ALL ABOUT OF CIVIL ENGINEERING, PDF NOTES , GENERAL KNOWLEDGE, ETC

Velocity The velocity of flow ahead of and through the screen varies and affects its operation. The lower the velocity through the screen, the greater is the amount of screenings that would be removed from sewage. However, the lower the velocity, the greater would be the amount of solids deposited in the channel. Hence, the design velocity should be such as to permit 100% removal of material of certain size without undue depositions. Velocities of 0.6 to 1.2 mps through the open area for the peak flows have been used satisfactorily. Further, the velocity at low flows in the approach channel should not be less than 0.3 mps to avoid deposition of solids. Head loss Head loss varies with the quantity and nature of screenings allowed to accumulate between cleanings. The head loss created by a clean screen may be calculated by considering the flow and the effective areas of screen openings, the latter being the sum of the vertical projections of the openings. The head loss through clean f...

Process of wastewater treatment plant Click here to read briefly

Sewer Appurtenances Sewer appurtenances are the various accessories on the sewerage system and are necessary for the efficient operation of the system. They include man holes, lamp holes, street inlets, catch basins, inverted siphons, and so on. Man-holes: Man holes are the openings of either circular or rectangular in shape constructed on the alignment of a sewer line to enable a person to enter the sewer for inspection, cleaning and flushing. They serve as ventilators for sewers, by the provisions of perforated man-hole covers. Also they facilitate the laying of sewer lines in convenient length. Man-holes are provided at all junctions of two or more sewers, whenever diameter of sewer changes, whenever direction of sewer line changes and when sewers of different elevations join together. Special Man-holes : Junction chambers: Man-hole constructed at the intersection of two large sewers. Drop man-hole : When the difference in elevation of the invert levels of the incoming and out...

Design of Sewers The hydraulic design of sewers and drains, which means finding out their sections and gradients, is generally carried out on the same lines as that of the water supply pipes. However, there are two major differences between characteristics of flows in sewers and water supply pipes. They are: The sewage contain particles in suspension, the heavier of which may settle down at the bottom of the sewers, as and when the flow velocity reduces, resulting in the clogging of sewers. To avoid silting of sewers, it is necessary that the sewer pipes be laid at such a gradient, as to generate self cleansing velocities at different possible discharges. The sewer pipes carry sewage as gravity conduits, and are therefore laid at a continuous gradient in the downward direction upto the outfall point, from where it will be lifted up, treated and disposed of. Hazen-William's formula             U=0.85 C rH0.63S0.54 Manning's for...

इलेक्ट्रॉन, प्रोटॉन, न्यूट्रॉन और पोजिट्रॉन इनमें से सबसे बड़ा कण कौन-सा है? – इलेक्ट्रॉन �दूध उबालने की स्फूर पश्चयता कितनी होती है? – 100°C � कौन-सा तत्व रासायनिक रूप में धात...

: ** IAS में पूछे गए कुछ प्रश्नोत्तर 1. मानव गुर्दे में बनने वाली 'पथरी' प्रायः बनी होती है- (IAS Pre परीक्षा- 2000) उत्तर: कैल्शियम ऑक्जेलेट 2. खदानों में अधिकांश विस्फोट का कारण है- (IAS Pre परीक्षा- 2000) उ...