Treating sludge for disposal not a simple task

I refer to an IWK advertisement in The Star (April 1 1997) which harps on two methods of treating domestic sewage by individual septic tanks and through central sewage treatment plants. It also stated IWK's role in the operation of sewerage disposal systems in Malaysia.

But the proclamation that IWK "are working round the clock to improve the quality of our stream and river water......" is a grossly inflated and misleading representation.

Take the sewage lifting station and treatment plant in Section 14, Petaling Jaya to which I had drawn attention through the courtesy of these columns between late 1995 and early 1996. Both these facilities were not in working order and raw and, at best, only partially treated sewage was been discharged into Sg. Penchala.

In February1996, IWK responded by assuring the public that both these facilities were programmed for refurbishment in August 1996. More than a whole year has passed since `95/`96. Raw and partially treated sewage is still being discharged "round the clock" into Sg. Penchala unchecked today. There is no telling for how long before `95 that raw and only partially treated sewage had been discharging into Sg. Penchala. And who knows how much longer this is to go on unchecked, IWK's assurance notwithstanding.

While musing over the fact that the plant in Section 14, Petaling Jaya is but one of over two thousand treatment plants entrusted to IWK, I am astounded to see its advertisement is also claiming that " septic tank sludge is further treated at sewage treatment plants before it is disposed of in an environmentally safe manner".

Treating sludge for disposal in an environmentally safe manner is not a simple task nor it is an inexpensive process. It requires adequate and proper storage, thickening, conditioning and dewatering facilities.

Only very few of our biggest sewage treatment plants have been provided with the facilities to do so. While in practically all other plants, namely, imholf tanks and oxidation ponds no sludge treatment facilities are provided at all. Can one expect IWK's operation to date to have completed improving and expanding existing treatment plants with these costly new facilities? If not, isn't IWK's advertisement simply pulling the wool over the public eye?

On the other hand, is it possible, perhaps, that IWK is simply going to put septic tank sludge into treatment plants together with all other normal incoming sewage? If so, this is certainly not "sludge treatment" in sewage treatment technology and this can also lead to the conclusion that either IWK's technical expertise has overlooked this technical fact or that it is, inadvertently or otherwise, yet another sweeping and misleading statement not unexpected from IWK.


An edited version of the above article was published in The Star (April 11, 1997). 2008