Question

Read the following statements and select the incorrect statement related to integrated waste water treatment at Arcata town.

• A. It is safeguarded by ‘Friends of the Arcata Marsh’
• B. In this approach, wastewater is treated using non-conventional methods only
• C. The wastewater is allowed to flow through a series of six connected marshes
• D. The plants, algae and other microorganisms present in the marshland neutralise and absorb the pollutants

Answer 1

The correct option is B In this approach, wastewater is treated using non-conventional methods only

Integrated waste water treatment involves coupling of both artificial and natural processes to treat wastewater including sewage.

The residents of Arcata town in California, in collaboration with Humboldt University, have created an integrated waste water treatment process within a natural system at Arcata marsh. It is safeguarded by ‘Friends of the Arcata Marsh’ (FOAM). Hence the statement in option a is correct.

The cleaning occurs in two stages:

• Conventional treatment - In the first stage of wastewater treatment, the waste water is subjected to sedimentation (a physical water treatment process using gravity to remove suspended solids from water), filtering (removes particles by filters) and chlorination (disinfection process to kill microbes). However, a lot of dangerous pollutants still persist. Hence the statement in option b is incorrect.
• Innovative approach - The waste water is allowed to flow through a series of six connected marshes spread over 60 hectares of marshland. The plants, algae and other microorganisms (bacteria, fungi) present in the marshland neutralise, absorb and assimilate the pollutants and the waste water gets purified naturally. Hence, statements in option c and d are correct.

Figure: The integrated waste water treatment at Arcata Marsh