On Friday I was invited to tour the aquaponics facility at the Clovis Surface Water Treatment Plant. Leon Penney, the Water Production Manager for the City of Clovis, extended this invitation after learning about this blog.
The Clovis Surface Water Treatment Plant is capable of delivering up to 15 million gallons per day of clean drinking water to the city of Clovis, California. And the city government is committed in educating everyone about where we get our water, and about the water cycle on our planet. An excellent way of teaching people about the water cycle is to present a simple closed system – and this is where aquaponics has come in. No, the aquaponics system isn’t creating clean water, it is just a great way to explore the water cycle!
Mr. Penney is driving this aquaponics project along with his regular duties as Water Production Manager. He has received assistance from the City of Clovis and the state of California – but more importantly the aquaponics demonstration system has received eager assistance and donations from local Clovis businesses.
The original plan for the system was pretty simple. A tank of fish, some grow beds, and a sort of plastic and electrical conduit hoop house for everything.
Instead, as you can see here, Lowes donated much of the materials needed to create a geodesic dome out of pressure treated lumber, Home Depot has assisted with some of the hardware. The Fresno Metropolitan Flood Control District assisted by giving the project a $2000.00 grant. Guardian Glass and Anlin Windows have supplied tempered glass cut in the proper shapes for the dome. Pacific Gas and Electric has supplied a 40 amp solar panel and the City of Clovis has provided a 15 amp solar panel – and when completed the entire aquaponics facility will be powered from solar and batteries.
I took plenty of pictures during the tour, and have them all available on my Flickr page. I’ll also link to individual images of interest here.
The facility is still under construction, but it already houses donated fish, bluegill, bass and crappie all living together in an 800 gallon tank. There are also a few Tilapia fingerlings left from an earlier purchased shipment. They haven’t done very well.
The Tilapia were purchased from an online vendor who didn’t check any relevant California law before mailing them. In Fresno County it is unlawful to raise Tilapia. Mr. Penney spoke to the local California Department of Fish and Game represenative to get an exception to the law. The DFG took his request all the way to Sacramento, where the Clovis Surface Water Treatment Plant Aquaponics Display was classifed as a educational demonstration and issued an exception to the current law.
The good news to take from this is that Sacramento is being petitioned all across California by fish growers to be allowed to raise Tilapia, and lawmakers are seriously considering changing this law.
The tank is a container spill tray – it was used as a chlorine containment tank (A secondary spill tank) from an old well site that is no longer in use. These tanks are usually expensive and out of the reach of most aquaponics hobbyists, but Mr. Penney got this tank for free. He buried the tank half underground so that it will be the lowest part of the water cycle – all water eventually runs back to this tank. In the photo you are only looking at the top half of the tank.
The grow beds are constructed out of modified Intermediate Bulk Containers (IBCs) connected to plastic pallets. These IBCs are donated, and have only contained food-grade items in the past. Mr. Penney only needs to rinse them before use. He is already growing some plants in pots and in IBCs, but not connected to the aquaponics because that plumbing is not complete. Plastic drainage pipes packed with gravel will be used to support the grow beds at a convenient height inside the dome. Right now it is not completely decided what kind of grow media to use. Expanded clay is a favorite, but gravel is cheap and easy to come by for the City of Clovis. Coconut coir is also under consideration as a grow media. It has an advantage of allowing the growth of root vegetables, but it can break down and clog an aquaponics system.
You can see here that the inside of the dome is still under construction, and that panels of glass are being attached by calk adhesive. The dome has been built under permit by the City of Clovis, and is rated by a structural engineer / architect as “overbuilt” in other words, extremely safe.
In the Central Valley, summer heat is a big problem, and a glass box in the sun is also called a solar oven. Since it isn’t a good idea to cook your fish and vegetables before they finish growing, Mr. Penney is adding several methods of cooling to the dome. The top glass panels of the dome are hinged to allow them to open to release excess heat. This will be operated automatically by a heat activated actuator. (Here’s an example.)
Besides vents, there is also a pair of 12 volt radiator fans donated from Clovis Foreign Auto Wreckers. They were the largest fans that they had! There is also a misting system, and Mr. Penny explained that the glass panels may eventually be treated to reduce the ultraviolet in order to reduce the greenhouse effect of the glass. Alternatively, he may instead use sun shade material designed for plants.
The aquaponics will be a flush and fill type of system driven by pumps on timers. Since the entire system is 12 volts, Mr. Penney had some difficulty finding 12 volt timers. He examined several battery powered garden timers for feasibility, but they were all stuck with a maximum of 5-10 cycles per day. This is not enough to run a system that is expected to flush and fill a few times per hour. But he hit on an ingenious solution. He used school bell timers! Here you can see the timers installed into the dome electrical panel. These timers cost about $10, and offer more than enough cycles per day. They are the ZYT08 programmable school bell timer, and you can find them here.
The dome has four of these timers installed, each controls a different function – aeration pump, grow lights, circulation pump, and fan/misters.
Mr. Penney has also started building specialized 12 volt grow lights for the plants. These lamps each contain two red LEDs and one blue LED for the mixture of mauve light needed for photosynthesis. These are high output LEDs, so I was surprised at how much power they used. One lamp will use just under 120 watts of power. They will be placed on a timer to supplement the daylight. When turned on, they are very bright!
A black soldier fly composter is also being tested. This is a converted plastic trash tub on wheels that currently lives in an outdoor accessible closet at the water treatment plant. Eventually the composter will be on display inside the dome, and will be discussed during classroom tours. To keep the “ick” factor down for the kids, soldier fly larva are not being called “maggots”, instead they are called “grubs”. They live on a diet of coffee grounds provided by Starbucks, and on whatever waste the dome generates. The pupa of these flies are fed to the fish. Some are allowed to escape to adulthood and lay eggs for the next generation of fish food.
As I’ve said, this project was originally supposed to be very simple. A down and dirty greenhouse with a basic aquaponics system inside. Mr. Penney was pleasantly surprised at just how generous the local businesses have been with their time and materials.
Also to be congratulated for their efforts are the rest of the staff at the Clovis Surface Water Treatment Plant – all who have pitched in. One person who stands out is Mr. Bill Hasson, the carpenter for the dome. As a woodworker myself, I couldn’t help but be impressed by the hexagonal gussets holding together the mitered ends of the 2×4 trusses for the dome. All screws were torx headed deck screws and the lumber is treated to resist the elements.
You can see the whole photoset at my Flickr page. If you have comments or questions for Mr. Penney, leave them here and I’ll direct them to him.
I can’t wait to see the whole aquaponics dome up and operational. I expect good things from this!
25 October 2011 edit: Corrections made about doners and details of construction.
28 October edit: minor correction made to calm down people on Reddit who assume an aquaponics system actually makes clean drinking water. That is not what aquaponics systems do.
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