Waterdoc

I'm a water engineer with a PhD, so not a tech nerd but definitely a nerd :) I came here mostly because I find the Reddit app annoying and the app I was using came here.

I don't know the details about alum production (assuming that is what you are referring to), but there are many alternative coagulants available now. Sure the supply logistics would be incredibly challenging and many people would have to boil their water or use point-of-use filters, but this take is pretty doomer in my opinion. Most plants use alum because it's cheap and easy, not because it's their only option.

Water is disinfected with either chlorine, chloramine (ammonia + chlorine), ozone, or UV light. In North America chlorine is almost universal because it provides disinfection residual, which keeps water safe while it is travelling from the treatment plant to the consumer. Fluoride is added solely as a supplement to improve dental health.

There are lots of things dissolved in our water that give it "flavour", but the goal of all utilities is to minimize this as much as possible. Some water objectively tastes better than others, and a common segment of local drinking water conferences is a taste test. That said, for normal people usually the water they prefer is what their palette is used to. Someone who grew up drinking groundwater with very high alkalinity and pH will prefer that over surface water that is actually more "pure". Similarly, if you normally drink water from a private well that you don't add chlorine to, you likely dislike the taste of "city water".

The common offenders for bad tasting water are excessive chlorine and some specific organic compounds. Both of these flavours can be removed using a granular activated carbon filter (e.g., a Britta), but you can actually remove the chlorine by just letting your water sit in the fridge for a while.

Some facts I posted in another thread about this topic;

Background info.

• PFAS is a class of chemical substances with varying properties, but in general act as surfactants.

• PFAS are considered carcinogenic and impact birth weight.

• PFAS contain a carbon-fluorine bond, which is a very strong bond that does not naturally degrade.

• Some PFAS will naturally decrease concentration over time, but only to be transformed into other compounds that will not (often PFOS).

Regulation.

• The US EPA has taken the approach of regulating a select few PFAS, generally based on their known toxicity. PFOA and PFOS will essentially be limited to a concentration of zero.

• The US EPA has been working on this for years. Mr. Biden did not snap his fingers and make a regulation. These things move much slower than that, and the industry generally feels that this process moved too quickly because there is limited understanding of how much PFAS exists in drinking water.

• Health Canada has proposed a guideline which limits PFAS to 30 ng/L (ppt) as a total sum of all compounds that can be accurately measured. Currently their guidelines limit PFOA to 200 ng/L and PFOS to 600 ng/L. Health Canada does not regulate your water provider through, that is up to your provincial/territorial government, which may have different guidelines than this.

PFAS in the environment.

• PFAS is ubiquitous in the environment due to its travel through the water cycle. It exists in Antarctic ice and on top of Mount Everest.

• Usually the largest sources of PFAS in drinking water are firefighting training areas that used PFAS containing foams (airports and military bases), landfills, certain manufacturers (metal plating, paper, semiconductors), and municipal wastewater. There are many more sources than this though.

• Landfills and municipal wastewater tend to be the highest mass loading of PFAS because of the ubiquity of PFAS in consumer products.

Treatment.

• PFAS can be destroyed using electrochemical and thermal methods, but these are not feasible for drinking water treatment.

• The current approach for drinking water treatment is adsorption to either granular activated carbon (GAC) or ion exchange resin.

• Treating PFAS at the source is always the goal instead of treating it at a water treatment plant.

Feel free to ask questions, I will do my best to answer them!

Groundwater does not typically contain many particles because (a) water moving through the ground gets naturally filtered and (b) groundwater is typically anoxic, which causes certain things to dissolve. Accordingly, most filtration systems for well waters are focused on removing those dissolved contaminants.

The most common well water treatment is water softening. These systems remove hardness from your water (cations, typically calcium and magnesium). Water softeners are usually ion exchange based, so basically you are swapping out the calcium or magnesium for sodium or potassium.

Some wells have dissolved metals (manganese or iron are common) that can stain fixtures and laundry (manganese can also cause health problems for children). Arsenic is also common in some regions, which causes cancer, and hydrogen sulfide, which causes a rotten egg smell. All of these can be removed using a special filter system, which uses catalytic oxidation to oxidize and remove these contaminants. These systems typically use manganese oxide (often called greensand) and chlorine.

To remove salts or microbial contaminants it is common to use a reverse osmosis (RO) membrane filtration system. These systems reject salt ions and microorganisms by a combination of small pore sizes and charged surfaces - the salt ions can't pass through a positively charged surface because of electromagnetic repulsion.

If you have well water you should get it tested regularly and make sure your treatment system is appropriate for your water!

There are two approaches here. First, if you have a well, you can get a pressure filter system installed. Different systems achieve different things, such as reducing the hardness or removing iron and manganese or sulfur.

Second, if you have municipal water, you could get a tap filter. This type of filter goes directly on your tap and is used to remove particles. Usually these are overkill, but they use them in areas with lead pipes to reduce lead exposure (they will remove the pipes eventually, but it will probably take a decade or more in some cities). Your classic pour over Britta doesn't do anything for particles, instead it adsorbs certain dissolved contaminates and removes residual chlorine. This may make your water taste better, but it won't protect you from lead if you have lead pipes.

Unfortunately there really isn't a replacement for these types of adsorptive filters because they work using activated carbon. Activated carbon comes from natural products (primarily coal, but also coconut shell and other materials), but it has to undergo a heating process to "activate" it, which goes well beyond what you can do at home. That said, other than the improved taste there is likely no benefit to using it, and you can dechlorinate your water by simply leaving a jug in the fridge for a few hours.

If you are on a well I can explain some of the other options!

That's certainly unusual. Does this occur after having water sit, or is it after cleaning them? You should call your water provider to report it and ask for their advice. If it isn't something your neighbours are dealing with then it's probably (a) something to do with your dish soap, or (b) the plumbing in your home. Regardless, that's not normal and you should call your water provider.

Water infrastructure is very expensive and the industry is dealing with more problems than ever before (impacts of climate change, PFAS, aging infrastructure). Lots of money and effort is needed to fix these problems, but it is worth remembering that tap water is safe for the overwhelming majority of consumers in developed countries. It is worth knowing more about your drinking water, but don't assume that your water is dangerous because of headlines like this.

Feel free to ask any specific questions you might have about your water!

Abolished is one way to put it... I suspect Louis had stronger words when it was his turn to meet Madame Guillotine.

Math using janky excel spreadsheets, tell drafters what we want drawings to look like, but mostly a lot of reading and writing. The secret to engineering (at least in my area) is that communication skills are just as important as technical understanding.