Sunday, March 31, 2013

Kampung Temasek

I have the privilege of being invited to Kampung Temasek (KT) located in Johor, Malaysia (near Ulu Tiram). It is designed to be an outdoors learning centre, open to school activities and corporate workshops.

On my part, I am checking it out as a potential location for my school's outdoor activities and a potential site for green projects. It turned out that they are looking at implementing a rainwater harvesting programme for their visiting groups. Currently, their huts are harvesting rainwater for toilet flushing but more can be done, especially when large groups go over and these large groups cannot fit into the huts. Also, rainwater can be used for more applications than just toilet flushing e.g. washing of dishes and hands. Naturally, washing of hands and dishes will require a better water quality compared to toilet flushing and irrigation so a treatment train will probably be needed. Of particular potential is their main hall which can be modified into a giant rainwater collection device.

Figure: 2 of the 6(?) huts. Notice the raised above ground architecture for ventilation and avoidance of floods. Also, check out the solar panel on the roof of the hut on the left. Unfortunately, solar power is limited due to the heavy cloud cover in the tropics. Rainwater is harvested for toilet flushing in each hut but in my excitement, photographing this unit has simply slipped my mind. (Side note: KT is still tied in to the grid and water supply for the area. Sanitation is provided by septic tank.)

Figure: The main hall with nice sloping roofs. Great for rainwater harvesting. We may not even need all 4 sides!

Figure: The kampung style of lighting

Figure: The eutrophic pond where students do their confidence jump together with ducks and geese

Figure: Our highlight of the day. 1 of 2 banana plants we transplanted to a location we believe to be more suitable than the original one. Partial shade, raised ground, soil is well drained yet still moist

Figure: A not so green practice. Solid waste is disposed by burning on site. Without municipal solid waste collection, this is a common practice in rural parts of Malaysia. A partial solution will be to compost the biodegradable waste, producing compost for the vegetable on site. But this idea MUST BE sold to the local caretakers on its merits in contrast to the extra work of composting vs. burning.

Sunday, March 24, 2013

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.
    Australia - copper and gold mining can create a leachate with hazardous levels of copper, manganese and zinc.
    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?

Sunday, March 17, 2013

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

For those working in developing countries:
In case you are still not sold on the idea of drinking from rainwater based on my previous post (Overseas community service (OCS)/ Youth expedition project (YEP) part 1: Is that water safe?), read on. Incidentally, some communities do not want to drink rainwater because of tradition and culture. They have drinking from surface water (ponds, rivers, lakes) since the time they were born, they do not see other sources of water as viable. Depending on the situation, you may not want to fight an uphill battle to suddently switch their drinking habits to a rainwater source. Perhaps, you may be better off convincing them of implementing some treatment method.

I have been consulted by organisations which want to operate in developing countries and know more about the safety of their drinking water. An approach similar to the one below may be used.

1. Geography
If you are collecting surface water, know what is upstream. (This was covered in the previous OCS/YEP post but I will add some more information here.) Residences, villages, resorts, tourist attractions or heaven forbid, industries and agriculture upstream should light up a big red flag with a buzzing alarm... Drink the raw water at your own BIG risk.

But knowing the land use should extend to more than just along the waterways. Know your watershed! (In Singapore, we call it catchment basin or drainage area instead.) Your watershed is basically the land area acting as a big umbrella to catch and convey the rain to your water point. It includes the forests, parks, carparks, roads, other built up areas for the rain to flow over before reaching your water collection point. Naturally, any substance (e.g. litter, oil, animal droppings, soil, minerals) on the ground surface is fair game for the rainwater to pick up as it flows to your water point.

So you say that your river does not flow past any industry but if your watershed has a leather tannery or beer brewery, their waste chemicals may find their way into your river (and your mouth if you are drinking from the river).

Traditionally, we use topographical maps to delineate the watershed. In simple terms, water always flows from high to low points. Join up all the high points surrounding your water collection point and you have set the boundaries for the funnel into which water flows. (You may refer to Georgia Adopt-a-stream file here for a better description of the process. In fact, I strongly recommend that website as it contains a lot of useful information for water quality monitoring.)

However in current times, computer software and GIS (geographical information system) are used to calculate the watershed.

Of course, you may not have a topographical map. (Some countries consider this a state secret. Even in Singapore, it is not easy to get one.) Much less the digital map for your area of interest. Then the next best method will be to check out the areas adjacent to the waterway upstream of your water point. An area 1-2 km from your waterway will be a good start. Same as before, check out the landuse patterns in these areas. Does anything stick out like a sore thumb?

Figure: Sample topographical map. Useful to delineate your watershed if you don't get overwhelmed by the amount of details in the map. It also tells you quite a bit on the landuse in your watershed.

Figure: Students' rendition (sketch) of the landuse patterns around Ngee Ann Stream

To be continued...

Sunday, March 10, 2013

What water filter does the military use?

This piece of news jumped at my attention immediately, partly because of the connection to the U.S. Military. Items used by them (military specifications or milspec) are usually quite good and certainly up to the rigours of combat and heavy outdoors use.

Water Purifier Meets Requirements of US Military Small Unit Tests (28 Feb 2013)

Figure: Seldon Technologies WaterBox™ 300 MIL ( Look closely at the left compartment and you will see 3 filters (within seemingly conventional housing) with labels (jack up your magnification to see clearly). R to L: some sort of pleated sediment filter; some sort of depth filter (melt blown?) to remove smaller sediments and protect the main filter; the main filter and the star of the show - a nanofilter made into a mesh of carbon nanotubes hence giving rise to nanometer sized pores (

I have extracted some of its highlights from

  • Setup time is under five minutes
  • Requires no maintenance, no chemicals, and no heat to operate
  • No waste water is generated as a result of the purification process
  • Removes bacteria, viruses, Cryptosporidium, and Giardia to USEPA drinking water standards: 99.9999% of bacteria, 99.99% of viruses, and 99.9% of cysts
  • Reduces sediments, chlorine, total organic carbons, bad taste, and odors
  • Reduces chemicals and many harmful heavy metals (e.g., mercury and lead)
  • Self-priming system can pump from any water source with up to 4.3 meters (14 feet) of lift
  • Patented Nanomesh technology for high-performance contaminant removal

  • Capacity: up to 30,000 liters (8,000 gallons), depending on water quality
  • Flow rate: 1.89 liters (0.5 gallons) per minute
  • Weight: 78 pounds (31.8 kg)
  • Power source: 12VDC, 24VDC, 115VAC 60-Hz, or 230VAC 50-Hz

Looks good. Their Nanomesh technology is a form of nanofiltration. In simple terms, it can filter off particles down to nanometers in size, meaning most microbes and many types of molecules and ions (the big ones). NOTE that it is not designed to filter off sodium chloride which is the salt in seawater so it is not for desalination.

It can accept DC and AC from the more common voltages. BUT it still needs electricity basically to run the pump (top left on the right compartment). Meaning that in a grid down situation that you and I are likely to face in an emergency, this thingy will just sit pretty there. On the other hand, I believe, Seldon Technologies has a version that works on manual pumping. (Check out my previous posts on an alternative water filter for emergencies: Do we really need water filters 2?, Do we really need water filters?, Introducing the British Berkefeld filter - something you can count on when the chips are down)

Weight of 31.8kg is not exactly a walk in the park to carry around so plan on having a helper or a trolley if you want to move it around much. Capacity of up to 30000L (before replacement of the main filter?) is pretty impressive, considering that a person needs 2L per day for purely survival mode (no sweating and jumping around). A flowrate of 1.89L/min is quite decent for a small group, similar to a squad of Navy Seals or Special Forces that this filter is designed for.

Sunday, March 03, 2013

PUB drinking water quality report 2011

Readers interested in our drinking water quality may want to check out this report on tap water quality in 2011.
It compares our tap water values against WHO drinking water guidelines and indicates whether there is compliance. Not surprisingly, all those parameters that have a corresponding WHO drinking water standard show compliance.

Let's see... it contains data on 1 microbiological parameter, 2 physico-chemical parameters, 3 radiological parameters and 90 chemical parameters! Wow, that makes almost a hundred water quality parameters which is a big improvement from the 21 parameters (20 physical/chemical + 1 microbiological) from another PUB water treatment webpage comparing the waters from various water treatment plants. Astute readers will course notice that some of the parameters from the water treatment webpage are not included in the water quality report e.g. pH, conductivity, taste, odour, total alkalinity, total hardness, total dissolved solids. Nevertheless, such a report is very useful for citizens who want to know more about our tap water quality - beyond the common yes/no statement that the water is drinkable and follows WHO standards.

However, the statisticians out there may be disappointed to learn that no other details on the testing regime are given.
  1. How many samples were tested?
  2. From where? Water treatment plant, tap, distribution network, storage tank?
  3. How frequent were the samples collected? Any specific dates?
  4. Which testing lab(s) were involved?
  5. Were other parameters tested? (My personal belief is more testing had been done than what is reported.) Did they clear the standards?
Despite the lack on information on the above points, I am glad that such a report is available to the public. It goes a long way to educating the public on such a vital resource as water. And I think this is the current trend our society is following. The end user becomes more educated and hence wants to find out more about the resources he is using in order to make an informed decision in synch with his beliefs. Hopefully, this will lead to a more sustainable future.

Figure: Students learning about water quality testing in SP