Overseas community service (OCS)/ Youth expedition project (YEP) part 3: Are there still more things to check if my water is safe?

This post follows from 2 previous posts.

1. Overseas community service (OCS)/ Youth expedition project (YEP) part 1: Is that water safe?
2. Overseas community service (OCS)/ Youth expedition project (YEP) part 2: How do I know if that water is safe?

So you have checked out your watershed and everything looks ok. No industries, agriculture or villages around. Are we home and dry?

NO! We have not checked out the history or to be more exact, the geographical history of the watershed! Find out what the area used to be...

2. Historical geography

Example 1: Mining
Mining (granite, coal, metals etc.) can especially be nasty to health and environment even after closing down for years. Digging deep into the earth can release toxic substances (lead, radiological compounds, heavy metals etc.) found underground into water once the mine fills up with water after closure. Not surprisingly, mining can also impact groundwater quality so those looking at using well water do take note as well.


Or sometimes, the mining operation itself left hazardous waste which remains uncleared after closure.

Google "toxic legacy of mining" and you can find tonnes of examples. Here are a couple.

1. http://www.abc.net.au/rural/news/content/201102/s3142796.htm
   Australia - copper and gold mining can create a leachate with hazardous levels of copper, manganese and zinc.
2. http://keeptheban.org/?p=678
   France - uranium mining - "accumulation of radioactive metals in sediments and plants of rivers, ponds, and lakes by contamination around former mine sites has also been found to have high enough contamination to be considered “radioactive waste”"

And a common example is acid mine drainage in which sulfide ore from underground turns into sulfuric acid upon reaching the ground surface (chemistry is involved). This can be quite serious as it can turn water very acidic - pH of 1 or less.

Example 2: Agriculture
Depending on the type of agriculture, you can find different pollutants in the soil or sediment. And these pollutants may subsequently leach into the adjacent water bodies. If the pollutant load in the soil/sediment is heavy, the leaching can occur over a long period of years. Short of dredging the entire load of sediment or bulldozing the whole lot of earth, the problem can only be treated symptomatically without eradicating it source. (See a potential case study in a previous post - How to get rid of your seemingly unstoppable pond algae at Sungei Buloh.)

If we are talking about crop land or plantations, there is a likelihood of pesticides and fertiliser residues in the soil/sediment. On the other hand, animal farms will likely introduce animal waste (which is also a source of nutrients) into the soil/sediment. Nutrients/fertilisers are especially good at promoting eutrophication in water bodies while pesticides can be toxic to the ecology and us.

Most of you probably knows that Sungei Buloh used to be house prawn and fish farms in its mangroves before being converted into the wetland reserve we know together. However, do you know that it used to house pig farms too? (Wetland forest of Sungei Buloh mangroves) Has all the pig waste been cleared from the area? If not, can this be a source of nutrients leaching from the soil/sediment into the current mangrove area and causing eutrophication?



Example 3: Estuaries
In simple terms, an estuary is the intersection between a river and the sea. It can be in the form of a swamp, bay, delta etc. Not only does it accumulate (depending on the tidal and hydrological conditions) stuff from the river (think about oil, pesticides, heavy metals), it can also receive pollutants from shipping (ballast, waste, cargo overboard), especially along a busy shipping channel or near a port.

The port and upstream factories may not be there anymore but the pollants remaint in the sediment, possibly for a long time of decades and slowly releasing its toxic load of heavy metals and persistent organics (including dioxins, PCBs (polychlorinated biphenyls), -cides (pesticides, insecticides, herbicides)). BUT if someone decides to dredge the sediment (perhaps to keep the channel deep for shipping), you may see the serious problem of a massive dosing of pollutants into the water. Morale of the story: don't disturb the sediment unless you intend to remove the whole chunk as a long term solution.

Incidentally, heavy metals or persistent organics can show up in bottom feeders such as shellfish (mussels, clams etc.). They accumulate the substances as they wade through the sediments for food. Of course, what this means is they are potential bioindicators - indicating the health of the environment without doing a chemical analysis first.

The other more serious implication is if the locals feed on these bottom feeders, they may very well be intoxicating themselves.

Figure: 1969 topo map of the area around Ngee Ann Stream. Notice that the old railway track splits into 2 lines near the Bukit Timah station. Old maps are a good source of information on the geographical history of the area. Another source is old aerial photographs.

Figure: Google Earth view of the same Ngee Ann Stream (imagery data 2009, 2010). Some roads and waterways remain after all these years.

Figure: Photograph from The Straits Times, depicting the floods in 1978 and men rescuing their pigs. More importantly, it tells you that Woodlands, Braddell Road, Potong Pasir to Changi used to be a "farm belt". Such old news are another source of information.

Figure: Quarry lake on Pulau Ubin. Disused after the granite quarry has closed. How does such a mining activity affect the water quality?

Some random thoughts on floods and water quality

I have been wanting to write something on floods and water quality since our Orchard Road floods make headline news in June 2010. But other committments in life came to the fore and this task became relegated to the background.

Brisbane floods: Up close (18 Jan 2011, ABC News)

Figure 1: This looks like some sort of water treatment or wastewater treatment plant in an industrial area

Figure: Same area as Figure 1 after the flood. Notice that the treatment plant is overwhelmed. If it is a water treatment plant supplying tap water, you can expect contaminants from the flood to go into tap water. If it is a wastewater treatment plant, you can expect untreated or partially treated wastewater to be carried by the flood to who knows where. Depending on the type of wastewater, contaminants can include raw sewage, industrial effluent (heavy metals, solvents etc.) or agricultural waste (animal waste, pesticides, fertilisers etc.).

Orchard Road Floods Straits Times/ Stomp (June 2010)

Figures: The same principle applies here. We had a flood. Flood washed everything around Orchard Road in its path. Let me hazard a guess - "everything" should include motor oil/ fuel (from vehicles), rubbish (glass, paper, aluminium), animal waste (stray animals, rats), pesticides/ fertilisers (lawns, green spaces) and lots of sediment (notice the "kopi susu"-like flood water). Where do you think the flood water eventually end up? Orchard Road is part of the Marina Reservoir watershed so yes, the contaminants end up in our reservoir. Our water treatment plants are supposed to be very effective so most of these stuff should be removed before reaching our taps. Even if this were true, treatment costs will likely rise from an increase in wear and tear of the treatment units handling such a heavy and diverse load of contaminants.

Figure: Tsunami caused by earthquake in Japan (Mar 2011) (japantsunamipics.com). The same can be said of a tsunami. It can carry everything nasty land pollutant in its path far inland, impacting water supplies and wastewater processing. I remember first learning about this term "tsunami" in secondary school geography. It didn't strike a chord with me then. Perhaps there weren't that many tsunamis then. But nowadays, even children know about this term when everyone can see horrific images of death and destruction following its wake. It has also receive much publicity since the tragic Asian tsunami in Dec 2004.

A disaster may be split into 2 phases with respect to its damage. The 1st phase is the disaster itself. Energy from an earthquake or flood causes loss of life and property. This phase usually lasts a short while (though there are floods that take months to recede). The second phase comes in when the population starts to rebuild their lives. The economy is torn to pieces. Food, water and fuel become scarce. Ditto for daily necessities. If law enforcement is weak and the people desperate, social disorder ensues. Without clean water (and food) and proper sanitation, people start coming down with water borne diseases which may spread without check, especially when people are herded into cramped refugee camps. See my earlier post for a fuller discussion on the aftermath of a disaster.

I have tonnes of water at my door but none in my pantry - Queensland floods

If you have been reading into floods, earthquakes and other disasters, you should have guessed that the scene portrayed in the following figure is "normal". In fact, this photo immediately caught my attention, prompting me to write this post.

100,000 to lose power, supermarkets bare as flooding crisis continues (11 Jan 2011)

Figure: Actually, the amazing thing about this scene is there ARE still bottles of water on the shelf. I imagine the photographer positioning himself capture the shot in the midst of hordes scrambling to grab water, food, batteries, flashlights, fuel, candles, first aid items and toilet paper (TP) (yes, TP is incredibly valuable in an emergency though few people talk about stocking it up) in the supermarket.

Regardless of the country (developed e.g. Australia, developing e.g. Haiti, communist) and the type of disaster or emergency (flood, earthquake, civil disobedience, war), the same patterns are often observed.

The chain of event goes something like this (also see this earlier post on the earthquake in Chile based on similar themes):

1. Dysfunctional  utitlitiesElectricity usually goes down. This has wide ranging implications as many other services depend on this modern convenience. And in the case of floods, the power company may turn it off to prevent accidental electrocution. Same goes for gas lines during an earthquake, the gas company turn them off to prevent explosions due to gas leakage.
   
   Water supply may or may not be disrupted. Even if your tap continues to run, the water may not as clean as before due to contamination at broken lines or inadequate treatment at the water works.
   
   Though fixed line phones are not directly tied to the electrical supply (i.e. your phone may still work even if your power is down), the physical cables and switches may still be affected by the disaster. In case you think your cellular phone has a better chance, don't count on it as the disaster can strike at the wireless transceivers placed around you. (Next time when you are outside, watch out for those usually grey boxes with 2 antennae hanging above you e.g. lamp post. There, you have your cellular transceiver.)
   
   Sanitation - big and ugly problem. What are you going to do if your WC stops working. Do you have a chemical toilet tucked away somewhere? Not likely. This is a very real problem yet few people want to come face-to-face with it (same as for TP).
   
   Not really counted as a utility but highly valuable and useful - money. Due to a lack of power or communications, forget about  using your credit card or debit card. Even cheques are viewed with suspicion. (Is your bank still going to operate after the flood/earthquake/emergency?) Cash is KING. And it pays to have small change and denominations for the small value items. By the way, your ATM is probably not working or out of cash.
2. The mad rushPeople may initially be in a state of denial about the extent of damage. (Right, the government will fix things up. Or we can depend on the utilities companies to bring everything back to life within hours.) Once they wake up to the fact that our modern conveniences are not going to be back for some time, panic rushes in. Supermakets are raided for food, water.... Even items of dubious value (e.g. caviar) are cleaned up with all the cash one can master. If you are heading to the supermarket at the same time when the hordes are on a spree of panic buying, good luck.
3. Civil disorderDepending on how strong the authorities are and how fast they can deploy policemen and soldiers, civil order may break down. (Remember, policemen and soldiers may also be affected by the disaster so whether they turn up for work is a big question.) When people go hungry and thirsty and uncomfortable (or worse still, their children are experiencing these problems), morality, legality and decency can go the way of the window. Riots, looting, burglary, kidnapping and daylight robbery crawl out of the woodwork. I added kidnapping because I have read of criminals kidnapping children in exchange for food and essential items from the parents during Hurricane Katrina.
4. Health issuesIf normalcy is not restored soon (say days or weeks), the lack of clean water and food and adequate waste disposal (both liquid and solid) will take a toll on the population's health. Water borne diseases like cholera and typhoid are incredibly easy to spread among people packed together in refugee camps having less than proper sanitation. Dead bodies of humans and animals may lie (or float) in the streets waiting to be cleared. Add in malnourishment and you have the recipe for diarrhea and dysentry in addition to the big 2 above. Children and the elderly normally suffer the most. In the tropics, you can also count on vector borne diseases like dengue rearing its ugly head.

I am sure I can continue writing on and on but the idea is disasters suck. And they suck worst when you do not know of its consequences and/or are unprepared for them. (Yes, I have not written anything about the preparation part but that would be too much for a single post, right.)

Australia inundated by flooding

We seem to be seeing more flooding and at more serious intensities around the world these years. From New Orleans to Malaysia, Pakistan and now Australia, floods have had a busy decade. While some fingers point to climate change, others point to El Nino/ La Nina effects and still others decry the destruction of natural buffers such as wetlands and coral reefs as the culprit to widespread flooding.

The latest flood on the block:
Australia floods larger than France strand 200,000

"The muddy water inundating thousands of homes and businesses has led to a shortage of drinking water and raised fears of mosquito-borne disease...

The town was facing food shortages, power outages and sewage-contaminated floodwaters..."



And like all floods (and most natural disasters e.g. earthquake in Haiti, Chile), the victims are facing a shortage of clean drinking water, lack of sanitation services, contamination from wastewater (sewage) and water (and vector) borne diseases in addition to all the other inconveniences such as power outages, shortage of food and lack of shelter.

How to reduce flooding in Singapore? Harvest more rainwater!

Harvesting of rainwater may sound foreign to most of us even though this term is commonly used in other countries. It simply means collection and storage of rainwater. It may be on an individual, residential, community or even national basis.

Actually, Singapore has been harvesting rainwater for a long time on a national basis. From PUB's webpage, two-thirds of the land area here is available for rainwater catchment (Yes, right, "catchment" is more commonly used here).

(Figure: www.pub.gov.sg/water/Pages/LocalCatchment.aspx)

Is so much of our area covered by reservoirs? NO! It means that land (residential, industrial, recreational, waste etc.) is used to funnel all that rainwater into reservoirs. For example, rainwater falls on rooftops, flows into drains which lead into canals, ultimately joining up with a reservoir. Because of the flash floods in June, everyone now knows that Orchard Road is part of the catchment area for the Marina Reservoir. Talk about practical environmental education.

Indeed a very clever system to alleviate the shortage of water in this densely populated island. However, it suffers from a few drawbacks.

One, in times of heavy rainfall, no way will the reservoirs be able to hold so much water. The natural thing to do is to drain the excess into the sea. (E.g. the Marina Barrage is well touted to be able to do this in the event of heavy rains.) This of course means a waste of fresh water. AND IF the excess CANNOT be drained (e.g. blockage of some water way), flooding will result. In the (good?) old days when Singapore is still a tropical jungle, most rainwater will be soaked up by the vegetation and soil. But with the increase of built-up area, we no longer have such a luxury. Most rainwater will flow over the ground surface straight into drains and canals or perhaps accumulate in some low lying area as a flood.

Another challenge of open reservoirs like ours is the loss of water through evaporation. In the dry months, the water level in the reservoirs drops not only because of the lack of rainfall but also through the above mentioned loss.

This article predicts that the rainwater harvesting (RWH) markets in Europe and India are set to experience high growth rates in the coming years due to a rising fresh water shortage. More RWH systems will be installed at the residential, commercial and industrial levels.

Guess what? This is nothing new in Singapore! Changi Airport has such a system. Nanyang Polytechnic has one too. The airport is reported to satisfy one-third of its water demands in this manner, saving $390 000 per year. Such water is normally collected on the roof-top and undergoes minimal treatment for non-portable use e.g. toilet flushing, firefighting drills, watering of plants.

Imagine... if we have more of such systems, not only will our reservoirs be less stressed in times of heavy rain, there will also be less loss of precious fresh water through evaporation.

If your interest has been piqued, how do you set up a RWH system. SIF Technologies is selling a "chemical free RWH system". Chemicals are sometimes added in conventional water storage to discourage microbial growth. (Chlorine in PUB water does this job.) In the case of SIF, they are using a proprietary non-chemical means to do the same thing.

But RWH can be simple and cheap. Consider this 3rd world method of RWH. However, remember to always discard the first 10min of so of rainwater as it may contain pollutants from the air or your roof-top.

Figure: using a tin roof to collect rainwater (Water for Life, Hesperian Foundation)

Figure: My own version of a RWH system for use in a high-rise flat from a project several years back. (Naturally, we can't have every household in a HDB block harvesting rainwater. I suspect only the top floors will get any significant amount. The other concern is not to have a high-rise RWH system becoming killer litter.)

Oh, before you rush out to install a RWH system, here is an extract from Singapore Law.

SEWERAGE AND DRAINAGE ACT

PART V PROTECTION OF WATER RESOURCES
Prohibition on extraction of water
No person shall, without the approval of the Board (PUB), construct any works for taking or intercepting water from any place or sea, within the territorial limits of Singapore.

However, I believe the law has been relaxed for residential installation provided the storage tank is less than a size of 5x2x2m. Anyting bigger will require a water-borne fee to be paid. But if you are planning a system for your company or school, you still have to go through the bureaucracy for permission. One last point, check out the guidelines for collection of rainwater at NEA.

(Update: Rainwater Harvesting Seen as Solution for Drought and Flood Control: In Kenyan cities like Nairobi, rainwater harvesting is seen as a solution to multiple problems.)

Introducing the British Berkefeld filter - something you can count on when the chips are down

The latest earthquake in New Zealand (Christchurch and surrounding area, 4 Sep 2010, 4:35a.m. Saturday, 7.1 magnitude) got me thinking about the supply of water again but this time round it prompted me to pen it down. (Long post as follows)

If you have been following this year's (2010) natural disasters - earthquakes in Haiti, Chile; flood in Pakistan, public water supply has always been a fragile creature. Infrastructure can be destroyed, piping and storage tanks can be broken.

In Pakistan, the deluge caused natural sources of water (e.g. wells, springs, streams) to be contaminated with whatever the flood water carried - human and animal waste, pathogens from corpses and carcasses, pesticides from farms, heavy metals from industry. In the short term though, it was the water borne diseases that caused the most problems - diarrhea, dysentry, cholera, typhoid etc. The breakdown of sanitation and water supply led to a nightmare for public health (probably nowhere near top notch even before the flood).

Bottled water naturally became a valuable commoditity as seen in Chile when it became one of the top looted items (together with bread and candles). I imagine the same would have occurred in Haiti if there was enough bottled water to go around to be looted.

Being a developed country, New Zealand was spared from serious looting (some still took place according to the news) or outbreaks of water borne diseases. Heck, no one was killed by the quake as according to some experts, the strict building codes to quake-proof its structures have helped. (Compare against 230 000 killed in the Haiti quake.) Nevertheless, the sewage pipes were broken in the quake, allowing sewage to mix into the drinking water supply which probably probably suffered from broken piping too.

Consequently, residents in affected areas were asked to boil their tap water for drinking. I am thinking: these people are lucky (despite the quake and all). They still have electricity or/and gas. Imagine... if you have no gas, no electricity and only sewage infused tap water, how are you going to boil your water?

Imagine some more.... the NZ scenario (without the gas and electricity) happens right here in good old SG (assuming we survive the quake), do you have a wood burning stove and charcoal at home? How about a camp stove with extra gas tanks? The lucky ones will be those NOT using piped gas. The years of effort to heft around those gas cylinders would have been worth it.

Do you have Aquatabs on hand? Bleach? Do you know how much to add into water? Personally, these are not my favourite choices because of strong chlorine taste and many health controversies of overchlorination. By the way, if you opt for bleach, only use the straight ones without extra ingredients e.g. scent.

Boiling is good if you can do it but it only removes the bugs and not all the other nasty stuff (pesticides, metals) in the water. Imagine having a Pakistani scenario here. I will boil my water before running it through a good filter.

I personally recommend the British Berkefeld (or Doulton) gravity filter. (In America, it is sold under the name of Berkey.) No water pressure, no electricity needed. Simply pour your water through the top and collect clean water at the bottom. The key element in the setup is the filter candle with the ATC SuperSterasyl being the best. It has a ceramic outer shell impregnated with silver. The ceramic physically remove microbes and particulate matter from the water while the silver suppresses bacterial growth. The water next enters a granular activated carbon core containing a metal ion removal medium (works by ion exchange, I believe) to eliminate many organic compounds (e.g. pesticides), chlorine and metals (e.g. lead, cadmium).

Figure: The external setup of the British Berkefeld stainless steel gravity filter minus the faucet which should be attached near the bottom. It is certainly not small (this is already the smallest stainless steel model) so it should be used for the family or small group at a static location.

Figure: Opening the lid reveals 3 holes for fixing a filter candle each

Figure: The heart of the filter system - ATC SuperSterasyl filter candle. Notice the white ceramic exterior. Water enters through the ceramic and filtered water leaves through the black nozzle on the right.

Figure: The top portion is removable for fixing the filter candles. Filtered water goes into the bottom portion for dispensing via a faucet.

Having one of these filters will certainly add a great degree of water security to any family. And if you are involved in overseas community projects, keeping one with you serves as insurance, especially if you are not sure of the water quality or source of your drinking water.

This line of filters may be procured locally from Arkwater. Of course, I am in no way affiliated with the company except for purchasing these filters from them.