Ammonia Processing Facility At Water Treatment Plant The Best Solution

While the current drought has created water shortages throughout the country, the problem is exacerbated by the ammonia contamination in water treatment plants.

According to the Indah Water Consortium (IWK), the source of the ammonia contamination is the septic tanks and it is no small matter as there were an estimated 1.2 million premises with individual septic tanks in the country.

In the Klang Valley, a study by the Department of Environment (DOE) found the Langat River Basin being most vulnerable to ammonia and sewerage pollution due to presence of more than 33,000 individual septic tanks in the area.

The ammonia pollution happens when the septic tanks are not emptied periodically, at least once every three years, causing the sewage to get stuck in the pipes and overflow into the drains and rivers which are the sources of drinking water.

THE CONSTRAINTS TO REMOVE SEPTIC TANKS

Mohd Ridhuan Ismail, the executive director for the National Water Services Commission's (SPAN) Sewerage Regulatory Department when asked whether these septic tanks can be eliminated altogether said: "Septic tanks will continue to be used for a small scale development outside water catchments areas."

Nevertheless, developers were encouraged to provide centralised sewerage system for development of more than 30 unit of houses or 150PE (Population Equivalent), he told Bernama recently.

And on whether these individual septic tanks could be connected to the centralised sewerage system, Mohd Ridhuan said the cost could prove to be prohibitive and inconvenient for the house owners.

"This means digging up the back lanes and the front roads of the premises as well as installing the connecting pipes to the septic tanks that has been buried within the premises," he said.

Also, who would foot the bill? Will house owners want to pay a hefty sum to connect to the central sewerage system when they can still live use their septic tank?

"These are some of the issues that need to be considered before embarking on projects converting septic tanks to centralised systems," he said.

AMMONIA PROCESSING FACILITIES BEST SOLUTION

However, Mohd Ridhuan believes there is a more economical and logical solution for ammonia contamination than connecting individual septic tanks with centralised systems - setting up ammonia processing facilities at the water treatment plants.

"For the Langat river catchments, there are about three other water treatment plants upstream of Bukit Tampoi facility that can be considered for investment in ammonia stripping systems," he suggested.

He added that the ammonia treatment would only kick-in when the ammonia level in the raw water exceeds the threshold value of 1.5ppm (part per million).

Ammonia processing facilities in water treatment plants are crucial as there were more than 500 public sewerage treatment plants within the Langat river catchments, including the private treatment system where the number may reach more than 1,000 facilities.

"Many of the facilities were constructed before 2009 where ammonia was not a treatment parameter and these sewerage treatment plants would continue to discharge ammonia into the river," Mohd Ridhuan said.

HIGH DESLUDGING CHARGES

In the meantime, owners of premises with individual septic tanks should consider desludging the tanks periodically but many lament of the charges imposed.

What has the Association of Water and Energy Research Malaysia (AWER) to say on this?

"Yes, these septic tanks are designed to operate efficiently for two to three years and it must be desludged in which solids settled in the tanks must be removed," said its president S.Piarapakaran.

It is not carried out by mandatory legal requirement and the fee to carry out desludging is very high that ranges from RM200 to RM350.

"We have suggested the SPAN to impose lower monthly charges (lower than IWK charges) and carry out periodic desludging. This will lower the cost of desludging and ensure septic tanks operate efficiently," he said.

Piarapakaran also concurred with Mohd Ridhuan that the ammonia treatment facility at water treatment plants should be seriously taken into consideration.

"It is better to upgrade the water treatment plant as upgrading the sewerage treatment plant may not reduce ammonia levels significantly.

"There may be other sources of ammonia pollution along the way especially at water treatment plant in Cheras. Dealing directly with the plant will be safer, faster and smarter move," he said.

Once this is done, he believed further improvement to raw water quality could be carried out as an ongoing process.

Meanwhile, Mohd Ridhuan said the commission with the help of Energy, Green Technology and Water Ministry and IWK has been conducting campaigns on desludging service to public and the importance of emptying the septic tanks every three years.

-- BERNAMA