SHOTS - ENVIRONMENTAL ENGINEERING

💥 Use of metering system causes the decrease in per capita consumption. 

💥 1.5 is the hourly factor, 1.8 daily factor and 2.7 is the peak demand. 

💥 The distribution mains are designed for maximum hourly demand. 

💥 Geometrical method is used for young and rapidly developed cities for forecasting the population. 

💥 Arithmetical method is used for large cities. 

💥 As compared to geometrical method arithmetical method gives less value. 

💥 Intakes are installed for drawing the water from the sources. 

💥 Reflux valve provided on the suction pipe in a tube well. 

💥 The maximum discharge in tube well is 50lit/sec. 

💥 As compare to the shallow wells deep wells have more discharge. 

💥 Ground water is generally free from suspended impurities. 

💥 Malaria is not a water borne disease. 

💥 The most common cause of acidity in water is co2. 

💥 The phenol compounds in water supply not more than 0.001ppm. 

💥 1.5mg/litre is the permissible limit of fluoride content. 

💥 Standard EDTA test is used to test the hardness of water. 

💥 Alkalinity in water is expressed in calcium carbonate. 

💥 Turbidity is measured on standard silica scale. 

💥 Color on platinum cobalt scale. 

💥 The turbidity of drinking water should be 10ppm. 

💥 Residual chlorine is tested by starch iodide and orthotolidine method. 

💥 Total solids not more than 500ppm. 

💥 Total chlorides not more than 250ppm. 

💥 Iron and magnesia 0.3ppm. 

💥 Lead and arsenic 0.05ppm 

💥 Copper 3ppm, fluorine 1.5ppm. 

💥 The dissolved oxygen in natural unpolluted water is 10mg/litre. 

💥 The length of the sedimentation tank should not be not more than 4 times the width. 

💥 The over flow rate of plain sedimentation tank is 500 - 750litre/hr/m^2. 

💥 The settling velocity of a particle depends upon surface area of tank. 

💥 Efficiency of the sedimentation tank depends upon surface area of the tank. 

💥 For effective coagulation the PH value of water found to be 6 - 8.5. 

💥 The detention period of coagulation tank is 2 – 6 hour. 

💥 The alum when added as coagulant it decreases the PH value of water. 

💥 Lime is used to increase the speed of the sedimentation sewage. 

💥 Air binding phenomena in rapid sand filters occurs due to excessive negative head. 

💥 Backwashing provided in rapid sand filters. 

💥 2 - 3 months is the period of cleaning of slow sand filter. 

💥 Time contact of chlorine is at least 30min. 

💥 The percentage of chlorine in fresh bleaching powder is 30 to 35%. 

💥 The treatment of water with bleaching powder is called hypo chlorination. 

💥 The suitable method of disinfecting the swimming pool water is ultraviolet rays treatment. 

💥 Sulphur dioxide used for dechlorination of water. 

💥 Disinfection efficiency reduced at higher PH values. 

💥 Copper sulphate is used for algae control. 

💥 Activated carbon is used for removing odours. 

💥 Dead end system is used for irregularly growing towns. 

💥 Radial system is used when the water is flowed towards the outer periphery. 

💥 Grid iron system is used for well planned cities. 

💥 Circle method is used when fire demand is considered.

💥 Sluice valve provided to regulate the flow of water. 

💥 Reflux valve provided to prevent the water flow back in the opposite direction. 

💥 Scour valves are provided at every depression head and dead ends. 

💥 House sewer - lateral sewer - common sewer - main sewer - trunk sewer - outfall sewer. 

💥 For country like India where rainfall is mainly confined to one season separate system is adopted. 

💥 Combined system adopted when the rainfall is distributed throughout the season. 

💥 135 litres domestic consumption. 

💥 Sewerage system is generally designed for 25 years. 

💥 For long and narrow pipe system equivalent pipe method is used. 

💥 Circular shape sewer is preferred in separate system. 

💥 Egg shape sewer is preferred in combined system. 

💥 The time of concentration –the time taken by rainfall to run from most farthest point to the point of disposal. 

💥 1 to 1.2m/sec is the self cleansing velocity of sewer in Indian condition. 

💥 The slope of sewer should be in the direction of natural slope of ground. 

💥 6*DWF for separate system. 

💥 Rainfall+2DWF for combined system. 

💥 15cm &300cm is the minimum and maximum diameter of sewer. 

💥 The velocity of flow does not depend on length of sewer. 

💥 Circular brick sewer is used under culverts. 

💥 Egg shaped sewer is suitable for both separate and combined system. 

💥 The characteristic of fresh and septic sewage is alkaline and acidic. 

💥 The pathogens likely killed by chlorination. 

💥 Standard BOD is measured at 5 day 20 degree. 

💥 TOD>COD>BOD. 

💥 5 day BOD is less than 4 day BOD. 

💥 The ratio of 5 day BOD to ultimate BOD is 2/3. 

💥 4ppm is the minimum DO to avoid the fish kill. 

💥 Dissolved oxygen in streams is maximum at noon. 

💥 The means of access for inspection and cleaning of sewer is manhole. 

💥 Sewerage system is designed for maximum and minimum flow. 

💥 Sewage treatment plant designed for average flow only. 

💥 Laying of sewers is usually done with the help of boning rods and sight rails. 

💥 In sewage oil and grease removed by skimming tank. 

💥 Detention period of grit chamber is 1 minute. 

💥 Sludge digestion tank and septic tank unit works on anaerobic condition. 

💥 The maximum efficiency of BOD removal is achieved in oxidation ditch. 

💥 The working condition of imhoff tanks are anaerobic in lower compartment and aerobic in upper compartment. 

💥 The detention period of oxidation pond is 10 to 15 days. 

💥 Compositing and lagoning are the methods of sludge disposal. 

💥 Facultative bacteria works with or without oxygen. 

💥 For satisfactory working of sludge digestion tank the PH value of water is 6 - 8.5. 

💥 Normal value of sludge index is 150 - 350. 

💥 Bangalore method practise anaerobic method of disposal. 

💥 Antisiphonage pipe is used to preserve the water seal traps. 

💥 In two pipe system one soil pipe, one waste pipe and two vent pipes required. 

💥 The gas from sludge digestion tank mainly composed of methane. 

💥 Most of the bacteria in sewage are saprophytic. 

💥 Chlorine is used to separate grease. 

💥 Shrouding is provided in slotted pipe tube well. 

💥 Ozone layer in the outer atmosphere get destroyed by chlorofluoro carbons. 

💥 The intensification of green house gases is due to CO2. 

💥 Electrostatic precipitator is used to control particulate emission. 

💥 Spray tower is used to control both gaseous and particulate pollutant. 

💥 PAN and ozone are the secondary air pollutants. 

💥 Sulphur dioxide and nitrogen oxide are the primary air pollutant. 

💥 The depletion of ozone layer in the outer atmosphere causes the skin cancer. 

💥 The acid rains are caused due to SO2 and NOx. 

💥 Blue baby disease caused due to excess of nitrates. 

💥 Dechlorination of water is achieved by sodium thio sulphate. 

💥 The efficiency sedimentation tank does not depend upon depth of the tank. 

💥 Sewage sickness caused due to clogging of pores in soil due to excessive application of sewage to land. 

💥 Soil pipe carry human excrete. 

💥 Screening - grit removal - primary sedimentation - aeration - secondary sedimentation. 

💥 Traps are used to prevent the entry of foul smelling gases. 

💥 Coal based thermal power stations produce SO2,NOx and SPM. 

💥 Zone of degradation - zone of active decomposition - zone recovery - zone of clear water. 

💥 River water contain maximum amount of turbidity. 

💥 Ringle man scale is used to measure grade density of smoke. 

💥 Eutrophication of water is rich in nutrients. 

💥 Zero hardness is achieved by ion exchange method. 

💥 Excess lead causes anaemia, goitre caused due to absence of iodide. 

💥 Aerosol is dispersion of small solid or liquid droplet. 

💥 A commonly used hand pipe is reciprocating pump. 

💥 1 st stage is carbonaceous demand 2nd stage is nitrification demand. 

💥 P trap used for water closet. 

💥 The sound level of jet air plane is 140 decibel.