ohthanks · HackerTrans

há 9 mesesdiscuss

The vast majority of these 400 heat deaths have nothing to do with the power grid. They are people living outdoors, roofers, elderly, etc. When the temps hit 105+ for long periods there are bound to be people who don't have access to AC or overexert themselves outdoors.

ohthanks

há 2 anosdiscuss

They don't boost the feed pressure, just isolate the output permeate line from the back pressure of the storage tank. Instead of the membrane output pushing against the increasing pressure of tank as it fills (decreasing output) it produces into a void in pump body which the pump periodically pushes into the tank from spring mechanism wound by the output waste water.

They work pretty well to reduce waste but do add complexity to what is already a somewhat complicated device under the sink. They will also create bad TDS creep if used without an auto-shutoff valve installed in the RO.

ohthanks

há 2 anosdiscuss

I have built and sold RO systems for 20+ years. It's a weird industry and there are some competing desires in place. In general it's kind of a mess and it's difficult for consumers to navigate.

You can build your own system for less than $150 from cheap parts on ebay. You can buy a branded unit at a big box or amazon for $150-250. Or a "health" branded version for $300-800. Or have an installer put whatever they sell in for $500-1500.

My experience is that you will get nearly identical water quality from each of those systems. There are different options and some fine details but the fundamentals haven't changed in decades and you are paying for some collection of service, parts quality, future replacement costs, marketing and snake oil.

NSF certification is good, it will rule out products that are flat out harmful. I have seen lots of cheap filters with fake certifications and there are many great filters that it don't carry certification. NSF material and safety cert (51) is a good one to look for, beyond that is has more to do with how the product will be sold and marketed than a real measure of performance.

$250-500 is probably the right price range for a diy install unit. Check for replacement part costs, buy something with standard components and cartridge sizes. Learn how it works, change the filters on time and expect to replace components every now and then.

ohthanks

há 2 anosdiscuss

The articles state higher levels in bottled water treated with RO but there are many stages of treatment and delivery involved in industrial scale bottled water production. Unclear if RO itself is the underlying cause.

RO membranes are tight enough and should effectively remove all microplastics from the output water. On a consumer RO system the water will still pass through a few final treatment stages and a few feet of plastic tubing before getting to your glass.

Very possible some additional plastic is being introduced in the post membrane stages and delivery but my assumption is that a point of use RO system is going to reasonably effective.

There is some chance the manufacturers are omitting the fact that all membranes are bleeding microplastics during use. At the moment I don't think we have enough evidence to say they are and most testing has shown them to be effective as a removal method.

ohthanks

há 3 anosdiscuss

ZeroWater uses a mixed bed ion exchange resin (anion and cation) to attract and hold dissolved ionized solids. Mixed bed resin is very effective and will remove nearly 100% of dissolved solid content which will includes all heavy metals.

The downside of mixed bed resins is that they are not selective and water with high dissolved content (TDS) will deplete the resin at very fast rate. Price per gallon is comparable to bottled water with moderate to high TDS. They are simple and very effective as long as the filter is replaced as needed.

ohthanks

há 3 anosdiscuss

There can be downsides to the permeate pumps, but not many.

Installed with a standard hydraulic shut off valve (ASO) you won't see any issues but you won't get much in the way of improved storage pressure. You will just see improved product/waste ratio as the pump negates the back pressure from the tank. The downsides are the periodic thumping noise and the added complexity of the extra tubings and fittings.

Installed without an ASO valve the permeate pumps will cause some TDS creep and bleed high TDS product water into the storage tank each time the system stops and starts. This will mix with the low TDS product water and raise the average up somewhat. The amount will vary on usage behavior but it's a noticeable TDS bump for most users.

ohthanks

há 3 anosdiscuss

I sell residential RO systems. Industry wide the tubing is typically LDPE and the housings/fittings are mostly polypropylene. There is no real practical way to build a residential RO system without using these materials.

It's a trade off between different types of plastic / chemical exposure. Not really ideal but I suspect nearly all sources of treated water will have traveled through a similar amount of plastic to get to you.

Copper is avoided on RO systems because the post membrane water typically drops 1-3 points in PH and will slowly corrode and leech copper into the treated water. All post membrane fittings and tubing should be plastic/stainless, cheap brass fittings with high lead content are the biggest concern. This can be resolved with post membrane PH amendment but you then create a failure point that can cause heavy metal exposure or leaks if it isn't maintained.

You could build a system with steel housings and braided stainless hose but the size/weight and cost are not practical.

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