Most of the solid waste startups I have encountered in the last few years in India have been working in MSW. waste from commercial sector (hotels hospitals etc), E-waste or in agrcultural waste.
I have seen very few startups focussing on the industrial solid waste segment.
And that is surprising, given that the industrial solid waste sources and supply chains are more organized than those for MSW or even commercial (both of which suffer from small individual quantities with only low-medium valorizability).
In addition, many industrial wastes could have ingredients that can fetch a good value in the market if recovered efficiently.
So why aren't there are many more startups for this sector?
Part of the reason could be that, for some industries, easily monetizable waste would have already been monetized - examples are bagasse from the sugar industry (used as biofuel for boilers), or ash from thermal power plants used in brick making. Some of the industrial wastes or hazardous and thus the only way they can be disposed of with current wisdom is through secure landfills. There might not be effective technologies or pathways available for valorizing the wastes of some other industries.
But something tells me that, even after factoring all the above, there ought to be enough industrial wastes going to the landfills or secure landfills or simply being burnt because we have not figured a way to use it.