Sludge treatment analysis in potable water treatment plant (PWTP) in Logroño (Spain)

In a Drinking Water Plant the first step in purifying water is the removal of the suspended solids and other organic or inorganic compounds (silts, clays and very fine particles). The separation is based on settling processes that is carried out through coagulation and sand filtration and the resultant product in the process is sent to sludge line. In this line, the sludge is flocculated, decanted and then thickened. As the water obtained is recirculated to first-stage treatment, the concentrated sludge is dehydrated for later use. The sludge contains a large amount of flocculants and as a result, the sludge recirculation would be possible so as to reduce the dosages of the chemical polymer streamlining the process of dehydration. This study shows the inefficiency of the sludge recirculation, and therefore proposes sludge removal process for future designs and sludge lines projects