Novel methods and apparatuses are disclosed for the treatment of wastewater to reduce often associated offensive odors by promoting aerobic conditions through decreasing the amount of oxygen required to maintain aerobic cultures and/or aerobic biological activity in the wastewater. Also, the wastewater is screened or otherwise separated the wastewater to remove or concentrate the solids which are anaerobically digested. By concentrating the solids, a smaller digester can be used. The anaerobic digestion produces biogas that may be collected and used, or burned by a flare or oxidized by a semipermeable membrane to deodorize the biogas. The heat produced from the biogas may have a variety of uses, including raising the temperature of the anaerobic digester and the bacterial metabolism. The wastewater is also clarified to remove nitrogenous and organic carbon wastes.
RELATED APPLICATIONS
This is a Continuation in Part of U.S. application No. 09/789,265, entitled "Methods and Apparatuses for Treating Wastewater," filed on Feb. 20, 2001, and now issued as U.S. Pat. No. 6,630,072.
A system and method of wastewater treatment in a tank provides large mixing bubbles generated in the lower portion of the tank. In embodiments providing aerobic wastewater treatment, the system further provides oxygen to the wastewater by way of tiny aerating bubbles provided by diffusers. At least one sensor in the tank provides measurements of at least one wastewater treatment parameter such as total suspended solids, dissolved oxygen, ammonium or nitrate. An automatic controller in the system, responsive to measurements provided by the sensor, adjusts the rate of mixing provided by the large mixing bubbles. In some aerobic embodiments, the controller, responsive to measurements from the sensor, further adjusts the rate of oxygenation supplied to the wastewater by the tiny aerating bubbles.
A system and method of aerobic wastewater treatment provides large mixing bubbles along with small oxygenating bubbles supplied by diffusers. The mixing bubbles are large enough to move wastewater and generate a mixing current as they rise to the surface. The mixing current mixes the wastewater, bacteria and other microorganisms, and the small oxygenating bubbles from the diffusers to promote the bacteria and other microorganisms' conversion of the pollutants contained in the wastewater. The mixing provided by the large mixing bubbles enhances the efficiency of wastewater aeration provided by the small oxygenating bubbles.
A system for wastewater treatment comprises a tank and includes a mixer that generates large mixing bubbles, for example a bubble having a largest dimension of 6 inches to 10 feet. In some embodiments, the mixer is located in the anoxic zone. The mixing bubbles are large enough to move wastewater as they rise to the surface and generate a mixing current in the wastewater. The mixing current mixes the wastewater, and bacteria and other microorganisms to promote the bacteria and other microorganisms' conversion of the pollutants contained in the wastewater. The system further comprises an Integrated Fixed-film Activating Sludge (IFAS) system.
A system and method for converting animal waste, in the form of waste slurry, to energy and useful byproducts. A screen mesh filters out large objects from waste slurry and the filtered slurry is chopped and fragmented to reduce binding of fibrous materials. The fragmented slurry is mixed at a rate to maintain solids in the fragmented slurry in suspension while minimizing aeration and turbulence within the mixing unit. A solids recovery unit recovers about 95% of the suspended solids. A polymer is introduced into the solids recovery unit for providing agglomeration of solids particles. The recovered solids are gasified to produce at least methane/ethane gas. The produced gas is provided to an energy production unit to generate electrical and/or heat energy. Liquid remaining after the solids recovery is treated to remove undesirable contaminants to an extent in compliance with water quality standards set for animal waste flushing, animal washing and animal drinking water, as the case may be.
A method and apparatus for removing settleable solids and unsettleable solids from a partially closed flush system in a diary milking operation whereby a first processing tank bottom removes settleable solids contained therein where the net current flow vertically in the process tank is less than the settling rate of the settleable solids contained therein. The process tank batch feeds a plurality of thickening tanks that are each allowed to settle for a period of time before transferring fluid is to a second separator. The method and apparatus is particularly conductive for feeding a digester.
