Methods and apparatuses for the direct electrochemical generation of high concentration, stable aqueous solutions comprised of mixtures of free halogen species, N-halosulfamate compounds, N-halosulfonamide, and other compounds for biocidal applications is disclosed. Solutions containing the desired content of these species, with the desired concentration and pH value, is achieved through the electrolysis of aqueous brines containing mixtures of metal halide compounds, sulfamic acid, and other additives as desired. Controlling the relative compositions of the brines used to prepare the desired biocidal solutions, as well as the electrolysis conditions, can produce the biocidal solution with the desired composition and properties.