Some embodiments of the present disclosure relate to a method of regenerating at least one filter medium comprising: providing at least one filter medium, wherein the at least one filter medium comprises: at least one catalyst material; and ammonium bisulfate (ABS) deposits, ammonium sulfate (AS) deposits, or any combination thereof; flowing a flue gas stream transverse to a cross-section of a filter medium, such that the flue gas stream passes through the cross section of the at least one filter medium, wherein the flue gas stream comprises: NO.sub.x compounds comprising: Nitric Oxide (NO), and Nitrogen Dioxide (NO.sub.2); and increasing an NO.sub.x removal efficiency of the at least one filter medium after removal of deposits.

Described herein are methods for reducing odors produced from terpenes. The methods involve treating air comprising one or more terpenes in order to reduce the odor. In one aspect, the air comprising the terpenes are circulated through compositions that can convert the terpenes to new chemical species that are not as odorous or possess no odor at all. The methods described herein have numerous applications where terpenes are produced or processed and it is desirable to reduce the odor produced by these compounds.

The present invention is directed to a gas scrubbing process for removing at least one odorous vaporous compound from a gas stream generated by a rendering process or at least reducing the concentration of that odorous vaporous compound. In one embodiment, a series of two gas/liquid contactors is used, each having a different liquid scrubbing solution, with one scrubbing solution controlled at an alkaline pH and the other scrubbing solution controlled at an acidic pH. In another embodiment, the pH of the respective scrubbing solutions in each of the two gas/liquid contactors is reversed.

Techniques for removing sulfur compounds from a sulfur-containing gas stream can include contacting the gas with an absorption solution comprising a metal cation capable of reacting with the sulfur compound to form a metal sulphide precipitate and/or a metal mercaptide precipitate. In addition, the treatment can include controlling a concentration of the precipitates below a threshold to maintain rheological properties; subjecting the precipitate-enriched solution to vitalization; subjecting the precipitate-enriched solution to regeneration including oxidation; and/or other features to enhance the sulfur removal operations.

Certain exemplary embodiments can provide a system, machine, device, manufacture, and/or composition of matter adapted for and/or resulting from, and/or a method for, activities that can comprise and/or relate to contacting an aerobic contaminated gas stream with a solution comprising approximately Ferric MGDA, the aerobic contaminated gas stream comprising hydrogen sulfide.

A method for removing NO.sub.x from flue gas by SCR includes supplying a reagent for the SCR reaction of NO.sub.x into the flue gas, then contacting the flue gas with a catalyst. Supplying the reagent includes supplying a less than stoichiometric amount of reagent, and after contacting the flue gas with a catalyst a final NO.sub.x removal step is provided.

Certain exemplary embodiments can provide a system, machine, device, manufacture, and/or composition of matter adapted for and/or resulting from, and/or a method for, activities that can comprise and/or relate to contacting an aerobic contaminated gas stream with a solution comprising approximately Ferric MGDA, the aerobic contaminated gas stream comprising hydrogen sulfide.

The invention is a device and method for purifying sulfur dioxide and nitrogen oxide in flue gas with an electrolysis-chemical advanced oxidation enhanced ammonia method. The device includes a thermal activation reactor, ammonium hydroxide storage tank, absorption tower, electrolytic bath and crystallization separator. The method takes raw material part of an ammonium sulfate solution that is a reaction product of ammonia and sulfur oxide in flue gas, and an ammonium persulfate solution prepared by electrolysis of an electrolytic bath as an oxidant to enhance the efficiency of purifying sulfur dioxide and nitrogen oxide in the flue gas with an ammonia method. A thermal activation reactor activates an ammonium persulfate containing solution to generate a strong oxidizing SO4..sup., so that NO.sub.x and SO.sub.2 in the flue gas may be more efficiently converted into a product having higher solubleness for enhanced removal of sulfur dioxide and nitrogen oxide in the flue gas.

A method for controlling mercury emissions within a FGD system, the method includes preparing a treatment composition for application on FGD system components, the treatment composition comprising a biocide, applying the treatment composition to an FGD system, wherein the FGD system includes an FGD scrubber, monitoring the bacterial load present within the FGD system, and optimizing the operating conditions of an aqueous system to determine when additional treatment is required.

A device controls levels of carbon dioxide and water in a controlled environment. The device comprises a first electrode chamber, which receives an input fluid comprising first concentrations of carbon dioxide and water and is configured to deliver a first output fluid having concentrations of carbon dioxide and water lower than the first concentrations to a first environment, and a second electrode chamber having an outlet configured to deliver a second output fluid having third concentrations of carbon dioxide and water to a second environment. A reduction catalyst layer in the first electrode chamber reduces carbon dioxide and water in the input fluid to form ionic carrier species, an ion-transporting membrane is positioned between the first and second electrode chambers and comprises carrier species, and an oxidation catalyst layer in the second electrode chamber oxidizes the ionic carrier species to form carbon dioxide and water.