Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
2002-08-05
2004-08-10
Prince, Fred G. (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
C210S622000, C210S623000, C210S195200, C210S259000, C435S262500
Reexamination Certificate
active
06773594
ABSTRACT:
The present invention relates to a system of waste-water purification in cattle-breeding systems, more specifically in relation to manure processing, wherein the products to be produced from the manure are deployed as much as possible at the location where the residue is produced. This is mainly energy and water.
Domestic farming animals such as pigs, cows, horses, rabbits and furred animals produce urine and feces; chickens, by contrast, only produce solid manure.
Producing meat/eggs in the current production techniques has a great environmental impact when the discharge of residues from farming is involved. Air, soil and groundwater are subject to undue application of manure, so that the natural equilibrium is disturbed. In the current view, these residues are regarded as waste matter, but in the present invention, this waste is regarded as a raw material for a recycling process. The starting-point is that the waste is processed/treated so as to yield a product which, either at the farm direct, or indirectly, generates a surplus value for the producer of the waste. In the present invention, manure is regarded as “raw material” which, after being processed, yields an economic surplus value to the stock farms.
In intensive stock-farming, animals, such as cows, pigs, sheep, goats, chickens, furred animals, and the like, are housed on grids. The manure produced by the animals falls through the grid and is collected in a subjacent pit. The collected manure consists substantially of a combination of urine with solid manure. This mixture causes ammonia emission, both in the stable and when stored outside, which may lead to acidification. Also, it is undesirable for man and animals that in the housing/working space too high a concentration of ammonia gas is present. This may give rise to diseases of the lungs and liver and to reduced growth.
To obviate the problem, it is attempted to remove the manure mixture from the stable as fast as possible. This is done, for instance, by providing flushing drain/discharge drains, whereby any manure produced is discharged from the stable as fast as possible.
Another solution to this problem is found by keeping urine and feces separate on a conveyor belt. A belt arranged at a slant, or a spherically or semispherically shaped belt, causes the manure to run directly to the lowest point of discharge, either to a parallel discharge drain (drains) or along a drain integrally formed on the belt. The amazing attendant effect is that the enzymatic action is undone and through the absence of direct contact between manure and urine, no ammonia formation can arise.
Such a method already solves many problems, but what remains, obviously, is the necessity of the further processing of the residue streams, such as the solid manure constituents and the liquid manure constituents, but also the contaminated air from the stable. Further, there is an ongoing need for the furthest possible integration of the various processing systems.
Accordingly, the present invention concerns an integrated system for the purification of various residue streams of intensive stock farming, which are all grouped around the waste-water purification.
Accordingly, in a first embodiment, the invention provides a method for purifying waste water using microorganisms, preferably originating from an integrated stock farming system, which method comprises supplying waste water to a non-aerated section of a biological waste water purification plant, supplying the effluent of said non-aerated section to an aerated section, recirculating at least the greater part of the microorganisms and at least a part of the effluent of the aerated section to the aerated and/or the non-aerated section, and separating at least a part of the effluent using a membrane filtration.
In combination with this waste-water purification, an integrated system for a stable has been developed, which is based on the surprising insight that a far-reaching integration and compaction is possible.
If, accordingly, in the stable means are arranged that provide for, an immediate separation of urine and solid manure, it becomes possible to reuse the various product (waste) streams from the stable, without necessitating unduly dimensioned and complicated operations (purifications).
The invention now provides an integrated system for stock farming, in which the material streams, gas, solids, liquid, coming from the stable can be reused in a useful manner.
In the broadest embodiment, the invention concerns a method for purifying waste water using microorganisms, preferably originating from an integrated stock farming system, which method comprises supplying waste water to a non-aerated section of a biological waste water purification plant, supplying the effluent of said non-aerated section to an aerated section, recirculating at least the greater part of the microorganisms and at least a part of the effluent of the aerated section to the aerated and/or the non-aerated section, and separating at least a part of the microorganisms using a membrane filtration, the content of microorganisms in the waste-water purification being preferably above 10 g/l.
The liquid manure streams coming from the stable can, after adequate processing, be converted to products that are suitable for reuse in the system. To be considered in this connection is, inter alia, the purification of the liquid fraction in a biological manner in a high-loaded biological purification plant (biological oxidation, nitrification+denitrification). This plant is preferably provided with means for separating the liquid from the biomass, for instance using membranes, rotor separator, sawdust filter, and the like. In any case, the plant is provided with a membrane filtration, with optionally a prior pre-purification, to relieve the membranes. Used as membranes are conventional systems, for instance based on round tubes or on flat membranes. In the case of round tubes, a pressure drop across the tubes of 2 to 10 bar is used, with a flow rate of 5 to 15 m
3
/h, while flat membranes are preferably operated with a reduced pressure, the pressure on the clean water side being preferably between 0.25 and 0.75 bar.
In the biomembrane reactor, the liquid manure component can be processed, the stream being purified by consecutive denitrification and nitrification. This takes place in a reactor in which the content of microorganisms is maintained high (>10 kg/m
3
to 60 kg/m
3
or more) by the use of membranes or other techniques. Through the initial separation of the manure streams, an increased efficiency of such a biological purification of the liquid stream is obtained, which provides great advantages in the compactness of the plant and the operation thereof.
After the purification, the liquid is optionally post-purified through reverse osmosis, if desired after treatment in an algae or duckweed cultivation reactor, or in a reed field.
In the stable, preferably means are present for substantially preventing the formation of ammonia through contact of solid manure and urine, so that also at least a part of the heating requirement can be furnished by using heat coming from the stable in parts of the process. An additional advantage is that there is less ventilation needed, so that in cold periods there is less loss of heat.
The materials thereby obtained can be processed into composted or uncomposted solid manure, biomass, algae or duckweed, which can be combined with any additives in the desired ratio for furnishing an intermediate product for the manufacture of feed.
According to a preferred embodiment, a belt separator is placed under the stable, for instance a conveyor belt which separates the solid and liquid phases from each other. This separator can consist, for instance, of a belt arranged at a slant, having on the low side a discharge drain for the liquid, or a belt whose central axis is higher than the sides, with discharge drains on either side.
If placing belt separators is not possible, it may suffice to separate the manure as soon as it is present in the pits. T
Merchant & Gould P.C.
Prince Fred G.
van der Wijngaart Adriaan Johannes Hubertus
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