China's dirty drinking water dilemma

(Ecns.cn) -- Despite the strictest-ever national standards, pollution of drinking water and drinking water sources remains a serious issue in the Chinese mainland, writes Southern Metropolis Weekly magazine.

The new standards for drinking water came into force on July 1, 2012, pushing the number of quality indicators up to 106 from 35, almost on par with the European Union.

But as the public dreamed of cleaner and healthier water, few were aware that the government had also decided to give water companies a five-year period to comply with those higher standards.

Meanwhile, when Guangdong Province recently conducted random inspections of 18 water treatment plants, samples from 14 of them failed tests carried out by the Center for Disease Control and Prevention.

The provincial public health authority says those samples did not meet the sanitary standards for heavy metals because they contained higher than trace levels of lead.

The problem at the plants may have been caused by poly-aluminum chloride (PAC), a compound widely used for water treatment, says Liang Xi, head of a water quality monitoring station in Dongguan.

He adds that the other four plants employed more advanced technology called ozone/activated carbon processing, apart from traditional phosphorous removal techniques.

Most water treatment plants are still using the traditional method first adopted by Belgium in 1902, which involves flocculation, sedimentation, filtration and disinfection with chlorine or other chemicals, but it was invented at that time only to kill germs, notes the Southern Metropolis Weekly.

To deal with heavy metals, ozone/activated carbon processing has become essential, says Xie Zhiyong, manager of the No.3 Dongjiang Water Treatment Plant in Dongguan.

Our facility does not have the technology and equipment for that process, but the plant's water source is comparatively clean and doesn't require it, says Xie.

Nevertheless, the sources for many water treatment plants have deteriorated over the years, so traditional techniques can no longer ensure that unboiled tap water is safe to drink, especially when the sources are contaminated by pollutants such as heavy metals and other chemicals, he adds.

In the first half of 2012, 15.5 percent of the country's surface water fell into class 5, the lowest ranking on the Water Quality Index, while 51.5 percent ranked between 1 and 3. 33 percent fell into class 4, according to Southern Metropolis Weekly.

Of the seven major river systems, water quality in the Yangtze and Pearl rivers remains stable and in good condition. However, pollution in other rivers is much more serious, says the magazine.

Currently, only surface water that falls into class 1 or 2 is usable, while the rest challenges the efficacy of traditional treatment methods, says Song Lanhe, chief engineer of the Quality Monitoring Center for the Urban Water Supply.

This means that less than 50 percent of the country's water resources are eligible for treatment plants, which forces them to constantly look for new resources, he says.

Since 1990, Shanghai has changed its resources for water treatment plants many times, switching from the Suzhou River to the Huangpu River, and then from the Songpu to the Yangtze.

The water quality of lakes is not much better, so the problem in cities is often more severe. Beijing and Guangzhou msut divert water from other places to meet the demand of urban development, says Shi Lei, an environmental expert at Renmin University.

However, water diversion not only costs a tremendous amount of money; it also causes many ecological and environmental problems that may lead to permanent damage to river systems, so it can never be the ultimate solution, according to Liu Wenjun, a professor specializing in drinking water treatment at Tsinghua University.

In recent years, more and more international water service providers have rushed into China to capitalize on the country's water problems. Most of these companies devote themselves to improving water quality, preserving resources and producing cleaner drinking water with new technology.

The government should encourage investment in this field and facilitate the promotion of the industry, experts agree.