waste disposal services 234 wastes 199 recycling of wastes 160 house-hold wastes 53 environment protection 47 waste incinerators 40 secondary raw materials 39 more ... composts 35 sorting 35 biological wastes 33 legal regulations 32 provisions 25 storage of wastes 24 biofuels 23 synthetic polymers 23 health harmful substances 22 dumps 19 industrial wastes 18 environmental pollution 17 ecology 15 unconventional energy sources 15 sludge management 14 biomass 12 laws 12 waste water treatment plants 12 construction materials 11 toxic waste 11 air pollution 11 costs 10 municipalities 10 less ...