Rainwater harvesting in HDB flats? Check out Treelodge @ Punggol

I had the privilege of given a tour of Treelodge @ Punggol by HDB staff some time back. The tour includes a sneak review of the various green implements on the rooftop (normally locked from the public) of this housing development.

Of particular interest to me is the rainwater harvesting system. Some highlights:

1. Rainwater is harvested from the rooftop, treated and channelled into storage tanks at the top level.
2. Grating is installed at inlets on the rooftop to remove large contaminants e.g. leaves, litter
3. The system is designed to make use of gravity to minimise pumping.
4. A first flush system is used to remove the first portion of each rainfall event. (As mentioned in my previous posts (1, 2), a first flush device or system is absolutely essential to remove the initial and dirtiest portion of rainwater.)
5. The treatment of rainwater involves something called DPA system or technology.
• "proprietary technology which harness on the works of Hydrocavitation, where liquid is subject to forces of fluctuating pressures within the enclaves of its cavitational chamber, is a chemical-free water treatment process.
• DPA system is effective in controlling pH levels, increasing dissolved oxygen and significantly reducing bacterial and algae growth in the water."
• Installed by a company called Sif Eco Engineering Asia. Tried to visit its website at www.dpasys.com but ended up at a page under construction so I don't know anything more about this company. 
6. Not surprisingly, the treated rainwater is only used for:
• Washing of staircases, void decks, corridors
• Irrigation
7. Obviously, potable use of the treated water is out of the question. Neither is it used for toilet flushing.
8. No mention of how successful the system is but I don't think there are any problems. Rainwater is one of the cleanest forms of water.

Figure: Garden beds on the rooftop. Nice touch. Cool the top levels?

Figure: Experimental wind turbine. In Singapore, you have to go high for wind turbines to capture the energy of the stronger winds.

Figure: Photovoltaic (PV) panels on the rooftop to provide extra juice to power consumption in the common areas

Figure: Explanatory panel on the rainwater harvesting system. Unfortunately, this panel is on the rooftop so the public normally does not read it. Not sure if there are similar panels in the accessible areas.

Figure: Notice the grating inlet fixed into the floor (rooftop). It is designed to filter off the gross (in size) contaminants in the rainwater. Also, notice the small white pipes jutting out of the garden beds. The plants probably help to clean up the rainwater a bit before channelling it to the inlet.

Figure: Treelodge @ Punggol

Advice on purchasing water testing kit for JCU Singapore

I found your blog online whilst looking for water testing equipment. I hope you don't mind me contacting you! 

I am a sessional lecturer at JCU Singapore and teach a first year subject called Environmental Processes and Global Change. It is essentially an introductory amalgam of geography and ecology. I take my students on at least two field trips (and a 3rd if we have time and the weather is kind to us!) Last year, for one trip, we went around the corner to Bishan Park to do a number of activities, including water quality testing. The kit I used was borrowed from (removed by blog owner) and was really far too basic for our needs (although none of the students had ever done ANY field work before so it was still fun). I would like to order a kit for the department (we don't have one yet), preferably one that has a number of options and could be used for other subjects (e.g., marine science, aquaculture etc). 

Do you know of a brand / local supplier you could recommend? Ideally it would be robust (come in a lightweight case) and give accurate enough data to compare DO, pH, salinity, temp etc between locations. I have found a kit online from a company based at Ubi Ave (bksna.com.sg), but would appreciate any recommendations or advice before I go any further!

It would be nice to touch base with you anyway, as it seems we may be teaching similar subjects.

Kind Regards,

M


Hi M,

Glad to see that you bring your students for field trips. I always believe that our students don't go out of their classroom enough. There are of course logistics and safety to be concerned with but something suitable can usually arranged.

Previously, I minimise mentioning about companies, brands and models as I don't want to be seen to be endorsing them. However, there had been many requests from my readers to recommend vendors and equipment to them, whether for water filtration, water quality monitoring (WQM) or water engineering. I realise that I am doing a disservice to you by withholding such information.

But first my caveat: throughout my blog, any recommendation of companies, brands, models is purely based on my experience and knowledge. Unless stated explicitly, I am in no way affiliated to them and derive no benefits from recommending them.

You may want to read my book "Your first guide to water quality monitoring in Singapore" for a description of the WQM equipment that I have used. It is available online free at PUB's website.

There are actually many distributors of many brands of water testing equipment in Singapore but the following are the few I have worked with and feel comfortable enough to recommend.

1. Most of the equipment comes from the brand, Aqualytic. Local distributor is Quantum Technologies Global Pte Ltd.
2. The Hach series of products (including test strips) is also very good as it is a very established supplier in the area of water testing. Local distributor is Fluke South East Asia Pte Ltd.
3. The YSI brand is also very reputable and their products are usually designed tough for field work. One distributor is Spectra-Teknik.

I am not sure about bksna as I have never used their equipment before or heard any reviews about them. Still, you can go ahead to check out their specs and prices and compare to the others above.

Good luck!

Water quality of wetlands - Sengkang Floating Wetland

My name is J, and I am an undergraduate studying Environmental Studies in NUS. I will be starting on my honors thesis with my professor Dr. L this coming semester, and it is based on water quality monitoring at constructed wetlands-Sengkang Floatingwetland and Lorong Halus wetland. I have been reading your blog, and it has a lot of wonderful information very useful to me. I am still in the midst of my research before I start fieldwork, and I would like to ask you a few questions.

1. What are the parameters that you have measured in these wetlands before, and is it possible for me to obtain the data of these parameters? Considering the fact that I will be conducting some tests, a comparison with previous records of your data would be very useful.

2. Also, have you done a dissolved carbon analysis of the waters in Singapore/pCO2 analysis?

Thank you very much Sir!

Regards,

J


Hi J,

Glad that you like my posts. And I am happy to see that you are doing some field work at Sengkang Floating Wetland and Lorong Halus Wetland. I feel that not enough is being done to monitor the water quality in our water bodies.

1) I have not done any monitoring at Lorong Halus.

As for Sengkang Floating Wetland, I have conducted a workshop for teachers (1, 2) there in collaboration with PUB. No data was officially documented as that was a training workshop rather than a scientific monitoring session. But I have dug up a photo of the white board when the participants presented their results. See if you can make sense of it.

Figure: Results of water quality monitoring workshop at Sengkang Floating Wetland (11 Nov 2011)

 

 

2) No, I have not a dissolved carbon/ pCO2 analysis. My choice of parameters in water bodies is determined more by the demands of a healthy ecology. (Naturally, if I am working with drinking water or wastewater, the demands and thus parameters will be different.) In my opinion, dissolved carbon/ pCO2 are indirect parameters when it comes to water ecology as they reflect the interactions of water and geology more.  There are already so many parameters to monitor. No need to complicate matters or use up more resources unnecessarily :-)

 

Good luck!