Liquid purification or separation – With gas-liquid surface contact means
Reexamination Certificate
2002-06-14
2003-12-23
Popovics, Robert (Department: 1724)
Liquid purification or separation
With gas-liquid surface contact means
C210S615000
Reexamination Certificate
active
06666965
ABSTRACT:
TECHNICAL FIELD
This application relates generally to filtration systems and, more particularly, to a water recirculating system for use in producing fish.
BACKGROUND
Raising fish in water recirculating systems requires nitrification treatment systems that maintain acceptable levels of ammonia and nitrite within a water supply. A water recirculating system needs to be able to oxidize an ammonia load that is generated by fish as a result of daily fish feedings.
FIG. 1
illustrates one type of prior art filtration system
10
that may be used in a water recirculating system. The filtration system
10
includes a chamber
12
that contains microbeads
14
. Microbeads
14
are sufficiently buoyant such that they float on top of filtered water
16
that collects in the bottom of chamber
12
. The microbeads
14
on the bottom are partially submerged in filtered water
16
because they support the weight of the microbeads
14
located above them.
Contaminated water
18
is delivered to filtration system
10
from a number of potential sources, including fish raising tanks where the water supply is contaminated with unsatisfactorily high ammonia loads. Contaminated water
18
is supplied to chamber
12
from above microbeads
14
using any method that uniformly distributes contaminated water
18
over microbeads
14
, such as nozzles
13
arranged in a uniform pattern. Gravity forces contaminated water
18
downward through microbeads
14
where it collects in the bottom of chamber
12
. Contaminated water
18
applies a force to microbeads
14
as it impacts microbeads
14
such that contaminated water
18
submerges some additional microbeads
14
. An exit pipe
20
circulates filtered water
16
back to the contaminated water source.
Microbeads
14
provide a substrate for bacterial growth during operation of filtration system
10
. The bacteria on microbeads
14
utilize the ammonia and nitrite as nutrients for even further bacterial growth. The bacterial growth on microbeads
14
also tends to reduce the buoyancy of microbeads
14
. Heterotropic bacteria living on the same beads utilize fine organic solids as nutrients for growth resulting in water polishing and general improvement in water quality.
One disadvantage of using a system
10
that includes microbeads
14
is that such systems are limited in size. In systems with large chambers, the strong buoyancy of microbeads
14
causes microbeads
14
to short circuit the flow of water through microbeads
14
in some areas of the chamber. Short circuiting the flow of water through microbeads
14
inhibits the ability of the bacteria on microbeads
14
to oxidize ammonia loads in the water passing through microbeads
14
.
The size limitations associated with conventional filtration systems that include microbeads makes it necessary to utilize several chambers when oxidizing commercial ammonia loads (e.g., 9 kilograms TAN per day) that are generated from commercial fish feedings (e.g., 300 kilograms per day). The large number of chambers that are required to handle commercial ammonia loads adds unwanted expense to systems that include microbeads
14
.
SUMMARY
A filtration system having a chamber with a hydraulic loading area that is divided into a plurality of cells such that each cell has a hydraulic loading area less than 2.3 square meters. The system further includes a filter media, such as microbeads, positioned in each cell to filter water passing through the chamber. In some embodiments, the microbeads are spherical and have diameters between 1 mm and 3 mm.
The size limitation of conventional microbead filter systems is addressed by dividing the hydraulic loading area in a large chamber into cells with smaller hydraulic loading areas. The smaller hydraulic loading area through each cell promotes efficient filtering by bacteria that grows on the microbeads in each cell.
Another aspect relates to a water recirculating system for use in producing fish. The water recirculating system includes a fish raising tank that provides an environment for fish to grow. A supply system, such as a pumping system, delivers water from the tank to a filtration system. The filtration system includes a chamber with a hydraulic loading area that is divided into a plurality of cells with smaller hydraulic loading areas. Filter media, such as microbeads, are positioned in each cell to filter the water received from the supply system. A delivery system returns the filtered water back to the tank.
REFERENCES:
patent: 5200081 (1993-04-01), Stuth
Cornell Research Foundation Inc.
Popovics Robert
LandOfFree
Cellular microbead filter for use in water recirculating system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cellular microbead filter for use in water recirculating system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cellular microbead filter for use in water recirculating system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3124462