Water Supply Engineering Questions

• Purpose of chemical coagulation in drinking-water treatment What is the primary reason for adding coagulants (e.g., alum, PAC) in conventional water treatment plants?
• Rapid sand filters – cause of air binding Air binding in a rapid sand filter is primarily caused by which condition?
• Urban water demand categories – what is excluded from “public uses”? In municipal water-demand accounting, which item below is not counted under the “public uses” category?
• Tube-well construction – where is “shrouding” (gravel pack) essentially provided? Select the well type that primarily employs shrouding (a graded gravel pack around the screen) to prevent sand entry and stabilize the formation.
• Hydraulics and soil mechanics — unit for coefficient of permeability: In geotechnical and groundwater engineering, the coefficient of permeability (hydraulic conductivity) of soils is generally expressed in which unit?
• Plain sedimentation design — typical surface overflow rates: Normal values of overflow rate (surface loading rate) for plain sedimentation tanks are generally in which range, expressed in L/h per m^2 of surface area?
• Water quality — turbidity standard reference: The historical “1 turbidity unit” (Jackson scale) was defined as the turbidity produced in 1 litre of distilled water by 1 mg of finely divided which reference substance?
• Slow sand filtration — allowable raw-water turbidity: A slow sand filter is generally used when the maximum turbidity of the raw water is less than which value (use standard unit mg/L or NTU)?
• Water hardness — temporary (carbonate) hardness removal: Which treatment can remove temporary hardness of water most directly under household or plant conditions?
• Allowances in water-supply design — distribution losses: For preliminary municipal water-supply sizing, what allowance is commonly assumed for system losses (leakage, theft, meter inaccuracies), expressed as a percentage of demand?
• Centrifugal pump fundamentals — need for priming: A centrifugal pump must be primed before starting when it is installed at which relative level to the water surface in the source reservoir?
• Rapid gravity filtration — key characteristics: Which of the following statements about rapid gravity filters (RGFs) is/are correct?
• Soil–water terminology: The property of earth that describes its ability to allow water to pass through it is called
• Aesthetic/acceptability limit — chloride in public water supplies: According to common drinking-water acceptability guidelines, the chloride content of treated water supplied to the public should not exceed
• Buried and embankment conduits (Marston–Spangler concepts): For external load per unit length, which proportionality statements are correct for the following cases? • A pipe laid on or projecting above undisturbed ground and then covered with embankment (projecting/embankment condition) • A flexible pipe buried in a narrow trench with thoroughly compacted side fills • A rigid pipe buried in a narrow trench with thoroughly compacted side fills Assume customary soil-structure interaction behavior used in municipal pipeline design.
• Water treatment fundamentals: Disinfection of drinking water is primarily performed to remove or inactivate which contaminant class?
• Head loss in full-flow conduits: Which named formula is the general, dimensionally consistent relation used across fluids, sizes, and Reynolds numbers?
• Reservoir sedimentation arithmetic: A reservoir accumulates on average 0.15 million m³ of sediment per year. Dead storage = 8 million m³, total capacity = 36 million m³. Which statement is correct regarding siltation timeline and onset of useful-capacity loss?
• Dupuit–Thiem steady radial flow to wells: The derivation of Thiem’s formula relies on which set of assumptions?
• Indian urban water supply practice: In which of the following cities is raw water commonly conveyed from source to treatment plant predominantly under gravity (classic scheme)?