Water management in the urban areas of developing countries is overwhelmed with a range of problems. These problems are basically due to lack of proper management. In urban areas there are two main water systems, the clean water supply system and the waste water (or sewerage) system. The clean water supply system has similarities with urban areas of developed countries, while sewerage system has not. Water borne sanitation systems has been provided to very few households in urban areas of developing countries.
Disorder of facility to the communities is often brought about with the collapse of water systems in urban areas of most developing countries. Residents will possibly fetch water from unimproved sources when there is a failure in water supply system of a town. The waste water from rainwater or urban overflow creates destruction in many towns and cities due to the lack of proper drainage systems or even because they are in-operation where they are available. The failure of the water systems is largely because of lack of synchronization between the different authorities concerned with water management.
Dar es Salaam is the major city and organizational, business and industrialized centre in Tanzania. It is located on the eastern coast of the country along the Indian Ocean which comprise of total area of 1393 Sq. km. The entire city is politically and administratively divided into three Municipalities (Temeke, Ilala and Kinondoni). The city area is growing at a rat e of 7% per year and it is estimated that roughly 70% of the population in the city live in informal or unplanned settlements (Kaseva & Mbuligwe, 2005).
This paper focuses the wastewater management system of one of the area Mwenge area in the city of Dar-es-salaam which is in Kinondoni municipal. Mwenge area was selected for this study because it has mixed land use (industrial, residential and commercial areas) with unmanaged wastewater system without having proper future plans or forecast. Since the author is also well informed about this particular area the collection of data and analysing them would be practical.
Wastewater generation and handling in Mwenge area
J.M. Lusugga Kironde states in his article on waste management in Dar-es-salaam that "less than 5% of the population of Dar es Salaam (of 4 million people) is connected to the sewer system, which is 130 km long, grouped into 11 systems and supported by 17 pumping stations". Where the central areas, some industrial areas, and a few outlying residential areas are covered by this system. The waste matter is released into oxidation ponds and local water streams and directly into the sea.
He further says that "the central areas discharge directly into a sea outfall, where the end of the 1,040 m long pipe lies in less than 2 m of water numerous fractures discharge raw sewage onto the mud flats exposed at low tide. Many of the oxidation ponds no longer operate, as a result of a lack of maintenance, and raw sewage therefore discharges into the surface drainage system".
Mwenge area has a number of land uses which are all prone to the production of different type waste (household waste, industrial waste). Mwenge area has a very limited sewage disposal channels for the whole area. People residing in the area have a system of disposing their wastes into the nearby river that is Mlalakuwa River which passes through the Mwenge area, which eventually takes the dirty waste to the ocean.
From the estimated data by J.M. Lusugga Kironde, "about 80% of the 4 million people living outside the central areas have access to on-site facilities - 70% of these use pit latrines, 30%, septic tanks - and the remaining 20%, or about 800,000 people, lack even elementary sanitary facilities." Mwenge area is outside the Dar-es-salaam central area the estimation shows how people face trouble related to sewage disposal.
Dar es Salaam had a population of 1.7 million according to 1988 population data. Every day people, industries, and institutions generated some 126 ton of biochemical oxygen demand, 133 ton of chemical oxygen demand, 212 ton of suspended solids, 372 ton of dissolved solids, 18.7 ton of nitrogen, and 3.77 ton of phosphorus. An approximate 2.46 million inhibiter corresponding were being produced each day. (J.M. Lusugga Kironde, 2009)
There are some efforts done by the Dar-es-salaam Sewage System Department (DSSD) and the Health Department that manages tanker lorries to empty pit latrines and septic tanks, usually at the request of people living in the area. Furthermore, a number of private business individuals and organizations have their own emptier, like the Coca-Cola Company have their emptier which empties their septic tanks on a regular basis. However, a small number of the publicly possessed vehicles are working at any particular time, one needs to call them and pay for the service. The usual trend is for people to take out the liquid waste but leave the solid waste.
Water tables are high in most parts of Dar es Salaam, particularly during the rainy season, which intensifies problems with poor sanitary conditions, as many septic tanks and pit latrines overflow into the surrounding public lands and drainage systems.
Groups of entrepreneurs offer manual pit-emptying services, but the waste is discharged into on-site trenches, rather than being transported to oxidization ponds. This considerably pollutes the surface drainage systems, the groundwater, and the ocean.
There are some intense industries nearby which has a tendency of disposing their hazardous chemicals into the river, which eventually is being discharged into ocean, while affecting a lot of and people living nearby, species, plants in river channel and in the ocean.
Industrial-waste generation and handling
During the first two decades of independence, Dar es Salaam introduced many industries to enhance economic development. These industries in Dar es Salaam include those for metal-working, steel, and iron; cotton textiles, leather, and sisal; chemical; food processing and beverages; paper and wood products; and nonmetal products, including cement and asbestos. Although most of these industries have had major problems since the 1980s and many are working at below 50% capacity, they generate considerable waste. Indeed, their economic problems make this situation worse, as the machinery gets worn out and cannot be replaced, and they therefore have no resources to operate an efficient waste-disposal system.
The amount of waste generated was discussed above. Rough calculations suggest that about 94% of the industries in Dar es Salaam are connected to a piped-water sewerage system. About 6% are connected to septic tanks and soakaways. The major mode of treatment is through oxidization and stabilization ponds, and the treated waste is then usually discharged into rivers and thus ultimately into the ocean. Various studies suggest (Haskoning and M-Konsult 1989) that industrial waste is not pretreated before it is discharged into oxidization ponds. The level of water pollution is high, as is evident from findings on one of Dar es Salaam's major rivers, the Msimbazi, known for its clean water during the colonial times and currently the recipient of many industrial effluents.
The coliform count in the Msimbazi at entry into Dar es Salaam (at Kiserawe) is 75-100 per 100 mL of water, a relatively low count, indicating good-quality water. When the Msimbazi leaves Dar es Salaam (at Salander bridge), the coliform count is between 250 000 and 400 000 per 100 mL of water, indicating heavy contamination. This is more than 1 000 times the coliform count considered safe to just swim in. The lower stretch of the Msimbazi is, therefore, an open sewer. Causes of this pollution are varied, but they include the city's excessive reliance on on-site modes of sanitation and its tendency to discharge raw domestic and industrial effluents into rivers and natural channels (Yhdegho 1991). Even toxic waste, including pathogenic waste from hospitals, is crudely dumped, without any pretreatment.
Although 58 pieces of legislation deal in one way or another with the environment, most of these laws are unknown, unenforceable, or outdated. The NEMC, created in 1986, lacks regulatory powers and can therefore only advise. Much industrial pollution is in practice uncontrolled.
The experience of water management system in the urban areas of Tanzania, in this case Mwenge area one of the urban area of Dar-es-salaam is the focus of this paper. The author is of the opinion that the experience of Tanzania is not very different from that of other developing countries.
ENVIRONMENTAL IMPACT DUE TO POOR WASTE WATER MANAGEMENT IN MIXED LAND USE AREA (INCASE OF MWENGE AREA IN DAR-ES-SALAAM CITY)
Introduction
The city of Dar-es-salaam is a coastal industrial hub of Tanzania with huge manufacturing industries and also some huge residential areas, as the population is very high compared to the other parts of Tanzania. Dar-es-salaam is the main gateway through which the nation is connected to the international community in all the sectors, sectors like importation and exportation of good and raw materials, agricultural, manufacturing, important service infrastructures and others.
Currently the city of Dar-es-salaam is facing problems which are the by-product of the mixed land use and unplanned areas. Some part of Dar-es-salaam is very well planned and implemented as planned but some areas are planned but not well implemented, there are also places which are completely unplanned areas with huge mixed use settlements.
For places which are planned and implemented as planned, is to some extent in good shape and organised in terms of its spatial organisation, services and requirements.
For places which are planned but not well implemented are in a bad shape as there are a lot of activities which are going on which were not planned for, like having a disco and a pub right in the middle of residential area.
Whereas the unplanned areas are totally in a poor conditions as there are no services installed, services like water supply, sewage, electricity supply, garbage disposal area, communication infrastructure and others. The land use is also undermined as any place could turn into any use. So for the inmates who live in these places or work in these places face huge problems in their daily activities.
The area selected for the observing the environmental impact of mixed land use
The major mixed land use in the city of Dar-es-salaam as observed in unplanned areas and unimplemented planned areas is residential areas with industrial activities. One particular area in Dar-es-salaam which is Mwenge area was selected to observe the effects of mixed land use (industrial and residential).
The selection was based on the criteria of having all areas that is, the implemented planned area, unimplemented planned area and unplanned area all in one area. Mwenge area is located along the Bagamoyo road which has planned and unplanned areas and its located 10 kms from the city centre. Mwenge areas have various land uses like industries, residential, commercial area, public buildings and institutional buildings.
Mwenge area
