In Japan, 1000tons/day (1,000,000 populations) Waste-to-Energy (WTE) plants cost about 500 million US$, whose capital, maintenance and operation costs are mainly covered by the tax income. In China, 1000tons/day (1,000,000 populations) WTE plants cost about 70 million US$ by the private sector investment with the income of about 20US$/ton tipping fee (1/3 of the income) and that of selling the electricity (2/3 of the income), and the number of big WTE plants are rapidly increasing in major cities. But for small-to-medium scale cities, there are no solutions for MSW treatment other than landfilling. In many developing countries, the tipping fee is still very low or even zero, and there are not so strong incentive policies to promote installation of WTE plants, which make it difficult to improve the quality of the MSW management. This presentation proposes an economically feasible mass treatment process of MSW for developing countries based on the experience on 4000 tons/day MSW management in Egypt without tipping fee income. MSW will be first mechanically pre-separated into organics, the heavy fraction and the light fraction (mainly plastics). The light fraction will be sold as RDF and/or pyrolyzed into fuel oil, while the heavy fraction and organics will be converted into coal alternative fuel employing the hydrothermal treatment (HT). 50tons/day scale HT process for MSW are well demonstrated using one batch reactor. 50-300tons/day scale HT process for MSW are ready to implement using several batch reactors. In order to compete with the incineration process, we need to step forward to 300-1000tons/day scale, where mechanical pre-sorting of MSW is essential (already available for 500tons/day scale with the cost less than 1 million US$) and continuous-type HT reactors shall be developed for the non-slurry feed to avoid waste water treatment.

Pay as you throw (PAYT) is a usage-pricing model for disposing of municipal solid waste. Users are charged a rate based on how much waste they present for collection to the municipality or local authority. Waste is measured by weight or size while units are identified using different types of bags, tags, containers or even RFID. Services for waste diversion, like recycling and composting, are often provided free of charge where pay-as-you-throw systems are implemented. The system is based by a waste collection door by door (kerbside) with 5 streams (food waste, plastic packaging and metals, glass, paper and cardboard and unsorted waste). The results after the introduction of the combined system (door by door collection and PAYT) are almost immediate (3/4 weeks from the start of the system). The secret of the system is the "Invisible Hand" effect generated by the combination of the available volume reduction for the undifferentiated fraction conferring and the creation of a personal saving potential of each individual user.