This research aims to analyze the effect of canal damming on surface water level stability in the drainage canals in the peatland area of Central Kalimantan, Indonesia. The focus of this research is the investigation of surface water level in Kalampangan Canal and Taruna Canal, the two biggest canals on the peatland lying between Sebangau River and Kahayan River. Surface water levels in this research were measured using automatic gauges and loggers for 11 stations. Research results indicate that the surface water level in the dammed area (Lg2) has the most stable water level compared to the ones of other stations. Statistical analysis using box plot method stated that Lg2 has the lowest range of normal water level compared to other stations. The research results also showed that the water level of Lg2 in the canal has specific water system, which did not depend on the flow regime in the vicinity. Based on the analysis, the dams in the canal were able to retain water in the canal for a long period of time. The dams were able to maintain the water level in Lg2 at an elevation of about + 18.0 m in the condition without water supply or water loss to other areas.
The need to save energy at sewage treatment plants is a common issue in Japan and China. We applied a sewage treatment plant performance evaluation system to study the energy-saving effects and effluent water quality by studying values of the control parameters. The evaluation system is a simulator applicable to the sewage treatment plant process as a whole. It performs an overall evaluation of effluent water quality and energy consumption by linking water treatment with sludge treatment. Analysis was made of two medium-sized plants with a treatment capacity of 10,000 m3/day and one large treatment plant with a capacity of 150,000 m3/day. We studied the control settings for MLSS, return sludge ratio, and reactor DO. The analysis indicated that power consumption could be reduced by 7 to 17%.
The concentration levels of seven organophosphoric acid triesters (OPEs) and nine polycyclic aromatic hydrocarbons (PAHs) in Phragmites were measured to investigate the bioaccumulation characteristics. Phragmites was sampled from Yamato River basin in Japan in 2009 and 2011. To investigate the bioaccumulation characteristics, the concentrations of the micropollutants in stems, leaves, ears, and roots of the Phragmites were measured. All of the OPEs and eight PAHs were detected, among which tributyl phosphate, tri-2-chloroethyl phosphate, triethyl phosphate, tris (2-ethylhexyl) phosphate and fluoranthene were detected frequently. The total concentration of OPEs ranged between N.D. and 4,020 ng/g dry weight and that of PAHs ranged between N.D. and 396 ng/g dry weight. The concentrations tend to be higher in the ears than in the stems, leaves and roots. Significant proportional relationships were observed between the concentrations in the stems and those in the other parts. The concentrations of OPEs and PAHs tend to decrease as the stem height of Phragmites increases.
In this study, high-intensity, UV-A (ranging from 360 to 370 nm, peak wavelength at 365 nm) produced by a light-emitting diode was used for the inactivation of MS2 phage and Cryptosporidium parvum oocyst. In the irradiation experiment with MS2 phage, approximately 44 and 65 J/cm2 of UV-A were required to obtain -2 and -3 log inactivations, respectively. The -2 and -3 log inactivations of Cryptosporidium oocysts required 338 and 508 J/cm2 UV-A, respectively, which were 7.7 - 7.8 times greater than those required for MS2 phage. The possibility that high-intensity UV-A irradiation can inactivate both protozoa and viruses (phage) was demonstrated in this study.
Heavy metal removal from anaerobically digested sewage sludge and phosphorus (P) retention in the sludge were investigated through batch experiments using H2O2 and Fe2(SO4)3 as the agents for oxidizing insoluble metallic compounds under acidic condition at pH 2.5. The addition of H2O2 to the sludge eluted Cd, Cu and Zn from the sludge more effectively than that of acid only. The initial concentrations of H2O2 required for the maximum elution efficiency were 1 g/L for Cd and Zn and 5 g/L for Cu. The addition of ferric ion (Fe(III)) also improved the elution efficiency of Cu. Ferric iron addition under the initial H2O2 concentration of 0.2 g/L gave rise to a more effective elution of Cu from the sludge than that in the absence of H2O2 or Fe(III). The addition of acid only or both acid and H2O2 caused the elution of P together with heavy metals. However, the addition of Fe(III) (1 g/L Fe) could retain P in the sludge, most of which was present as a slow-acting P fertilizer.
Chlorpyrifos is one of the major pesticides used today which has a chlorinated aromatic moiety of a pyridine analogue of 2,4,5-trichlorophenol and can be a potential direct precursor of another pyridine analogue of 2,3,7,8-T4CDD (2,3,7,8-tetrachlorodibenzo-p-dioxin). In the recent study, PCDF compounds have been detected in chlorpyrifos samples, however, the presence of this analogue of 2,3,7,8-T4CDD has not been assessed yet to our knowledge. Here, we analyzed the ecotoxicities of this dioxin-like compound in the early developmental stage embryos (Oryzias latipes). Chlorpyrifos and its analogue, 3,5,6-trichloro-2-pyridinol, were thermally treated in closed glass ampoules at 300, 340, and 380°C for 10 minutes and exposed to medaka embryos in early developmental stage for 48 hours, to assess the response of the 20 biomarker gene expressions. The thermally treated 3,5,6-trichloro-2-pyridinol enhanced the expression of CYP1A1 (Cytochrome P450 1A1) and AhRR (aryl hydrocarbon receptor repressor) as 2,3,7,8-T4CDD and PCBs, suggesting that the potentially ecotoxic compounds like 2,3,7,8-T4CDD is newly produced during the thermal treatment of 3,5,6-trichloro-2-pyridinol. The expression profiles of the 20 biomarker genes in the embryos exposed to 2,3,7,8-T4CDD and 3,5,6-trichloro-2-pyridinol were almost the same, strongly suggesting that the thermally treated 3,5,6-trichloro-2-pyridinol sample contained 2,3,7,8-T4CDD-like ecotoxic compounds.
Water scarcity is a major issue in the Kathmandu Valley. Also, from a health perspective, it is important to evaluate the relationship between the quantity and quality of available water. In this study, we identified the water source used, and its availability and quality at the source and point of use. This was done by conducting a questionnaire survey and measuring the level of indicator bacteria and free residual chlorine in domestic water sampled at households. The results showed that most households used mixed water sources, with piped water being preferred for consumption. Nonparametric statistical tests showed that the total coliform was significantly high in source water with a longer supply interval and also high in stored water. In addition, but not of statistical significance, Escherichia coli was mostly detected in source water with a longer supply interval and also in stored water. In contrast, the proportion of samples with free residual chlorine was lower in water with a longer supply interval. Partial correlations showed that a longer cleaning interval of water storage vessels was associated with lower water availability and might lead to contamination of stored water. Therefore, safe storage of water should be promoted at the household level, and water supply services should be improved at the regional scale.
Humans can be infected percutaneously by pathogenic Leptospira found in polluted water. In this study, an infection scenario was considered in which Leptospira swam in still water, came in contact with skin, and then invaded it. Specifically, adhesion potential of Leptospira onto skin was estimated by applying an interfacial free energy concept. In addition, the swimming force of Leptospira in still water and its invasion force to invade soft agar, used as a surrogate for skin, were estimated using a spiral-type magnetic micromachine. These results showed that the change in free energy (ΔGadh) of the experimental strain L. biflexa was approximately equal to -21 dyn/cm (-0.0021 N/m). This value would readily allow its adhesion onto skin, which was demonstrated with experiments of L. biflexa adhesion onto human fingers. Leptospira could rotate when its torque was greater than 2.9 × 10-18 Nm and swim in still water when the flagellar motion was assumed to be 100 rotations/s. Leptospira could also invade soft agar with an invasion force of 9.0 × 10-13 to 2.2 × 10-12 N. These factors could be used for controlling leptospirosis before medical intervention is necessary and may help in developing means for infection prophylaxis.
Boron is widely used in industry, and is regulated by the effluent standard (10 mg/L) in Japan. The standard azomethine H absorptiometric method for determining boron concentration requires long time; therefore, we have developed a simple, rapid azomethine H method for the management of the wastewater treatment equipment. The amount of boron was determined by measuring the absorbance of the boron-azomethine H complex after 5 min by using a simple spectrophotometer with a photodiode (370 - 600 nm) and a light-emitting diode (470 nm). Phosphate buffer with ammonium chloride was used, because the ammonium salt accelerated the formation of the boron complex. The effect of a large amount of calcium ions in the wastewater, which originated from calcium hydroxide, was eliminated by adding an excess of the buffer reagents. A combination of powdered azomethine H, L-ascorbic acid, EDTA, potassium dihydrogenphosphate, disodium hydrogenphosphate, and ammonium chloride was appropriate for the simple, rapid on-site determination of boron using a portable spectrophotometer.