Dirty thought

I had a dirty thought earlier today, I thought about an alternative way to deal with sewage. It is a thought I often have. In an alternative Alan-world, sewage would flow into evaporation chambers that have a partial vacuum that is low enough to lower the boiling point of water to 10°c. The lower the air pressure is, the lower the boiling point is. The water would just boil away until all the water vapour is pumped out and the sewage is dry. I drew a simplified diagram of what happens. 

The dry sewage would then pour out into an incinerator. The incinerator would burn up all the dry sewage. The heat from the burning dry sewage would power the pump that lowers the air pressure of the evaporation chamber and all the other parts of the area. The ashes of the burnt sewage would then be sent to a sorting area to separate the different grains. Some of the grains would be hard and dense like limestone deposits, others would be soft and soluble like carbon powder. There would even be minerals that are turned to a glass like substance because of the heat from the incinerator. 

The hard and dense grains would be gathered and placed into drones that fly over the coast, they would drop the hard dense ashes in coastal areas that are having problems with sea erosion. The deposits would build up until small islands appear and they would have gardens growing on them. When storms emerge, the little islands take most of the punishment. 

The softer grains would be used to make bricks and roads, they would be mixed with cement to make concrete slabs that can be exported. 

Someone said my ideas are crap once, I think they're onto something.