Seminars @ AIT
‘Motivational Factors in Australian Construction Industry Workforce,’ to be held on Monday, 7 August from 10 a.m. to 12 noon int Room E220, Academic Building. The seminar will be delivered by Mr. Swapan Kumar Saha, Lecturer, Construction & Building Sciences from the University of Western Sydney, Australia. All interested persons are cordially invited. Construction Engineering and Management students are expected to attend.
The Geotechnical Engineering Program, School of Civil Engineering, will hold a special lecture on ‘Mechanism of Arsenic Pollution of Groundwater and Counter Measures for the Pollution in Bangladesh’ to be held on Wednesday, 16 Aug. 2000 from 1:30 – 3:30 p.m. in Room N240, SCE Building. The lecture will be conducted by Prof. Hiroshi Yokota from the Department of Civil & Environmental Engineering, Miyazaki University.
Abstract
Arsenic-contaminated groundwater has been found in 59 districts (as of January 1999) out of a total of 64 districts in Bangladesh where almost all drinking water is supplied from groundwater. The cause of arsenic contamination of groundwater is not clear yet, and it is estimated that about 40 million people are at risk of arsenic poisoning accordingly. The arsenic-free water supply system is, therefore, urgently needed in Bangladesh. Since March 1997 we have been investigating the causes of the arsenic contamination in groundwater and developing arsenic-free water supply systems in Samta village, which we have chosen as a model village for our research.
Ninety percent of the tube wells in Samta village had arsenic concentrations above the Bangladesh standard of 0.05mg/l as shown in Fig.1. Tube wells with higher arsenic concentrations of over 0.50mg/l were distributed in the southern part with a belt-like shape from east to west and the arsenic concentration was decreasing toward northern part of the village. In order to examine the characteristics of arsenic distribution in Samta, we have investigated the flow of groundwater, the vertical distributions of arsenic in soil by boring tests and horizontal distribution of the upper muddy layer including arsenic highly. From the discussion about these investigations and the tendency of increasing arsenic concentration in groundwater with time in Samta obtained in these years, we propose a model for explaining the characteristics of arsenic pollution in Samta. The model will be shown in this lecture.
One of the water supply systems we have tried is to use the water in ponds; namely, a Pond Sand Filter system (‘PSF’ hereafter). Water, pumped up from the pond, flows horizontally through the voids of the packed gravel in 3 compartments of the filter bed in PSF, which is an alternative process of coagulation-sedimentation since the surfaces of gravel particles provide a large bed for the settlement of suspended solid particles in the flowing water. The performance of PSF will be stated in this lecture.
