Dynamic Fish Pond Cleaning System



Fins for Filtration Team
Sponsors	Mechanical Engineering Department Clear Springs Inc.
Team Name	Fins for Filtration
Duration	Fall - Spring 2013/2014
Faculty Advisors	Dr. Steve Beyerlein Dr. Tao Xing
Mentor	Jeremy Cuddihy
Team Members	Jeremy Schroeder Matt Francis Kate Wicher Levi Dawes

Cleaning fish and food waste from fish hatchery raceways is a problem that has yet to be completely solved. The accumulation of waste is a problem because it can lead to disease and cause other fish health related problems. Fish waste and food particles can accumulate at the bottom of raceways and are easily re-suspended in water by turbulent flow or fish movement. The current method of cleaning fish raceways is a very tedious and slow task that does not clean the raceway 100%. The goal for our project is to successfully create an automatic cleaning system for the raceways that would significantly decrease the human component of cleaning, as well as increase the efficiency of the process and quality of the cleaning.

Design Goals

Design an automated cleaning system with little maintenance.
Reduces fine particulate in raceways from accumulating downstream to increase fish health.
Maintains Current Phosphorous levels and Healthy Dissolved Oxygen levels.
Analyses of flow using computational and experimental fluid dynamics.

Design Specifications

Our design must accomplish the following

Fit within the existing specifications of the raceways (only minor raceway modifications)
Be more effective than the current system.
Reduce downstream flow of particulates
- While continuing to produce 5 to 7 cfs of flow in the raceway
Stay within EPA regulations of flow and waste
- Current EPA standards and regulations: http://water.epa.gov/scitech/wastetech/guide/aquaculture/index.cfm

Project Learning

Background Research

Current Methods

A push screen that re-suspends particulate from the bottom and sides of the raceway

Push Screen Method

A vacuum that cleans waste once it has reached the quiescent zone

Vacuum System

Baffle Methods

Increases the flow at the bottom of the raceway to move waste
Has been implemented before but due to problems it is not currently in place

Brine Methods

Injects a solution with a density higher than water and the particulate to float the waste along the bottom to the quiescent zone
Has been tested in a controlled environment but never in an actual fish raceway

Interviews

Scott Williams, Aquaculture Center

Scott has previously worked for Clear Springs Inc. and had a vast knowledge of their operations
Suggested the baffle idea be our main focus due to simplicity and amount of previously tested ideas with same basic design

Ken Cain, Fisheries Immunologist

Ken has also previously worked for Clear Springs Inc.
Suggested we move away from baffle idea because it has been tried many times and has never been successfully implemented
Confirmed that the introduction of a brine solution will not harm fish, but will actually help to kill bacteria in fish gills and scales. We will however have to test the brine method with fish in order to determine the effect fish movement has on brine solution at the bottom of the raceway.

Jim Liou, Hydraulic Engineer

Provided brine solution research and method
Has previously used the brine solution method in a controlled environment (without fish)to test how it works as a waste removal system

Visit to Clear Springs

On November 23rd our design team visited the Clear Springs facility in Buhl, ID. They gave us a tour while we asked questions and discussed design parameters and options. They're facility is primarily a food stock farm (producing fish primarily for food purposes) but it also has a few brude stock (spawning) operations.

Important design restraints gathered from the trip:
- The flow in each raceway is roughly 7 cfs, it cannot drop to below than 5 cfs or fish in the downstream raceways will start to die
- Current QZ zones are cleaned 1/3 at a time and the water from the cleaning goes into an 8 in. pipe and is transported to a settling lagoon from there
- The furthest upstream raceway is the most sensitive to flow change because it has the youngest fish
- Automated cleaning design would be most effective if it were portable from raceway to raceway, rather than a model being built for each individual raceway
- Cost is the number 1 deciding factor

They seemed most interested in our baffle idea because:
- Ease of use
- Low cost
- No modifications to the raceway required
- Possibility for adjustments and easy maintenance
Their thoughts on the movable pump design:
- More effective at cleaning than the baffle
- Would require installation of equipment inside of the raceway
- Outflow would have to be carefully monitored to maintain adequate flow in the raceway
- Could tie into the 8 inch drainage pipe already in place
- Potentially more costly but could clean more effectively and require less man hours than baffle

Concept Development

Baffle Method

Have tested a simple baffle design in our small flume
Exploring several new designs
- Multiple baffles
- Baffle with diffuser
- Movable baffle
This option is our first priority because of its ease of use, cost effectiveness and overall portability

Baffle Systems
Type	Parameters	Test Results
Straight Baffle	Straight baffle spanning entire width of raceway Model Statistics:6" wide X 12" deep 1" gap between baffle and flume floor	Successful in moving solid particulates to end of raceway Particle resuspension could differ in a wider raceway CFD confirmed our results
Multiple Baffles	Includes multiple horizontal baffles	Not tested
Baffle with Diffuser	Would include a diffuser off the back of the horizontal baffle Integrated to fit the current fish herding equipment	Not Tested
Moving Baffle	Would include a baffle on a cart/pulley system to allow downstream movement Would be more costly and difficult to move from raceway to raceway	Not Tested

Moving Vacuum Method

Movable Pump

We have tested two similar methods for this method
Both were constructed from pvc and used siphon methods to create a suction along the bottom of the raceway
- First method had small holes along the bottom of our vacuum piece
- Second method had a small slit along the bottom of the vacuum piece
- There was no noticeable difference between the two in terms of suction
This method is second in priority after the baffle because it is slightly more complex and has the potential to be more costly

Vacuum Systems
Type	Description	Effectiveness	Discharge
Vacuum 1	Made from 1/2" PVC Vacuum opening was 1/16" slit across the bottom facing side of PVC Controlled by syphoning a 1/4" tube and hand dragging across flume floor	Successfully cleaned flume floor of all particulate	To be determined
Vacuum 2	Made from 1/2" PVC Vacuum opening consisted of 14 staggered 1/8" drilled holes Controlled by syphoning a 1/4" tube and hand dragging across flume floor	Successfully cleaned flume floor of all particulate (no different than vacuum 1)	To be determined

Final Design Development

Movable Baffle

Our final design was a movable baffle, designed specifically for our small scale flume, that was pushed by the force of the moving water along the length of the raceway. We found this to be the most effective and cost conscious method available. The final design was also retrofitted with a removable horizontal baffle that extended the distance between the baffle and the cleaning front of the fish bio-solids. This design was displayed at the Engineering Expo by our team on May 2nd. Our team won best technical presentation and judges choice best booth presentation for the work completed.

Movable Baffle and Cart Specifications
Part	Description
Assembly	Full Cart Assembly
Gusset	Gusset used to support baffle connection
Channel	Channel used to hold and adjust baffle
Frame	Machined aluminum frame for attaching wheels and baffle