China’s water worries
As trivial as drinking a glass of water straight from the tap is in Europe, as unthinkable it is in China. 83% of China’s water supply is sourced from surface water from lakes and rivers and many of them do not comply with drinking water standards. Nearly 7% of water samples tested by the Ministry of Ecology and Environment in 2018 were even too contaminated to be used in either agriculture or industry. Of the little groundwater that is available, 60-80% is classified as polluted.
The government has made the improvement of water quality a priority with the Water Ten Plan, which was implemented in 2015 and the first effects are measurable: Most of the major waterways like Yellow, Huai, Yangtze and Pearl river are indeed cleaner, but Liao and Songhua river in northeastern China were found to be even more polluted than in 2017.
City dwellers enjoy good infrastructure
Supplying the growing population with potable water will remain a challenge. It is expected that urbanization will increase until 80% of the population lives in cities, growing from currently 58%. However, already now Beijing, Shanghai, and Tianjin each have extremely low water resources. Aggravating this situation, the technical equipment is not up to par and pipe networks are corroded, thus 10 billion m³ water per year trickle away unused.
The South-to-North water diversion project is an attempt to compensate the imbalance in rainfall between China’s wet south and the dry north. However, its completion will take another 30 years while the consequences of climate change over that period are unforeseeable.
Even if inhabitants could be supplied adequately, what they leave behind needs to be treated as well. Big cities usually have wastewater treatment plants in place, but in rural areas, a lot of communal sewage runs into rivers untreated.
The situation in industries with strong environmental impact has improved by relocating polluters into industrial parks with state-of-the-art waste and wastewater treatment. A lot of the technology used in these plants comes from international companies, among them many German ones. Specialty pumps, membranes for micro- and ultrafiltration, control and monitoring units, as well as analytical equipment, are in high demand. Germany is one of China’s major suppliers of specialty pumps as well as apparatus for water filtration and purification.
Closing loops and getting value from waste
Wastewater technology worldwide is currently undergoing a major change – away from the disposal aspect towards regarding wastewater as a resource. Water reuse, especially in the industry is the fastest growing value driver. In addition, recycling of substances contained in wastewater is becoming increasingly attractive. Phosphorus, for example, can be recycled from sewage sludge and used as fertilizer. The sludge also makes an excellent substrate for biogas production, which can replace natural gas as a fuel. Research on how these techniques can be adapted to the conditions in China is underway in Germany in close cooperation with Tongji University Shanghai.
A trend for industrial wastewater is avoiding it altogether. For zero liquid discharge, membrane technologies up to reverse osmosis are used. The membranes separate water into a permeate that is reused and a concentrate which is further treated. The polluted concentrate is then evaporated and crystallized into a solid “salt cake”. Sometimes even this can be reused or it is disposed of to landfill.
AchemAsia, 21-23 May at NECC Shanghai, is the event to meet leading Chinese and international companies in the water and wastewater treatment sector. They offer the latest in piping, pumps, membrane technologies, analytics and laboratory gear, aiming to bring Chinese water technology to international standards. AchemAsia is the international forum for sustainable chemical production and has been known as a meeting point of Asian dynamics and German engineering tradition since 1989.