Liquid purification or separation – Processes
Reexamination Certificate
2000-10-19
2004-03-02
Silverman, Stanley S. (Department: 1754)
Liquid purification or separation
Processes
C210S500100, C210S903000
Reexamination Certificate
active
06699389
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to methods and devices for using processed straw to remove organic waste (ammonium, nitrites, nitrates, and hydrogen sulfide), from water, effluent and sludge.
2. Description of the Prior Art
Effective disposal of and recycling of organic waste can pose significant challenges. There are many techniques for removal of organic waste from water or for recycling of this waste into fertilizer. Similarly, the removal of organic waste through known processes can yield a useful fertilizer and substrate for plant growth. The availability of processed straw, manufactured according to U.S. Pat. No. 4,924,808 issued May 15, 1990, which is incorporated herein by reference, encouraged its evaluation in a broad range of applications beyond its original intended use as a cat litter.
Organic waste in water, particularly nitrogenous waste, is undesirable and must be removed before the water can be drained into waterways. Increased nutrients are known to harm the ecosystem into which the contaminated waters flow. Furthermore, organic waste, particularly nitrogenous waste, can accumulate in sources of water used in drinking or in agricultural applications as well as in closed aquatic systems, such as aquaria and closed fish and aquaculture systems.
Human and animal waste, including waste from food processing plants and effluent from aquaculture operations are sources of water-soluble nitrate-nitrogen which accumulates to dangerous levels in groundwater, drinking water, ponds, lakes, rivers and estuaries. Consequences of this build-up include poor water quality and the stimulation of unwanted and often dangerous growths of algae, which require nitrate as an essential nutrient. One example is the accumulation of nitrate in aquaria, resulting in algae blooms. A whole industry has been spawned, producing chemicals and devices for algae growth prevention, for removal of nitrogenous compounds, and for testing for levels of these compounds.
In aquaculture environments, nitrogenous waste (ammonia, nitrites and nitrates) result from the metabolic process of creatures living in a given body of water and from decay of organic matter in the water. A great deal of organic waste can accumulate in a confined body of water such as an aquarium or fishery, due to the unnatural overcrowding of animal life in these settings. Accumulation of organic waste is harmful to animal and plant life within these closed aquatic environments. While ammonia and nitrite accumulation can be particularly devastating, resulting in the rapid demise of the inhabitants of the aquarium or fishery, accumulation of nitrates is also harmful to these inhabitants. Removal of nitrogenous waste from water, including nitrates, is therefore desirable.
Contaminated water, whether in an aquarium or a fishery, or in a municipal waste facility, is generally treated similarly to convert nitrogenous waste to nitrates. Water or sludge containing nitrogenous matter, is contacted with a substrate having certain microorganism deposited thereon, where it is aerobically converted to ammonia, nitrite, and later to nitrate. The substrate is often contained within a trickle filter. The microorganisms are of the types best adapted to the nutritional and physical conditions of the treatment system and include certain aerobic chemoheterotrophic bacteria and fungi which often arise by selection from the microorganisms initially present in the waste. For instance, degradation of organic waste and/or animal metabolism often results in production of ammonia, which is aerobically converted to nitrite and then to nitrate by Nitrosomonas and Nitrobacter species, respectively. The process of conversion of ammonia to nitrate is known as nitrification.
Removal of nitrates after decay and treatment of organic matter in water can be achieved in a number of ways. In waste water treatment, the nitrate-containing water either can be discharged, or further treated to remove nitrates, often by assimilation into plant matter. In an aquarium environment, nitrates can be removed by a number of methods. The simplest method for reducing nitrates is through water changes or by assimilation into plant matter. Assimilated ammonia, nitrites and nitrates, as well as phosphates and other contaminants are removed from the enclosed aquatic system by continuous harvesting of the plant matter. Growth of and harvesting of plant matter is often effective, provided the plants and/or algae can be efficiently grown. For many reasons, efficient plant and/or algal growth may be unattainable or undesirable in certain systems as they may clog filtration and piping systems. In marine environments, protein skimming can aid in maintaining lower nutrient levels by removal of organic waste before it can be degraded to ammonia, nitrite and nitrate. Combined with low levels of denitrification (conversion of nitrate to N2) that can occur in anoxic areas of the aquatic system, nitrates can often be effectively controlled. However, achieving very low levels of nitrates through this method is often difficult or impossible to achieve, especially when fish are kept in the aquatic system.
A number of unique methods have been developed to combat accumulation of nitrates in an aquatic system which involve passing a quantity of water into a portion of a filter system where anoxic conditions are present, wherein denitrifying organisms grown. These systems can be difficult, expensive and/or complicated to maintain. There is also a risk that anaerobic production of hydrogen sulfide can result. Therefore there is a need for a simple, inexpensive and safe method for reducing nitrate levels in aquaria, aquaculture and waste water treatment systems and of hydrogen sulfide as well.
Sewage sludge is a by-product created in sewage plants during waste water treatment. A similar sludge results from agricultural waste or animal waste and effluent produced by the animal industry (cattle, especially dairy cattle, pigs, horses, intensively housed sheep and goats, poultry, and aquaculture). Treated, rotted, and partially solidified effluent and sludge is mostly spread on agricultural fields as a fertilizer and growth substrate. The benefits for the agricultural industry are that the nutrients in the effluent/sludge provide various nitrogen compounds, phosphate and potassium salts, which are important for plant growth. Favorable times for the application of sewage sludge are between Fall and Spring since most fields are easily accessible at this time, prior to cropping. However, little to no plant growth at this time makes this impractical because the nutrient use and absorption by the plants range from very little to none. In addition, large amounts of precipitation can wash out nutrients and allow the nitrogen compounds to penetrate into groundwater resources. The elution of water soluble nitrogen compounds is one of the greatest threats to ground and drinking water.
Nitrogen in sewage sludge consists mostly of ammonium-nitrogen (NH4—N). Ammonium-nitrogen is a common compound found in anaerobically rotted sludge. After sludge application, ammonium-nitrogen is converted into nitrate-nitrogen (NO3) within only a few days, making it water soluble and, thus, available to the groundwater. Drinking water has strict limits for both nitrate and ammonium.
It is therefore an object of the present invention to provide a simple, inexpensive and safe method for removal of nitrogenous waste (ammonia, nitrite and nitrate) from water and a filter apparatus for direct removal of nitrogenous waste from water.
It is a further object of this present invention to provide and improve an organic fertilizer having reduced levels of elutable nitrogen compounds, to provide a method for imparting sustained nitrogen release qualities to composted organic material, i.e., effluent/sludge, for use as fertilizer and to provide a method to increase the rate of production of fertilizer from compost.
SUMMARY OF THE INVENTION
A water filtering apparatus is provided, including a porou
Boensch Thilo
Charles Scott
Jöchle Wolfgang
Global United, Inc.
Medina Maribel
Silverman Stanley S.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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