Sunday, 11 December 2011

Clean Water - chemistry at work

UPDATE: 1/1/2012

In an earlier post I had described a talk concerning the harnessing of the power of sunlight.  This and other topics concerned with macropolymers was discussed in Melvyn Bragg's In Our TIme series.  The programme is well-worth a listen and though it had been recorded, it has the spontaniety that one expects from a group of interesting people. 
There was some disagreement among the panelists, who included:

Tony Ryan - Pro-Vice Chancellor for the Faculty of Science at the University of Sheffield
Athene Donald - Professor of Experimental Physics at the University of Cambridge and a Fellow of Robinson College
Charlotte Williams - Reader in Polymer Chemistry and Catalysis at Imperial College, London

The programme can be heard on:

** end of update

The last talk in the Royal Society of Chemistry (RSC) public meetings was about water and was given by Phil Souter of Procter & Gamble (P&G).  The talk was chaired by Stephen Elliott, Chief Executive of the Chemical Industries Association (CIA) (

This lecture can be viewed and listened to at   To the non-chemist, some of the language may need some explanation.  There’s quite a lot of coagulation, flocculation and precipitation and these have specific chemical meanings.  Phil also mentioned Arrhenius, the Swedish physical chemist who had several theories named after him.  One concerned the effect of heat on the rate of a reaction.  This is important in the storage of functional chemical products as they can decompose when stored at high temperatures.  (Arrhenius is a good name to drop if you happen to be in a self-catering chalet on skiing vacation and someone complains that the potatoes have taken a long time to cook.  You may have to explain the concept of boiling point at altitude, but Arrhenius would give you the rate of cooking of the potatoes!  Also, a professor emeritus at Edinburgh knew Arrhenius and delighted in telling stories about some of the experiments so – I knew someone who knew Arrhenius!)

It was a well-attended lecture and shows how, with a bit of thinking and their unique ability in creative processes, chemists can make a difference in very large corporations.  Phil Souter described his company as being based on strong brands in the fast moving consumer sector.  Many of P&G’s brands will be well known such as Pampers, Ariel and Pringles potato chips.  Many of their products involve handling of liquids, powders and granules using a variety of chemical engineering processes.  The lecture, which was accompanied by samples of videos, was of a new product which Phil Souter’s team had developed mainly as a philanthropic investment in cutting infant mortality caused by water borne infectious diseases.  P&G have decided to put their own name on the product – the first time they have done this for decades.  You can learn more about the programme and product at:

Most people know the chemical formula for water is H2O.  Many of us take it for granted that it flows out of a tap, ready to drink and we dispose of liquid waste down the waste pipe without giving any thought on how the water got there in the first place.  However, water borne diseases are sadly a way of life in many developing countries, where people have no access to clean drinking water and the source of water - be it river, pond, lake or even flood water - has various hazards.  Some of the hazards are due to organisms, while others are a result of heavy metals, including arsenic.  Natural disasters such as earthquakes, flooding, tsunamis and drought create acute shortages of safe drinking water. 

Traditionally, in most of these countries the fetching and carrying of water would be done by women and children, and in order to purify it the water would have to be heated to boiling point.  This involves additional fuel gathering, so that an investment in a clean drink is huge. 

The product that P&G developed has several components.  One of them is ferric sulphate, which helps to sink much of the heavy metals and some of the fine particles using processes indicated above.  The second major ingredient is calcium hypochlorite, which is commercially available but tends to decompose if stored at high temperatures over a long time.  This calcium hypochlorite provides an active form of chlorine for disinfection purposes.  The whole mix is designed to clarify the water, remove the heavy metals and to disinfect the water and keep it disinfected from further microbial contamination for a couple of days.  We take this for granted at home with water from the tap which has been chlorinated. 

Some practical experience was illustrated by case studies from Uganda, Pakistan and Bangladesh.  In Uganda, P&G worked through one of their organisations in conjunction with non-governmental organisations (NGOs), including some charities.  P&G’s product costs around 2 cents or 2 pence per sachet, and this can treat up to ten litres of water, which can then be used in the family for drinking.  Interestingly, even in this day of consumerism it seemed people were more likely to use something for which they had actually paid, albeit 2 cents per sachet.  If people are given something for nothing, it tends to have no value and can be left unused.  In Bangladesh, where high levels of arsenic are encountered in well water leading to severe cases of arsenic poisoning, the P&G product has been shown to reduce these levels. 

There were some interesting discussions at the end of the talk and later over coffee.  Those attending included a mix of public health, water treatment specialists and those in education. 

In summary this was a good way to round off the International Year of Chemistry with the RSC and the Chemical Industries Association (CIA) putting on an excellent topic.  Access to clean drinking water is obviously an area where a bit of creative chemistry can make a difference.  While geologists and engineers can find and deliver the water, including the desalination of sea water, it takes a chemist to make it potable!  After all, drinking water has to contain essential minerals such as calcium for bone growth, other ions are desirable to maintain a TDS (totally dissolved solids) or hardness. 

The programme for the RSC talks in 2012 can be found on: