Utilization of organic waste from some industrial factories for composting   Singangjeaw Piriyaprin Vanlada Sunanthopongsuk Pitayakon Limtong and Chaveevan Leaungvutivirog   ABSTRACT         Study on utilization of organic solid wastes from industrial factories for composting were carried on the laboratory scale at Agricultural Development Research Center in the North-eastem Khonkean Province during 1991 - 1993. Completely randomized design is used for the comparison of rice residue cassava residue cassava peel bagasse sweet com peel mango peel pineapple residue tomato residue and corn cob residue and 20 pereent rice straw for composting. There were 10 treatments in 3 replications. Animal manuse 20 percent and urea 0.2 percent were added in each treatment. Composting plant residues were placed in incubator at 450 C. Plant residue were turn over and watered every 7 days until the final of composting process. The results indicated that cellulolytic microbial activities and decomposition time of each plant residue were depended on composite and quantitative of carbon and nitrogen in organic residue.       Composting plant residues could be devided in to three groups by consideration of decomposting time. In the first group such as rice residue sweet corn peel mango peel pineapple residue tomato rasidue and sweet corn cob take the shortest time of decomposing process as 21-42 days and the C/N ratio value decreased from 33-46 to 17-20. The number of cellulolytic microorganism were quite high from 8.19-10.01 to 9.38-12.02 log no.per gm of plant residue. Furthermore nitrogen phosphorus and potassium content in this group except rice residue were also high as between 0.88-2.57 0.84-2.71 and 1.02-1.23 percent respectivaly. Xylanase activity had shown superior than other enzymes which changed from 0.01-0.52 to 5.33-27.45 unit per gm of plant residue. In the second group which is consist of rice straw cassava residue and cassava peel consumed longer time than the first group in composting process as 53-77 days and C/N ratio value changed from 53-87 to 19-20. Increment of microbial number had quite low but cellulase activity was dominant from 0.01-0.06 to 1.82-5.73 unit per gm of plant residue. Mineral nutrients in this group is below 1 percent. The third group bagasse composting take the longest time as 168 days and C/N ratio value decreased from 161 to 29. Polyphenoloxidase activity had clearly appeared from 0.061 to 130.41-166.16 unit per gm of plant residue and the plant nutrients was also below 1 percent. At the end of composting process pH value in composts were increase from 5.0-7.2 to 7.2-8.7 which is a little bit higher than neutral point.         Keywords: organic waste, industrial factories, composting