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Systems in Use for Arcata Wastewater Treatment Plant
Systems involved with Wastewater Treatment and Aquaculture of Arcata Marsh
- Treatment of incoming water from Wastewater Treatment Site
- Fish Egg Incubator
- Juvenile Fish Rearing Pens
- Yearling ponds
- Adult Fish Hatchery ponds
Incoming Material (effluent) from Wastewater treatment plant
- The water that is treated at the plant is pumped and mixed with saltwater from the bay to produce a mixture that the fish can survive in.
- This is accomplished by a pump at the headgates that controls water salinity as well as a forced air pump that helps regulate dissolved oxygen and screens water for dangerous compounds.
- Prior to 1991 the systems were all closed, but with the addition of numerous pipes connecting the ponds, it is now a continuously flowing system.
Fish Hatchery Systems
The growth cycle of the fish at the marsh is as follows:
- Egg incubators
- Recirculating Rearing Pens
- Yearling ponds
- Adult fish ponds
- Release or transportation for continued use
Figure 2- Diagram of the AMWS ponds for HSU Fisheries aquaculture project. Map from AMWS Aquaculture Page.
Each stage of the Hatchery has specific guidelines that must be followed to achieve maximum output of fish and maximum fish health. During each stage of fish life, different conditions are needed, and they are simulated through the different environments described below.
- The system uses trays of eggs that are constantly being treated with flowing water.
- The water is drawn from a 500 gallon reservoir located underground.
- Water exiting the system as well as returning to the reservoir is run through filtration systems to insure that dissolved organic material is removed from the system.
- Fry and Fingerlings (fish development stages) are kept in rearing pens under a 2000 gallon recirculating system.
- Sterilizing and filtration system are in place to ensure water quality and fish health.
- Two chamber plastic lined tanks are used to hold the fish, they also include rocks and oyster shells to mimic natural habitat.
- Here the fish are in ponds where they reach the smolt stage of life, preparing to become an adult. These are shown in Figure 2, they are the southern most ponds.
- North Pond and South Pond are both used to house the adult fish which have made it through the adolescent stages of growth, they are the largest ponds and have the largest fish.
Information referenced from:
- Fish Hatchery Tour
- AMWS Aquaculture Page- http://www.humboldt.edu/~ere_dept/marsh/aquaculture.html
- Salmon Life Cycle Page- http://www.angelfire.com/ego2/salmonguy26/#Fry