4. ConclusionsBased on the findings, it can be concluded that the different types of plastics would degrade but at different rates and would produce composts which varied in quality.The highest thermophilic temperature (63.3 °C) was recorded for GBIO after three days from the start of the composting process.The moisture contents for the three composting processes remained above 60% throughout the experiment.A net reduction in volatile solids contents of 61.8%, 56.5% and 53.2% were obtained for G, GBIO and GDEG, respectively.An increase in bulk densities, in the range of 250–350 kg/m3, was noted for G, GBIO and GDEG at the end of the composting process.Rapid stabilisation of the organic matter was observed for GBIO on the third week as compared to G and GDEG, which reached stability on the fifth week.A decrease in COD concentrations until day 22 was recorded for G and GDEG and this may be due to the mineralization of the organic matter. However, an increase in COD concentration was observed for GBIO until day 22 due to the availability of much organic matter.Reduction in material masses for G, GDEG and GBIO were 60%, 46% and 56%, respectively. Yields of 40.8%, 49% and 54% of fine composts (through a sieve size of 2.362 mm) were obtained for G, GBIO and GDEG, respectively.High nutrients contents (NPK) were also obtained for GBIO.Good compost quality was also obtained for GBIO as from the phytoxicity test it has been observed that a diluted extract of GBIO compost has produced the longest length of radicle.The most striking feature about the composting of green wastes with biodegradable plastic (Mater-Bi product) was that after one week of monitoring, all the strips of plastic have completely disappeared, while 2% of the original degradable plastic still remained at the end of the composting process.The presence of strips of plastic for the GDEG compost may have a detrimental effect on the physical appearance of the compost when applied to land, as well as on soil quality.Davis et al.(2005) concluded that the rate of degradation of PE (polyethylene) did not match the rate of degradation observed within the organic wastes.In addition, these strips of plastic can also be easily carried away by wind and be deposited on plants and the surrounding environment.