Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from wastewaters such as coke-plant or coal conversion wastewaters. The process involves adding alkali to these wastewaters in amounts sufficient to react with fixed ammonia salts present in the wastewater and to enable substantial amounts of the ammonia to be evolved upon distillation, and subjecting the thus treated wastewater to distillation to remove substantial amounts of the ammonia and acid gases present from the wastewater. This process is achieved by two separate and successive distillations. In this process, the vapor streams being withdrawn from the first and/or second distillations are subjected to an impurity removal process to thereby produce a vapor stream substantially reduced in impurities, and useful as a stripping vapor in this process, and then reusing this vapor stream as a stripping vapor in the process.

Abstract: A process for the substantially complete removal of acid gases and ammonia from aqueous solutions is disclosed, which comprises a two stage distillation operation wherein the pressure in the first distillation stage is substantially less than the pressure in the second stage, the ammonia concentration in this stage decreases downwardly so that an aqueous bottoms stream has a pH less than 8, this aqueous bottoms stream is treated with alkali and then distilled in the second stage. A portion of the aqueous bottoms can be vaporized by indirect heat exchange with vapors evolving from the second stage. The improvement lies in adding ammonia to the overhead vapor from the first stage to reduce corrosion of the condenser and preferably, the amount of vapor condensed is controlled to further minimize corrosion.

Abstract: A process is described for the removal of acid gases and ammonia from dilute aqueous solutions. This is achieved by two separate and successive distillations. In the first distillation, substantially all of the acid gases and free ammonia are removed. In the second distillation, substantially all of the fixed ammonia is removed. Exemplary aqueous solutions are waste waters from coke oven and coal conversion plants.

Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from waste waters such as coke-plant or coal conversion waste waters. The process involves adding lime to these waste waters in amounts sufficient to react with fixed ammonia salts present in the waste water and to enable substantially all of the ammonia to be evolved upon distillation, adding a threshold amount of a scale inhibitor compound chosen from the class of certain organic phosphonates and subjecting the thus treated waste water to distillation to remove substantially all of the ammonia and acid gases present from the waste water. Preferably, this process is achieved by two separate and successive distillations. In this preferred process, the first distillation substantially reduces the amount of the acid gases and free ammonia. In the second distillation, the amount of fixed ammonia is substantially reduced.

Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from waste waters such as coke-plant or coal conversion waste waters. The process involves adding lime to these waste waters in amounts sufficient to react with fixed ammonia salts present in the waste water and to enable substantial amounts of the ammonia to be evolved upon distillation, adding a threshold amount of a scale inhibitor compound chosen from the class of certain organic phosphonates and subjecting the thus treated waste water to distillation to remove substantial amounts of the ammonia and acid gases present from the waste water. Preferably, this process is achieved by two separate and successive distillations. In this preferred process, the first distillation substantially reduces the amount of the acid gases and free ammonia and is conducted at a pH of more than 9. In the second distillation, the amount of fixed ammonia is substantially reduced.