Alexander Szabo and Oscar Engle - Svenskt Vatten

According to assumptions and calculations the activated sludge system will give the best treatment
efficiency in terms of BOD, nitrogen and phosphorous removal. An activated sludge system will achieve
standard A requirements according to Malaysian recommendations and according to Malaysian standard
the activated-sludge system will have an footprint area of around 1 ha if the system receives water from
more than 10 000 people. The current pond received waste water from around 10 500 people at the time
this report was written.
The treatment technology will however be comparatively expensive to build and run. An activated sludge
system is also less effective, compared to the other suggested alternatives, in removing pathogens and
there may be a need for some pathogen removal device after activated-sludge treatment.
The second suggestion to upgrade the current treatment pond does not achieve the same treatment
efficiency as the activated sludge system. On the other hand it is less expensive to run and easier to
maintain. It will also reduce pathogens more effectively than an activated sludge system. According to
assumptions and calculations it will be wise to install oxygen generators as the upgraded treatment pond
system is overloaded and the oxygen the algae produce is not sufficient for organic breakdown. If
conservative assumptions and calculations are made the treated water will barely fulfill the requirements
for Malaysian standard A, but at a low price. If optimistic assumptions are made, the treatment result will
reach down just below standard A.
Our recommendations are for financing reasons and for simplicity to keep the old treatment plant,
improve it by installing screening, installing aeration and baffles and redirecting the flow from parallel
flow to serial flow through all four treatment ponds.
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