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Raw water reaching new pollution-level highs
The majority of Jakartans make their own drinking water by boiling tap water, while others buy bottled water
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The majority of Jakartans make their own drinking water by boiling tap water, while others buy bottled water.
The common method of boiling water is both a waste of energy and also proof that the majority of city dwellers are aware that their tap water is not safe for drinking.
“People need to take a long, hard look at what makes treated water in Jakarta not potable,” Firdaus Ali, a hydrologist from the University of Indonesia, told The Jakarta Post recently.
He explained that the majority of the city’s tap water supply originated as raw water that was siphoned from the Jatiluhur dam in West Java and piped to various water treatment plants.
“Stored water at the Jatiluhur dam is channeled through three canals, the North, East and West Tarum Canals, the last of which provides a supposedly consistent supply of water for drinking and irrigation to Jakarta and Bekasi,” he said, adding that the raw water from the dam was reasonably clean.
However, he said, the problems began when the raw water entered the West Tarum Canal, a 70-kilometer-long open waterway that intersects the Cibeet, Cikarang and Bekasi rivers, all of which are heavily polluted with human and animal feces, industrial effluents and untreated domestic sewage.
“On its route to the city, the raw water becomes highly polluted, and it needs to be processed and purified at water treatment plants,” he said.
He said the canal’s capacity to transport water was decreasing due to a build up of rubbish and other pollutants, deteriorating banks that were falling into the canal and sediment accumulation on the canal bed.
Water treatment in Jakarta is managed by two private water tap operators, PT Aetra Air Jakarta and PT PAM Lyonnaise Jaya (Palyja).
Both own a number of large water treatment installations, including those in Pejompongan, West Jakarta, and in Buaran and Pulogadung, East Jakarta, where the quality and the quantity of water supply are monitored hourly.
Together, these water treatment plants across the city must provide a constant production capacity
of 17,800 liters per second, or equivalent to 1.54 billion liters of water per day, to meet the demand of roughly 800,000 tap water subscribers.
However, the plants are failing to provide enough clean water to the ever-increasing population of Jakarta.
According to a water expert, the city needs an average of 200 liters of water per day per person, or 2 billion liters per day for the approximately 10 million people living in the capital.
According to Aetra Air Jakarta’s director of business services, Rhamses Simanjuntak, the first step at a water treatment plant is siphoning off solid waste from the raw water via filtration. The water is then treated with coagulants to rid it of smaller particles that were not filtered out.
The untreated water from the canal is so severely contaminated that it fails to meet the raw water minimum standards laid out in the 1995 Gubernatorial Decree No. 582.
The decree requires that raw water have a turbidity level of about 100 NTU (nephelometric turbidity units).
However, the canal water’s turbidity level can reach 28,000 NTU on some days, an increase of 2,800 percent compared to 1987 levels of about 1,000 NTU.
The higher the turbidity level, the greater the risk that a person can develop gastrointestinal diseases.
“Chlorine is added to kill microorganisms before the water reaches the public,” Rhamses told the Post, adding that when the purification process was complete, the water was drinkable.
However, Firdaus, who is also a board member of the Jakarta Water Supply Regulatory Body, said that the potable water was then re-contaminated by chemicals and microorganisms on its way to customers due to filthy or damaged distribution pipes.
“Many distribution pipes can be as old as 60 years, and are made from DCP [duct cast-iron pipes] and steel that are very prone to chemical abrasion, meaning they are susceptible to changes in water pressure, which is one of the major causes of leakages,” he said. (tsy)
