ABSTRACT
Sulfite ions may occur in boilers and boiler feedwaters treated with sulfite for dissolved oxygen control. Excess sulfite in boiler waters is deleterious, because it lowers pH and promotes corrosion. Sulfite in natural waters or wastewaters is a result of industrial pollution, and in a treatment plant, dechlorination with sulfur dioxide. Sulfate is one of the major dissolved constituents in rain. The amount is related to natural and human pollution of the atmosphere. This soluble substance may be derived from dust particles, oxidation of sulfur dioxide, and hydrogen sulfide gases released from the decomposition of organic material, volcanic discharges, forest fires, and bacterial decay. Sulfur oxides form sulfuric acid, nitrogen oxides form nitric acid. Both are powerful acids. They may accumulate in clouds and fall in rain and snow.
