Sewage treatment can be done by integrating artificial and natural processes. Explain this using the example of Arcata town.

Explanation

The people of Arcata with biologists created an intergratd waste water treatment process within a natural system . The cleaning occurs in two stages.
a. The conventional sedimentation , filtering and chlorine treatments are given. The remanining pollutants were removed in the second stage.
ii. The biologists developed a series of six connected marshes over 60 hectare of marsh land. Appropriate plants alage , fungi and bacteria were seeded into this area which neutralise , absorb and assimilate the pollutants. Hence as the water flows through the marshes, it gets purified naturally.