How to Purify Muddy Water





Introduction: How to Purify Muddy Water

About: I like to make things more simple with easily available resources. My favorite quote: A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write...

One of the major problems we face during camping trips is finding clean water suitable for drinking and cooking. Even though you select a camping site near a water source, one can not be sure that the water is fit for consumption. Further, what can one do in the event of an unpredictable rain, muddying the entire water source...?

Do not worry. This Instructable will take you through the steps involved in cleaning and purifying the muddiest of muddy water and make it suitable for drinking and cooking.

Step 1: Chemicals Required

Aluminium Sulfate

Aluminium Sulfate, Shortly known as Alum, when added to raw water reacts with the bicarbonate alkalinities present in water  and forms a gelatinous precipitate. This floc attracts other fine particles and suspended material in raw water, and settles down at the bottom of the container. The water over this sediment is almost clean other than some fine particles dissolved in it.

Alum is in a crystallized form which you can powder and store in a clean glass container.

Bleaching Powder Solution

Bleaching powder or chlorinated lime is used to disinfect the water from bacteria. The chlorine present in the bleaching powder solution kills almost 90% of the bacteria present in water.

Bleaching powder also known as Calcium hypochlorite is in a powdered form. Add one or two teaspoons of the powder in a glass bottle, add water and mix well. Use a metal cap for the container as it may corrode plastic cap.

Both Alum and Bleaching powder are commonly available in most of the grocery stores.

Step 2: Water Sample

Look at the water collected from the source after heavy rains. It is muddy and also contains lots of floating material. Now let us see how we can convert this dirty water in to clean drinkable water.

Step 3: Treatment of Muddy Water With Alum

Coagulation and Sedimentation

  • Here, I have collected the muddy water in a bucket, poured more water to overflow and brushed away most of the floating material with hand.
  • Using a fine cloth, filtered the muddy water into another vessel. The filtered water contains no floating material and less silt.
  • Took about five liters of water in a plastic bucket and added half a teaspoon of powdered Alum (that is about 50 mg which works out to 10 mg per liter of water) and stirred well.
  • This bucket of water needs to be kept still for about 6 to 7 hours so that the sediments get coagulated and settles down at the bottom.

Step 4: Draining Clean Water

Drain out Clean Water

After about seven hours, most of the dissolved particles have settled down at the bottom of the bucket. Drained out the clean water into another vessel very slowly without disturbing the sediment.

About half a liter of water is left out in the bucket with the sediments.

The water collected thus may still contain some fine dissolved particles, which can be removed by filtration. If you carry a small water filter during camping, you can fill this water after disinfection (next step) to get more pure water.

Step 5: Disinfection


The clean water we got by sedimentation still contains lots of bacteria, so it needs to be disinfected before being used. Here, I have used home bleach solution, which contains Chlorine.

The prescribed normal rate is about 2 drops of bleach solution per liter of water. So, I have added about nine drops into the water in the vessel and stirred well. This water may smell little bit of chlorine. Either keeping it open to air and intermittent stirring for about 30 minutes or using a portable filter to further purify the water will remove the chlorine smell.

The chlorination process kills almost 90% percent of the bacteria present in the water. Now I got about four and half a liters of clean water which I can use for cooking and drinking during my camping trip.

Step 6: Experiment in Plastic Bottles

I have carried out the cleaning process in a two liter water bottle. Here I have increased the Alum content to about 15 mg per liter of water. the outcome seems to be better than with 10 mg per liter of water.

Step 7: Foot Note

Some tips on usage of Alum and Bleach solution:

  • The prescribed dosage of Alum varies from 5 mg per liter for a relatively clear water to 85 mg for a highly turbid waters like industrial waste. However, the normal dosage for drinking water is about 17 mg per liter.
  • The dosage of bleaching solution as 2 drops per liter is suggested considering 60 to 70 percent of chlorine available in the bleaching powder. you can increase or decrease the amount by smelling the chlorinated water. More chlorine smell, add some clean water. Add a few more drops in case of no smell.
  • Keeping buckets of water mixed with Alum overnight will give you enough clean water in the morning for use.
  • Over-dosage of Alum may cause temporary dizziness, diarrhea and vomiting (but not dangerous). So, take care while adding alum.
  • Bleaching solution is corrosive. Take care not to get your skin or cloth in contact with the solution.

So, Campers, do not forget to add a little bit of Alum and Bleaching solution to your camping kit next time. It may come in handy when you are in the middle of nowhere with only mud to drink



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    2 Questions


    Hi, I am a student and I have conducted this activity. The steps are fairly simple, I appreciate that. Just that at the end, is it that easy to obtain clear water which has a turbidity that low! I tried to compare the coagulation process between Aluminium sulphate( Alum ) and ferric sulphate. In both the situations, the water has not appeared that clear. This may be due to the dosage of chemical. But how did you calculate the amount (concentration) of chemicals used to achieve the clearness of the water. Is there a formula? Or trial and error method?


    Silver nanoparticles or Copper-silver oxide as long as the silver nitrate is washed carefully and removed could be an additive to kill fungi and bacteria.

    Downside Silver nitrate, Citric acid, etc can be expensive.

    Copper powder, and distilled water with silver nitrate works well.


    Note that you should avoid any water that is stagnant with this method. While Chlorine can kill most bacteria some like Listeria can be resistant to even high doses of chlorine (100 mg Chlorine an L).

    As a project with waste and water management, I found pond water had 6 million bacteria (Listeria) per ml Yikes. The infection causes a 25 percent death rate even with treatment. Listeria toxins are neurotoxins putting holes in the neurons causing them to self-destruct.

    Really good Instructable but this must be POINTED OUT.

    Also filtering (coffee filter) with carbon too may help as well.

    I trained in Biotech and Waste and water management at Algonquin College. This is an excellent Instructable tho. You could use IR waves from the Sun (Additionally) if you want to, to kill up to 99 percent organisms by leaving those bottles sealed in sun. They do that in Africa too. It does Help.

    :) Good luck with other reasearch similar to this!

    Pls advise quantity of Alum and Bleaching powder required to clean and disinfect 25 feet Dia Well and 12-15 feet water height.

    3 replies

    Instead of trying to purify the water in the well, pump the water through a pressure filter, chlorinate and then use it. If you want to treat the whole well, then take water sample and follow the guidelines in this instructable for determining the quantity required for total capacity of water in the well

    Sharing my experience of cleaning well water. Originally, the well was lined with simple bricks and mud. It was ok during summers & winters but, during monsoons huge amounts of dirty water would percolate even through the upper layer of bricks and form a muddy reservoir. This used to be treated with Alum dissolved in a bucket of water and then water sprayed into the well, practically every second day. This worked up to a level. Later one summer, we pumped out the well water and cement plastered the whole well right up to the bottom. Water had to be kept pumped out for three days till the cement solidified. Thereafter, as the water would now have to travel 25 ft through the earth it became fairly clean. Even then we still treat it with ALUM dissolved in bucket of water but more sparingly.

    The problem is getting the settled sludge out of the well. Some times for a day we pump very dirty water, which obviously must be the sludge.

    Now, we are putting the pump on a small pontoon with only one meter of suction pipe to avoid the sludge which can be extracted during summers.

    sir , your contact number please..

    As said in the article, bleach only gets around 90% of the nasties, something like Chlorine Dioxide would do the job, but in a survivalist situation, I guess if all you ahd was Alum and bleach from the store, it's better than drinking Balderick's coffee -muddy water.

    One thing I'll suggest, if you have another plastic bottle large enough, you could cut the bottom off of it, leaving the screw cap end alone, then invert the bottle, and place the muddy water to be cleaned in that, having supported the upturned bottle from falling over -say in another vessel/pot. Then, when the Alum has done its job, you can lift out the bottle, then unscrew the cap (now on the bottom) and slowly drain off the sediment without it mixing with 'clean' water.

    Very, very good Instructable. Thankyou for sharing.

    1 reply

    Hey, one heck of an ible good sir. Great information and presented very well. I actually just picked up some alum from my local grocer. It was surprising hard to come by, took three shops before finding it. I can't believe something this useful should be this hard to come by.

    1 reply

    Thank you for your nice comments. Alum is also used in Barber shops to apply on face after a shave. Good to know you got it from your local grocer.

    How do I purify a water well located beside a Soakaway

    1 reply

    Instead of trying to purify the water in the well, it would be better if you pump the water through a pressure filter, chlorinate and then use it for domestic purposes. Also, I would recommend to give a water sample to authorized laboratories for testing.

    Thanks for making clear about amount of alum to be mixed with water... Which is bothering me for long time ... Now its clear like purified water after alim :-)