Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
2000-03-24
2002-06-04
Upton, Christopher (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
C210S620000, C210S622000, C210S617000, C210S151000, C210S175000, C210S176000
Reexamination Certificate
active
06398959
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus and method for the purification of agricultural animal waste and, more particularly, to a system for treatment of manure and wastewater and the reuse of wastewater produced and as a byproduct of agricultural facilities.
2. Description of the Background Art
Over the past decades there has been a shift from smaller localized family farms toward larger integrated confinement agricultural operations. Specifically, large agricultural operations referred to as concentrated animal feeding operations (CAFO's) may utilize confinement barns to house a large number of livestock such as swine, poultry or dairy cows. Using the swine industry as an example, often numerous hog-(CAFO's) are grouped in close proximity forming “mega-farms” which may house tens of thousands of hogs. Similarly, the dairy industry operates using large factory farms that house thousands of animals in a relatively small land area. While these larger agricultural operations have numerous advantages, attendant with these larger facilities are pollution problems relating to the handling and treatment of manure and wastewater (hereinafter collectively “wastewater”). By way of example, pollution problems associated with liquid animal waste, such as produced by the swine industry, include nitrogen, phosphorus, solids, bacteria and foul odors that result from anaerobic digestion. Environmental concerns more specifically center on odor and water quality issues.
Currently, most agricultural facilities use anaerobic digestion for treatment of animal wastes and wastewater. The primary reasons for using anaerobic digestion is simplicity and cost. Wastewater is simply discharged from the animal storage facility into an open lagoon or plurality of lagoons (ponds used to store and treat thousands to millions of gallons of animal waste) where the waste undergoes natural anaerobic digestion. After retention in the lagoon system, wastewater is usually land applied via spray irrigation. However, over forty (40) noxious gases may be emitted from anaerobic lagoons at hog and/or dairy farms including ammonia, methane and hydrogen sulfide. Additionally, the time required for digestion of the organic wastes is relatively long, from weeks to months. Some current regulations require a residence time of 180 days for animal waste facilities using anaerobic lagoons for digestion. Neighbors find odors emanating from lagoons, confinement houses, and fields onto which wastes are sprayed to be a nuisance. In fact, as a result of odor problems associated with anaerobic lagoons, certain states have legally mandated buffer zones or designated land areas between lagoon sites and populated areas.
Oftentimes, the reduction of organics and nutrients within an anaerobic lagoon is minimal and therefore high quantities of nitrogen, phosphorus, etc. are applied to the land during spray irrigation. These nutrients readily build up high residual concentrations in the soil, leach directly into the groundwater or run-off into surface waters causing algal blooms, oxygen deficiencies and fish kills.
New studies have also shown that lagoons are leaking and there have been pollution problems with the groundwater, rivers, lakes and coastal waters primarily in states where the high concentrations of hog or other farms are located. Another problem attendant with traditional anaerobic settling lagoons is that occasionally the water overflows the lagoons or the earthen containment berms collapse, primarily during periods of heavy rainfall, and the wastewater runs-off into streams, rivers and lakes, causing severe pollution problems. When wastewater escapes from these lagoons, either resulting from overflows or other failures, the high concentration of pollutants has adverse effects on the receiving waters and commonly results in groundwater contamination and massive fish and other aquatic life kills.
The most critical problem in the recent past has been with the microorganism
Pfiesteria piscicida. Pfiesteria piscicida
is a dinoflagellate related to the species of dinoflagellates that cause “red tides”. This bacterium has the ability to take on up to twenty four (24) different forms during its life cycle and can attack and kill fish within hours. Recent outbreaks of
Pfiesteria piscicida
could be attributed to the increase in nutrients in the water or to the weakening of the fish due to stress caused by lack of oxygen and/or elevated ammonium levels, among other factors.
By way of example, hog anaerobic lagoon liquid effluent has nutrient characteristics including high levels of biochemical oxygen demand (BOD
5
), Total Nitrogen (TKN) and Total Phosphorus that cannot be decreased to acceptable levels by anaerobic treatment alone.
Even with bacterial digestion within an anaerobic lagoon, significant amounts of sludge accumulate in an anaerobic lagoon. Anaerobic lagoons may fill to capacity fairly quickly which displaces the designed retention capacity of the lagoon fairly quickly and often serve to provide only partial pretreatment.
Hogs produce two to four times as much waste, per hog, as the average human and, in North Carolina alone, hogs produce about 9.5 million tons of manure a year. Dairy cows produce up to 20 times as much waste, per cow, as the average human. Therefore, a great deal of land is required for spreading the highly concentrated waste since often no discharge is permitted from animal waste facilities. Farmers who specialize in raising large quantities of animals are forced by regulations to use larger and larger areas of land in which to spread the large quantities of wastes generated from higher numbers of animals. This has, and will continue, a trend toward having to sacrifice more land to simply dispose of the waste. The land utilized for land spreading of waste cannot be just any land rather must be carefully selected or altered so as to prevent any rainfall runoff discharging into any surface waters. The land must be planted with species capable of tolerating high nitrogen and high phosphorus containing wastes. The farming industry is running out of places to spread or spray the waste from lagoons.
At least one state has imposed a moratorium on new hog farm facility construction until such time as a solution can be devised to resolve agricultural wastewater treatment issues. Additionally, in North Carolina, owners of existing agricultural waste management systems which were constructed prior to Dec. 31, 1993, must register with the state and have their animal waste management plan certified by a technical specialist.
Continuing efforts are being made to improve agricultural and animal waste treatment methods and apparatus. By way of example, note U.S. Pat. No. 5,472,472 to Northrop and U.S. Pat. No. 5,078,882 to Northrop. U.S. Pat. No. 5,472,472, discloses a process for the transformation of animal waste wherein solids are precipitated in a solids reactor, the treated slurry is passed to a bioreactor zone where soluble phosphorus is precipitated with metallic salts, the slurry is aerobically and anaerobically treated to form an active biomass. The aqueous slurry containing bioconverted phosphorus is passed into a polishing ecoreactor zone wherein at least a portion of the slurry is converted to a beneficial humus material. In operation, the system requires numerous chemical feeds and a series of wetland cells comprising microorganisms, animals and plants. See also U.S. Pat. Nos. 4,348,285 and 4,432,869 to Groeneweg et al.; U.S. Pat. No. 5,627,069 to Powlen; U.S. Pat. No. 5,135,659 to Wartanessian and U.S. Pat. No. 5,200,082 to Olsen et al. (relating to pesticide residues); U.S. Pat. No. 5,470,476 to Taboga and U.S. Pat. No. 5,545,560 to Chang.
Another grouping of background patents are those which disclose methods of treating wastewater rich in nutrients. Note U.S. Pat. No. 5,626,644 to Northrop; U.S. Pat. No. 4,721,569 to Northrop; U.S. Pat. No. 4,183,807 to Yoshizawa et al.
Another grouping of background patents are those which disclos
Derrick, Jr. John R.
Samad Nidal A.
Teran Alfredo J.
Willoughby W. Todd
Wood Richard G.
Agrimond, LLC
Smith Ronald E.
Smith & Hopen , P.A.
Upton Christopher
LandOfFree
Aerobic treatment of liquids to remove nutrients and control... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aerobic treatment of liquids to remove nutrients and control..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aerobic treatment of liquids to remove nutrients and control... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2942984