Upflow Filtration Process

This article begins by presenting an overview of past research on upflow filtration. The article then discusses small‐scale laboratory upflow filtration studies conducted at the Lawrence, Kansas, Water Treatment Plant. The objective of these studies was to evaluate the feasibility of purifying Kansas River water by combining coagulation and filtration in one high‐rate process. The method used was similar to the Russian contact clarification process, and coagulants were injected into the raw water immediately ahead of two upflow sand filters, with coagulation and clarification taken place within the filter beds. Studies included investigation of the effects of the rate of filtration and the depth of sand on the operation of the filters, with emphasis on studies of high filtration rates. Alum was used as the coagulant. Addition of a polymer with the alum was also studied. Jar tests were conducted prior to each filter run to determine the minimum alum dosage that would produce a pin point floc.