25
  • RO water, boiled to half - TDS 257, ph 9.5
  • RO water, lemon for 6 hours - TDS 190, ph 5
  • RO water, cucumber for 6 hours - TDS 200, ph 7

Chemical filtration

Carbon filter

  • When used as a pre-filter - removes chemical contamination - chlorine, chloramide, fluoride etc.. Hence AKA chemiblock.
  • When used as a post-filter, it removes bad odor and improves taste.
  • Carbon cartridge needs to be flushed before installation - else it may send black water downstream and damage RO filter. +++(ALERT!)+++
  • Contains activated carbon, which has high surface area - so high abrsorptive power.

Quality

  • Check how much it is filled by shaking it or breaking open. Half filled filters specially useless if installed horizontally. Slight noise is ok.
  • Natural coal contains high sulphur - so not suitable. Coconut shell made ones are better - 10 times better than natural coal.
  • Quality of coal is measured with IV (iodine value). 1100 to 1200 good.
  • Good filter should get chalked.

Simple membrane filtration

  • Simple Gravity filters. Good for removing mud etc..

.1 micron

  • Aka Microfiltration
  • Ceramic filters (Used in old water filter candles) - 0.2 microns pores
  • Sediment cartridges come in .1 microns (Filterkart) as of 2020. Sediment cartridge gets chalked over time with sand, silt, rust etc. (if good quality). Filterkart vid.
  • very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia); moderate effectiveness in removing bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); not effective in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); removes microplastics, not effective in removing chemicals.

.01 micron

  • Water is forced to flow through insides of small hollow fibers
  • Membranes used are predominantly created from polymer thin films.
  • Aka UF (Ultrafiltration)
  • Pore size
  • very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia), bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli); moderate effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); low effectiveness in removing chemicals.

.001 micron Nanofiltration (NF)

  • Good for low TDS
  • Smaller (nanometer) pores than microfiltration and ultrafiltration; just larger than RO membranes.
  • can “soften” water by retaining scale-forming, hydrated divalent ions (e.g. Ca2+, Mg2+) while passing smaller hydrated monovalent ions.
  • very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia), bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli), viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus); moderate effectiveness in removing chemicals.

RO (Reverse Osmosis)

  • filters 98% heavy dissolved solids: metals, particulates, minerals
  • Recommended for TDS 200-2k.
  • uses semi permeable membranes
  • Wastes 2x or 3x water. Green RO water purifiers better.

Effectiveness

  • very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia), bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli), viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus)
  • remove common chemical contaminants (metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead; may reduce arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate, and phosphorous.

Drawback

Removal of beneficial minerals like ca, mg and cobalt (part of vitamin b12).

Membranes

  • Longer membranes (more windings in filter cylinder) imply more filtration (provided the pump has the ability to push water through it).
  • GPD = Gallons per day.
  • Aquaguard Reviva 2016 used 75 GPD membrane.

TDS regulator

  • Regulates the water flowing through RO membrane.
  • Vids - 1
  • Applied to waste water pipe in RO system.

Flow restrictor

  • When flow restrictor is applied there is higher water pressure.

Zero wastage RO

  • Pump back rejected water to pipe.
  • Have 2 tanks - one to collect rejected water.

Distillation

  • very high effectiveness in removing protozoa (for example, Cryptosporidium, Giardia), bacteria (for example, Campylobacter, Salmonella, Shigella, E. coli), viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus)
  • remove common chemical contaminants (metal ions, aqueous salts), including sodium, chloride, copper, chromium, and lead; may reduce arsenic, fluoride, radium, sulfate, calcium, magnesium, potassium, nitrate, and phosphorous.

Disinfection

  • UV (Ultraviolet filtration)
  • Distillation

Generic Fittings

  • john guest push fittings - a ring air-tight seals the connected pipe when the pipe is pushed all the way through. To release, one pushes this ring (by hand or screwdriver).
  • Weight sensor - breaks the circuit of filtration pump when the output tank is filled with water.

Pump

  • Good pumps come with heat sinks.
  • Capacity is measured in Gallons Per day GPD.

Filter replacement

  • Aquadyne video here.
  • filterkart site in India - used once. Good quality filters, it seems.
  • Good idea to change external sediment filter every 6 months or so.
  • Service near sahakAranagara
    • Manju and chandan - INR 2800 in 2023 for replacing prefilter, sediment, carbon, RO filters, + flow restrictor. 3k when another pre-filter was serviced.
    • alt 2024 - INR 3500 for replacing pump, coil