Archive - Abstract
Vol.53 No.1 (March, 2022)
- Technical Paper (Japanese)
Estimation of the Bulk Density of Livestock Manure Compost Materials (Part 1)-Study on the Mixture of Swine manure and Supplementary Materials-
- Takeki MAEDA, Masaki SAITO, Yoichiro KOJIMA, Yoshiyuki ABE
- The bulk density values were examined for mixtures in which swine manure was mixed with sawdust, rice husks, and returned swine manure compost as supplementary materials. The mass per unit area and the bulk density up to a deposition height of 2 m were estimated from initial bulk density and the regression equation of the settlement rate of the load test using a small vessel. The initial bulk densities of the mixtures were lower in the saw dust mixture and higher in the returned compost mixture than in previous studies. The amount of subsidence was larger when the moisture content was higher in the sawdust mixture, however the relationship with the moisture content was unclear in the rice husk mixture and the returned compost mixture, and the difference due to the supplementary materials was also small. The obtained bulk density values were about 60 to 70 % for the rice husk mixture, 80 to 90 % for the rice husk mixture, and 110 to 120 % for the returned compost mixture than the previous values. These differences were caused by the different dry mass ratios of swine manure and supplementary materials and the different properties of the supplementary materials, so the influence of the changes in the properties of swine manure was considered to be small.
Keywords:bulk density, swine manure, supplementary material, composting, pile state, moisture content
- Technical Paper (Japanese)
Estimation of the Bulk Density of Livestock Manure Compost Materials (Part 2) - Study on the Mixture of Dairy cow Manure and Supplementary Materials -
- Takeki MAEDA, Masaki SAITO, Yoichiro KOJIMA, Yoshiyuki ABE
- The bulk density values of compost mixtures made by mixing dairy cow manure with saw dust, rice husk and returned dairy manure compost as supplementary material were investigated. The mass per unit area and the bulk density up to a deposition height of 3 m were estimated from initial bulk density and the regression equation of the settlement rate of the load test using a small vessel. The initial bulk densities of dairy manure mixtures were 60 % to 70 % of those of swine manure mixtures in saw dust and rice husk mixtures, and 40 % in returned dairy compost mixtures. The amount of subsidence tended to be larger for materials with higher moisture content, however the amount of subsidence at the maximum load was generally larger in the order of returned compost mixture, rice husk mixture, and rice husk mixture. The estimated bulk density of the dairy cow manure material obtained by this study was smaller than that of the swine manure material, and the previous value using the same type of material was about 70 % to 80% for both sawdust mixture and rice husk mixture, and the returned compost mixture was 50 % to 60%. The reason for this is considered to be the difference in the dry mass ratio between the manure and the supplementary material, and the difference in the experimental operations.
Keywords:bulk density, dairy cow manure, supplementary material, composting, pile, moisture content
Vol.53 No.2 (June, 2022)
- Research Paper (Japanese)
Ratio of Biodegradable Plastic Accumulating Bacteria to Total Number of Bacteria in Cow Feces Using Double Staining Method
- Koichi Shimada, Atsuo Ikeguchi, Tatsuo Hishinuma
- Livestock feces has the potential to be a useful biomass resource, but the majority of livestock feces (90 %) is composted, which has resulted excessive amounts of compost. To rectify this problem, livestock feces will need to be utilized to produce other materials. In this study, we focused on Polyhydroxyalkanoate (PHA), a biodegradable plastic, and confirmed the presence of PHA-accumulating bacteria in cow feces by measuring the amount of these bacteria and total bacteria found in the feces from three dairy milking cows (Holstein) and three fattening beef cows (Japanese black cattle) from A farm and B farm in Tochigi prefecture (n=12). PHA-accumulating bacteria were counted using the double staining method with Nile blue A and DAPI (4’,6-diamidino-2-phenylindole) stain. The average number of PHA-accumulating bacteria and total bacteria were 1.0 ~ 11.0 × 107 cells/g-wet basis，5.4 ~ 50.4 × 107 cells/g-wet basis, respectively. The ratio of PHA-accumulating bacteria to total bacteria was 18.5 ~ 20.9 %. There was no significant difference between the number of PHA-accumulating bacteria in the Holsteins and that of the Japanese black cattle, however, there was a significant difference between the Holsteins from the two farms. This difference may be due to the type and amount of feed given at the two farms. The ratio of PHA-accumulating bacteria to total bacteria was approximately 20 %, regardless cow species.
Keywords:Livestock feces, Biomass, Material use, Double staining method, PHA
Vol.53 No.3 (September, 2022)
- Technical Paper (Japanese)
Development of Intermittent Aeration Composting with Time-Varying ON/OFF Control (Part 1)―Temperature Change and Methane, Nitrous Oxide, and Ammonia Emissions in the Early Stage of Dairy Manure Composting―
- Fumihito MIYATAKE
- The purpose of this study is to investigate changes in temperatures and CH4, N2O, and NH3 emissions during the early stage of dairy manure composting using a time-varying intermittent aeration system that automatically controls arbitrary set times of aeration and interval according to the compost temperature range. The experiment performed time-varying intermittent aeration with six different ON/OFF settings in the laboratory-scale composting device and compared it to conventional composting with continuous and intermittent aeration. Our results showed that the modified aeration system increased the duration of high compost temperature above 55 °C compared to conventional composting and simultaneously increased the maximum temperature during composting by up to 5.0 °C. Depending on the setup conditions of the system, even an approximately 80 % reduction in the percentage of aeration time reduced greenhouse gas emissions by up to 58 % compared with conventional continuous aeration composting and simple intermittent aeration. Additionally, this system reduced the NH3 emissions generated during the thermophilic phase of composting by up to 93 %. There is the possibility that the time-varying intermittent aeration method is more effective than the conventional method in suppressing environmentally hazardous gases. The method may also contribute to more hygienic compost production.
Keywords:composting, intermittent aeration, temperature, greenhouse gas, ammonia gas
- Technical Paper (Japanese)
Wind Pressure Coefficient of Three-Span Greenhouses with Different Eaves: A Wind Tunnel Testing
- Hideki MORIYAMA, Masahisa ISHII, Ryota TSUCHIYA and Yuta OHASHI
- The wind pressure coefficients Cp on multi-span greenhouses with different eaves were evaluated by wind tunnel test to elucidate the influence of eave height on Cp. In this research, the three-span greenhouses were targeted with eave height of 2 m, 4 m and 6 m, respectively. For the experiment, 1:20 scale models were used. The Cp distribution was obtained for various wind directions θ from 0° (normal to the ridge line) to 90° (parallel to the ridge line) at an increment of 5°. The Cp at the center of the greenhouse showed complicated distribution when θ = 0°. The negative Cp on the windward roof increased in magnitude with an increase in eave height. The local minimum values behind windward eave were -0.23, -0.82 and -1.43 in order of eave height. On the other hand, the influence of the eave height on Cp decreased on leeward roof and leeward wall. For the model with eave height of 4 m, the minimum Cp value was about -3.02 near the ridge corner when θ = 30°. For other models with eave heights of 2 m and 6 m, the minimum Cp were -2.62 (θ = 20°) and -3.56 (θ = 30°), respectively. The extreme Cp value was also affected by eave height. Applying extreme Cp value to the wind load on the roof near the gable wall contributes to the reasonable design for three-span greenhouses, especially for ones with high eaves.
Keywords:flow separation, high eaves, pointed arch, wind resistant design, negative pressure, wind direction
Vol.53 No.4 (December, 2022)
- Technical Paper (Japanese)
Effect and Economic Efficiency of Feeding Warm Water Heated by Exhaust Heat from a Full-scale Suction-type Aeration Composting Facility to Dairy Cows in Winter
- Yoichiro KOJIMA, Yoshiyuki ABE, Koichi AMAHA and Soichi OKAMOTO
- The aim of this study was to demonstrate the enhancement of milk production and its economic effect by adopting a warm water feeding system, which used fermentation heat recovered from a composting facility in winter. On a dairy farm with approximately 100 lactating cows, a monthly repetitive experiment was conducted in winter over two years, alternating between a warm water condition where water warmed up using heat released from fermentation was fed to the lactating herd, and a cold water condition where unheated water was provided. The water was heated from 6.1 °C to 22.8 °C in the warm water condition via heat exchange using an exhaust system at an average temperature of 47.8 °C. The warm water condition significantly increased water intake and milk yield by 7.6% and 3.9%, respectively, compared with the cold water condition at 7.3 °C. The amount of fermentation heat used to heat the water was estimated to be the kerosene equivalent of 85 000 yen/month, and the increased income from providing warm water to the lactating herd in winter was approximately 327 000 yen/month for 104 cows. Therefore, we concluded that the warm water feeding system effectively used fermentation heat in dairy farms with approximately 100 lactating cows when it was implemented for more than 3 months a year, generating more revenue than the initial and running costs.
Keywords:composting facility, composting fermentation heat, dairy cow, warm water feeding system, milk yield increase
- Notes (Japanese)
Development of Intermittent Aeration Composting with Time-Varying ON/OFF Control (Part 2)―Effectiveness of the system and reduction in power consumption through demonstration testing―
- Fumihito MIYATAKE
- This study aims to apply an intermittent aeration composting system with time-varying ON/OFF control to a composting facility in operation and demonstrate the composting characteristics such as temperature and moisture content and the effect of reducing blower power consumption. The results showed that the system sustained high-temperature periods of 60 ˚C or more than conventional continuous aeration and simple intermittent aeration methods, leading to a more uniform fermentation of the compost material. The persistence of this high-temperature period resulted in a moisture content reduction comparable to that of continuous aeration, contributing to the drying of the compost. Furthermore, the power consumption of the blower with this system was reduced by 81 % compared to continuous aeration and by 60 % compared to simple intermittent aeration. The practical advantages of these time-varying intermittent aeration systems are sufficiently high compared to conventional aeration methods.
Keywords:composting, intermittent aeration, temperature, power consumption
