PROJECT ON WATER TREATMENT PLANT IN DURGAPUR MUNICIPAL CORPORATION, ANGADPURDONE BYASHUTOSH KUMAR

ROLL NO. 12/BT/57BIO TECHNOLOGYNIT DURGAPUR

Introduction

• Since ever, nature is able to provide high quality drinking water. But contamination, modifications and overexploitation of the natural water resources make clean water to a more and more scarce and precious treasure. To preserve this treasure for future generations is one of the most important tasks. Water science, water management and water technology has to play a dominant role in designing our social and industrial structure for tomorrow. Most of the knowledge, the experience, the skills and tools that are needed are available.

• Suitable concepts and solutions in water technology are based on several scientific and engineering branches as hydrology, hydrogeology, hydrobiology, water chemistry, microbiology, fluid mechanics, civil, mechanical, electrical and chemical engineering. Water and wastewater technologies interfere with natural processes and should be designed, operated and controlled in a way, which does not stress the hydrological cycle..

The Need for Wastewater Treatment• Wastewater treatment is needed so that we can use our rivers and streams

for fishing, swimming and drinking water. Increases in both the quantity and variety of goods produced can greatly alter the amount and complexity of industrial wastes and challenge traditional treatment technology. The application of commercial fertilizers and pesticides, combined with sediment from growing development activities, continues to be a source of significant pollution as runoff washes off the land.

• Water pollution issues now dominate public concerns about national water quality and maintaining healthy ecosystems. Sewage is a major carrier of disease (from human wastes) and toxins (from industrial wastes). The safe treatment of sewage is thus crucial to the health of any community.

• Micro pollutants in wastewater are a challenge to wastewater professionals. The presence of contaminants in Waste Water Treatment Plant effluents may cause a severe risk for the drinking water preparation. Upon discharge of the effluent into the receiving water body dilution and further degradation will occur.

 Source of Raw waterSurface i) River ii) Reservoir iii) Dam iv) Lake v) Canal.Ground i) Well ii) Tubewell iii) Infiltration well/gallery

GENERAL PRINCIPLES AND TREATMENT STAGES• Water treatment plants treat surface water from the dams. Raw water contains suspended and inorganic material, plant

material, bacteria, protozoa, algae, gases etc. In order to remove all these foreign particles from the water and make the water suitable for drinking purposes the following procedures should be carried out:

• Removal of suspended matter.

• Decolourisation and oxidisation of the inorganic material and killing of all pathogenic micro-organisms by adding chlorine (prechlorination).

• Aeration of water. Raw water reservoir

• Flocculation of colloidal/organic matter with aluminium sulphate and anionic polyelectrolyte.

• Sedimentation.

• Filtering.

• Addition of lime.

• Postchlorination.

1.Screening (Removal of suspended matter)

Suspended matter present in the water like leaves, water plants, soil etc. is retained at the raw water reservoir of the treatment plant. •Removes large solids logs branches rags fish.•Simple process may incorporate a mechanized trash removal system.•Protects pumps and pipes in Water Treatment Plants.

2. Prechlorination

Chlorine has oxidising and disinfecting properties. With the addition of chlorine the various organic and inorganic materials like iron, hydrogen sulphide etc. are oxidised and all the pathogenic and other micro-organisms are killed or inactivated.

Chlorine is present at all stages of water treatment in order to ensure that there is no development of pathogenic micro-organisms.

3. Aeration of Water Air is added to the water in order to kill all anaerobic micro-organisms and to oxidise the organic material present in the water.

4 . Flocculation

•Small particles are not removed efficiently by sedimentation because they settle too slowly•they may also pass through filters•easier to remove if they are clumped together•Coagulated to form larger particles•Addition of aluminium sulphate The addition of aluminium sulphate is necessary in order to remove the organic particles present in the raw water and to change the colour of the water from green to clear. The aluminium sulphate attacks the colloidal particles of the water and flocs are formed. As these flocs are heavier than the water molecules, they gradually settle down to the bottom of the reservoir as the sludge.

. Addition of anionic polyelectrolyte

The addition of anionic polyelectrolyte helps the aluminium sulphate to react more quickly with the organic matter. Larger and heavier organic flocs are formed, which settle much more easily, in a period of 2 to 3 instead of 6 to 8 hours.

The addition of anionic polyelectrolyte is done in cases when the aluminium sulphate doesn't react quickly with the organic matter, especially at low temperatures in winter, in spring, when the raw water contains big quantities of algae and in the autumn when the water is very turbid, especially after very heavy rainfall.

5. Sedimentation

After the addition of aluminium sulphate and polyelectrolyte the flocs settle down, as sludge, in the sedimentation tanks. The sedimentation tanks are sometimes called clarifiers because here, the water is being clarified. The removal of sludge is done on a daily basis and the sludge is transferred to the sludge drying beds, while the water is transferred to the filters.

6.Filtering After the sedimentation tanks, the water passes through special rapid sand filters where it is filtered in order to remove all the remaining flocs/particles which are present in the water..

•The filtration apparatus is a concrete box which contains sand, gravel and underdrain.

•After the filter is operated for a while, the sand becomes clogged with particles and must be backwashed

•Flow through the filter is reversed and the sand and particles are suspended

•The particles are lighter than the sand, so they rise up and are flushed from the system. When backwashing is complete, the sand settles down onto the gravel, flow is reversed and the process begins again.

Disinfection:

•With particles removed, it only remains to provide disinfection, so that no pathogens remain in the water•Protozoan pathogens are large in size and have been removed with other particles•Bacteria and viruses are now destroyed by addition of a disinfectant

Chlorination•Enough chlorine is added so that some remains to go out in the water distribution system, protecting the public once the water leaves the plant.

.

7. Addition of lime

Lime is added to the water to correct its acidity (pH). •Areas where water comes into contact with limestone, there may be high levels of calcium and magnesium present

•these chemicals make the water "hard“

•Hardness is removed by a process called softening

•Two chemicals (lime, CaO and soda ash, Na2CO3 ) are added to water

•causing the calcium and magnesium to form precipitates

•solid substance is then removed with the other particles by sedimentation and filtration.

8. Postchlorination

After the water treatment process is completed, chlorine is again added to the water to ensure that there is no growth of any pathogenic micro-organisms in the water supplied to the Water Boards etc. The quantity of chlorine is much less than the quantity added during the prechlorination stage.

Water Supply provided by DMC

In existing water supply system of Durgapur town, Durgapur Municipal Corporation provides water supply to the major part. The infrastructure available with DMC includes treatment plant at Angadpur, Clear water Reservoir and Pump house at Angadpur, CWR and Booster pumping station at Piyala, Service Overhead reservoir at various localities, connecting rising main pipeline and distribution network from OHR.

The Treatment plant, Rising main pipeline, Booster Pumping stations, OHR and distribution network, which are in existence today, have been installed through the Public Health Engineering Directorate in two phases. Extension of the distribution network to cover added areas to meet shortfall in demand have been carried out by DMC from time to time.

THANK YOU