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AquaRanch™ Systems Liners for Tanks & Ponds Aquaculture in Education Comments & Articles |
PVC... a Versatile Option for Aquaponics By Myles Harston
PVC Tank Liners, PVC Clarifier, PVC Valves, PVC Pipe and Fittings.
Everyday in my work at AquaRanch Industries, I use PVC (Poly Vinyl Chloride), which is a versatile and relatively inexpensive material that has several forms and can be made into many different items, including Flexible PVC Liner Material, Reinforced PVC Fabrics, Ridged PVC Plastic, and PVC Pipe. Many needs for the aquaculturist can be met with some form of PVC. Flexible PVC liner material and flexible reinforced PVC fabrics can be cut into many sizes and shapes and can be welded and glued into many different configurations. Ridged PVC plastic can be welded and glued into many shapes and combined with PVC pipe to satisfy many special needs.
To reduce the initial expense of high cost fiberglass tanks, many growers choose to use fish grade PVC liners. The fish grade PVC liner material we use is unsupported and 30 mil thick. We've chosen to use 30 mil because it is thick enough to get the desired strength (we have found 20 mil to be too thin). Because the PVC liner material is unsupported, it can stretch some to match little nooks and crannies in the tank without tearing, like a Poly Ethylene liner would, and the sides of the liner can be pulled up over the top edge and down the sides to secure the liner in place. A great advantage to using PVC liners and reinforced PVC fabrics is that a variety of custom made fittings can be glued right to the PVC material. We custom make a series of PVC fittings with flexible or rigid flanges that can be bonded to PVC liner material or reinforced PVC fabrics, for the purpose of going through walls and keeping a watertight seal.
A unique A grower in Ohio, Evans Farms, designed and built a trout operation and then ordered fish grade PVC liners to fit his special design. He used aqua colored PVC liners for the fish so he could see the fish, and black PVC liners for the bio-filters and clarifiers. Sharing information about his facility, Mr. Evans explains, "This system has been set up in a converted Hog/Nursery building. This building is approximately 34' x 285' long divided into 13 rooms that are approximately 21' x 30' with a 4' exterior hallway. These rooms have a generally sloped cement floors with 4' of the 8' perimeter walls being concrete. Each room has been fitted with two production tanks by laying 8" cement blocks on the interior of each room and placing an aqua PVC liner in the inner perimeter. Each tank is approximately 9' x 22' in dimension. The remaining area is broken into two 4' x 21' sections. These sections are used as a ring filter and bio-filter, utilizing the black PVC liner."
He continues, "This system is set up as a re-circulating system. In which water is introduced into the ring filter and air lifted in PVC pipe over an interior block wall into the bio-filter. There, it is aerated, and houses bacteria that converts the ammonia in the water down to a state that is not harmful to the fish. This water is then air lifted in PVC pipe to the front of the production tanks and circulates through to the settling area, the solids fall to the floor of the tank and are vacuumed out daily while the water continues over a weir dam and re-circulates back through the system. Each tank has the capacity to finish approximately 3000 lbs. of Trout per year."
Scott Jones, is using fish grade PVC liners and reinforced PVC fabrics in his specially designed raceways in his large-scale commercial aquaponic operation in Philadelphia, PA. He uses PVC black liners because he feels the fish will be more comfortable with the dark liners. Black PVC liners match closely with the native muddy waters that Tilapia frequent in their natural environment. The dark color helps reduce stress and keeps them on their feed more consistently. Scott is using a canal system with white reinforced PVC fabric to move water from the fish to plants and back again, which gives him a considerable cost savings over large diameter PVC piping. We also helped him design and then build a special air header made from reinforced PVC fabric welded in an 18" diameter tube that is 157' long. It has 20 4" PVC flexible flange fittings bonded into the sides of the tube that deliver air to 10 greenhouse aquaponic systems. This will allow him to have one very large air blower with a back up and will save him thousands of dollars in small blowers, both in initial installation and electrical costs.
For years, we have worked closely with the National Marine Fisheries Service making custom products using black reinforced PVC fabric. One design, used often, is called Mesocozm bags. Dr. Massee describes the Floating Marine hatchery they use for the production of lingcod larvae: "Floating bag systems have been used to rear a variety of fish species from fragile marine larvae (Van der Meeren, 1991) to pacific salmon (Heard, 1979). Our current lingcod marine fish culture system is designed to utilize existing net pen cage structures at the NMFS Manchester Research Station as well as to eventually be utilized by commercial salmon net pen operations."
Dr. Massee continues, "Large, black, conical shaped reinforced PVC bags, approximately 1.8 m in diameter Dr. Massee adds, "There are several advantages with these types of systems. These large rearing containers allow the fish to find their preferred depth and light level and also reduce a phenomenon known as wall nosing. Since the PVC bags are floating in the surrounding water, low water exchanges can be used and temperatures maintained. This reduction in water exchange rates also allows the live food organisms to remain in the culture system for a longer period of time. Another advantage is in the relatively lower cost compared to a land based system. The cost of the land, tanks, and associated power costs with a land based system are enormous. The low cost PVC bags and low head pumping costs of the floating hatchery are much more economical. Our current water supply system incorporates a 3 hp Jaccuzi pump, sand filter equipped with a pressure activated auto backflush system, and a UV sterilizer. This system supplies between 400 - 500 L/min. to the PVC culture bags."
Southern Illinois University at Carbondale is using a similar design with reinforced PVC fabric called a vertical raceway to grow hybrid striped bass fingerlings. This design calls for a constant supply of fresh water, which is supplied by an airlift system with the water exiting through a screened bottom. Using a vertical raceway lets them take advantage of deep-water ponds. Their preliminary results are very positive.
Ridged PVC plastic comes in 4' x 8' sheets with thicknesses of ¼" to 1". It comes in gray, white, and clear. Ridged PVC can be cut and made into many shapes and sizes. It can be both welded and glued to itself. It can be welded to PVC pipe and PVC pipe fittings. It can be glued to PVC liners, reinforced PVC fabrics, and PVC pipe. We weld ridged PVC to itself to make several different sizes of Fecal/Particle Clarifiers, Biological Filters, and boxes. We weld it to pipe fittings to create different parts for our Aquaculture Systems, including: the airlift stabilizer, the center/base drain, clarifier outlets and inlets, and ridged flange fittings. We glue PVC fabric mesh to ridged PVC to make clarifier screens. We glue ridged PVC to reinforced PVC fabric to make handles and drains on Bio-bags and to make flexible flange fittings. We have used ridged PVC to make chairs and tabletops. The ridged PVC piece can be screwed onto a base or welded onto a PVC pipe base. Ridged PVC is durable and strong.
Our ridged PVC Clarifier has been sold to over 200 growers. Mark McSpadden of Missouri, has been into aquaculture for a number of years and uses our ridged PVC clarifier. When he started out he was using a filtration system that had him frustrated. He switched to using our ridged PVC Clarifier and had this to say: "Since I converted from the rotating biological filter system from another company to the Fecal/Particle Clarifier system, there has been less maintenance in cleaning and less odor involved when producing fish in an enclosed environment."
PVC in its various forms and colors can be made into many products. Most Aquaculture and Aquaponic needs can be met using one form or another of PVC plastic. We have found PVC to be versatile and pleasant to work with. PVC can be glued and welded to all kinds of PVC. It can be cut and shaped into just about any configuration. We have also found PVC plastics to be economical to the grower. It has relatively inexpensive start up costs and it is easily cleaned and maintained. We highly recommend the use of PVC plastics in your aquaculture system.
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application of creative use of PVC products
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and 4.6 m deep are currently being used. These PVC bags are cylindrical for 3 m, then conical for the remaining 1.6 m and hold 9.3 m3 of water. Each PVC bag is attached to a HDPE ring to which floatation is also attached. The PVC bags float independently within a net pen framework. A PVC pipe, which extends to the bottom of the bag, introduces filtered UV sterilized water. The water exits at the top, creating an upwelling flow pattern. Exit screens are made of 2" PVC pipe with a cut out and the appropriate size screen attached. Each PVC bag is stocked with about 5,000 lingcod larvae and fed a combination of wild zooplankton and enriched artemia nauplii."
of different types of PVC. The fish grade PVC tank liner, the ridged PVC clarifier, the PVC growbed liner with its drain made of reinforced PVC fabric attached to a PVC pipe, the ridged PVC bio-filter and its bio-media, the directional aerators made from PVC pipe frames with attached reinforced PVC fabric and their bio-media, the PVC pipe airlift and it's stabilizer made from ridged PVC welded to PVC Ells, the center piece made of ridged PVC welded to a PVC Coupling, the PVC gate valves, and all the adjoining PVC pipe and pipe fittings.