Mathematical description of anaerobic treatment of wastewater in upflow reactors.

A quantitative description has been presented of anaerobic treatment in an upflow reactor of dilute wastewater containing lower fatty acids as the main pollutant. It contains as its principal elements mathematical descriptions of the dynamic behavior and the distribution of both the fluid and the anaerobic sludge in the reactor, and a quantification of the kinetics of the anaerobic conversion of the organic waste and of the formation of bacterial products and methane. These elements have been taken together in mass (organic carbon) balances for the substrate, the methane, and the bacterial products, over the two most important reactor parts: the sludge bed and the sludge blanket. In the second part of this article, the description has been used for prediction and determination of the optimum reactor dimensions and process conditions. These optimum values can be used for the design of new reactors and for the establishment of the best suited process operation, which is important for obtaining the best purification results and process reliability at minimum investment and operation costs.