What historical events led to the discovery of water-borne pathogens?

(b) What municipal drinking water disinfection method led to significant reductions in water-borne pathogenic diseases in cities?

(c) What is the main disadvantage of the disinfection method listed in part (b)?

(a) What type of reactor is ideal for treatment with an AOP? (b) Why?

(c) Practically, how would you design the reactor to achieve your desired goals in parts (a) and (b)?

Reynolds Experiments

Aim- The aim of the experiment is to investigate different flow regimes in pipe and find critical Reynold number

A CSTR activated sludge system is being designed for the Fulton Fish Processing Plant. The flow is relatively small (0.25 mgd), but the wastewater is strong due to all of the fish waste (BOD5 = 4500 mg/L). Primary settling removes 20% of the BOD5. In order to discharge to the town sewer the BOD5 must be reduced to a concentration that is 95% of the influent. What is the Dimensions of the basin assuming a 3:1 L:W ratio. Also, what is the sludge production rate?

Design Parameters

θc = 10 days

X = 2100 mg VSS/L

MLVSS is 75% of MLSS

Aeration Basin = 20 ft deep

Yobs = 0.3 mg MLSS/mg BOD5

Recycle Ratio = 50%

Select a lightest American Standard Channel that will safely support a tensile dead load of R/2.5 kN and a tensile live load of R/2.0 kN. The member is 5m long and is i to have one hole for an 18 mm bolt through each flange. Use U=0.85, A36 the AISC Specification.

take R=1266

A rigid strip footing with a width of B is constructed above the ground on a clay deposit, overlying bedrock. The depth of clay layer is H and the water level is at the natural ground surface. Before construction of the footing, laboratory tests on a saturated clay sample, taken at a depth of H/2 below the ground surface, provided the following properties:

Compression Index = Cc , Recompression Index = Cr , Consolidation Coefficient = cv

Over Consolidation Ratio = OCR, Water Content = w% and Specific Gravity = Gs

Assume the vertical uniform surcharge stress on the footing including the weight of footing and column = q

(a) Calculate the initial saturated unit weight of clay deposit.

(b) Based on the elastic theory (Boussinesq’s equation), calculate the excess pore water pressures at the depth of H/2 immediately after applying the surcharge load. Assume the vertical stress (q) is applied instantaneously.

(c) Using theory of 1-D consolidation, calculate the total average settlement of this rigid footing due to consolidation of the clay layer, long time after applying the total load.

(d) Determine the average settlement of this rigid footing after n days of applying the total load due to consolidation of clay deposit. Assume the bedrock is permeable (i.e. Drainage path = H/2)

(e) Plot the graph of settlement versus time (in log scale) for this footing.

The sediment settling velocity, ωs (ms-1) in stagnant water is dependent on the sediment diameter, d (m), sediment density, ρs (kgm-3), water density, ρ (kgm-3),dynamic viscosity of water, μ (kgm-1 s-1), and gravitational acceleration, g (ms-2).By applying the dimensional analysis, develop the equation in terms of phi, π to
explain the ωs.

PROCUREMENT METHOD

There are a number of different types of procurement routes available for clients to select. Each different type of procurement (Traditional, Design and Build, Construction Management, etc) has its own advocates and inherent strengths and weaknesses. Describe in detail the most suitable procurement to be used based on the scenario below.

The explanation shall include the definition of the suitable type of procurement method, its characteristic, and the reason for selection. You may use figures to explain it.

What all factors an engineer must consider for designing a retaining wall to retain a soil of height 10m? How those factors are different for a cohesionless soil, a cohesive soil and a saturated soil?

An amount of P 250,000 is now deposited into a savings account that earns 12% compounded continuously for the school requirements of a civil engineering student on the succeeding 5 years from now. If the every year the student will withdraw P 51,651 from this account, how many years would the deposit lasts?

How shape and size of soil particles influence the properties of soil? Justify your answer with appropriate examples. (Mention minimum two properties and corresponding justifications)

Equal – quarterly deposits of P 2,000 for 2 years which starts immediately is made at a savings account that earns 4% compounded quarterly. What is the amount in the account when the last deposit is made? What is the amount in the account at the end of the last quarter?

: A wet soil sample with a water content of 15% and percentage air voids of 20% was oven dried. If the soil sample is cylindrical in dimension with length as 100 mm and diameter as 50 mm, then how much mass of water is present in the soil? Also calculate the mass of soil. Assume specific gravity of soil is 2.69 Interpret your answer and conclude how water content influences the unit weight of soil.

One proposal for treating water in developing country is for individual families to use a small, home made slow sand filter followed by storage of filtered water in a clear plastic bottle exposed to the sun for a day. Explain the purpose of the slow sand filter and the mechanism that disinfects the water.

( Please type the answers not hand writing )