Questions tagged [water-treatment]

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

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1answer
38 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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2answers
37 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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25 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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40 views

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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1answer
57 views

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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1answer
205 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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2answers
60 views

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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1answer
28 views

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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2answers
137 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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61 views

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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1answer
31 views

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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1answer
18 views

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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84 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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1answer
30 views

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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38 views

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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1k 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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1answer
29 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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96 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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1answer
41 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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1answer
71 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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1answer
710 views

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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2answers
1k 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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1answer
107 views

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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1answer
33 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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29 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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89 views

Adjustment of calcium, magnesium and alkalinity in drinking water?

It's been a long time since I did any molar chemistry in school and despite doing a lot of reading on the subject this week, I am making a mess of some basic calculations. I hope that someone who ...
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1answer
96 views

Making hard water

Does anyone know how to make hard water with a hardness of 200+ ppm in terms of $\ce{CaCO3}$? I live in Seattle and we have very soft water and we need hard water for testing purposes. Obviously you ...
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1answer
34 views

How can I reduce sodium chloride levels in water, without removing other minerals?

How can I reduce sodium chloride levels in water, without removing other minerals? Good day, I make a sole from Himalayan Salt which I add to my Reverse Osmosis treated water to ensure my body isn't ...
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1answer
34 views

Is it stupid to put used acid into a pool after cleaning the chlorinator? [closed]

I have a salt pool, and when the chlorinator salts up with calcium, I clean it with a diluted acidic solution. What happens to the acidic solution after the reaction happens? I.e., does the pH change?...
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how can I predict the rate of water ions precipitation on a surface?

Consider a titanium pot that contains 1kg water with the following ions: $[Ca^{2+}]=22000$ ppm, $[Mg^{2+}]=1500$ ppm,$[Sr^{2+}]=791$ ppm,$[Na^{1+}]=48000$ ppm,$[Cl^{1-}]=120000$ ppm,$[SO_4^{2-}]=...
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2answers
93 views

Waste water treatment [closed]

This is a very simple question: Why are oxidized compounds generally thought to be less toxic/polluting than reduced species? This is used in waste water treatment where oxidizing agents (such as ...
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159 views

Why we don't we save water by boiling the contaminated water to get the pure steam?

I see lot of drinkable water wasted in household and industrial activities, water usually gets contaminated with detergents(and other household materials),chemical effluents released from factories . ...
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2k views

How does chlorine in water evaporate?

Drinking water (e.g. from your home's tap) is spiked with chlorine, for an amount of just some ppm. Purpose of this operation is to kill bacteria, for our health. Background: chlorine in water is ...
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2k views

The effect of pH and solubility on coagulation in water treatment

In water treatment, a specific pH range must be met in order for the process of coagulation to occur properly. Sources have stated this is due to the pH affecting the solubility of the coagulant, but ...
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1answer
78 views

How does the water pollutant sodium nitrate affect the concentrations of other ions in tap (dam) water? [closed]

Context In my assignment I've been given two water samples from the hinze dam. The first sample has been untouched, however the second has been contaminated with an unknown ionic compound. To ...
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1answer
48 views

Biological contamination from ground

I took samples of tapwater in order to examine concentrations of Escherichia coli and enterococcus in a rural area. I was told, from an analytical lab, to take samples in four sterilized vessels ...
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1answer
62 views

Is Reverse Osmosis Sanitizer safe to use? [closed]

The Sanitizer is called Sani-System (For Reverse Osmosis). The purpose is to get rid of the bacteria within a Reverse Osmosis system (Priority is the tank: that holds the water) -- edit Safe meaning ...
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0answers
61 views

Amount dry acid or sodium bisulphate needed for varying hardness values [closed]

My question is regarding the use of sodium bisulphate to lower the hardness of water. I am attempting to come up with a label to let consumers know how much product (dry acid or sodium bisulphate) is ...
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2answers
852 views

Water cooling by evaporation

For many years of drinking water has been cooled in hot climates by evaporating it from the surfaces of canvas bags or porous clay pots. How many grams of water can be cooled from $\pu{35 ^\circ C}$ ...
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1answer
186 views

How does Ozone disinfect water? [closed]

How does ozone remove the impurities in water? I know that there is a process which some European countries use water purification systems based on ozone. It would be beneficial if you could provide ...
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1answer
97 views

What are the ways to make radioactive water drinkable again? [closed]

Let's say survivors in the area contaminated by radioactive fallout need to somehow process the water from rivers, rain or pipes. How could they go about it? Is it even possible to 'remove ...
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1answer
444 views

Can iodine be used to disinfect water?

I think it was Nat Geo.. Not sure exactly.. Where I heard, years ago, that a drop of iodine can be used to disinfect water of say, 1 litre. But isn't chlorine used to kill all bacteria? I mean I don'...
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438 views

Which is more likely to form: silver chloride or silver phosphate?

If silver nitrate is added to an aqueous solution (such as tap water) that contains both chloride ions and phosphate ions, which precipitate is more likely to form: silver chloride, silver phosphate ...
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563 views

Remove only salt from salt water

I have a bottle of salt water I collected on a local beach. I want to see what is in it, apart from water and salt. If I boil the whole bottle and wait for it to evaporate, mostly salt will remain. I ...
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58 views

Magnetic Water Softener

I've been asked to install some kind of technology to a building with 40 rooms to soften the water. Browsing through the product catalog I found this so called "Magnetic Water Softener", however ...
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2answers
2k views

Does adding slices of lemons to water reduce its chlorine content?

Often restaurants add slices of lemon to water. They seem to make the water taste better and perhaps reduce or at least cover up the chlorine taste. I've heard that Vitamin C tablets can be used to ...
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618 views

Can Aquatabs be used to clean swimming pool water?

Can Aquatabs be used to prepare/chlorinate water for swimming? They are used to clean water for drinking so is it safe to assume that if used in proper quantity they can also clean water for ...
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1answer
190 views

What happens with ammonia ions in tap water after they are separated from chlorine?

Tap water is increasingly treated with chloramine which is composition of chlorine and ammonia. Chlorine can be removed by catalytic activated carbon and ammonia ions are then left. What happens with ...
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557 views

How to effectively remove chloramine from tap water

I am looking for a way to remove or substantially reduce chloramine from tap water. From what I learned chloramine is created when ammonia is added to chlorinated water. It is now a method of choice ...
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1answer
409 views

DIY spectrometers limits as a water quality sensor

What pathogens or harmful stuff IN WATER can you detect with these homemade video spectrometers (webcam) + UV light? https://www.youtube.com/watch?v=IA5BTD-aelo I'm trying to do a cheap spectral ...