Utilization of beer sewage in bagasse decomposition   Pitayakon Limtong Vanlada Sunantapongsuk Siangjeaw Piriyaprin Chaveevan Leaungvutivirog and Prasod Tumakat   ABSTRACT         Utilization of beer sewage in bagasse decomposition was carried out in the laboratory at Soil Microbiology Laboratory, Organic Matter and Waste Products Subdivision, Soil and Water Conservation Division and field experiment at Banpong, Ratchaburi. Changes of chemical, biological properties and decomposition rate of bagasse composting process were studied during 1992-1993. Such sewage has nitrogen 0.89%, phosphorus 44.55 ppm and potassium 2240 ppm. which showed that high content of major plant nutrient, especially phosphorus and potassium. Minor plant nutrient in sewage was also high, and electrical conductivity (EC) was 9.0 mS/cm.       For Laboratory experiment beer sewage was utilized at 0, 10, 20, 30 and 40% of bagasse(by wt.), controlled temperature at 450 C, and used completely randomized design, which consisted of 5 treatments and 4 replications. The content of nitrogen, phosphorus and potassium of bagasse were increased through 60 days of bagasse composting. In addition of beer sewage clearly increased such plant nutrient in compost. And result of 60 days experiment of bagasse composting showed that application of beer sewage from 10 to 40% could accerelate decomposition rate, C/N ratio of bagasse decreased to 20:1 in 60 days of composting, when beer sewage was applied at rate of 30-40%       Field experiment was carried out, bagasse 1 ton was piled in each treatment and beer sewage was applied at rate of 0, 20 and 40% of bagasse (by wt.), used observation trial 3 treatments and 2 replications. The result showed that nitrogen content was increased from 0.56 to 1.29 and 1.49%, when beer sewage was applied at rate 20 and 40% respectively. In case of phosphorus content was increased form 0.14 to 0.18 and 0.21%, respectively. Potassium content in bagasse was increased by beer sewage, from 0.36 to 0.53 and 0.63%, respectively. Application 40% of beer sewage enhanced reduction of C/N ratio of bagasse, form 114 to 64, 26 and 22 in 2, 4 and 6 months of this experiment, respectively. pH of bagasse in early treatment was in range 7.8-8.1. EC was increased to 1.34-1.49 mS/cm, when beer sewage was applied at 40%, EC at this level did not effect to soil and plant. The change of bacterial population range of 3.66x108 - 5.85x108 cell/g, and increased rapidly in the first month of experiment and slightly decreased. Application of 40% beer sewage could sharply increase fungal population from 3.40 x 103 to 2.2 x 105 cell/g in the first month of experiment, and fungal population was slightly increased in 2-4 months of experiment. The total microbial population in bagasse of every treatment were increased in the first month of experiment, when beer sewage was added at rate 0 to 20 and 40% and their population still in high level at 2-4 months of this experiment. Turn over and aeration the compost pile could reduce foul odor from decomposition process, and optimum rate of beer sewage should be 20% of bagasse (by wt.), at this rate did not have impact on foul odor. It was necessary to aerate or turn over the compost pile at suitable time, when 40% of beer sewage was applied.         Keywords: compost, beer sewage, bagasse, decomposition rate