Articles, Blog


August 15, 2019

Let’s do a small experiment. Would you rather drink
this water, or this water? Well, of course you would
choose the water on the left. Unfortunately, some people
in other parts of the world have no choice at all. Did you know that small floating
particles in drinking water can make you sick? Imagine we have a super
powerful microscope and we can zoom into the water. Zoom. What will we find? What are these small
floating particles, and how do they float? These particles
are of two types. Inorganic, like clay,
silt and mineral oxides. And organic, such as algae,
protozoa, and bacteria. The bacteria, once ingested by
humans, can sometimes be fatal. All of these small
particles are able to float because they are not heavy
enough to settle to the bottom by gravity. Suspended particles that are
too light and small to settle are called colloids. When looked at
together, these colloids cause a state of cloudiness, or
haziness, known as turbidity. The more cloudy a fluid
looks, the more turbid it is. Here. we see four
beakers of water with increasing levels of
turbidity from left to right. There is a relation
between turbidity and the risk of
getting a disease. Science shows that
the more turbid the drinking water is, the
higher the risk of getting sick is. Now, why is this? This is because toxic
compounds can adsorb, that is stick to, the surface
of the suspended colloids. The more colloids there
are, the more toxic the water can become. These toxic materials
and bacteria can cause cholera,
salmonellosis, hepatitis A, dysentery, and E coli infection. These illnesses affect and
kill millions of people a year, and are especially dangerous
to children whose weak immune systems cannot provide
an adequate defense. Fortunately, we can do
something about this. One of the very practical ways
to clean this turbid water is called flocculation. Flocculation is the process
in which colloids aggregate, or come together, to form
larger particles called flocs by the addition of a
chemical called a flocculant. Typical flocculants units
include alum and ferrix, because they work well with
high turbidity fluid mixtures. Now, let’s demonstrate
how flocculation works. First, we’ll need to go out
and collect some muddy water from the Charles River. Here are two beakers
filled with the same amount of muddy Charles River water. On the left is our control,
which will remain untouched, and on the right we’ll
add three milliliters of prepared flocculant solution. Then we’ll stir for
two minutes and wait. [MUSIC PLAYING] Wow, what just happened? The colloids in the turbid water
on the left may never settle. Whereas, with the addition
of just a little bit of flocculant, the water
on the right became clear. In order to make
this water potable, it will require skimming
and filtration, and maybe some additional treatment. If you’re wondering
what’s going on, let’s explain how this
flocculant business works. Almost all colloids have
negatively charged surfaces. This means that positive ions,
or charged particles in water, will attract to the colloid
surface, forming a first layer. Recall how like
poles of a magnet will repel, while opposite
poles will attract. The same occurs with
colloids in water. A diffuse layer, made up of a
mix of positive and negative ions, will then
surround the first, forming what is
called a double layer. This double layer
provides a repulsive force that prevents two colloids
from sticking to each other. Once the flocculant
is added, it adheres to the surfaces
of the particles, compressing the double layer,
and allowing the colloids to stick to each
other and form flocs. These flocs are now heavy
enough to settle to the bottom by gravity. Given how effective
flocculation is, many countries around
the world use this method for cleaning their
water supplies. Did you know that
Singapore, for instance, produces drinking
water from sewer water, using a number of methods
including flocculation. As the global population
increases, and fresh water resources become
more and more scarce, flocculation is
one tool that can supply clean, healthy, and
tasty drinking water worldwide. [MUSIC PLAYING]


  • Reply Leslie Carreiro April 7, 2014 at 7:05 pm

    That was a great explanation.  I work in water treatment and will share this with others having to give educational presentations. 

  • Reply Hamguy Bacon April 25, 2014 at 1:54 am

    the world is 70% water and due to Money we are reduced to drinking our own filth.

  • Reply Julianne Mora May 11, 2014 at 2:39 pm

    Really cool video!

  • Reply misterRISK83 May 19, 2014 at 12:13 am

    so you could take salt out of the ocean? o_O

  • Reply Jack Douglas June 10, 2014 at 5:18 pm

    Very helpful.  It does help me to see why flocculation is important in cleaning water, the mechanics of how it works and why mining companies would use this process in the tail end.  

  • Reply hing983 July 1, 2014 at 2:29 am

    hi where to buy alum

  • Reply Thomas Houha July 7, 2014 at 8:06 pm


  • Reply kai zhu July 14, 2014 at 8:24 pm

    What is the prepared solution of alum? 

  • Reply Anas Mahmoud July 17, 2014 at 9:36 am

    great explanation .. many thanks for ur time and effort

  • Reply Ran Tallion August 5, 2014 at 6:35 am

    i tried flocculation once but my mom caught me and said i would go blind if i continue.  needless  to say i stoped when i needed glasses. 

  • Reply ruqaya suadad January 21, 2015 at 11:51 am

    so beautiful

  • Reply Jarod R. February 5, 2015 at 7:00 pm

    Realllllllllyyyyyyyyyy informative
    Subscribed !!

  • Reply Rama chinzah February 10, 2015 at 7:51 pm

    Thank you very much.. One of the best lecture l ever seen..

  • Reply Arlette Al February 25, 2015 at 2:17 am

    oh my God! this video is freaking amazing

  • Reply Tom Atkinson February 25, 2015 at 9:58 am

    You're shit

  • Reply Erastus kavezeri May 20, 2015 at 12:17 pm

    Thank you for the video…

  • Reply First Last May 22, 2015 at 5:46 pm

    Ms Kelly brought me here

  • Reply digitalPimple June 10, 2015 at 2:42 pm

    Floc me? Floc you!

  • Reply aMulliganStew June 21, 2015 at 3:49 pm

    2:32 — Love that dirty water.

  • Reply ashok sah August 2, 2015 at 4:20 pm

    Making clean and tasty water with cool science!

  • Reply Dhanya Kumar August 4, 2015 at 2:26 am

    with the help of this video i got some knowledge.>>>>

  • Reply nomaswazi digani August 24, 2015 at 2:35 pm

    so informative…..

  • Reply Adeel Rafiq December 12, 2015 at 9:10 pm

    How to prepare alum solution?

  • Reply Bilal Almouadab 1983 December 29, 2015 at 12:30 pm

    thank bro, was useful

  • Reply PUO JKA WAFWA January 8, 2016 at 4:55 pm

    permission to use this video in my work..

  • Reply امبراطورية m.a.d February 22, 2016 at 9:35 am

    thanks for you about this information 👍

  • Reply Zeenat gazi February 24, 2016 at 1:58 am

    excellent explanation… thank you a lot.. 🙂 really very nice

  • Reply igna chan April 6, 2016 at 11:00 am


  • Reply Patrick Enright May 3, 2016 at 11:01 pm

    Great vid, thank you! We just bought a Lovibond flocculator today in work, I set it up and we will be using it over the next few wks. Great to get a simple overview as to what's it all about.

  • Reply Srikanth 3087 May 4, 2016 at 4:40 am

    heartful thanks

  • Reply Daniel Holley May 24, 2016 at 11:01 am

    Nice work with this video. Terrific explanation.

  • Reply nour yehya May 24, 2016 at 4:32 pm

    is flocculant same as emulsifying agent ??

  • Reply Sreehari Amala July 26, 2016 at 3:49 pm

    thanks for the information.

  • Reply ali akbar September 3, 2016 at 11:03 am

    great vd

  • Reply Özgür Derince November 17, 2016 at 10:47 pm

    Thanks for great explanation.

  • Reply Haritha K November 21, 2016 at 4:59 am

    great video. Thankyou 😀

  • Reply Sofía A December 7, 2016 at 9:45 pm

    thank you, this really helped!!

  • Reply Command and Conquer December 8, 2016 at 9:31 am


  • Reply QuratulAin Ansari December 19, 2016 at 9:52 pm

    greattt such a helpful video (y)

  • Reply Brianne Li January 6, 2017 at 12:04 am

    Thank you for explaining all this in a fun way 🙂

  • Reply David Pratt January 9, 2017 at 1:38 pm

    Alum and Ferric are cationic coagulants, not flocculants.  Cationic coagulants neutralize the net negative charges on the suspended solids which allows the colloidal particles to naturally join together as you demonstrate.  Flocculation, if necessary, follows coagulation and is done with very high molecular weight, long chain polymers.

  • Reply F A January 22, 2017 at 4:35 am

    i think this is coagulation not floculation

  • Reply DINESH BABU S February 13, 2017 at 6:10 pm

    nice vedio with very detailed and with easy understandability

  • Reply ikhlas saufi April 13, 2017 at 5:51 pm

    youre explaining better than my lecturer did haha

  • Reply national leblanc May 25, 2017 at 10:52 am

    really nice work, very grateful for your contribution to science broadcasting.

  • Reply Ankit Sharma June 15, 2017 at 11:45 am

    very much helpful..!

  • Reply Elmumeen Isaa June 22, 2017 at 6:27 am

    Waoo…very educating simplified…thumb up!

  • Reply Rupan Bera August 16, 2017 at 4:37 am


  • Reply Colin Savage August 26, 2017 at 6:03 pm

    Was the control also skimmed and filtered?

  • Reply amene nourmohammadi October 4, 2017 at 9:05 am

    That's perfect. Thanks!

  • Reply Alfa Fathima October 15, 2017 at 1:58 pm

    Can u show complete use of floc

  • Reply shubham shegavkar November 6, 2017 at 11:13 am

    Whate a gret …….

  • Reply Haura Nooraini November 21, 2017 at 9:10 am

    it helps me ALOT !!! thank u :*

  • Reply Khaleej Kha November 30, 2017 at 9:26 am

    Thanks sir

  • Reply ResonansDeX January 20, 2018 at 1:13 pm

    I think I can use this to easily collect clay from mud

  • Reply Gobinda Khadka January 28, 2018 at 5:19 am

    wow its an amazing. Can u tell us that how much amount of alum would be added in a liters. or if we would like to use in reserve tank then how we can use. another thing is, Is that flocculation process helps to reduce the iron and ammonia from the water? [email protected]

  • Reply gue st January 30, 2018 at 6:22 pm

    oyster, shrimp (filter feeder) maybe can filter water

  • Reply #JLSoCool # March 5, 2018 at 6:15 am

    jacqueline is mental

  • Reply sayali jadhav March 9, 2018 at 4:08 pm

    How is the alum solution prepared

  • Reply Jai Bhimadevi April 16, 2018 at 8:30 am

    "Love that dirty water…" 😉

  • Reply Brent April 23, 2018 at 3:03 am


  • Reply Edian Sheikh Farouk April 26, 2018 at 1:04 pm


  • Reply 2019 july May 4, 2018 at 1:23 pm

    What a good video

  • Reply mohammed binil May 9, 2018 at 4:47 pm

    Good video,but alum is coiagulant,not flocullnts

  • Reply Dreamer June 6, 2018 at 3:28 pm

    When you add flocculent to precipitate out iron from a pool how much aluminum is left in the pool? How dangerous is it to ingest aluminum if you swallow pool water with leftover aluminum?

  • Reply 6 Gorillian Sea Monkeys June 11, 2018 at 1:01 am

    If they don’t have clean water, R.O. Filters, distillation apparatus, or… think going to have flocculants? I’ll just head on down to local empty shop, get bottled water, antibiotics, and flocculants, which one? 🤔 💭 “All your flocculants, shop keep!” Sanctions, because of Zionist/proxy american cuckoldry agreement, forgot, just hurts children and poor, wealthy untouched At least we have no water and power, hospital, food, medicine, luxury goods! Greater Israel plan, yeah! How many wars, and 4 million middle easterners dead and mounting, US servicemen, getting a few more according to plan, and un winnable too, evil people not central banking debt slaves! We are, maybe could use on Detroit on lead, nah! Sorry good information, bullets and bombs bumming us out! English language, well thanks for explanation though! Fun learning! Hope don’t get captured and sold into bondage, that’s still real, not just water, Libya was nice once, too NOBODY went without!

  • Reply Alexander Pulido June 29, 2018 at 3:56 am


  • Reply shot on August 6, 2018 at 2:44 pm


  • Reply Arjun Sen August 8, 2018 at 6:48 am

    Thank u sir

  • Reply Sonu Singh August 14, 2018 at 5:19 pm


  • Reply herjik dimaano August 16, 2018 at 1:55 am

    We used anionic polymer and polyaluminum chloride for flocculation. .

  • Reply samantha lim August 16, 2018 at 9:02 am

    How Does Water Get to You?

    Hello! I am Samantha, a chemical engineering student at Universitas Indonesia. My team and I would like to ask for your participation to help us to win the AIChE Video Competition 2018 with the topic "Chemical Engineering in Water Treatment".

    Please watch and like our video through this link:

    Your likes will be extremely helpful to us. Thank you and have a good day!😁

  • Reply Mohd Adil August 29, 2018 at 1:59 pm


  • Reply Nilesh sinchury September 9, 2018 at 9:13 pm


  • Reply Jimmy WHITE September 17, 2018 at 7:53 am

    Great! Shoutout to Henry! Yeee yeee

  • Reply Eric Kosak September 17, 2018 at 6:47 pm

    So what happens with the tap water from Flint, Michigan?

    Would you drink the tap water from Flint?

  • Reply Eric Kosak September 17, 2018 at 6:49 pm

    Do you know the dangers of ingesting a little bit of aluminum?

  • Reply Eric Kosak September 17, 2018 at 6:55 pm

    This is almost like alchemy science but in reverse.

  • Reply Marco Manuel October 4, 2018 at 6:47 pm

    a very good explanation, i was wondering what it meant. I got past the term by a yeast for beer, became curious and used the search term on youtube and got a clear explanation. my beer will be much clearer now, hope my mind stays clear too 😉

  • Reply sanchit kawale October 28, 2018 at 5:54 am

    how do we sepeate dissolved detergent and soap from water?

  • Reply Asian StevenP October 30, 2018 at 8:33 pm

    how do you get alum solution?

  • Reply Sibhat Gebreslasie November 1, 2018 at 1:50 pm

    special thanks

  • Reply Baban Lambde December 30, 2018 at 3:15 pm

    nice video

  • Reply rangaraju penmatcha February 4, 2019 at 12:45 pm


  • Reply Jeff Kaminski February 14, 2019 at 1:44 am

    very cool

  • Reply Nothing but nothing February 22, 2019 at 1:44 pm

    How do you make that flocculation solution?

  • Reply Nothing but nothing February 22, 2019 at 1:56 pm

    Where to buy that ferrix?

  • Reply Ryan Shi February 24, 2019 at 12:02 am

    谢谢 好视频

  • Reply sudharsan March 12, 2019 at 3:05 pm

    ZOOOOOOOOM !!!!!!!1 lol

  • Reply Avinie Nakhro March 18, 2019 at 2:37 pm

    Good explanation…. Keep it up👍👍

  • Reply mohamed abd elrhman March 18, 2019 at 9:44 pm

    thank u

  • Reply butingting everything April 11, 2019 at 3:28 am

    What chemical you used

  • Reply Pratik Bane April 21, 2019 at 5:51 pm

    Brilliant explanation sir…..u made me understand every bit of it👍

  • Reply Rambabu S May 5, 2019 at 5:13 am

    Hi, Iam Planing Non Ferric Alum Manufacturing Plant, Pls Give Me Tips.cell:919848370603

  • Reply Bhuvnesh kumar Sharma May 21, 2019 at 12:07 pm

    Good explanation

  • Reply Sofia Sacoor June 9, 2019 at 4:53 pm

    Why do colloids have negatively charged ions? Are all substances mixed in with water ionic? If not, how do they remove them?

  • Reply LagiNaLangAko23 June 17, 2019 at 7:29 am

    But is it safe to drink after adding that alum?

  • Reply Parmod Siroha July 1, 2019 at 3:55 pm

    Best fucking explanation with best illustrations dude. My thumbs up

  • Reply rahul naik July 12, 2019 at 7:07 am

    But adding alum ph of water increase….

  • Reply Howard Petrie August 12, 2019 at 11:41 am

    So about how many mg of Alum did you put into the beaker. The volume of the solution was mentioned but not the concentration of the solution or mass of alum.

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