Questions tagged [water-treatment]

Questions about any process which makes water more acceptable for an end use.

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Fluoride coating of aluminum oxide [closed]

I'm currently reading into fluorine flow water filtration & desalination [1]. The idea is to use fluorines to have minimal friction to water while repelling ions. One of the use cases is using ...
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What happens to sodium and calcium after hypochlorite salts are exposed to the sun?

A hypochlorite salt (sodium, calcium) needs to be added to a swimming pool every one or two weeks. This pool "shock" neutralizes algae and other contaminants before they have a chance to ...
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Is calcium hypochlorite as effective as sodium hypochlorite in sanitizing a swimming pool from algae?

Question From this question we know that what swimming pool stores refer to as "liquid chlorine" (sold in 10 gallon jugs) is most likely sodium hypochlorite ($\ce{NaOCl}$). In the spirit of ...
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Are liquid chlorine and super-shock chlorine the same?

To shock a swimming pool one uses either calcium hypochlorite ($\ce{Ca(ClO)2}$), commonly sold from at least one major brand in pouches, or the more obscure "liquid chlorine". I'm saying &...
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1 answer
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TV Program Said Remove Some of Chlorine in Water By Putting Hose On Fine Spray

A UK TV program suggested that some of the chlorine in tap water can be removed if you fine spray it from your hose, such as with un upside down fine sprayer. Is this true? How effective is it?
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Determining the concentration of chloride in water using ppm vs mg/L

I'm currently testing my drinking water for chloride, but I'm running into issues on units and what is an acceptable level of chloride in drinking water. According to the CDC the acceptable level of ...
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-1 votes
1 answer
124 views

Why is desalination waste usually disposed back into the sea instead of converting it into chemical products?

I was reading about the desalination processes such as reverse osmosis and capacitive deionization and their alternatives. They all work on removing ions from water and disposing them back to sea/...
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1 answer
134 views

I want to dechlorinate my tap water to use in an organic garden. I've purchased a product called Seachem Prime that is typically used for aquariums [closed]

I purchased a product called a seachem prime to dechlorinate my tap water so I can use it in my organic garden inside. I want to know if the product itself is safe to use on my plants and if there ...
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Can a TDS meter have a false initial reading due to some instrument artifact?

I have total dissolved solids (TDS) meter which is built in to a water purification system and this meter always reads high, around 90-100 when the machine is turned on, but over the next 30 seconds ...
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The use of far-infrared ceramics for water purification?

I am struggling to understand how exactly far infrared ceramic balls help purify the water. It is stated that active ceramic taormine balls help purify the water by forming a 2 micrometer wavelength ...
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Characteristics of metals compatible with semiconductor grade Ultra Pure Water (UPW)?

I am looking to build a water conductivity sensor for semiconductor grade Ultra Pure Water (UPW). UPW conductivity sensors already exist, but because of price and low water volume I need to fabricate ...
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1 answer
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Why isn't there hydrofluoric acid in fluoridated water? [closed]

From what I've read, when water is fluoridated it's done so either by $\ce{NaF}$ artificially or $\ce{CaF2}$ naturally. If this is correct, shouldn't the reaction $\ce{CaF2 + H2O -> CaO + 2HF}$ ...
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How to compute a needed volume of solution to adjust to a target pH

I am a software engineer and I would like to solve a chemistry problem. I have revised the subject a bit to understand the basics :) My goal is to maintain a constant pH of a water tank (tap water). I ...
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-2 votes
1 answer
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Why do we clarify water with alum, but beer/cider/wine with bentonite?

My understanding of clarifying (floccing) liquids is that we add a mineral with an electric charge, which attracts suspended particles (like bacteria) which I assume have the opposite charge. The ...
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Reaction of propanoic acid with chlorine used in wastewater treatment

I'm asked in a problem to write down the equation of the reaction of propanoic acid with chlorine used in wastewater treatment: $\ce{CH3-CH2-COOH +Cl2}$. The problem also states that, in this reaction,...
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Waste management of hazardous solvents

How should one safely dispose of chemicals like dichloromethane, toluene or acetone that were mixed with water? Is the water contaminated to a degree that it needs also treatment? For example ...
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Hazardousness of Chlorothalonil & metabolites in shower water? [closed]

Recently it came out, that in some parts of Switzerland (where I live), there is Chlorothalonil & metabolites/breakdown-products of it in the drinking water. Yikes. Problem is, chlorothalonil ...
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Total concentration conversion

when dealing with waste water and the total values of P, N, C are given in ppm units, what molecular weight is used for converting from ppm to molar? for Example- what will be 12 ppm of P(T) in Molar ...
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2 votes
1 answer
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Hard water filtration

Why does hard water have to pass through the cation exchange resin first followed by the anion exchange resin? Why can't it be the other way around?
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1 answer
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What about sodium triphosphate in drinking water?

Recently, at my place, a sort of filter for hard water was installed. They told me that it contains sodium triphosphate which is dissolved into all the water that enter home, i.e. both cold and hot ...
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1 answer
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Do antimicrobial abilities of copper boilers decrease over time?

As copper boilers age and develop oxide buildup, does this lessen the copper's antimicrobial abilities in killing bacteria? I was thinking since that coating would be on the copper, there would be ...
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For what chemical purpose did soldiers in WW2 carry small ion exchange resin columns in their survival kits?

My textbook [Chemistry Live, Declan Kennedy] states that ''During WW2 small ion exchange resin columns were part of a soldier's survival kit.''. I can't find any further info about this online or ...
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Any idea why tap water goes stale overnight? [duplicate]

We have great tap water here in Hungary. My only problem that it goes stale overnight sometimes in some glasses or sometimes even the 2L water boiler has this problem too. But microbes cannot resist ...
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2 answers
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Is there a safe way to neutralize bleach at home [closed]

I don't want to simply replace one hazardous chemical with another. The bleach is stubbornly clinging to my shower walls and I feel its effects every time I take a shower. Ascorbic acid seems like the ...
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1 answer
545 views

Why is RO water more corrosive?

According to several articles from the American Water Works Association, permeate from RO should be stabilized in terms of pH and hardness to avoid corrosion of the distribution piping. How does ...
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2 answers
194 views

What are the properties of water in glaciers? [closed]

Does water from glaciers have many minerals (hard water) or would it be considered pure or distilled water?
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1 answer
145 views

Devarda's alloy procedure

Hello dear I have a small question I want to do kjeldahl distillation for a 100 mL sample of water after reduction with devarda's alloy to measure the concentration of nitrate nitrogen... I want to ...
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Generating hypochlorous acid for disinfecting water using HClO2

I use a product that contains $\pu{700 ppm}$ of $\ce{HClO}$ to disinfect water at $\pu{1 ml}$ per $\pu{1 l}$ and let it rest for about $\pu{2 hrs}$ before I use it so there is no $\ce{HClO}$ left ...
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How can I measure the scale in water?

I have hard water in my house. All the taps have tartar around. It generates some problems in some of my home appliances so I have bought polyphosphate salt but when I boil water I don´t get the ...
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4 votes
1 answer
223 views

TKN: Why are they called Missouri tablets?

When analyzing for Total Kjeldahl Nitrogen (TKN), you can make a copper sulfate digestion solution in the lab or purchase a variety of pre-prepared digesting tablets for example on VWR. My question is,...
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2 votes
2 answers
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Heat effect on diluting concentrated NaOH solution

I am an engineer in water treatment and have a chemistry question. In water treatment we dose $32\%$ sodium hydroxide solution for $\mathrm{pH}$ adjustment and there is a concern that our dosin lines ...
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-1 votes
1 answer
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Variations in solubility of total dissolved salts in water with temperature [closed]

I want to know the solubility of "total dissolved salts" or mainly Calcium Chloride and Magnesium Chloride causing hardness of water. Is this data published anywhere at different temperatures?
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2 answers
605 views

Can Na2CO3 remove temporary hardness of water?

This was asked in my test and I remembered that all compounds that can remove permanent hardness of water can remove temporary hardness of water also. But my teacher marked it wrong and I cannot find ...
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Could the Superoxide Radical Anion Be Responsible for the Removal of Chlorine Dioxide Used to Treat Natural Waters?

Some background facts: $\ce{ClO_2}$ is a gas that is highly soluble in water (some 8 g/L at 20 °C). However, per Wikipedia , to quote: It does not hydrolyze when it enters water, and is usually ...
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0 votes
1 answer
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Creating 1L of 1000 ppb stock solution of Pb2+

I’m testing on samples that require a concentration of 1000 ppb (or 1 mg/L) of Pb 2+. My first thought was to simply dissolve 1 mg of Lead nitrate in 1 L of deionized distilled water to create 1 L of ...
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1 vote
1 answer
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Methods to quantify lead(II) concentration in water on the ppm/ppb level

While there are several ways to quantify metal concentrations in water, a lot of them are only specific to select metals. For example, there is the orthophenanthroline method for quantification of Fe(...
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0 votes
3 answers
119 views

Is it possible to measure light absorbance for analysis of lead concentration without photospectrophotmeter

I’m designing an experiment which requires I measure final and initial lead concentrations for the determination of aqueous lead uptake by different mediums. Because lead concentrations would be ...
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2 votes
1 answer
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How concentrated does the analyte solution need to be in order to perform a (chelatometric) titration

I’m currently investigating a method to chemically pretreat cellulosic waste as bisorbents for enhanced uptake of lead in water. I intend to measure the initial and final concentration of water to ...
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4 votes
0 answers
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membrane for a reverse osmosis desalination experiment

We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some ...
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0 votes
2 answers
2k views

How much of Sodium dichloro-s-triazinetrione dihydrate should I use to replace bleach? [closed]

I am trying to determine how much sodium dichloro-s-triazinetrione dihydrate powder I should add to water to create a dilution that can be injected into my water supply to react with the Hydrogen ...
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0 votes
1 answer
65 views

Using charcoal to clean water [closed]

I have read about charcoal being used to clean water before it is then boiled or mixed with a UV light stick. I have some questions about this: 1) Does it have to be activated charcoal? 2) Can ...
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-3 votes
3 answers
104 views

Is boiling tap water a must to destroy human mucus, proteins, fats, sugars and nucleic acids it may contain?

I understand that humans consume tap water which are chemically treated after pumped from natural or artificial reservations. Sometimes people contaminate these reservations by spitting, pissing and ...
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5 votes
3 answers
1k views

Tap water pH adjustment using citric acid

I'm treating tap water to prepare fresh water suitable for the aquarium. I receive water with $\mathrm{pH}~7.6$ from a dechlorinator and I need to lower ammonia level. For every unit decrease in $\...
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1 vote
1 answer
57 views

Clarifying question about chloride ions, water softening & corrosion

I have a question regarding the use of NaCl as a water softener. Recently i was asked to comment on a series of test results from a water softening device were a lot of corrosion had occurred post ...
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1 vote
1 answer
114 views

Precipitation of water-insoluble materials from shower or laundry greywater

I am currently working on a project to build a filter that aims to separate or salt out the 'dirt' in shower or laundry greywater. The ideal result from this chemical reaction will be such that the '...
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1 answer
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What happens when you mix Hypochlorous Acid (HClO) and Hydrogen Peroxide (H2O2) in water (H2O) [closed]

I currently use Hypochlorous Acid (HClO) in my plant reservoir. I really want to use Hydrogen Peroxide (H2O2) also. Is there any reason why not to use Hypochlorous Acid (HClO) and Hydrogen Peroxide (...
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3 votes
2 answers
4k views

Dangers of using activated carbon past its lifespan

Activated carbon (AC) is one of the most widely used media for water filtration. It's effective at removing chlorine taste and odor, and it's recognized as being safe. However, most activated carbon ...
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1 vote
1 answer
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Will sodium thiosulfate react with nitrate and/or nitrite ions [closed]

I am doing nitrate and nitrite quantification in raw water and treated water using a colorimetric method. The manufacturer of the instrument states that water with chloride will interfere with the ...
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0 votes
3 answers
91 views

Additive to an aluminum sulfate and water solution to lower pumping pressures

I am currently looking for a surfactant (powder form) that I can add to a solution of aluminum sulfate and water. My current solution is comprised of 34 gallons of water and 4 (four) 50 lbs bag of ...
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1 vote
0 answers
30 views

Do TDS meters measure HCO₃⁻/CO₃²⁻?

I am trying to add $\pu{2 g}$ of $\ce{KHCO3}$ to $\pu{20 L}$ of RO water $(\mathrm{pH} = 5.2)$ which theoretically it will add $$ \begin{array}{lr} \hline \ce{K+} &\pu{10.32 ppm} \\ \ce{HCO3-} &...
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