Thursday, September 11, 2008

Notes from CPG Site visits

I was lucky during the first two weeks of my work to go for a couple of places for site visits. The places I visited include Changi Waste Water Reclamation Plant, Pulau Serangoon Reservoir Scheme, and the NEWater Infrastructure pipeline. These would have been places that excited any boys who are into big machines and projects.

Changi Wastewater Reclamation Plant (CWRP)
At the CWRP, after the Deep Tunnel Sewerage System brings all the waste water from all around Singapore, a massive bore hole of 60 +m in diameter is dug 27 storey into the ground to pump it all up again to be treated. To stand in the hole which is completely lined in concrete is very impressive indeed. At this point, you will have to pay due respect to the government of Singapore because many governments will choose not to be involved in such infrastructural projects because they are often out of public eyes (imagine sewers), it is better for governments to throw their money into hospitals and trains which will be easily visible to the public and earn the government some votes. Hence, we, Singaporeans have to be grateful for having such a stable political system that allows our government to plan ahead.
However, the biogas that was derived from the waste digesters are just all burned off and it is such a waste of resources. Consider this in the context whereby they actually have a diesel oil tank store and a power station in case of power failure.

Pulau Serangoon Reservoir Scheme (PSRS)
It was an irony to visit this site when just 2 weeks ago I was there with a bunch of canoeists near Cooney Island, and they were complaining about the work being done there which deprived them of another place to canoe to. PSRS in general, is a project to damn up Sungei Serangoon and Sungei Punggol to create a reservoir to increase Singapore’s water supply.

Marine Clay Dredging
In the course of the river, marine clay has to be cleared for structural strength of the banks structure even though it may not be polluted by pig farms. However the marine clay is dumped at Pulau Semakau, shouldn't it be used for other landfill purpose? I heard that they are still looking into research to mix marine clay with other materials in order to improve its suitability for landfill purpose. Personally, I just thought that does it make any difference in terms of strength of material if we just use marine clay for the bottom most layer in land reclamation project?

Water transfer between Sungei Serangoon, Sungei Punggol and Upper Pierce Reservoir:
One may also be puzzled by the fact of why did they bother build a transfer pipeline to bring water from Sungei Serangoon to Sungei Punggol and then another pipeline where water from Sungei Punggol is pumped to Upper Pierce Reservoir. Why bother? And waste the energy in the pumping process? At the end of the day, I summarized the following 2 reasons:
- If the water level rises in the future Sungei Punggol or Sungei Serangoon Reservoirs, these freshwater will be waste if they had to released via the dam gates. It is better to bring this fresh water to be store at Upper Pierce Reservoir.
- Also, there is a raw freshwater treatment facility at Upper Pierce Reservoir already, instead of building more of such facilities at Sungei Punggol and Sungei Serangoon; they probably just need to expand the existing one.

Cut-off wall at Lorong Halus
They are also building a concrete cut-off wall for the site of the Sungei Serangoon that meets Lorong Halus – the previous landfill of Singapore. The question then is there geo-membrane lining for the sides and bottom of Lorong Halus? There may be none, since it may be a landfill of the previous era. If there is geo-membrane lining, there should be no need for the concrete cut-off wall to prevent the flow of leachate into the reservoir. However, the current cut-off wall is built using a TRD machine which can only dig 18m; it may not be deep enough to prevent the flow of leachate from Lorong Halus into the future reservoir.

Global warming and level of walls
It was very interesting to note that all the walls of the PSRS have a further 0.5 m above the highest water level record expected in a 100 year storm. This 0.5m allowance is for the rise in sea levels due to global warming. The Mr. Yeo I spoke to who used to do the reclamation work at the Tuas extension said they had allowance for rise in sea level too during that time. It seems like more than a decade ago, our Singapore government already recognized the inevitability of rise in sea level and yet we have not really done anything till NEA’s efforts this year to address the causes. Food for thought. Who told you that global warming is friction?

NEWater Infrastructure Plan (NIP)
After the raw water has been treated at CWRP, part of it will be treated to become NEWater. There is then this ridiculous long pipeline of 87? km to bring it to the north of Singapore and then all the way south to Jurong Island again. I understand that the project is fast tracked to meet the industrial needs at Jurong Island. It seems ridiculous for me to pump the water one entire huge round around the island when there is going to be a Tuas Wastewater Reclamation Plant like the CWRP in future, but I heard they put the Tuas one on hold.

Final Notes:
Something that touched me the most was the number of foreign workers and the period they have been working in Singapore. When I worked in a factory in the past, I realized how dependent was the Singapore economy especially the manufacturing on Malaysians. However, these Malaysians are near neighbours. There are some India workers who have been working here for the past 12 years with their wife and children back in India. The whole family probably only meet once or twice a year. Now that I have lived overseas and going to again, I really wonder if that is too heavy a price to pay. A couple of years is fine, but 12 years of separation from your family for financial reasons. Sigh…
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