6 Articles of metal, namely, mild steel, stainless steel, steel in sheet form, cast iron, hollow steel pipes, steel for further fabrication, aluminum alloys for use in the sewage treatment industry; articles of metal, namely, mild steel, stainless steel, steel in sheet form, cast iron, hollow steel pipes, steel for further fabrication, aluminum alloys for use in apparatus or installations, namely, thermal dryers for waste processing; articles of metal, namely, mild steel, stainless steel, steel in sheet form, cast iron, hollow steel pipes, steel for further fabrication, aluminum alloys for use in apparatus or installations, namely, thermal dryers used to dry and mill waste including sewage; articles of metal, namely, mild steel, stainless steel, steel in sheet form, cast iron, hollow steel pipes, steel for further fabrication, aluminum alloys for use in apparatus or installations, namely, thermal dryers used to incinerate waste including sewage; articles of metal, namely, mild steel, stainless steel, steel in sheet form, cast iron, hollow steel pipes, steel for further fabrication, aluminum alloys for use in apparatus or installations, namely, thermal dryers used to deodorize gases that are used to dry waste including sewage