The sulfate content of natural waters is an important consideration in determining their suitability for public and industrial water supplies. The amount of sulfate in wastewaters is a factor of concern in determining the magnitude of problems that can arise from reduction of sulfate to hydrogen sulfide. In anaerobic digestion of sludges and industrial wastes, the sulfate is reduced to hydrogen sulfide, which is evolved with methane and carbon dioxide. If the gas is to be used in gas engines, the hydrogen sulfide content should not exceed 750 ppm by volume. A knowledge of the sulfate content of the sludge or waste fed to digestion units provides a means of estimating the hydrogen sulfide content of the gas produced. From this information, the designing engineer can determine whether scrubbing facilities will be needed to remove hydrogen sulfide, and the size of the units required.
In the engineering and operation of treatment processes, especially anaerobic ones, knowledge of sulfate content can be of great importance. Sulfate-reducing bacteria generally outcompete methanogens kinetically for organic carbon in anaerobic treatment of high-sulfate organic wastewaters. Additionally, the sulfide produced can be toxic to methanogens. Thus, sulfate can have a highly adverse impact on the methanogenic process. In a similar manner, high sulfate concentrations in groundwater can hinder the natural anaerobic biodégradation of chlorinated solvents such as trichloroethene and tetrachloroethene. Many organic compounds contain sulfur as sulfate, sulfonate, or sulfide. During aerobic treatment of such wastes, complete utilization or dissimilation results in release of the organically bound sulfur as sulfate ion, but under anaerobic treatment, the sulfur is generally released as sulfide.
Was this article helpful?
Thousands Have Used Chemicals To Improve Their Medical Condition. This Book Is one Of The Most Valuable Resources In The World When It Comes To Chemicals. Not All Chemicals Are Harmful For Your Body – Find Out Those That Helps To Maintain Your Health.