Composting toilet using sawdust matrix has a potential to keep pathogens that might be occasionally contained in human feces. Especially pathogenic viruses should be taken care of, because they have higher tolerance than pathogenic bacteria. Therefore it's important to monitor pathogenic viruses. In this study, we focused on fecal enterococcus and investigated whether it could be available for viral indicator in composting toilet . Firstly, it was confirmed that fecal enterococcus was consistently detected in actu-ally composting toilet, and the concentration was so high that the fluctuation of the indicator could be detected. Secondly, the fate of fecal enterococcus was compared with that of coliphages in various conditions. Finally, it was investigated how to control pathogenic risk of compost, and check the availability of enterococcus as viral indicator in some operating conditions. The fate of enterococcus and coliphages were confirmed in high pH sawdust which was added calcium oxide (CaO). As the results, except for the case of higher water content and lower temperature, or high pH, fecal enterococcus could be an appropriate indicator for pathogenic viruses.
Soil structure is heterogeneous with cracks or macropores where bypass flow would waste applied decontamination chemicals without interaction with soil matrix. We investigated the efficiency of bioremediation for oil contaminated soils by changing infiltration rate, i.e., saturated and unsaturated flow, for two types of soils, one had macropores inside and the other did not. Resultant biological activities in effluent increased dramatically for the experiment with an unsaturated flow with macropores. Unsaturated condition prevented bypass flow, allowed dispersion of nutrient in soils, and achieved appropriate water content for biological activity, while macropores prevented clogging during the infiltration experiment.
The suspended dust generated in the tunnel construction work is one of the causes for tunnel workers becomes Pneumoconiosis. Therefore, the ministry of Health, Labor and Welfare of JAPAN dictated the employer has a management duty to measure the density of suspended dust twice a month from 2008. Ordinary, the density measurement of suspended dust had done by the digital dust meter. However, the digital dust meter is expensive and it need the measuring time for 10 minutes. In addition, it require the conversion coefficient factor individually. The simpler measurement method for the density measurement becomes stringent. It is well known among the tunnel engineer that the suspended dust reflects flashlight during flashed photography. By using this phenomenon, the authors proposed the dust density measuring technique for suspended dust by the flashlighted image of digital camera. In this study, the authors propose the simple dust measuring technique by using artificial neural network. And the authors applied it in real tunnel construction site, and compare with the results obtained by the digital dust meter, and the effectiveness of this method was confirmed.
In recent years, a small amount of endocrine disrupting chemicals (EDCs) were found in urban river water despite of EDCs elimination through sewage farm. Phytoremediation using quatic organism is one of remarkable methods to remove such a very small quantity of EDCs. In this study, the removal rate of EDCs such as 17β-estraziol (E2) and bisphenol A (BPA) by aquatic plant and periphyton is determined from laboratory experiments as a function of water temperature and weight of the quatic organism. Field observations revealed that concentrations of BPA and E2 decrease with flowing down in Nikaryo canal, Tokyo, Japan, where the aquatic plant and periphyton grow thickly. The prediction model using the experimental result on the removal rate can explain the observed decrease. These results suggested that the quatic organism in urban river ecosystem has a self-purification capacity for EDCs.
A new pipe heating system which uses only groundwater stored in a large underground tank was developed in the present study. This paper outlines its design and construction, and provides fundamental data on the developed system. Specifically, it reports on snow-thawing effects and ice prevention, and presents thermal properties based on long-term measurement over 3 years. In addition, the paper presents a possible heating method; circulate water in the tank to the pipes when the road temperature is higher than the water temperature. According to the test results, this method could increase the water temperature even by running the water for short periods of time in winter.