recycling of wastes wastes 188 waste disposal services 99 secondary raw materials 56 synthetic polymers 37 environment protection 32 construction materials 29 more ... treatment 24 permanently sustainable development 22 house-hold wastes 21 industrial wastes 21 waste incinerators 17 sorting 17 waste water 16 storage of wastes 16 concretes 15 civil engineering 15 waste water treatment 15 ecology 14 unconventional energy sources 14 alluminium 13 machining 13 simulation and modelling 13 environment 12 briquetting 11 demolition 11 paper 11 dumps 11 sludge management 10 glass 10 less ...