Instrumental methods of analysis were used to study sewage sludge formed during its processing by the enzyme-cavitation method for further water reuse. It was revealed that sewage sludge samples are multiphase porous aggregates containing both amorphous and crystalline components in their structure. X-ray phase analysis helped to determine the mineralogical composition, as well as the presence of fertilizing properties. Transmission electron microscopy showed that the studied sewage sludge has several scale structural levels of porosity from 5 nm to 6 μm. The sorption properties of sewage sludge, as well as the ability to absorb and retain water, were revealed.