7
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, submersed motors for stirrers, fillings for trickling filters, sewage and sludge pumps, mixers, agitators, all for the use in the automatic operation of facilities for mixing and aeration of sewage, floating sludge, and return sludge as part of a biological sewage purification process
11
Sewage clarification and wastewater treatment plants, sewage purification and treatment plants, namely, sewage treatment plants for mixing and aeration of sewage, floating sludge and return sludge, for working of a biological sewage purification process, and for biological phosphorus removal and de-nitrification
42
[ Engineering, architectural consultation, construction drafting and technical consultation, all in the fields of aeration, drainage and treatment of sewage and sludge; Computer programming for others ]