Continuation septic tank sanitary well Hemin Johnson BGI
Continuation septic tank & sanitary well Hemin Johnson BGI
Septic tank is a sanitary installation for the purification of human excreta. It consists of a water – tight Tank built of cement. design of a tank - capacity- the capacity of a tank depends upon the number of users. A cubic capacity of 21/2 -5 c. ft. - Length - the length of a septic tank is more than it’s breath in proportion of 2: 1.
Septic tank diagram. .
Design of a tank Depth – the depth of the tank is 5 -7 feet. But liquid depth is only 1. 2 m. Air space – there should be a minimum air space of one foot. Inlet & outlet – the septic tank has an inlet & an outlet. Cover – a cover is placed with a ‘manhole’ on the top. Retention period – the septic tank is designed to allow a retention period of 24 hours.
Working of a septic tank. A heavy night soil settles down at the bottom of the tank. The night soil is attacked by anaerobic bacteria & fungi & is broken down or ‘digested’ into simpler chemical compounds. This process of purification is known as “anaerobic digestion “. The accumulated solid after digestion are called ‘ sludge’.
The liquid which passes out of the septic tank from time to time through the outlet pipe is called “ effluent “. It is impure & contains numerous bacteria, etc. The effluent is allowed to pass into a soakage pit. The soakage pit is a pit dug into the ground about 3 feet deep, & filled with broken bricks and metal. The effluent percolates (pass by a substance) through the soakage pit, & gets purified by the action of the aerobic bacteria. This process of purification is called “Aerobic oxidation “.
Soap water and disinfectants Maintenance should not be thrown into the septic tank because they destroy the bacterial flora in the tank. The tank should be opened, & the sludge removed yearly.
Sanitary well Definition A sanitary well can be defined as a well which is : - * properly located * well constructed * protected against contamination.
Well
Conditions A sanitary well must fulfill the following conditions – Location – it should be trapped in a good soil & should be at least 50 feet away from any possible source of contamination. The well should not be more than 100 metres from the users. The site should be sufficiently high to prevent entrance of water from out sides into the well. Lining – the site should be sufficiently high to prevent entrance of water from the outside Into the well. The sides should be built with bricks or stones up to a depth of 6 metres& lined with cement.
Parapet wall – the parapet wall should be up to a height of at least 70 -75 CMS, from the ground level to prevent the surface water entering the well. The parapet wall should be lined with cement both sides. Platform – there must be a cement concrete platform round the well extending at least 3 feet in all directions. The platform should have a gentle slope outwards.
Drain – a pucca ( permanent) drain must be provided joining public drain. Covering – the well should be properly covered to protect from dirt & dust. And also to prevent birds making their nest in the cervices of well wall. Hand pump – use of hand for lifting water will prevent The well from contamination. The use of rope & bucket must be discouraged, because it tends to introduce pollution into the well.
Quality – the quality of water should be tested in a laboratory to ensure that the water is fit for drinking. The surrounding of well should be kept clean washing of clothes, bathing, & dumping of wastes & refuse near the well should be avoided. Give health education to the public about the proper use of the well.
Question blog ? Explain the working of a septic tank? Explain slow sand filter with diagram & it’s elements ? Enlist the conditions to follow a sanitary well? Enlist steps in rapid sand filter ?
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