รูปแบบทางเข้าและออกของอากาศที่เหมาะสมสำหรับถังหมักปุ๋ยแบบแพสซีฟ

Abstract

The objective of this research is to determine an effective air inlet and outlet patter for a passive composting bin. Synthesis organic wastes and dry leaves with 21 wet weight ratio were composed. Three experiments were set up to (1) determine the best air inlet patter for foam box size 39 L under batch process, (2) determine the best air outlet pattern for foam box size 39 L under batch process and (3) investigate the performance when composting in plastic bin size 120 L with the best air inlet and outlet patterns from the first and second experiment respectively under continuous process. The first experiment, when four air inlet patterns were compared, showed that the composting bin that has a horizontal pipe at the bottom for letting air in and distributing air inside the bin achieved the best performance because microorganisms throughout the composting bin received sufficient air. The composting material was entirely decomposed in 25 days, the fastest, and C/N of the final product was 18.68, pH was 6.97, macronutrients were 4.97% and germination index was 144.79%. The second experiment, when four air outlet patterns were compared and the best air inlet patter from the first experiment was used, showed that the composting bin that has a vertical pipe for letting air out on the top of the bin with less cross sectional area than air inlet pipe achieved the best performance because air velocity is slower allowing microorganisms to expose more to the air. The composting material was entirely decomposed in 27 days, the fastest, and C/N of the final product was 21.09, pt was 7,49, macronutrients were 5.30% and germination index was 97.01%. After that, the organic waste was composted in plastic bin size 120 L, the organic waste was also entirely decomposed in 90 days. C/N of the final product was 15.46, pH was 5.21, macronutrients were 3.59 and germination index was 93.97%. Therefore, the composting bin that has a horizontal pipe at the bottom for letting air in and distributing air inside the bin and has a vertical pipe for letting air out on the top of the bin with less cross sectional area than air inlet pipe can achieve a complete degradation of entire composting materials under batch and continuous processes. C/N, pH and macronutrients of the final product of all three experiemnts meets the fertilizer standard except the moisture content. So that, the final product should be curred or mixed with soil to decrease moisture content before being added to the plants.