|
Friday, 13 February 2009 10:59 |
|
Low Cost Household Defluoridation to Remove Excess Fluoride in Groundwater
Third South Asia Geological Congress Lahore, Pakistan. In recent surveys conducted in Sri Lanka, it has been found that nearly 20 percent of the wells in dry zone areas have more than 2.0 mg/l fluoride in groundwater. In addition, in nearly 30 percent of the wells the fluoride content is 2.0-1.0 mg/l. This has led to mottling of teeth and unsightly brown discoloration of the teeth in the school children of age group 8-20 years. This has reached endemic proportions in dry zone areas in Sri Lanka. Several methods are available to defluoridate the water but the filter medium used has to be supplied from time to time. The defluoridation method developed, has unique feature of having the filter-medium in the very locality. The filter-medium used is freshly burnt broken pieces of bricks in PVC filter of 1 meter in height. The operation and maintenance of this filter unit has been found to be well within the capability of rural communities. The results clearly showed that this low cost method could be easily carried out in order to get defluoridated water. The efficiency level of these defluoridators changes from 85 percent removal at the start, and tapers down to 25 percent removal at the end of the cycle. This low cost method could be adopted in other developing countries successfully to reduce fluoride-rich water to acceptable standards. This is an appropriate and affordable technology for the rural communities in the developing countries. Author(s):
J.P. Padmasiri
National Water Supply & Drainage Board, Sri lanka.
|
|
|
Friday, 13 February 2009 10:57 |
|
Evaluation of Aquifer Hydraulic Properties of the Barind Area, Bangladesh: an approach for Groundwater Development
An approach for the aquifer evaluation using hydraulic properties (both geologically based method and method based on hydraulics) has been undertaken in the Barind area, Bangladesh to assess its groundwater development potentiality.
The values of aquifer transmissivity (T) derived from the well-section lithologies are generally less those determined by pumping test analysis. The hydraulic characteristics (T) derived by the latter have to be preferred to those obtained from the former, because of the variability in the aquifer materials of the study area. This refer to the tendency to flush out finest gravity suspended particles from the aquifer sediments through well discharges, not just for a few days from commencing of pumping but continuing for years and thus increasing permeability of surrounding materials due to new flow-path by re-arranging the sediment grains. Thus the transmissivity value obtained from virgin lithology no longer remains representative of the changed, coarser lithology as time elapses. An information of pumping test analysis gives only the values of the capillary drainage component of the specific yield, its gravity drainage component is evaluated in the present study from the analysis of the lithological constituents of the lithologs. Development potentiality of the study area as determined from transmissivity (T) values through pumping test data analysis indicates that the smaller area in the central part is only suitable area for the development of water supply and hand pump use but the majority portion has good development potential for irrigation and water supply. Author(s):
Chowdhary Sarwar Jahan and Musfique Ahmed
Department of Geology and Mining, University of Rajshahi, Bangladesh.
|
|
Friday, 13 February 2009 10:55 |
|
Elaboration of Aquifer System and its Application for Protection of Groundwater contamination in the Dhamrah Kas Basin, Wah Cantt. Pakistan. Interdisciplinary investigational techniques (Hydrogeogical reconnaissance, Geophysical survey, Testhole drilling, installation of tubewells and capacity tests0 were used for the interpretation of subsurface hydrogeology of the Dhamrah Kas Basin. A multilayered aquifer system spread over an area of about 150 Sq. Km was proved with the help of 20 test holes and 10 dug wells extending to a depth of 300 to 600 feet. The aquifer is classified as multilayered semiconfined fresh body with an average well capacity of 250-350 gallons. The shallow aquifer (A-layer) is in severe danger of contamination near northern boundary of the basin through induced recharge from a polluted nullah. The bacterial contamination (Coliform and Facecal Coliform) has polluted shallow aquifer very severely. Treatment and protectional measures are discussed, particularly for elimination of physical and bacterial pollution.
Author(s):
Sajid Rashid and M.H.Malik
Institute of Geology, Punjab University Lahore, Pakistan. M. Saleem Khan
Hydrogeologist, Khanpur Dam, Pakistan.
|
|
|
Tuesday, 10 February 2009 14:45 |
|
Hydrogeological Environment and Groundwater Quality of the Alluvial Aquifers in Parts of the Central Gangal Plain India The study area is a part of the Central Ganga plain. That falls under the climate zone and covers an area of 1340 sq. km in the Aligarh-Etah distt of Uttar Pardesh. Geologically, Bundelkhand granite forms the basement complex which is unconformably overlain by the Upper Vindhyan sequence, which is further is overlain by the Siwaliks and finally by the Quaternary alluvial. In the present paper, an attempt has been made to depict a comprehensive picture of the aquifer system, their dimensions and transmission characteristics. Moreover, occurrence, movement and behaviour of the water level fluctuation in time and space were also studied.
The water quality studied of surface and groundwater were made in order to ascertain their usability for municipal purposes. The study shows that water of the basin is alkaline, hard, moderately mineralized and alkali bicarbonate type. Further, the study shows that all major ions are within the permissible limit of WHO standards. But places in shallow aquifers, the concentration of heavy metals were found slightly more than the permissible limit which needs serious attention. However, in the deeper aquifer the water is observed free from contamination and hence recommended as safe drinking water. Author(s):
Rashid Umar and Asad Umar
Department of Geology
Aligarh University, Aligarh, India. |
|
Last Updated on Monday, 17 August 2009 12:06 |
|
Saturday, 17 January 2009 10:32 |
Vertical Electrical Sounding for Groundwater Appraisal for Balochistan Forest and Wildlife Department, Quetta, Balochistan, Pakistan.
Information Release No. 828. Geological Survey of Pakistan.
In response to a request by the Chief Conservator, Balochistan Forest & Wildlife Department, three vertical electrical soundings were conducted by GSP to study the subsurface lithology in context to the groundwater potential in the premises of Hazarganji Recreational Park Quetta. The findings indicate that within the explored depth Quaternary gravels/semi weathered/fractured hard rock hold potential for potable water at two probe sites. At third site, limited groundwater yield is inferred likely to be caused by increasing finer matrix in the gravels.
|
|
Last Updated on Tuesday, 28 April 2009 12:52 |
|
|
|
|
<< Start < Prev 1 2 3 4 5 Next > End >>
|
|
Page 4 of 5 |
