Saturday, December 26, 2015

Why do people want to learn about wastewater treatment?

Wastewater... what's that? Sounds yucky... what an unpalatable topic... Far removed from the drinking water that we are accustomed to... Something best left out of sight and mind... Let someone else handle it... Government, perhaps? Or PUB?

Yes, those will be the typical reactions to wastewater. Then why do people still pay money (albeit with PIC (productivity and innovation credit) grant from the government) to attend a course on wastewater treatment? And no, this is not a WSQ (workforce skills qualifications) course so you don't get the normal WSQ goodies from a typical WSQ course. (Well, neither do you need to fulfil the typical requirements from a WSQ course either.)

A bit of background... I just finished teaching this course over 6 evenings. It gives a broad overview of how wastewater is treatment. Of course, it does not go into design, construction of a wastewater treatment  plant. It is studied from the perspective of a plant operator about several standard unit  operations as follows.
  1. Activated sludge
  2. Sludge digestion
  3. Chlorination
  4. Industrial waste
  5. Coagulation & flocculation
  6. Sedimentation
  7. Filtration
Basic enough for anyone but still, why pay money to study it???

It turns out that most of these participants are working (or business owners) in the water and/or wastewater industries. They have extensive in the areas they are servicing e.g. project, pumps, controllers but they don't have a good idea of the overall picture in a water or wastewater treatment plant. No doubt, some of these participants are interested to expand their business into new areas in the industry. However, the others simply want to understand how their services fit into the overall scheme of things. And there is always the odd participant who does not come from the industry at all. He is there to satisfy his curiosity of this seemingly little known and perhaps confusing industry.

Just in case you also feel that wastewater should be kept out of sight and mind, always remember that what goes in (food, water) must come out somehow (solid waste, liquid waste). And nature does not discriminate between clean water and wastewater. Dispose of your wastewater without care and it will end up as your drinking water. This is especially evident after disasters when every relief agency is fighting to provide drinking water to the victims, yet ignoring the fundamental necessity of waste management. Water borne diseases inevitably break out and supposedly clean water sources are contaminated with waste.

Have a good holiday, folks! But don't forget to keep an eye on where your waste goes.

Wednesday, April 22, 2015

Some non-water related musing

Hi CK,

I just want to join with those to say a "thank you" to you for creating such an interesting blog!  I don't believe we can find the sorts of info you're writing about anywhere else!

You have also provided a certain level of "consumer" info e.g. on alkaline water etc. that is pretty useful to other laymen.  Once again, thank you - I enjoyed reading the articles you have put up.


Hey, thanks, S.

It is always nice to hear such encouraging words from my readers.

Being an educator myself, it is always uplifting to have current and former students providing positive feedback to reinforce the fact that what we are doing is right. (Don't be mistaken, negative feedback is valuable in helping us improve ourselves but the pure happiness of receiving positive feedback is irreplaceable.) 

Being humans, there are times when we doubt ourselves no matter how strong our convictions are. Are we walking the right path? Is this worth doing? Are we making a difference?

During those trying times, even a short encouragement or a few kind words make all the difference. And sometimes, our whole future can change from the decisions we make based on that short conversation with a kind soul.

I have been on the receiving end, as well as on the giving end. Sometimes, we may not think much of our own kind acts. To us, it may be the most natural thing to do. But to the other party, it can a virtual lifeline, a way out of the darkness into the light.

Therefore, I consciously try my best to spread kindness whenever possible. Small acts, quick words but the impact can be bigger than we think. And in a way, that is the right thing to do.

I may not be able to bring a whole nation out of poverty into the status of a developed country but I can help others along the journey of life, making a part of the world (no matter how small) a better place than I first encounter it.

I write because I like to. Water and its topics just happen to be what I am familiar with and working on. Education is a tool. Above all is the attitude to share your knowledge and willingness to better our own condition and that of others.


Sunday, April 05, 2015

Why I wouldn't be drinking alkaline (aka ionised) water

A bit long of a post but try to read it fully to get a well rounded story.

Alkaline or ionized water was all the rage some years back in the domestic water category. It hasn't lost it shine though. New and supposedly ever better models are still coming out and sales staff are still fervently promoting the benefits of drinking alkaline water.

In fact, in c2011, I was approached by one company to write a book on the health benefits of alkaline water. Being somewhat skeptical then (and even more skeptical now), I respectfully decline.

Then in c2013, another company approached me to conduct experiments to help substantiate the claims of its ionized water. This time, instead of talking about drinking the water itself, the company is interested in promoting the use of ionized water to preserve food, cooking and preparing beverages. It was convinced that food and beverages prepared as such were fresher, better tasting while retaining the benefits of drinking alkaline water. In this case, I must admit that the request was kind of outside my expertise so I happily pass it along to my food colleagues.

(It should come as no surprise that alkaline water can preserve food well because of its high pH which makes the environment hostile to most microbes, especially if the food is dipped in a large vat of alkaline water.)

So how is alkaline water produced anyway?
It is typically produced in a machine commercially named a water ionizer. One part of the resultant water has above neutral pH (alkaline) of 8-11. (FYI, the pH scale ranges from 0 (highly acidic) to 14 (alkaline).) You can actually make alkaline water yourself (DIY) by adding sodium bicarbonate (just a fanciful chemical name for baking soda) into your water. But since the profit margins for selling baking soda are simply too low compared to selling a shiny and sophisticated machine like a water ionizer, no self respecting company will want to mention the possibility of DIY to make alkaline water.

[Start of tech talk]
Back to the water ionizer... it makes use of electrolysis - passing an electrical current through water between 2 electrodes - 1 positively charged, 1 negatively charged. In simple terms, positively charged ions (cations) like calcium and magnesium migrate to the negatively charged electrode (cathode) while negatively charged ions (anions) like sulfate and chloride migrate to the positively charged electrode (anode). The cathodic region becomes alkaline due to reactions between the cations and water and no surprise, the anodic region becomes acidic due to reactions between anions and water.

To further prevent the cations and anions from coming together again, ion selective membranes (a really thin film with special properties) separate the cathodic and anodic regions, allowing ions to pass only in 1 direction. In proper technical speak, the whole process should be called electrodialysis (because of the membrane) rather than electrolysis but I suppose electrolysis sounds easier to digest for most sales people and customers.
[End of tech talk for now]

Lots of water ionisers come with filters and other water treatment accessories e.g. activated carbon. To me, they complicate the issues regarding alkaline water. If you become healthier after drinking alkaline water, is it because of the alkalinity itself or is it because the water is cleaner after filtration? Nevertheless, I will focus on alkaline water per se in this post. You can find out more about water filters in my other posts.

How does alkaline water benefit you?
If you read up on the advertised claims of the suppliers, alkaline water can:
  • delay ageing
  • counteract cancer
  • detoxify
  • lower blood cholesterol, sugar and pressure
  • remove stones
  • prevent arthritis
  • weight loss
  • improve energy levels
  • keep heart, liver, bones healthy
  • probably improve lots of other health issues you can think of
What a list! Don't get me wrong, there are indeed things that can improve many aspects of your health. Think of exercise for example. Exercise can do all of the above and more. It makes me wonder why some people are not doing it. Maybe they prefer to buy a quick fix like a water ionizer. After all, drinking ionized water does not come with the hassles of spending time and effort exercising and getting all sweaty and uncomfortable.

Naturally, I am skeptical when a commercial product or service comes with more beneficial claims than snake oil. After all, how do you effectively prove so many claims. It is not easy to do scientifically robust studies to prove a single health claim. You need time to do that. For example, drugs can take years or more before they are allowed to be sold on the market. The gold standard will be clinical studies of patients involving double blind experiments. You don't see that with alkaline water (and lots of other health supplements). Yes, I know drugs are different from alkaline water but the health claims are no less serious and in many cases, alkaline water sounds more omnipotent than any drug.

And in some cases, the suppliers use BIG words like "miracle" water. This really sets off the BIG warning alarms in my head and have me recoiling with BIG question marks.

Eventually, what you often see are "testimonials" from "satisfied" customers. "After drinking alkaline water form XYZ brand, I feel healthier... I no longer suffer from health problem ABC... At first, I am unsure but after trying it out, I am a true believer." I bet you see roughly the same testimonials as above more often than you care to count. In a way, they are selling hope but what you don't want is when hope and reality don't meet.

By now, I can hear some of you asking what does WHO say about pH in its drinking water guidelines. Well, in WHO 2011 edition, there is no recommendation for pH as it is not a health concern though Singapore's Environmental Public Health (EPH) regulations stipulate a pH of 6.5-9.5. I believe this range is more for protection of piping and equipment against corrosion in too acidic or alkaline an environment.

The Science behind the scenes
Sometimes, scientific theories are presented out of context. Yes, acid and alkali neutralise each other. So if you body is too acidic (bad for health), simply drink some alkaline water to achieve balance again. Simple, right?

If you believe that, maybe you also believe that you can remove your brain from you body and hook it up with wires and electrodes in a nutrient vat so that you can live beyond the demise of your body. (Just kidding) Unfortunately, our bodies are really complex machines. What works in a vat usually does not work in the real body with its many biochemical/biomechanical operations interacting in ways many times as yet not understood.

Figure: An interesting and ultimately unanswerable question: "How do you know you are not a brain in a vat somewhere and your whole reality simply fed into your brain via electrochemical/biochemical signals?"

Take pH for example. Human blood pH is an average of 7.4 (slightly above the neutral of 7). Drop below 7.35, you get acidosis. Go above 7.45, you get alkalosis. Both conditions can lead to serious health complications. The reason why human (and animal) blood needs to maintain such a stable pH is because pH is often quoted as the master parameter in any system, be it human body or a pond. It affects how chemical and biochemical reactions will play out. A different environmental pH will lead to a different reaction pathway, giving rise to different products. Or the reaction may not even proceed at all.

So why are people talking about the body being too acidic? The body will automatically correct the blood pH within the narrow range of 7.35-7.45. (WE are talking about blood pH here. Saliva and urine will have a slightly different pH range. Stomach pH IS acidic - see below. Healthy fetal blood pH is also slightly different.) How in the world is alkaline water helpful?

For those who remember your biology, stomach pH is acidic, say 1.5-3.5. You need this level of acidity to properly digest your food and to kill off many pathogens. (IN chemical terms, the acid is to break up the chemical structures of foodstuff like proteins so that your digestion enzymes can do their work on the fragments.)

IN case you are worried that drinking alkaline water will neutralize this acidity, good news - a healthy stomach can automatically compensate for such actions and retain it normal pH range. So my point is - when you drink alkaline water, it ends up mostly in your stomach where it is neutralized by your stomach acids. How are its benefits supposed to be transferred to your body??? (FYI, once your acidic stomach contents reach the small intestine, bicarbonate is secreted to neutralize the acids so that the acidity does not travel further down your system.)

Lastly, if anyone reading this feels strongly about alkaline water being really vital for health, please do not flame me and just go ahead to drink it if it makes you feel better. This is after all a free society. As for me, I will keep alkaline water at a distance. More often than not, we just need an adequate dose of good old plain water to function efficiently at optimum health. Keep this a priority before you open your wallet to other "healthy" options.

Figure: If you find yourself feeling lethargic, sometimes all you need is to hydrate yourself. Above is my favourite type of water bottle - stainless steel. Tough, no chemicals to leach and possible to use it for boiling the water if necessary.

Sunday, March 29, 2015

Enough clean water for my children and their children - remembering Mr Lee Kuan Yew (LKY)

This week (23 - 29 Mar 2015) marks the mourning of the passing of our first prime minister, Mr Lee Kuan Yew (LKY), widely recognised as Singapore's founding father.

As I was going through the historical documentaries of the man shown continuously on TV, I was reminded of his contributions to the water supply in Singapore. The early years of Singapore (1960s, 70s) were trying times. Massive issues had to be resolved right there and then - housing, education, healthcare, security, jobs and of course water and sanitation. It was mind boggling to contemplate these issues all together, much less come up with workable solutions.

Anyone familiar with human nature should realise that once the basic human needs (e.g. food, water, shelter) are not met or disrupted, you are going to have lots of trouble on your hands. Think about looting, rioting and general social unrest - just look at Chile, Haiti after earthquakes. I am sure there are many more such examples if you google them up.

No, in the chaotic situation that is Singapore in the 1960s, water needs must be effectively addressed. (Sanitation too as I believe water and sanitation are merely 2 sides of the same coin hence the term, watsan but sanitation is a story for another day.)
'In 1963, just a few years after its self-governance was declared, Singapore experienced a severe drought. This harsh experience left a deep mark on the population. As the Prime Minister of Singapore at that time, Mr Lee Kuan Yew was determined to drive Singapore towards water sustainability. This, he did by making water a top priority in government policies. "This [water] dominated every other policy. Every other policy had to bend at the knees for water survival."'

In those early days, LKY already realised that there would not be enough water given the paces of development and population increase. Water from reservoirs and from Malaysia were not going to make it. (Only MacRitchie, Pierce, Seletar and Fort Canning (for the port) were operational as of 1963. Source: PUB) (As of the 1960s, the very first agreement signed in 1927 was no longer in force. 2 others - 1 signed in 1961, another one in 1962, were then operational. Source: Singapore Infopedia)

Looking at the scene now (2015), I am quite pleased to see the 4 National Taps operating - local catchment, imported water, Newater, desalted water. By 2060,
  • Total local catchment area will have increased from the current 2/3 to 90% of surface area (see previous post related to this topic)
    "Currently, NEWater meets up to 30% of the nation’s current water needs. By 2060, we plan to triple the current NEWater capacity so that NEWater can meet up to 55% of our future water demand."
    "Today, desalinated water can meet up to 25% of Singapore’s current water demand. The plan is to grow Singapore’s desalination capacity, so that the Fourth National Tap will be able to meet up to 25% of our future water demand by 2060."
  • What is so special about 2060?
    "Beyond 2061The Singapore government has stated that it will not renew the 1961 agreement which expires in 2011. Attempts to reach a new deal with Malaysia to secure water supply for Singapore beyond 2061 have not borne fruit despite years of tedious negotiations. To reduce Singapore's dependence on imported water, the government has taken steps to increase the size of the local water catchment area and to build up the supply from non-conventional sources, namely NEWater (reclaimed water) and desalinated water. With the various water projects progressing well, government officials have assured Singaporeans that the country can be self-reliant in water by 2061 if it needs to be."

    Yup, so that is it. The last 20% will be served by local catchment by 2060.
With such forward planning, I feel assured that the water needs of the country and my family will be well met...

But... (there's always a but) all these come at a price. Newater and desalted water are not cheap to produce. Requiring sophisticated reverse osmosis units using easily fouled membranes, they basically involve passing contaminated water through a filter that removes the contaminants. Imagine a filter with really small holes that only allow water molecules to go through. Even small stuff like salts and oils are retained on the filter. This is going to use lots of pressure to push the water through and  associated with it are high energy usage and costs.
"The first year (2003) tender price for NEWater from Singapore's Ulu Pandan plant was S$0.30/m3, which is significantly less than the cost of desalinated water. The selling price of NEWater is S$1.15/m3, which covers production, transmission and distribution costs."

"The cost of the desalinated water during its first year (2005) of operation was S$0.78/cubic metres."

Desalted water is naturally more expensive to produce than Newater because seawater is much more saltier ("contaminated") than normal wastewater in our sewers. As such, you need much higher pressure (translated into energy and cost) to filter off the salt in seawater.

In contrast, the production cost of tap water should be in cents/m3 (sorry, can't find a good source for this figure. I picked it up when I studied about reverse osmosis in university.)  

Finally, don't forget that to ensure water security for our small nation, energy security is a co-requisite. Without natural gas, biofuel or whatever to generate electricity, desalination and Newater production will be adversely affected.

Thursday, March 26, 2015

The curse on the waters off Pasir Ris

The waters off Pasir Ris seem destined to be cursed with massive fish kills now and then. Fish kills have been documented there for years! (See my previous posts on this topic.) The latest came as no surprise - Straits Times 1, 2; Today 3, 4; Channel News Asia (CNA) 5.

In response to an invitation from CNA to check out the waters there, a team of us headed down to the field for a quick water quality monitoring (WQM). It had been a week since the fish kill occurred so I was not expecting to see anything extraordinary in our WQM results. Nevertheless, it was a good chance to stretch those hands and legs on some good old field work.

Other than conducting field trips for my students as part of their curriculum, it has been some time since I have field work in WQM. For those following my blog, I had been involved in other aspects of water the past few years - rainwater harvesting, grey water recycling. Water is such a fascinating yet vast topic. It can cover indoors, outdoors, natural, industrial, agricultural, household, economics, political, war and many other areas besides.

Back to Pasir Ris... On 10 Mar 2015, we did WQ tests at 2 spots at Pasir Ris and 1 spot at Punggol for reference. Here is a summary of the results.

The number above may appear intimidating but worry not, below is a description in plain English.

Overall, the water quality looked pretty good for all 3 locations. A few points:

1.       The water at Pasir Ris has become somewhat saltier compared to my data in 2010.

2.       The water has also become somewhat more alkaline compared to my data in 2010.

3.       The water is significantly clearer (less turbid) compared to 2010. Less construction work going on?

4.       Nutrients (ammonia, nitrate, phosphate) are significantly less compared to 2010.

5.       Bacterial counts are significantly less compared to 2010. Can we all swim there now?

6.       Pasir Ris spot 1 appeared to have a slightly higher bacterial count compared to the other 2 locations. FYI, spot 1 is where a great deal of dead fish were washed up the previous week.

 Don't forget, about a week has passed since the fish kill. Don't expect to see problems in the water quality during our field trip or we will still be seeing dead fish on the shores for the entire week - a scary thought.

Figure: WQM team at work at Pasir Ris

Figure: The cozy CNA van that brought us and our equipment around our test sites

Tuesday, March 17, 2015

Fluoride and other contaminants in beer

Hi there,

I've browsed your blog many occasions and always found it a good read, irregardless of whether it answered a question I had at that point in time. 

A bit of background - Water is something key to my interests, as I have grown up with freshwater fish and currently have become a brewer(of beer). Therefore chemistry and quality of the local liquor has always concerned me. 

I have recently installed a water filtration system at home with activated alumina - with the intention of removing fluoride. Would you have any advice on where I could get a water test done up? Key substances would be chlorine, chloramine and fluoride. Also, I'd be open if you have other advice to share.

Best regards,

Hi E,

Thanks for sharing your interests and your thoughts on my blog.

You have touched on one of those controversial and hotly debated health topics in water and food - fluoride. Fluoridation of drinking water was initially touted as beneficial to the protection of teeth against decay. Over the years, studies have shown that an excessive amount of fluoride in our bodies can lead to fluorosis which affects the teeth and bones adversely. The irony is not lost to most people aware of this issue - too little fluoride, you get tooth decay; too much, you get teeth damage.

More about fluorosis in this WHO (World Health Organisation) page or feel free to google up yourself:
"The dental effects of fluorosis develop much earlier than the skeletal effects in people exposed to large amounts of fluoride. Clinical dental fluorosis is characterized by staining and pitting of the teeth. In more severe cases all the enamel may be damaged.

Chronic high-level exposure to fluoride can lead to skeletal fluorosis. In skeletal fluorosis, fluoride accumulates in the bone progressively over many years. The early symptoms of skeletal fluorosis, include stiffness and pain in the joints. In severe cases, the bone structure may change and ligaments may calcify, with resulting impairment of muscles and pain."

Naturally, one BIG question is what constitutes an excessive amount. Remember, our intake of fluoride includes the food we eat too. There are already arguments against fluoridation of drinking water since it is claimed that the dosage from our food is already enough to fight tooth decay. According to the drinking water guidelines from WHO, the limit of fluoride stands at 1.5ppm (parts per million). And based on the Singapore Drinking Water Quality Report 2014 from  PUB, our drinking water has an average of 0.48ppm and a range of 0.40-0.62ppm fluoride.

For people concerned about fluoride, filters containing activated alumina have been well known to remove fluoride. Back to answering E's question, my concern is given the already low level of fluoride in Singapore tap water (see previous post, Evaluating the necessity and usefulness of water filters for domestic tap water for an idea), how effective is your filter in removing fluoride? I was going to ask whether there is a need to remove the already low levels of fluoride but since you have already installed the filter, this question is moot. :-)

If your intention to test for fluoride, chlorine and chloramine is one-off, then you can approach a commercial testing lab. The ones I know are (in no particular order):
  1. Tuv Sud PSB
  2. SGS Testing
  3. Setsco Services
  4. CPG Laboratories
If you only have one water sample to test, I believe your tests should not cost more than a hundred dollars. BUT very importantly, do find out the detection limits for their tests. If the test results show zero, they simply mean that that particular contaminant is NOT DETECTED rather than totally absent.

On the other hand, if you intend to conduct these water quality tests on a long term basis, you may want to consider getting a test kit such as the Checkit Comparator from Aqualytic. The Local distributor is Quantum Technologies Global Pte Ltd. It is designed to test for fluoride from 0.2-2ppm. I feel that this should be enough for your purpose. To detect any lower concentration will require more complicated (and expensive) instruments normally found in a lab. And frankly, I am sceptical that there is a need to reduce the fluoride concentration any lower for beer. Not to mention that it may not be economical to do so - you will need technology more advanced than filters to achieve that low a level.

Similarly, the Checkit Comparator can also test for chlorine (free chlorine ) and chloramines (combined chlorine). But do note that each of these tests require the use of different chemicals. Please be careful about storage, handling and disposal. Wear protective gear and make sure other people are not unnecessarily exposed, especially children.

Figure: Aqualytic Checkit Comparator. Different coloured discs are used for different tests. The above discs are for nitrate (pink), ammonia (green), phosphate (blue).