reporter: the process is set to become more efficient, with the help of some students from the university of brasilial recently, their professor, paulo celso dos reis gomes, was deputy director of the municipal sanitation authority. he helped restructure brasilia's waste management systems. paulo: everybody is collecting something different. she's sorting out glass bottles. she's sorting out plastic bottles. further along, somebody is pulling out the cardboard. it's possible that the process could be made more efficient if the positions were switched around. that's something we need to tetest. reporter: but not all the trash delivered here to be sorted can be recycled. much of it has to be disposed of. the aim of the program is to increase the proportion of waste that can be recycled. paulo: everything that can be sorted and sold is returned to the production chain, to the recycling industry. it doesn't end up being dumped. so we're saving the cost of taking it to the landfill, extending the lifespan of that site, and reducing emissions. reporter: this is brasilia's new landfill site. far more waste