Electrical sewage and wastewater treatment apparatus and instruments, namely, stirrers, hyperboloid stirrers, drawing devices for stirrers, submersed motors or stirrers, [ fillings for trickling filters, sewage and sludge pumps, ] mixers, agitators, all for the use in the automatic operation of sewage clarification plants and wastewater treatment plants; electrical sewage and wastewater treatment apparatus and instruments, namely, stirrers, hyperboloid stirrers, drawing devices for stirrers, ...