The problem
A small river section that died
A small pond in the Huaihe River Basin was severely covered by filamentous green algae (Spirogyra), emitting a foul odor. There were no signs of life—only empty snail shells. Agricultural waste and pesticide bottles littered the shoreline. Dissolved oxygen levels were low at 6mg/L, and nitrite, phosphorus, and ammonia levels exceeded safety standards.
Our Solution
We cleaned up all pollution sources and manually removed the algae. Then we planted 250 native irises along the pond edge. Dissolved oxygen increased from 6.0 to 9.8 mg/L (Class I standard), nitrite decreased to 0.005 mg/L, total phosphorus to 0.1 mg/L, and ammonia nitrogen to 0.5 mg/L (both reaching Class II standards). Native species returned spontaneously without any restocking. Notably, Spirogyra declined without further removal.
