Authorities exceed cleaner waterways target
The proportion of the city’s level 5, of heavily polluted, waterways has been reduced to 8 percent from 38.7 percent two years ago, the Shanghai Water Authority said on Monday.
The authority’s aim was to reduce the proportion to 12 percent by the end of this year.
The process was challenging as different waterways had different issues.
No matter how many times efforts were made by local authorities to clean up Gaomenjing River in Minhang District it always reverted to a dirty state.
They said the nearby residential complex had finished sewage pipeline renovation and no polluted water was being discharged into the river.
Later, they realized that the force of the water in the river was too weak to wash away the excess nutrients which encouraged the growth of algae.
The solution was to release large numbers of plankton to feed on the algae.
Their excrement was also a natural inhibitor preventing algae from growing back.
Now over 10,000 square meters of water plants cover the riverbed and local authorities no longer have to worry about the water becoming polluted again.