gunplumber700 t1_iwgw5oo wrote
I’ve spent several years as a potable water and wastewater treatment plant operator. This is super misleading.
For example the average wastewater plant does not produce an effluent turbidity low enough to meet federal drinking water requirements. It’s not unattainable but the first thing water system owners will cry about is cost. The first thing people will say is gross. With the trend of plants moving toward liquid instead of gas chlorine cost will go up quite a bit there too.
Also, if we’re worried about water conservation how about fixing water loss in potable water (essentially tap) systems. The amount of water loss in US potable water distribution systems is insane.
ErroneousRecipe t1_iwh6h70 wrote
I'm assuming you operate a CAS system?
I work on potable-reuse membrane plants and we see turbidity easily less than 0.1 NTU, and a lot of WW plants are seeing IPR.
DPR isn't far off, and was recently approved by Colorado regulators in that state.
gunplumber700 t1_iwhn5t5 wrote
I’ve worked at several plants and used most major system types.
Relative to DISTRIBUTION systems. There is a huge need for system upgrades to combat water loss. Having worked all over the US I can say that, imo, we should be focused on upgrading leaking/ crumbling distribution systems first.
Recycled water for drinking is a hard sell. I’ll believe it when I see it, when it’s being used in any significant amount.
scotus_canadensis t1_iwibvd4 wrote
I'm currently looking into recycling our wastewater effluent (kind of a background project right now). It's certainly not as clean as our well water, but it's feasible for use.
As you say, the first hurdle is people saying "ick".
The second hurdle is that our effluent goes into a reservoir used for irrigation, and the reservoir users would likely object to any new diversion.
gunplumber700 t1_iwiymd2 wrote
Im not really sure what are you getting at. Just because we can doesn’t mean we should.
Why make potable water from recycled water from wastewater when you can more than make up for slight demand increases with addressing water loss?
scotus_canadensis t1_iwizhnf wrote
I run a small system, with minimal loss. We go from a regular summer high of 1800-2000 m3 daily to around 700 m3 daily at this time of year. I'm comparing effluent recycling to the cost (and load on our local aquifer, which I worry about during dry years) of drilling new wells. There is not enough loss in our distribution system to offset the need for a new water source if any of our wells drops off.
outofideastx t1_iwjeco4 wrote
The obvious answer would be that treating wastewater more is cheaper than replacing hundreds, if not thousands of miles of mains. Treating wastewater more is also forever, while you're going to have to replace all the mains again in 50-75 years if you want to prevent water loss from skyrocketing again.
The city I work for is doing proactive leak detection (the program I run), DMAs, transient monitoring, meter calibration, etc. to lower water loss. We've been doing some of these programs for years now, and we were one of the first in the state to do proactive leak surveying. We still have high water loss. We're talking thousands and thousands of leaks over the course of a year. Our system is old, and we don't have the money to replace it all at once, nor the physical resources.
As I said, I run the proactive survey program, so I'm a big proponent of reducing water loss. That being said, cutting 1-2% of water loss is difficult to do, and very costly. Any city that needs to drastically reduce consumption in the next decade will only be looking at water loss as a longer term plan.
gunplumber700 t1_iwjkqeq wrote
And what’s the life of a wastewater plant? It’s not forever…
Failing to replace distribution systems pipes is failing to properly maintain a system. When customers complain about main breaks they have a point. When they complain about their bill being skyrocketing because they have to pay for upgrades because of managers that neglect their systems they have a point.
I don’t get why the industry is so ok with wasting such large volumes of water but “it’s hard” is the excuse I guess.
If you went to the gas station to fill up your cars 20 gallon gas tank and paid 25 but received 20 would you think it’s ok?
outofideastx t1_iwjr7uq wrote
I completely agree with you.
The people in power don't care, and they don't intend to spend more money on main replacement. And they'd rather spend a few million here and there, so they can put off spending a couple billion until they are no longer in office. At the end of the day, recycling wastewater would be cheaper than replacing the mains, especially when you add in the fact that many cities have to buy their raw water from an outside entity. In Texas, we buy raw water from water districts. There are cities here that built reservoirs before the water districts ever existed, but now they have to pay for raw water coming out of their own lakes. Recycling wastewater means you pay for it once, and use it over and over. If I discharge it into a river and then pick it up again downstream, I get to pay for it all over again.
Another thing to add perspective to the main replacement thing: Chicago alone has over 400,000 lead service lines. These lines are an active, major health risk and they are only removing dozens of them per year, when they should be doing thousands. If death and lawsuits aren't bringing replacements, they definitely aren't going to go replacing mains over some water loss.
Lastly, forcibly reducing irrigation is the lowest hanging fruit, as we can see on the west coast right now. Irrigation use is much more than 10% of the treated water in the south. Eventually, I'm hoping we will get on board with mass-scale desalination, hopefully powered by nuclear power.
gunplumber700 t1_iwjt5kj wrote
Nah that’s too smart for CA.
They’ll continue to take water from farms to send to a place with 10 million people to feed that has no farms. Then they’ll continue to allow pg&e (the big electric company out there) to start wildfires and burn down cities amidst water shortages all while not installing one of the safest and most reliable forms of power (nuclear).
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IBeDumbAndSlow t1_iwgwvyd wrote
Can you share any information you may have on the amount of Rx medicine that's in waste water? I read years ago about how our wastewater is getting polluted by medication from renal excretion. I'm curious as to how known or unknown this phenomenon is.
gunplumber700 t1_iwgzwv4 wrote
Im sure it’s there, but not something that’s measured on a daily basis. It’s usually university researchers doing that type thing. It’s not really in the realm of day to day operations.
Most of it is pretty dilute. I don’t have any numbers for you, so I can’t give you an answer other than I don’t know and my speculating that it’s pretty dilute. I would be carful of apply research from specific cases and instances to the industry as a whole.
Percyheckendorf t1_iwi6gtq wrote
As someone who’s been in on this research. It is the main, non-policy related, impediment to DPR. They don’t degrade so they will get increasingly less dilute in a closed system.
hormones such as estrogen will likely be an issue for every application
gunplumber700 t1_iwiyrop wrote
So for me that’s another reason to avoid it.
Percyheckendorf t1_iwj2lks wrote
Which may not be an option, as southwestern cities such as Phoenix and LA are likely to fail within the century without it.
gunplumber700 t1_iwj5sfa wrote
From one of my other comments:
“This is for places like LA (who steals water from everywhere else) and Las Vegas. Look at LA’s water loss. In my 5 minute search it looks like they use 10,999 MILLION gallons of water a month. Their water loss is 7%. That means the lose 770 MILLION gallons of clean treated water a month. 770 MILLION gallons of clean potable water is wasted. We’re going to clean and reuse wastewater but we can’t even keep from losing clean water? I don’t think so. When LA stops stealing water from everywhere and they start doing this I’ll believe it.”
Percyheckendorf t1_iwj8j3y wrote
Well Vegas is already world class in water reuse. Basically only Israel beats them. we will certainly go to water reuse before we repair/replace LA’s entire pipe system. That is crazy difficult and expensive and an ordinary problem for most networks (though probably worse in la due to the seismic activity) Meanwhile there are already wastewater plants producing drinking quality effluent. It’s clear cut the cheaper solution short term
gunplumber700 t1_iwjcxy6 wrote
So the “it’s cheaper” excuse only works as a short term solution.
Look at all the municipalities with constant main breaks because they think “it was made better” back in the day.
I’m not saying replace the entire system overnight but it needs to be replaced as it ages, which include metering equipment that under report, meaning you’ll underbill someone as they age as well.
Still not saying there aren’t places that do it, just that it’s unnecessary given the alternatives that have to be addressed anyway.
It kind of avoids the fact that many plants don’t have the ability to just turn up chemical dosing and call it good.
Percyheckendorf t1_iwjgzh9 wrote
They will eventually, when they are done they will start again, because pipes will always leak. its only a max 7% increase, which is not enough
Yes the plants will need to be retrofitted with more advanced processes.
[deleted] t1_iwjrk06 wrote
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jkally t1_iwhs9sh wrote
There was recently a release about the amount of meth in the waste water in Shreveport Louisiana being the most in the country. https://www.ktbs.com/news/study-shreveport-wastewater-leads-the-nation-in-methamphetamines/article_1ede67a4-6084-11ed-ba96-f3dfba001cd9.html
AdultEnuretic t1_iwhd5hx wrote
I always wonder about this as well. I feel like I'm a walking pharmacy (13 scripts daily) so I know I'm excreting a lot. Most people are obviously a lot less, but I know the Rx contamination is out there.
smoked_papchika t1_iwj1v0o wrote
It certainly depends on the state and what the WWTP design looks like. From my experience, true direct potable reuse projects (known as toilet to tap) essentially use the WWTP effluent as the source water for the DPR plant. The onus will be on the DPR plant to be designed for worse-case water quality scenarios - typically what the discharge permit allows.
The key factor in these DPR projects is being able to achieve pathogen inactivation credits to drinking water standards. We’re talking upwards of 12-log depending on the state regulators. So these plants typically use low pressure and high pressure membranes and advanced oxidation treatment. UV as well.
And I completely agree with you regarding water loss in distribution. Finding alternative source waters for drinking water is admirable, but when 20-30% of your TREATED water is lost to the pipe gods, then it deserves the same consideration.
[deleted] t1_iwgxrsx wrote
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gunplumber700 t1_iwh284l wrote
There are lots of very specific very unique processes out there. I’m sure there’s somewhere that has particularly high constituents of interest and a process for it that works for them.
Whether it’s widespread and needed I don’t know.
I do know that cost is a relative term. A manager of a half million gallon a day plant will cry about spending 15 grand on a broken pump. A 20 million gallon a day plant usually has spares on the shelf and considers it part is maintenance.
SoigneBest t1_iwgz3u7 wrote
Please eli5- a low effluent turbidity.
Also could tell us the reasoning of moving from gas to liquid Cl?
gunplumber700 t1_iwh4cia wrote
Turbidity is the cloudiness or opaqueness of water. Essentially how clear it is, an indicator of how much stuff is in water.
Effluent is water leaving somewhere, the context in which I used it is leaving the plant.
Chlorine gas is cheap and effective as a disinfectant, but is one of the most hazardous substances to work with. I’m a little rusty from being out of the industry since I was forced out of my job, but the osha limit is 1ppm over a 15 minute period and the idlh (immediately dangerous to life and health) threshold is 10ppm. It expands roughly 430 times it’s volume when moving from liquid to gas, a small leak can quickly fill a room and incapacitate someone. This is relative to
Most people that don’t control the budget for things like that prefer some type or variation of sodium hypochlorite (bleach, much safer) because it’s much safer to work with.
SoigneBest t1_iwhos0x wrote
Thank you for the great explanation and I didn’t want to assume.
Oh so they’re moving to liquid sodium hypochlorite, not to using liquid chlorine. Knowing that chlorine is a gas under normal circumstances I was curious why would water treatment plants choose to move to it. Now liquid “bleach” makes sense from a defect and cost standpoint.
Water is so essential to our very being and waste so much of it.
markerBT t1_iwhe0sn wrote
I lived in Orange County where potable water is treated waste water. So water from the WWTP goes to the water district's potable WTP which they then feed into the aquifer. They use RO. I also worked in the water industry though not as an operator.
How much is the loss in your district's distribution? There is financial benefit in fixing NRW, unless it's already quite low.
spudmarsupial t1_iwhjsg7 wrote
I'd be worried about a buildup of a specific chemical they didn't know to test for.
Ratnix t1_iwi3op5 wrote
>For example the average wastewater plant does not produce an effluent turbidity low enough to meet federal drinking water requirements
Why would they though if it's not going to be treated for drinking and instead be dumped back into the water cycle to be treated further down the road?
I understand what you're saying but i think it's that way simply because they don't have to do any more than that. If it was going to be drinkable water i believe it would be treated to the standards needed.
gunplumber700 t1_iwid8w8 wrote
Do you know how wwtp’s work? It’s not as simple as turning up polymer dosing. Most processes and plants could probably handle it, but not without major upgrades.
The average wwtp has a hard enough time managing effluent quality during “high volume rain events” let alone the hundred year flood that seems to happen every 2 years now…
Add in old, antiquated, crumbling systems, poor planning and upgrading of wwtp’s and it’s not something that’s realistically going to be widespread.
This is for places like LA (who steals water from everywhere else) and Las Vegas. Look at LA’s water loss. In my 5 minute search it looks like they use 10,999 MILLION gallons of water a month. Their water loss is 7%. That means the lose 770 MILLION gallons of clean treated water a month. 770 MILLION gallons of clean potable water is wasted. We’re going to clean and reuse wastewater but we can’t even keep from losing clean water? I don’t think so. When LA stops stealing water from everywhere and they start doing this I’ll believe it.
Ratnix t1_iwitczq wrote
>Do you know how wwtp’s work?
Yes. We do water treatment at my work and I work with it.
>but not without major upgrades.
Of course. But again, why would they do more than they absolutely have to right now if people don't want to drink treated waste water?
gunplumber700 t1_iwiwp6f wrote
I literally told you why. Obviously you’re not an actual water plant worker or you wouldn’t be asking something so stupid right after I told you. If you were you wouldn’t have asked to begin with.
You literally are arguing with yourself right now.
S-contra t1_iwodq94 wrote
It's funny you bring up cost. If you're in the water sector you know the biggest impediment to dealing with non revenue water is the cost of pipe replacement vastly outweighs the value of lost water. My utility estimates we lose around 10-20% of our water to leaks/old pipes, which amounts to several million dollars a year in lost revenue and billions of gallons of water. That sounds insane right? Of course the cost of fully replacing all the past service life lines is in the billions, thus the driver for spending all the capital is tough to sell to rate payers. As water professionals it's our job to evaluate the best health outcomes for our customers against the reality of infrastructure costs that rate payers will accept. Basically if the solution someone is peddling for improving water security involves building a bunch of pipelines (eg. piping Mississippi out west) there's almost always a more economical alternative.
DPR has a huge value proposition in many areas because you can avoid a ton of cost from additional distribution infrastructure. Comparing the non-potable reuse system (purple pipe) in California, which is estimated to cost 8k/acre-ft, while building a full scale water purification plant like San Diego is around $500-$600/acre foot. This compares very favorably against desalination ($1000>), ipr and especially building new reservoirs (which in drought stricken areas really doesn't do much good).
I see some folks have brought up phaceuticals and other trace chemicals, another great benefit is dpr systems using UF to RO will exclude most of these organic compounds, pfas included.
Of course in places where water scarcity isn't a driver, added treatment systems will be excessive, but there are increasingly regions of the country experiencing long term drought and the need to secure stable water supply. In many cases, the costs make sense
gunplumber700 t1_iwpw40w wrote
The bigger point is look where source water comes from in LA. Look at all the water they steal from everywhere else. Don’t claim you NEED water if 10-15% of it gets thrown away.
If you went to a gas pump to fill your 20 gallon tank, paid for 25, but still only got 20 would you say there’s a problem? Why it’s acceptable in this industry BeCaUsE iTs ExPeNsIvE is beyond me.
Failing to maintain a distribution system because you don’t want to pay to fix it is just neglect. Regardless of whether poor management practices have set the precedent it’s ok to be negligent they still need to be maintained.
Rate payers will always complain whether valid or not. Years of poor managing and failing to raise rates creates its own set of problems. Incompetent water managers acting like rates can stay the same forever is half the problem.
thecr0tch t1_iwh1r7y wrote
So it seems like it would be best to NOT drink tap water?
gunplumber700 t1_iwh9o5t wrote
Tap water is generally safe. Yes, mains break, places occasionally (very infrequently) f up, but overall it is safe.
The source water for drinking water are reservoirs, wells, etc.
Wastewater enters the sanitary sewer system from toilet water, shower water, sinks, etc and goes to a wastewater treatment plant for treatment then to the environment. Some places use wastewater plant treated water to make recycled water. This is generally a cleaner and more treated version of that same water and used for for grass, golf courses, certain agricultural resources, etc… it’s not used for drinking water unless your an astronaut drinking your own recycled urine in space.
dbag127 t1_iwhbavd wrote
No, it's best not to drink the effluent of a wastewater treatment plant. In the US, wwtp effluent is generally cleaner than the natural water body it flows into, which is where a drinking water treatment plant gets it's raw water.
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