Former mining pool emits noxious gas

By TAN KARR WEI 

http://thestar.com.my/metro/story.asp?file=/2011/9/23/central/9452800&sec=central

EIGHT years have passed since Taman Sri Manja residents in Petaling Jaya first detected the stinking smell of hydrogen sulphide coming from the drains, and the problem has not been solved completely.

The problem began in 2003 when industrial waste was dumped into a pool in the area. The resulting chemical reaction from the industrial waste releases hydrogen sulphide which is carried through the drains in the housing estate.

The 46.13ha of land was a former mining pool that now belongs to four owners and residents living in the surrounding residential areas said they would occasionally catch a whiff of the gas.

Taman Sri Manja Flats resident S. Kaliamah, 40, said they could still smell the gas coming from the drains especially in the morning or after heavy rain.

Dumping ground: The former mining pool has been filled up and lorries can be seen coming in and out of the area with loads of construction waste.

“We have become used to it but friends and relatives who visit us will comment that it was hard to breathe,” said Kaliamah.

The drain leading from the pool goes past several residential areas and have since been covered up by the Petaling Jaya City Council (MBPJ) to prevent the gas from polluting the air.

Kaliamah said when the hydrogen sulphide emission was at its worst in 2003, metal grilles would rust quickly and electronic equipment with copper wires would also be damaged.

“I have changed three television sets and two refrigerators. Our copper vases for prayers would turn black very quickly and we have to polish it almost every week.

“It is not so bad now but we still have to clean it about once a month,” she said.

Question remains : Residents are also concerned whether their flats are still structurally safe.

Universiti Malaya solid and hazardous waste management professor Dr P. Agamuthu, who was part of a team who conducted a study in the area in 2007, said the presence of hydrogen sulphide was a tell-tale sign that organic matter had been dumped into the pool.

“The pool should only be filled with inert waste like construction material or sand.” he said.

During the study, the level of hydrogen sulphide was monitored at various locations around the pool and an average reading of 21ppm (parts per million) was recorded.

Dr Agamuthu said consistent exposure to that amount of gas could pose health risks to residents, with children and senior citizens being more vulnerable.

Another concern: There are pools of stagnant water at the perimeter of the former mining pool in Taman Sri Manja, especially near the Petaling Perdana flats.

Among the short-term measures proposed to tackle the problem was to neutralise the water with oxidising agents, cover up the drains, fill the pool with inert materials and vacate a nearby kindergarten to minimise the children’s exposure to hydrogen sulphide.

Dr Agamuthu said the treatment involved releasing hydrogen peroxide into the water before it flowed into the drains to reduce the gas emission.

“This is something that has to be done continuously until the pool is eventually filled up,” he said.

The kindergarten was not vacated but the covering up of the drains had drastically reduced the smell but Dr Agamuthu said there would still be traces of hydrogen sulphide as long as the pool has not been filled up.

“The smell becomes unbearable after a downpour because the rain compresses the gas so the concentration is higher at ground level,” he said.

The issue became a hot topic during council full board meetings last year due to the illegal dumping into the pool. The council even resorted to stationing enforcement officers round the clock to ensure that only construction waste was thrown at the reclaimed land.

MBPJ public relations officer Zainun Zakaria said the council was now monitoring the levels once every six months, the latest being from Aug 4 to 11.

“The readings have always been at an average of 2ppm. The treatment is still being carried out by the Alam Sekitar Malaysia Sdn Bhd (Asma) using mud balls and reclamation with construction materials and stones,” she said.

MBPJ engineering head Cheremi Tarman said a part of the reclaimed land had been designated as a retention pool and another identified as a road reserve.

Dr Agamuthu said the level was safe for residential areas but residents would still smell the rotting stench.

Another problem faced by residents was water becoming stagnant at the fringes of the reclaimed land.

Petaling Perdana Residents Association chairman Hamzah Harip said it was especially bad near Blocks O and N of their flats, which was next to the reclaimed land.

“When it rains, the water will rise near the flats,” he said.

Residents have made matters worse by throwing rubbish and old furniture in the area.

Hamzah said there were a lot of mosquitoes in the area due to the stagnant water and he hoped the pool would be filled and levelled properly.

Kaliamah said they were also concerned whether their flats were structurally still safe.

“We have seen what it has done to the grilles, so how will we know if the steel foundation of our flats has not corroded?” she asked.

There are many questions still left unanswered and Bukit Gasing assemblyman Edward Lee, who was part of the committee set up by the Selangor government to monitor the issue, said it was up to the state to consider taking back the land from the owners.

“My recommendation is to leave it as a open recreational area to ensure the safety of the people.

“It has been filled up but we do not really know what is inside,” he said.

Dr Agamuthu said the pool was 100m at its deepest and high-density development was not recommended.

“The land will take years to settle and even then, any development will have to be low-density ones or open spaces like golf courses and recreational parks,” he said.

He cited an issue in Kelana Jaya, where residents of houses built on a former landfill found compressed garbage under only 15cm of soil.

“That landfill was only 5m deep but even now, some of the land around the houses are sinking. The pool is much deeper so the soil would need time to settle,” he said.