Yes, Ductile Iron products can be successfully Glass lined. Glass lined pipe and fittings have been specified and utilized as a deterrent to interior build-up and clogging of problematic sludge and scum piping systems in wastewater and sewage treatment facilities for over 40 years. Not only is the excellent non-stick characteristic effective in combating the build-up of grease, sludge, and scum, but has been found to be the only deterrent to Struvite and Vivionite build-up as well.

See more here: Glass Lining (Porcelain Enamel)