Impact of septic tank sludge on filter permeability

The aim of the study was to determine the filter cake permeability. The research was carried out on the excessive sludge flushed out from a septic tank. Two types of laboratory filters: filled with fine sand and made of geotextiles were used. The permeability of the filter cake was inversely correlated linearly to the accumulated organic solids. Based on applied organic solids, the related filter cake permeability time of filter failure can be predicted. The shortest failure time, not exceeding two years, may be recorded when filter cake development and clogging processes simultaneously take place in small-pore diameter filters and when the concentration of volatile solids is high.