Assignment on substantially reduce in Dhaka City- Focus on DWASA

Dhaka Water Supply and Sewerage Authority (DWASA) is responsible for the provision, operation and maintenance of water supply, sanitation and storm water disposal services to the population of Dhaka City as stipulated in the Water Supply and Sewerage Authority Act, 1996.
Dhaka city is the capital of Bangladesh, a country of about 140 million people. Dhaka city is estimated to have a 2005 population of about 11 million people within the Dhaka Metropolitan Area (DMA) and 8.6 million within the DWASA service area. DWASA is responsible for operating and maintaining the: (i) water supply services; (ii) sewerage services and (iii) storm water drainage service of the city of Dhaka. It is estimated that DWASA presently serves total of 7.7 million (people with water supply, nearly 90% of the people living in the Dhaka WASA Service area. The remaining estimated 10% (860,000. people) are mostly served by private wells abstracting water from the same aquifer under the city.

The population of Dhaka City is growing at a frightening pace and based on detailed analysis of available census data and present land use pattern the population of the present DWASA service area is projected to increase to 17.2 million by year 2025 while another 4.4 million will be staying within Dhaka Metropolitan Area but in areas presently not served by DWASA.

The main environmental features of Dhaka City

Main Features
Topography and Soils
Bangladesh lies in the floodplain of the great rivers Ganges, Brahmanputra and Meghna and is thus mainly flat and low-lying, with fertile alluvial soils. Dhaka is in the centre of the country between the confluences of the rivers.
Sub-tropical with three seasons. In Dhaka Nov-Feb is coll (Ave 200C) with low rainfall (<30mm/month). This is followed by an unsettled period of increasing temperature, rainfall & wind (temps reach 290C in May). Monsoon occurs in May-September and rainfall is >300 mm/month in June, July and August (70% of annual total).
Air Quality

Air quality is very poor in Dhaka, mainly because of traffic congestion, inadequate control of emissions, industry using cheaper high-sulphur fuels, etc. Some improvement is expected as drivers change to CNG vehicles.
Surface Water
With flat topography, high rainfall & large rivers that drain 1.72 million km2 of and, flooding is a major problem in Bangladesh. Levees have been built in some areas, but still floods occur, In Dhaka the western embankment provides some protection but the eastern part is not yet built; and infilling of the floodplain for building reduces flood retention. River water is used as a source of municipal supply and is polluted by industry and sewage.
There are three main aquifers (upper, middle and lower); the upper is polluted with sewage, but there is no evidence of arsenic, In Dhaka 82% of municipal water is sourced from the middle aquifer, the level of which has dropped by 20 m in the past 6 years.
Geology and Seismology
Bengal Basin formed in the Oligocene when part of the Indian land mass fractured and sank below sea level. The basin then filled with sediment deposited by the Ganges and Brahmaputra. Dhaka is on the Dauki fault in an area of medium seismic risk. Shocks of medium intensity (6.5-7 on Richter scale) occur every 20-50 years.
Aquatic Ecology
Dhaka is enclosed by rivers and has large areas that flood each year, so aquatic habitats are the main ecological resource. Rivers are polluted by raw sewage and industrial effluent, and flood plains are degraded by infilling and development, so the extent and importance of both habitats is reducing. Some fish breed in floodplains and there are small commercial and artisanal fisheries here and in the rivers, but both are in decline.
Terrestrial Ecology
Agricultural development followed by urbanization has destroyed terrestrial habitats in and around Dhaka, and there are now few areas of natural habitat, no protected areas and no rare or endangered species.
Industry has grown rapidly over the past 30 years and there are now more than 7,000 industrial units in Dhaka. Manufacturing is the most important (leather, textiles, fertilizers, pesticides, chemicals, rubber, plastics, cement) and there are also heavier industries including iron/steel, ship repair, power plants, oil refineries, paper mills.
Much of Dhaka’s infrastructure is inadequate for such a large population. Piped water reaches 80% of the population, but is low in pressure, intermittent, contaminated with sewage and depleting groundwater. Only 20% of people are connected to sewer and most of the rest use septic tanks that discharge into drains or the river. Storm water drains are blocked and malfunctioning and most water runs through natural channels into rivers.
Transport planning and infrastructure has not kept up with population growth and roads are heavily congested. The problems are exacerbated by driver indiscipline, inadequate policing, and poorly maintained vehicles.
Land Use
Urbanization has occurred without adherence to planning laws and policies and there are inappropriate mixes of land use and development without supporting infrastructure (schools, water sanitation, etc). An influx of people from rural areas has increased the urban poor and the number and size of slums.
Power Sources and Transmission
Power is generated by the Bangladesh Power Development Board and distributed in Dhaka by and the Dhaka Electric Supply Authority. Pylons & poles are mainly beside roadways, and there are metered connections to houses. Plants are inefficient; there are high losses and inadequate cost recovery; and power cuts are frequent.
Economic Development

Industry, retail and commerce are the main economic activities, mainly in the city centre. There is agriculture in the urban fringe, and particularly outside the city, where rice, wheat and vegetables are the most important crops. The only mining is dredging of river sediment for building and infill, and tourism is little developed.
Population and Communities
Population has grown rapidly in Dhaka from 3.4 million in 1981 to 13 million in 2006, one of the largest rates of increase in the world. There are over 2,000 slums, which cover 4.8 km and house 1.2 million people. Over 98% of Bangladeshis are Bengali and 90% are Muslim, 9.2 % Hindu and the remainder Buddhist or Christian.
Health Facilities
Health facilities include public and private hospitals (general and specialized), health centres, etc. The public sector provides 5,000 beds, a very low ratio for a population of 13 million, and although facilities are better in the private sector, costs are high. Diarrhoea, dysentery, whooping cough and TB are the main diseases.
Educational Facilities
There are 12,000 primary and secondary schools in Dhaka, several hundred colleges and technical institutes and 52 universities (9 state funded and 43 private). There are some single sex institutions but in general boys and girls are educated together and there is little difference in enrollment between genders in schools.
Physical and Cultural Heritage
Older cultural sites include the 12th century Dhakeshwari temple, buildings from the Mughal period, and the century star mosque. Sites from the colonial period include memorials to the martyrs of the 1857 liberation war and the language movement of 1952. Modern sites include museums, park/garden and government buildings
Minority Communities

Over 90% of the people of Dhaka are Bengali and Muslim, and there are small Hindu, Buddhist and communities. There are 800 Hindu temples, and several Buddhist temples and Christian churches.

03. Objectives :
  1. The main objectives is to find a solution for Dhaka City to Substantially reduce, or eliminate, pollution arising from unhygienic disposal of domestic sewage and industrial waste water.
  2. Would be to build a common effluent treatment plant (CETP) for Tejgaon industrial area, to reduce the health hazarads originating from the different industries in the area.
  3. To formulate a strategy for sludge collection and disposal in areas not covered by a pipe born sewage network.
  4. For preliminary environmental assessments for the proposed common effluent treatment plant and the sludge collection and disposal work.    

No comments:

Post a Comment