SEWAGE WATER TREATMENT
GUHISHWORI
PROCESS:
It has got Two major treatment chamber, primary treatment and secondary treatment .
Primary and secondary treatment are further divided into 3 main stages at guhishwori.
1]Primary Treatment
1} Collection Chamber
a) Mechanical screening
b) Electrical bar Screening
c) Grit chamber
2} Oxidation Chamber
2]Secondary treatment
3} Secondary classifier
1}Collection Chamber
a) Mechanical screening
b) Electrical bar Screening
Here the machine is rotating regularly by electricity. There are tooth like structure protruded which can hold the large solid materiel and separate them from the water. now the large solid material are sold out if can be recycled. Otherwise sent away to municipality garbage collecting center. Here in this chamber too there is submersible pump , that electrically pump the water from low level to high level of Grit chamber.
c)Grit chamber:
In this chamber too there are two parts ie, Detector and Classifier . Detector have continuously ringing rotatory parts that don't let the suspended particle too condense and settle. from this part the water is sent to the classifier . Classifier make the particle that are suspended to go out of this chamber .
It is also said as oxidation ridge. Here the water is collected for nearly 8 hours. But totally from the entrance at collection chamber to exit it takes total of 16 hrs. It is also the important chamber. As we all know there are two kind of micro organism ie,aerobic and anaerobic. Due to the organic accumulation into the water the level of oxygen is decreased . This depletion of oxygen make the aquatic life difficult to survive. So it should be aerated . Here aeration machine is rotated with 1200 RPM . Along with rotation it adds Oxygen . It makes the aerobic bacteria easy to survive . Actually these aerobic bacteria and anaerobic are helper of the aquatic life. They consume the harmful nitrogenous , phosphorous, and other product. It finally make the water clear and somehow increase the quality of water.
3} Secondary clarifier
In Guhishwori it is the last chamber to purify the water . But in abroad advanced country they use another chamber too . There they use UV rays and Chlorine to make water consumable. This chamber is round in shape with 3 concentric circular compartment. There is centrally motor that rotate the filter like triangular net . It completes it one complete rotation in 45 min. Now silently the water is filtered to 2nd compartment. Still the water has brown colour . It then goes to 3rd compartment and the water here is so clear as compared to the water at collection chamber.
Sludge Removal
With these process in the last chamber at Guhishwori ,sludge is removed mechanically. There are two sucking pump that suck the sludge away from the secondary clarifier. The sludge finally is send to the drying bed. Here the dried sludge is sold after drying @ of 2 Rupees.
The remaining water is not utilized further as we don't have that technology. There is 572 meter long horse shoe shaped tunnel that drain the remaining water to the level lower than tilganga. It is not directly drained to the Bagmati above pashupati.
For the purity checking and testing the sample before entrance at collection chamber and sample after exit are taken, and sent to Lab.
LAB
The sample before Entrance at collection chamber and sample after exit are taken, and sent to Lab.
It is very important to test the purity of it before discharging to the river. We test various parameter ie, Turbidity, Concentration of impurity, Purity, BOD (biological oxygen demand), COD (chemical oxygen demand), Necessity of tit-ration, TSS(total suspended solid), Ammonia, Phosphorous, Nitrate, etc.
Its efficacy is 80 -85% now .Its efficacy has been reduced from 95 to 85 %.
Helping Hands:-
On the way
Mam:
Driver:
And, all group B student
At Guhishwori
Sub engineer :- Khadga Jung Shah
Lab assistance:-Anjilla
GUHISHWORI
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| Our observation group with Sub engineer at Guhishwori |
We left KMC Duwakot sharp at 9:15am. We were the first group to leave college for our destination, Guhishwori Sewage treatment plant. It is the Nepal largest sewage treatment plant.
Sewage is the waste product produced from household activities and locally by people mixed with water and make it polluted and useless.
Usually the waste product produced from our house are as follow;
Toilets product, Sink, Washing machine, Dolls, Papers, Plastic, Toys, Oil, Grease, Paint, Samphus, etc. According to WHO and UNIS-CO still 52% of world population are openly defecating ,these are also the source of water pollution . These sort of pollution make the life of the aquatic animal and plant threatened. SO the treatment is required.
OBJECTIVE
- To make water pure and usable for religious work at pashupati.
- To make believe inside people about religion.
- To collect the waste from the local society .
- To decrease the water pollution.
ABOUT
It is the Nepals largest sewage water treatment plant . IT is situated at Guhishwori , a place behind Pashupati temple . Most of the thirththalu takes bath over there on Bagmati river. As we know there is rapidly increasing water pollution . In the polluted and sewage disposed water how thirththalu can take bath.
Its planning and office was established on 2052 BS. It was officially established and actively started working from 2056 BS. It is extended in 100 Ropani. It is using Japanese technology , with the help of the Japanese government. It is fully under the governance of Nepal government and Ministry of Urban development. It was constructed at that time with the expenditure of 66 crore NRs .It has capacity of filtering 190 liter per sec of sewage water. If sometime overloaded then the overflown water is displaced.
The finally sludge prof water is not used again for various propose here at guhishwori ie, for drinking after sterilizing , irrigation as in abroad .
PROCESS:
It has got Two major treatment chamber, primary treatment and secondary treatment .
Primary and secondary treatment are further divided into 3 main stages at guhishwori.
1]Primary Treatment
1} Collection Chamber
a) Mechanical screening
b) Electrical bar Screening
c) Grit chamber
2} Oxidation Chamber
2]Secondary treatment
3} Secondary classifier
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| Schematic Diagram Of Sewage water treatment [Different stages] |
There are lots of underground pipes line that are joint together and finally drained to the collection chamber . Guhishwori has the capacity of purifying 17 MLD (million liter per day) . Here in guhishwori it collect the water from the area like Boudha, Tushal, Chabhil, MItrapark etc. If the sewage water will be over loaded it will be carried to next chamber by overflowing . Since it has capacity of 190 LPs there is overflowing regularly. There are other sub compartment like chamber whose function is proper at their own place.
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| Collection chamber |
a) Mechanical screening
Here the sewage water from the society collected is stored for sometime . At this time the waste which are heavy are settled down and the one which can float are floated. In Guhishwori there are labors who take out the settled waste with their hand. there is no any mechanical support. But the floated larger waste are Sent to the next compartment like chamber.
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| Collection chamber with electrical bar |
Here the machine is rotating regularly by electricity. There are tooth like structure protruded which can hold the large solid materiel and separate them from the water. now the large solid material are sold out if can be recycled. Otherwise sent away to municipality garbage collecting center. Here in this chamber too there is submersible pump , that electrically pump the water from low level to high level of Grit chamber.
c)Grit chamber:
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| Over grit chamber |
In this chamber too there are two parts ie, Detector and Classifier . Detector have continuously ringing rotatory parts that don't let the suspended particle too condense and settle. from this part the water is sent to the classifier . Classifier make the particle that are suspended to go out of this chamber .
Now, the sewage water is like free of particle. The remaining water contain some organic matter , bacteria, and water soluble matter. From this important collection chamber with the help of Two big pipe water is sent to Oxidation chamber.
2}Oxidation chamber
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| Water collecting oxidation chamber |
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| Aerator machine rotating |
3} Secondary clarifier
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| Secondary treatment chamber |
Sludge Removal
With these process in the last chamber at Guhishwori ,sludge is removed mechanically. There are two sucking pump that suck the sludge away from the secondary clarifier. The sludge finally is send to the drying bed. Here the dried sludge is sold after drying @ of 2 Rupees.
The remaining water is not utilized further as we don't have that technology. There is 572 meter long horse shoe shaped tunnel that drain the remaining water to the level lower than tilganga. It is not directly drained to the Bagmati above pashupati.
For the purity checking and testing the sample before entrance at collection chamber and sample after exit are taken, and sent to Lab.
LAB
It is very important to test the purity of it before discharging to the river. We test various parameter ie, Turbidity, Concentration of impurity, Purity, BOD (biological oxygen demand), COD (chemical oxygen demand), Necessity of tit-ration, TSS(total suspended solid), Ammonia, Phosphorous, Nitrate, etc.
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| Lab instrument |
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| Purity testing materials |
Conclusion
Guhishwori plant is old enough . For its support other plant like these should be established as soon as possible. It will help to add some support for the decrees of water pollution .
Helping Hands:-
On the way
Mam:
Driver:
And, all group B student
At Guhishwori
Sub engineer :- Khadga Jung Shah
Lab assistance:-Anjilla
For more detail you can watch this video at the given link.
https://www.youtube.com/watch?v=20Xk2XfDhuY