Describe the integrated wastewater treatment project in the town of Arcata,California.

(N/A) The treatment of wastewater,including sewage,can be done in an integrated manner by combining artificial and natural processes.
Such an experiment was carried out in the town of Arcata,situated on the northern coast of California. In collaboration with biologists from Humboldt State University,an integrated wastewater treatment process was developed in two stages:
$(a)$ Conventional sedimentation,filtration,and chlorine treatment are performed. However,many dangerous pollutants,such as dissolved heavy metals,still remain.
$(b)$ To remove these,a series of six connected marshes over $60$ hectares of marshland were developed. Appropriate plants,algae,fungi,and bacteria were grown in these areas,which neutralize,absorb,and assimilate the pollutants,naturally purifying the water as it flows through the marshland.
This marshland also serves as a sanctuary,hosting a high level of biodiversity,including various fish,animals,and birds.
$A$ citizens' group called $FOAM$ ($Friends$ $of$ $the$ $Arcata$ $Marsh$) is responsible for the upkeep and safety of this project.