Liquid purification or separation – Processes – Treatment by living organism
Reexamination Certificate
2000-08-07
2002-09-10
Simmons, David A. (Department: 1724)
Liquid purification or separation
Processes
Treatment by living organism
C210S617000, C210S629000, C210S747300, C210S150000, C210S167150, C210S170050, C210S219000, C210S903000, C210S908000, C210S926000, C119S227000
Reexamination Certificate
active
06447681
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wastewater treatment system and method of using same. More particularly, the present invention relates to a new and improved wastewater treatment system having a unique combination of three subsystems for employing biological, microbiological, and mechanical means to remove water contaminants in an aquaculture operation application, and other applications.
2. Description of the Related Art
As health conscious Americans begin to consume more fish products and the naturally occurring sources of fish become depleted, there is a growing need to fill the demand for fish products by turning to aquaculture. Aquaculture is defined as the production and husbandry of aquatic plants and animals in controlled environments. The term husbandry means the application of scientific principles to farming. Controlled environments are directed or regulated production environments ranging from a low level of control, termed “extensive,” where limited capital and management are applied, to a high level of control, termed “intensive,” where more comprehensive capital and management are applied to production.
Aquaculture has become a one billion dollar industry in the U. S. Nearly 15% of our seafood supplies are currently supplied by aquaculture. Growing at a rate of 20% per year, aquaculture is the fastest growing sector of the agriculture industry. Aquaculture is an ecologically efficient means of providing seafood for American consumers while significantly reducing pressure on our limited wild fisheries resources.
Foreign competition is having a major impact on U.S. aquaculture operations. More than 60% of our seafood supplies are now imported, resulting in a large annual trade deficit ($6.9 billion). A growing fraction of aquaculture imports comes from the warm climates of South America and Asia. These countries have the advantage of lower production costs by using abundant quantities of warm water that are available in the tropics. Often there are few or no environmental laws controlling their discharges which result in environmental degradation and little or no overhead costs associated with complying with environmental laws. Imports of fish grown in Colombia, Costa Rica, Ecuador, Taiwan, China, and Indonesia have increased markedly as the foreign competition adopts new culture technologies, often developed here in the U.S. These competing products are produced with low energy, water, labor, and environmental costs. As a result, many U.S. aquaculture products are not competitive with foreign aquaculture products.
Efficient, economical and productive aquaculture in the United States would meet the growing demands of fish in the American diet, would remove a huge burden on our natural wildlife resources and would also reduce our dependence on imports.
However, the industry of aquaculture is threatened by the environmental pollutants sometimes associated with the discharge of untreated fish farm effluents. The future existence and potential for expansion of the industry is in jeopardy unless methods can be developed to reduce the nutrients in the effluents emanating from fish farms that cause eutrophication in the receiving waters. Cage culture systems and pen culture farms are also hampered by nutrient contamination of ground water aquifers, drinking water reservoirs, and sensitive coastal estuaries. Catfish production in Mississippi is threatened by ground water overdraft, saltwater intrusion, and concerns about potential land subsidence.
Treatment of aquaculture wastewater to meet U.S. Environmental Protection Agency (EPA) effluent discharge regulations requires removal of settleable solids. Often treatment of dissolved nutrients is mandated as well. Many states are developing more rigid standards for biological oxygen demand (BOD), ammonia, total nitrogen, settleable solids, suspended solids, and phosphorus in an effort to prevent eutrophication and further degradation of natural resources. The EPA recently published a notice of proposed rule making in the Federal Register indicating that they will adopt guidelines and standards for effluents from concentrated aquatic animal production facilities by July 2004.
In order to address these issues, a broad spectrum of water treatment equipment has been marketed for years to treat virtually all of the pollutants created by fish and other farmed aquatic animals. However, the equipment currently available is based primarily on technologies developed for municipal sewage treatment that have been designed for heavily concentrated waste streams. Typically, the designs require large capital and operating budgets which can only be borne by governmental agencies and municipalities.
In addition, aquaculture facilities require a much higher degree of water quality for recycling than required by most treated municipal wastewater. Most of the existing technologies are generally not up to the task of producing high quality treated water suitable for aquaculture. In fact, the treated final discharge from a municipal sewage facility is often of poorer water quality than a totally untreated discharge from an aquaculture facility.
In general, intensive water treatment techniques have primarily been applied to closed-system aquaculture production processes. Closed system aquaculture utilizes purified recirculated water in the system. There have been several attempts over the past decade to develop closed system aquaculture operations in the U.S. Intensive, completely recirculated closed systems have been developed for tilapia, sturgeon, striped bass and catfish production.
The high cost of production associated with the expensive water treatment systems create a situation in which the price of the fish produced are not competitive on an open market when compared to fishery products and imports. In order to accommodate the high overhead expenses, many of these operations have resorted to selling product to a limited live fish retail market. These high production costs as well as numerous disease problems and off-flavor problems caused by poor water quality associated with closed systems have demonstrated that this method of production is impractical and unprofitable, at this time.
The use of traditional water treatment technologies has not been successful in commercial production to date and there have been many notable failures by companies attempting to use these methods. Each of the facilities cost millions of dollars to build. The types of treatment technologies that each of these companies utilized relied heavily on industrial design waste treatment components. These methods of waste treatment are expensive to purchase and operate and the resulting poor water quality often leads to disease and off-flavor problems. Even if the machinery functioned as was hoped, the operating costs were too high for what is essentially a farming venture to afford over the long term.
Unfortunately for the aquaculture industry, few manufacturers of biofiltration equipment have been able to develop truly low-cost technologies to meet the needs of this industry. Most existing biofiltration systems have been developed for the municipal sewage and manufacturing waste industries, fields in which significant public tax revenue or private profit margins have been available. The result has been the development of high-tech treatment components constructed of stainless steel or concrete and marketed by engineering companies focused tightly on high profit margin industries such as refineries and haz-mat cleanup. Almost all currently available water treatment equipment is too expensive to purchase and operate, to be useful and economical in the aquaculture industry.
In intensive, closed system aquaculture, the costs for water treatment often exceed $0.0566 per cubic meter ($70 per acre-foot). This is a relatively high cost that may be justifiable for holding broodstock in hatchery operations or for the production of high priced tropical fish held at low densities. However, water pumping or delivery costs f
Carlberg James M.
Chamberlain Rodney J.
Massingill Michael J.
Van Olst Jon C.
Clarke Richard D.
Kent Sea Tech Corporation
Prince Fred
Simmons David A.
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