The amounts of temporal carbon storage material, polyhydroxyalkanoate (PHA), were quantified in the course of wastewater treatment by different activated sludge reactors operated at Beijing University of Technology, Beijing, China. The studied reactors were five continuous ones and two sequencing batch ones. In all the reactors, PHA was detected, and its contents within activated sludge ranged between 0.2% and 3.2%. Soluble organic matters loaded to the reactors were mainly removed in the first anaerobic or microaerophilic tank and one fifth to all of removed soluble organic matters were tentatively stored as PHA in the studied reactors. It was concluded that not a small part of soluble organic matters in sewage is converted to PHA in the course of their removal by activated sludge.
The need for both global and regional assessment of water consumption has been increasing. This paper aimed to understand industrial water consumption both globally and regionally, and create the 1°*1° global map. From the analysis of data in Japan and China, it was determined that industrial water consumption correlated well with urban area which can obtain from GIS data. Based on this knowledge, industrial water consumption was distributed to the 1°*1° global map, and this calculation was named urban area model.
The Yodo River, which has two big tributaries and an annual mean flow of 268m3/s, flows out of Lake Biwa, runs through the Amagase Dam and flows into Osaka Bay. Point and non-point pollutant loads in Kyoto City and its adjacent cities discharge into the river. The frequency of our routine observation (once every three days) during the period from late April to late November 2003-2005 was ten times that of official routine water quality monitoring in Japan. We also carried flooding-stage observations at three transverse points across the river during the routine observation period in 2005. The total pollutant loads during five flooding events were larger than those observed by the routine observation during the periods. The mean pollutant loads during observation periods of every three days, every six days, every nine days and semimonthly data were different from those derived from monthly data. The annual total loads of runoff pollutant in 2003-2005 were estimated by extrapolating to both sides of the observation period and by compensating during flooding-stages using regression equations between flow and pollutant loadings.
From 2004 to 2007 we studied the contamination of the Kahayan and Rungan Rivers in Central Kalimantan, Indonesia, by mercury used in the processing of mined gold. Water, sediments and fish species were collected from both rivers. Total mercury concentration was determined by cold vapor atomic absorption spectrometry (CVAAS). In the Kahayan River and its tributaries, the highest total mercury concentration in water samples was 2260 ng/l. In sediment samples, the concentration ranged from 0.002 to 0.095 ng/mg dry wt. In the Rungan River, the total mercury concentration in water samples ranged from 16 to 117 ng/l and in sediment samples from 0.003 to 0.253 ng/mg dry wt. The highest total mercury concentration in a water sample came from a tributary of the Kahayan River; the level was higher than Indonesia's drinking water standard for total mercury (1000 ng/l). However, total mercury concentrations in water samples from both main rivers were lower than the standard. The sediment sample mercury concentrations from both rivers were lower than the USEPA quality guideline. Total mercury concentrations in fish obtained from both rivers ranged from 0.02 to 0.48 ng/mg wet wt. Mystus nemurus had a total mercury concentration close to the USEPA guideline value for fish for human consumption.
Nitrogen concentrations of drainage, percolation and irrigation were monitored periodically once a week at the experimental small rice-paddy watershed (EPW, 6.96 ha) for three years. Water level of the draining ditch was recorded continuously at the end of EPW. During the cropping period, load L of nitrogen through the drainage were evaluated from the concentrations C and the flow rates Q by integration interval method. During the non-cropping period, L was calculated from L(Q)-equations and Q. The L(Q)-equations were derived from the data measured during storm-runoff events. Concentrations of total nitrogen (TN) of irrigation, drainage and percolation were 0.403, 1.39 and 1.11 mg l-1, respectively, on average for three years. L of the drainage changed in wide range in response to agricultural practices and rainfalls; e.g. puddling, transplanting, fertilizing and plowing. The annual net-load of TN (unit load Ln) was 35.8±4.05 kg ha-1 y-1 on average for three years, of which the non-cropping period occupied 37 %. L for the puddling and transplanting period was discharged 27% of Ln, and strongly affected by the applied volume of irrigation. These results suggest that observations for only cropping periods or for only one year are insufficient for evaluating the precise Ln to assess the effect of the nitrogen discharged from paddy fields on lakes.