Abstract: Spectrophotometric sensors for measuring the concentration of various solutions are disclosed. Methods for controlling the introduction of disinfectants using such sensors for water treatment are also disclosed. Hypochlorite strength is monitored in at least some embodiments.

Abstract: Spectrophotometric sensors for measuring the concentration of various solutions are disclosed. Methods for controlling the introduction of disinfectants using such sensors for water treatment are also disclosed. Hypochlorite strength is monitored in at least some embodiments.

Abstract: A method for directly monitoring and controlling a continuous process stream for dechlorination residual is provided. A sample stream to which a dechlorination agent has been added to completely eliminate a residual disinfectant is continuously drawn off. An analyzing agent of iodine is provided by introducing an iodide solution, a chloramine-T solution, and an acetic acid buffer into the sample stream. The reagents quickly react to produce iodine that reacts with any residual disinfectant removal agent residual that may be present. Thereafter, the sample stream is continuously analyzed to determine the amount of unreacted iodine remaining in the process sample. Based on the amount of iodine added to the process sample and the amount of unreacted iodine remaining in the sample after reaction, the amount of dechlorination residual is continuously determined.

Abstract: A chlorination system in which brine is converted to sodium hypochlorite by an electrolyser. Brine (1) fed to the electrolyser (3) is passed through a filter (2) which is capable of adsorbing bromine or hypobromous acid. Some of the sodium hypochlorite produced in an electrolyser (3) is fed back to a point in the brine feed upstream of the filter (2) such that any bromide in the brine is oxidized to bromine or hypobromous acid and therefore adsorbed by the filter (2).

Abstract: A method and apparatus for determining the quantity of a substance in a solution. An exemplary embodiment of the method includes the step of introducing a first sample of the solution into a cavity in which a working electrode is located. A constant potential is applied between the working electrode and a reference electrode in electrical contact with the first sample until such time as the current through the working electrode has decayed to a minimum. The applied constant potential is maintained as the first sample of the solution is replaced by a second sample of the solution in a manner such that the cavity remains filled with solution during the replacement procedure. The applied constant potential is maintained until such time as the current through the working electrode has again decayed to a minimum, and the total amount of the charge passing through the working electrode subsequent to the introduction of the second sample into the cavity is determined.