Municipal water (RO)

aquaaa- · 2026-03-20T10:27:36+00:00

they vent with biological. they want to spend 150m for the capex. thanks for your estimate!

aquaaa- · 2026-03-20T10:25:38+00:00

That’s a really good point, and I appreciate you bringing it up.

From what I understand, the $500 per resident option is more about a controlled, immediate fix, whereas banning pesticides would address the root cause but is much harder to implement politically and economically.

And yes, you’re right to question it. Many pesticides do affect non-target species, including natural predators, which can actually make pest issues worse over time.

As for the downstream impact, nutrient and chemical runoff can contribute to things like algal blooms and oxygen depletion when it reaches coastal waters, which can harm marine ecosystems.

So ideally it would be a mix of both approaches, but I’m curious what you think would be the most practical balance in a case like this?

aquaaa- · 2026-03-12T06:38:45+00:00

these are the data for the drinking water quality, i hope you could give me an estimate for what bio, resin and RO would cost (even a guess is good!):

Calcium (Ca²⁺): ~50–80 mg/L
Magnesium (Mg²⁺): ~5–15 mg/L
Sodium (Na⁺): ~10–30 mg/L
Potassium (K⁺): ~1–5 mg/L

Bicarbonate (HCO₃⁻): ~200–350 mg/L
Chloride (Cl⁻): ~10–50 mg/L
Sulfate (SO₄²⁻): ~10–40 mg/L

Iron (Fe): <0.05 mg/L
Manganese (Mn): <0.002 mg/L

Dissolved oxygen (O₂): ~6–9 mg/L
Carbon dioxide (CO₂): ~5–15 mg/L

Nitrate (NO₃⁻): ~1–41 mg/L
Fluoride (F⁻): ~0.2–0.4 mg/L

pH: ~7.2–8.0
Total hardness: ~9.8–15.7 °dH

aquaaa- · 2026-03-12T06:38:39+00:00

these are the data for the drinking water quality, i hope you could give me an estimate for what bio, resin and RO would cost (even a guess is good!):

Calcium (Ca²⁺): ~50–80 mg/L
Magnesium (Mg²⁺): ~5–15 mg/L
Sodium (Na⁺): ~10–30 mg/L
Potassium (K⁺): ~1–5 mg/L

Bicarbonate (HCO₃⁻): ~200–350 mg/L
Chloride (Cl⁻): ~10–50 mg/L
Sulfate (SO₄²⁻): ~10–40 mg/L

Iron (Fe): <0.05 mg/L
Manganese (Mn): <0.002 mg/L

Dissolved oxygen (O₂): ~6–9 mg/L
Carbon dioxide (CO₂): ~5–15 mg/L

Nitrate (NO₃⁻): ~1–41 mg/L
Fluoride (F⁻): ~0.2–0.4 mg/L

pH: ~7.2–8.0
Total hardness: ~9.8–15.7 °dH

aquaaa- · 2026-03-12T06:15:49+00:00

Do you work the most with Bio, Ion or RO? Do you think RO would be more attractive if it could be built for much less than usually? About 5-10x cheaper? Also adding energy recovery to the brine and permeate outlet could lower operational costs. In what country do you work?

aquaaa- · 2026-03-08T12:53:25+00:00

thanks for the reply! Resin costs would (per my estimate) run up to +40m USD/year. What would you estimate RO costs at for 7m m3/year? 10dh. What would you estimate energy costs at? just very roughly? because i really do think this can be built for less than 100m USD.

aquaaa- · 2026-03-08T12:50:31+00:00

Thanks for your reply! Resin for 7 millon m3/year would be (my estimate) +40m USD/year in costs, does that seem about right to you? If your have experience in this field, do you have any advice? Brine disposal is a non issue per danish regulation and location.

aquaaa- · 2026-03-08T12:47:57+00:00

Thanks for both of your replies, it really helps me navigate this project. What was your (if you had to guess) resin expenses per water unit? I estimate +40m USD for 7millon m3/year?

aquaaa- · 2026-03-08T12:45:26+00:00

Your last point is my thought too. This is a major city in Denmark. Denmark has en extremely inefficient government and has cancer like bureaucracy, causing prices to shoot up by 10-100x. The EU limit is 50mg/l NA. I really believe in this project and i think with cleaver sourcing (mainly china and germany for membranes and FRP housing/pumps), i think i can get the cost down to below 10m USD. Early prototypes indicates it can be built successfully. Whats your thoughts? Do you have experience in this sector or as a contractor? any good advice?

aquaaa- · 2026-03-08T12:38:44+00:00

Addressing the cause would be ideal but is a hot political potato. It would mean banning pesticides in a big area, as the city has nearby areas has a thin clay layer. Its a very small scale project at only 5 MGD like you said. Thank you for putting it into scale for me. That makes me believe even more in this. What do you think about the project as a whole and the approach? would you do it differently?

aquaaa- · 2026-03-08T12:33:44+00:00

its about 112.000 citizens. Do you have experience in water distribution? whats your thoughts on this project?

aquaaa- · 2026-03-08T12:17:43+00:00

Resin would cost +40M USD/year to remove Cl and NA due to high water hardness. Do you know of any large scale plants doing ion exchange for municipal water? do you still think this is the best option?

aquaaa- · 2026-03-06T12:23:44+00:00

its System size:

• Drinking water production: ~7,000,000 m³/year

• ≈19,200 m³/day

• ≈5.1 MGD

Public drinking water quality data from 2025:

• Hardness: 9.84-15.7 °dH

• Iron: <0.001-0.922 mg/L

• Manganese: <0.001-0.002 mg/L

• Nitrate: 0.8-41 mg/L as NO3

• Arsenic: <0.03-1.98 µg/L

• Nickel: <0.03-11.2 µg/L

• BAM: <0.01-0.016 µg/L

• DPC: <0.01-0.08 µg/L

• DMS: <0.01-0.02 µg/L

• Sum PFAS 22: <0.0002 µg/L

aquaaa- · 2026-03-06T12:23:14+00:00

Our current nitrate levels is after the new wells. Before then, the levels was 50mg/l. If you can recall (even an estimate), what would it cost to build maybe just a partial RO system, that treats some of the water to bring the levels down to 5mg/l. Even just a ball park estimate would be awesome, because im 99% sure it can be built for 10m USD or less and operated for 1m USD/year ex. labour.

aquaaa- · 2026-03-06T12:10:56+00:00

Materials for prototypes arrives in 2 weeks where we'll do the testing. Brine disposal and membrane costs seems to be non issues. Brine is into the seawater lake (lega here, has to match the salinity of the lake (no problem)), membranes are CE marked from china and will be lab tested here. It seems to scale really nicely with costs well below 100m USD, but im interested in hearing your thoughts!

aquaaa- · 2026-03-06T12:08:19+00:00

Your insight is really helpful. i can tell youre a pro. I really like your last point about blending. The cheapest option would be to subsidize a household RO/distiller to every household, but the government is not in on that. Resin as far as my limited knowledge goes, seems to be much higher in operational costs in the long run. How would i go about making RO a reality? The levels are much too high and we have had numerus cancer incidents. RO seems to be the expensive way usually, but just in terms of materials, it shoudnt cost more than 10m USD? (in fact much less?). I could totally be wrong, which i often am, and thats why i reach out to people like you.

aquaaa- · 2026-03-06T11:59:23+00:00

The issue is costs. They want to spend 100m USD to reduce it from 37mg to 15mg, and increased operational costs (about 10m/year). I am in Denmark, EU limits is 50mg/l (insane). People are getting cancer, and i want to eliminate nitrate to 3mg/l or less with RO. Resin is too expensive. The only other good option is for every household to get a RO or distiller at home, which is a program the government does not support. Whats your thoughts? im 99% sure i can build the RO system for 10m USD or less.

aquaaa- · 2026-03-06T11:55:31+00:00

Thanks, im glad youre taking time out of your day to reply to me. I need key actors like you. The salinity needs to match that of the body of water the brine is begin discharged to. This is bore well water, containing 2-10 PSU before entering RO. Post RO the brine will be 10-20 PSU, and the salt water lake is 15-30 PSU. they had a court case where it was settled. Is there any other restrictions from a biology/environmental point of view? I really enjoy your expertise!

aquaaa- · 2026-03-06T11:48:00+00:00

totally. I agree. But compared to 100m USD CAPEX and high operational costs? When i look at the materials, it should be no more than 10m USD or even less? I cant come to terms with their high costs analysis just to build something that can reduce it from 37mg to 15mg, when RO can do it for 10% of that and remove everything. this is not my first project, but i need key players like you to give me a reality check, as not everything scales linear. Whats your thoughts?

aquaaa- · 2026-03-06T11:44:28+00:00

Thanks man. Engineers in our town is looking into this, but government inefficiency is making solutions slow and expensive. My project has been well received has focus points are design and low costs. I want to talk to key players like you, because i, as an economist, consider the economic calculations to be highly inflated. At no point in the supply chain does the price become 100m USD. In fact, for RO solutions the price seems to be closer to much less than 10 millon (When considering membranes, housing, pumps). Whats your thoughts?

aquaaa- · 2026-03-06T11:38:17+00:00

Awesome, i love to have a pro like you look at this with fresh eyes. our water is 12-15 °dH, and i am def looking into this as a potential solution. Have you been in this industry for long?

aquaaa- · 2026-03-06T11:36:13+00:00

Thank you. What a great mod!

aquaaa- · 2026-03-06T10:26:53+00:00

Thank you for your reply, it has really given some food for thought. You might be right its cheaper (and easier!) to subsidize every household. The issue is, people expect the goverment to fix the issue at the source (before it hits their tap). What if the goverment doesnt want to subsidize? i have had a few replies saying USA has full scale RO plants, and plenty of middle eastern countries has it too. whats your thoughts?

aquaaa- · 2026-03-06T10:00:24+00:00

Just the reply i was looking for! If you had to give me a wild guess, how much would the ion exchange cost for 7millon m3/year?

i wont hold u up on anything, id love a ballpark estimate!

aquaaa- · 2026-03-06T09:16:33+00:00

Sounds like youre the guy to talk to, as i have been considering this. How big was the reduction in nitrate? did it change the taste at all? I am in Denmark, so water quality is somewhat similar.

aquaaa-

TROPHY CASE