Abstract: This application relates to improvements to long vertical shaft bioreactors for the aerobic biological treatment of wastewater and aerobic digestion of biodegradable sludges. The invention comprises a flow control device and method which improves hydraulic flow, inter-zonal mixing and gas transfer in such bioreactors. The flow control device includes a ported upper plate which is mounted in an upflow chamber of the bioreactor and a lower plate located below the upper plate at the juncture between mix and plug flow zones of the bioreactor which are in fluid communication. At least some of the ports in the upper plate are fitted with adjustable valves for regulating the flow of liquor therethrough and hence the size of a hydraulic head loss imposed by the flow control device. Preferably the upper plate is mounted at a location in the upflow chamber upstream from the inlet where influent is discharged into the bioreactor.

Abstract: A method for oxidizing HCl to produce pure chlorine gas by reacting HCl with a mixture of sulfuric and nitric acids. Chlorine gas is evolved. Spent nitric and sulfuric acids are first regenerated by contact with air or oxygen. After regeneration, the entire stream of regenerated acid, or major portion thereof, is reconcentrated. The concentration of sulfuric acid occurs at lower strengths (60%-80%) and temperatures. The concentrated acid may be used to oxidize more HCl. Heat evolved by the regeneration of the spent acids is carried into the acid concentration stage.

Abstract: An integrated process for treating alkaline wash water effluent from nitroaromatic manufacture, principally containing nitro-hydroxy-aromatic compounds is described. The integrated process concentrates the alkaline wash water to recover chemicals and water prior to treating the concentrate through supercritical water oxidation. The supercritical water oxidation step consists of treating the concentrate in the presence of an oxygen source at conditions, which are supercritical for water to cause a substantial portion of the organic component of the concentrate to oxidize. The product effluent includes a gaseous component and a clean water component, and in the event that insoluble ash is formed, an ash component. The new integrated process results in reduced chemical and water consumption compared to existing processes. In addition, the treated wash water effluent can be recycled to process or directly discharged.

Abstract: A continuous process to nitrate a nitratable aromatic compound utilizing nitric acid and sulfuric acid feed stocks is described. The process includes the collecting of NO.sub.x O gases with water under pressure to and treating the NO.sub.x gases with water under pressure to produce weak nitric acid which is recycled to the nitric acid feed stock. The process is efficient, permitting the venting of NO.sub.x free gases to the atmosphere.

Abstract: Periodic self-cleaning apparatus of use in combination with a process tube which receives a process fluid therethrough such as a tubular reactor to form a looped system having a launching and receiving chamber for a cleaning device or pig which is propelled periodically through the tube by the motive force of the fluid to clean the tube without disrupting the continuous unidirectional flow of the fluid. The pig need not be spherical and extraneous fluid pumps are not needed.

Abstract: An apparatus to allow reaction in the liquid phase. The apparatus is a vessel having a baffle. There are openings in the baffle through each of which a liquid passes as a jet. Neighboring openings are sufficiently close to allow impingement of the jets thereby allowing for reaction of the liquids. The invention finds application in reactions where the reactants are immiscible and is particularly suitable in the nitration of aromatic hydrocarbons using mixed acids in aqueous solution. A method of conducting a reaction between at least two reactants in the liquid phase is also provided comprising passing a liquid containing the reactants through a plurality of adjacent spaced openings to create a series of impinging jets.