## The Beginning

In 1949, during the time Arcata's first sewers were built, the construction of the town's first wastewater treatment plant was complete. However, the plant only consisted of primary treatment (Figure 1), with no chlorination, and the wastewater was discharged directly into the bay. The problem with having only primary treatment, which only removes solids, is that it does not reduce Biological Oxygen Demand (BOD) and the effluent will carry suspended soils and possibly pathogens as well.[1]

Secondary treatment was added in 1957 when fifty-five acres of oxidation ponds (Figure 2) were built at the facility by diking off a portion of the bay.[2] Time, water, plants, bacteria, and fungi, all contribute to the purification of the wastewater to secondary standards.[3] These treatments were later followed by the addition of chlorination in 1968, which is used to reduce pathogen loads in the wastewater. And dechlorination in 1975, which is the use of sulfur dioxide gas to remove the chlorine from the wastewater.

## Possible Regional Plant

Eureka, a larger city 5 miles south was often dumping raw sewage into the bay, and Arcata's wastewater treatment plant was not adequately treating their wastewater.[1] In 1974, the California State Water Resources Control Board (SWRCB) passed the "Bays and Estuaries Policy," which prohibited discharge of wastewater into bays and estuaries. The only exception of continuing to discharge effluent into the bay was that if it was proven to enhance the quality of the receiving waters. "Enhancement, meaning that the receiving waters would be improved by the discharge or that a beneficial use would be created which couldn't otherwise exist." -Gary Grimm, Regional Water Quality Control Board (RWQCB) Legal Counsel.[4] The city of Arcata was given a period of 90 days by the (RWQCB) to complete studies that would show its disharge would "enhance" the bay, but studies would not be able to be proven without years of study.

Figure 2: Kloop Lake was built during the construction of the enhancement marshes. Photo by: Steven Padilla.

## A Six-Marsh System

Before any of the wastewater is released into the Bay, it must circulate through one of the three treatment wetlands, which removes algae by shading it out to die. At a split flow, some of the water goes through the chlorination facility while some is sent to the enhancement marshes. The wastewater will then circulate through all three enhancemeent marshes which will continue to remove solids, BOD, and nutrients. The six-marsh system consists of:

• Three Treatment Wetlands, completed between 1987-1990.
• George Allen Marsh, completed in 1981
• Robert Gearheart Marsh, completed in 1981
• Dan Hauser Marsh, which used to be a waste area.

From here, water is then returned to the treatment plant.

## References

1. Arcata's Constructed Wetland. Accessed Online. 11/02/2008. http://web.archive.org/web/20090709085717/http://www.ecotippingpoints.org:80/ETP-Stories/indepth/usaarcata.html
2. Arcata Marsh & Wildlife Sanctuary. Accessed Online. 11/04/2008. http://www.cityofarcata.com
3. Arcata Marsh and Wildlife Sanctuary Map and Guide (April 1994). Personal Viewing. 10/17/2008.
4. F.O.A.M. Newspaper Articles. Personal Viewing. 12/09/2008.
5. Wastewater Aquaculture Project & History. Accessed Online. 12/02/2008. http://web.archive.org/web/20150625033720/http://www2.humboldt.edu:80/fisheries/programs/wastewaterhistory.html
Page data
Authors Steven Padilla 2008 CC-BY-SA-4.0 248 No lead section, No main image Steven Padilla (2008). "Arcata Marsh Plant development". Appropedia. Retrieved August 16, 2022.
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