This paper aims to develop an alternative complete technology and to assess its potential to manage municipal solid waste (MSW) properly to reach the state of zero waste disposals in Lebanon and developing countries. Meanwhile, Lebanon continues to face serious MSW management challenges associated with urbanization and the absence of a reliable policy plan. Thus, two different sorting modes were followed to prepare two categories of MSW samples: (i) samples A correspond to MSW from which only recyclable materials are removed and (ii) samples B correspond to MSW from which recyclable materials and food waste are removed, whereas samples A and B were thermally treated at low temperature. The conditions of catalytic thermal treatment were studied, and the effects of many parameters such as nature and rate of catalysts and additives, heating rate and maximum heating temperature on the yield of different pyro-products were examined. Interesting pyrolytic conditions were optimized. They are an oxygen free environment, a heating rate of 2.5 °C min-1 during six hours and low temperature of 300-350°C at which the disintegration of carbon chain start, sodium hydroxide (1%) as catalyst and Calcium carbonate (2%). Obviously, under these operating parameters, the volume of gas flux was reduced, volatilization of heavy metals trapped in solid phase and formation of dangerous substances were avoided and poisonous gases were neutralized by additives. Thus, emission control is easier; operating and maintenance costs are greatly reduced. This process is called soft pyrolysis. Under soft pyrolysis conditions, high yield of pyro-water (55 %) and low yields of energy carrier pyro-products (oil 4.5 % / char 21 %) were obtained after the pyrolysis of samples A, inversely to the yields obtained using samples B (water 14 % / oil 33.6 % / char 26 %). These results proved the necessity to remove organic materials (food waste, vegetables and plant debris) from MSW before been thermally treated. Furthermore, pyro-products were physicochemically characterized, and their modes of treatment, recovery and recycling were defined. Before treatment, the analysis of pyro-char showed a carbon rich mixture (55%) and a high content of ash (45%) including eventual pollutants (salts, heavy metals,...). Several interesting uses of pyro[1]char have been tested successfully such as its incorporation in asphalt roadway paving operation in a fractional ratio 1/10, or after treatment as energy carrier (calorific value = 20071 KJ/Kg) and feedstock in chemical industry. The analysis of the derived pyro-oil indicated that it is chemically complex, composed of a mixture of different hydrocarbons, with an increasing viscosity along the pyrolysis process. The pyro-oil is water free and characterized by a high calorific value (39 000 kJ/Kg), presenting a good fuel for internal use as well as for external. Moreover, the generated wastewater (pyro-water) was analyzed and treated properly. Non-condensable fraction (syngas), volatile hydrocarbons can be used as an inner fuel in the reactor. Therefore, combined technology based on three complementary processes in triangular shape (Sorting of recyclable materials and food waste as per sample B - Composting of food waste and vegetables - Soft pyrolysis of the remaining rejects) was defined, satisfying the specificity of developing countries such as limited resources, high content of vegetables (60-70%) in accordance with the environmental restrictions. MSW are converted into giving valuable (recyclable materials, compost, char, oil, …) and solid residue with many uses leading to zero waste disposal, or simply disposed in safe conditions. These technologies (SCP) could be the convenient treatment methods to solve the acute Lebanese problem of MSW management and may constitute a model of management for developing countries.
