The Environment Bureau of HKSAR Government has recently proposed legislation for the proper management of waste electrical and electronic equipment (Hong Kong WEEE) in Hong Kong, and has consulted public views. Do you think Hong Kong WEEE should copy from the EU WEEE or China WEEE Directives? Justify your answers in 6 bullet points (or short paragraphs).

Give a real world example where a structure collapsed or became structurally unsafe, or settled excessively due to insufficient soil strength.

3. What soil type or types are most prone to frost heave and why? What are the conditions that can lead to frost heave?

Q3: When a mild steel rod was tested under tension, it was observed that a load of 8 kN causes an
extension of 0.024 cm in the rod. The maximum load carried by the steel rod was observed to be
20 kN and the load beyond which stress is not proportional to strain was noted as 10 kN. When the
specimen breaks, the elongation in the rod measured was 5.25 cm and the diameter at the fracture
observed was 0.455 cm. What will be the length and diameter of the steel rod if the total
elongation of the steel rod was found to be 25% and the area of contraction at fracture estimated
was 12%? Based on the test results, determine the values for the stress corresponding to limit of
proportionality, modulus of elasticity of the material and the ultimate stress developed due to
tension.
Experiments were conducted on another brass rod having diameter same as that of the steel rod
and the changes in the dimensions were tabulated. Within elastic limit, the extension of the brass
rod is found to be 35% more than that of the steel rod for a length of 18 cm, suggest a suitable
value for the applied load and determine the percentage increase in the values of stress and the
strain? Given modulus of elasticity of brass is equal to 0.88 times that of the modulus of elasticity
of steel. Compare the properties of steel rod and brass rod based on the test results. (8

What data is needed from each traffic analysis zone to forecast future volumes?

1. population, no. of vehicles, miles of roadway, and no. of buses
2. no. of licensed drivers, no. of vehicles, and no. of households
3. zone boundaries, traffic nodes and centroids, employment
4. forecasted population, no. of jobs, and no. of households

Maximum Service Flow Rate is determined under…

1. ideal weather and pavement conditions
2. ideal driver and vehicle conditions
3. ideal roadway and control conditions
4. ideal vehicle user conditions (no trucks)

3. The watershed shown in the figure below is located in Bowling Green, Kentucky (western Kentucky).  The entire watershed is 100 acres in size and is predominantly forested (woods in good condition) before mining begins.  The soils are Macomber (HSG C) and Saragosa (HSG B) with about 50% of the entire watershed in each. These soil types do not change when mining happens.  One seam of coal is to be surface mined as indicated in the figure below (hatched area), with this strip mine land-use being considered “cultivated land without conservation treatment.”  The remaining non-mined land use remains as forested. Please feel free to treat the mining strip (hatched) area as a rectangle with the width 180 ft and length 4500 ft (18.6 acres).

1. (2.5 points) Calculate the Curve Number for the Before Mining watershed condition

2. (2.5 points) Determine how much of the rainfall falling on this before mining watershed would be removed as initial abstractions.  

3. (2.5 points) Calculate the Curve Number for the After Mining watershed condition.

4. (2.5 points) Determine how much of the rainfall falling on this after mining watershed would be removed as initial abstractions.  

) Consider three monitoring wells, each located at the vertex of an equilateral triangle. The distance between any pair of wells is 200 m. The head at each well, referenced to some common datum, is as follows: well 1, 100.1 m; well 2, 100.2 m; well 3, 100.3 m. Sketch the well field and find the value and direction of the hydraulic gradient.

1. Sketch the well field and find the value and direction of the hydraulic gradient.
2. The aquifer has a hydraulic conductivity of 1000 m/d and a porosity of 0.35. Estimate the travel time for the groundwater to flow between well 1 and well 2.

) Consider three monitoring wells, each located at the vertex of an equilateral triangle. The distance between any pair of wells is 200 m. The head at each well, referenced to some common datum, is as follows: well 1, 100.1 m; well 2, 100.2 m; well 3, 100.3 m. Sketch the well field and find the value and direction of the hydraulic gradient.

1. Sketch the well field and find the value and direction of the hydraulic gradient.
2. The aquifer has a hydraulic conductivity of 1000 m/d and a porosity of 0.35. Estimate the travel time for the groundwater to flow between well 1 and well 2.

Shown below are the results of water quality analyses of a groundwater source. Because all of the constituents were not analyzed, an ion balance may not be achieved. The pH of the water is 7.6.

a. (8 points) Prepare a bar chart of water composition.

b. (6 points) Based on the bar chart, determine the total hardness, carbonate hardness, non-carbonate hardness, and alkalinity (in the unit of mg/L as CaCO₃).

c. (6 points) Estimate the concentrations of carbonate (CO₃^2-) in the water. Express your answer in mmol/L. Given that pK_a1 and pK_a2 of H₂CO₃ are 6.35 and 10.33, respectively.

d. (6 points) Dolomite (CaMg(CO₃)_2(s)) is found in the aquifer sediment where the water sample was collected. Based on the water composition, is dolomite dissolving or precipitating? Given that the Ksp of CaMg(CO₃)_2(s) is 10^-17.09.

Explain in detail why is coordination required at all phases of construction for MEP systems? What are the outcomes when a job is not coordinated properly? Why is in important to coordinate at time of bid and what are the downsides to coordinating at the time of bid?

Sketch water surface profile in two rectangular channels that are joined with the following information. a. Slope is changing from 0.0016 to 0.015 ? = 0.013 ? = 10 ?? ? = 400 ??? ?0−?ℎ????? 1 = 0.0016 ?0−?ℎ????? 2 = 0.015

Q3

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

A completely mixed activated sludge process is to be used to treat a flow rate of 2.5 MGD. Design a rectangular activated sludge reactor with a 4:1 ratio of length to width. (design only 1 reactor for all flow). The effluent from the plant must not exceed 15 mg/L of BOD5. Use the following design criteria:

a. BOD5 influent = 250.0 mg/L

b. MLVSS (X) = 3500 mg/L

c. Reactor depth = 11 ft

d. Effluent BOD5 must be less than 20 mg/L

e. Y = 0.6 mg VSS/mg BOD5

f. K = 6 day-1

g. KS = 65 mg/L BOD5

h. Kd = 0.08 day -1

i. MLVSS/MLTSS = 0.75

Determine the following: a. Determine the minimum solids retention time (SRT) in days to meet discharge criteria

b. If the actual solids retention time is 4 days, what would be the volume of the activated sludge basin if the wasting flow rate is 40,000 gpd containing 6,400 mg/L of solids.

c. Using the volume of aeration basin in question (b) determine the dimensions of the basin, if the depth is 11 feet, to the nearest even foot

d. What is the hydraulic retention time (HRT) in hours, in the activated sludge basin?

4. Which chemical bond is involved in each of the following? Explain your answer. Justify
each answer with a reason.                                                                                                            []
a. Copper
b. Salt (Nacl).
c. Plastic cup.

* Please answer in clear and readable writing or by typing. The solution is with all the right steps.

The stratigraphy in a site from top to bottom are (1) 4.5 m thick sand; (2) 4.5 m thick clay; (3) impermeable shale. The water table is at a depth of 2 m below ground. The sand above the water table has a void ratio of 0.52 and a saturation degree of 37%. The clay has a moisture content of 42%. The specific gravity of both the sand and clay is 2.65. If constructing a foundation whose bottom is at a depth of 3m, resulting in the extra stress at the top and the bottom of the clay layer is 100 kPa and 40 kPa, respectively. According to the consolidation test, the void ratio of the clay corresponding to 50, 100 and 200 kPa are 1.02, 0.922 and 0.828, respectively. The settlement of the clay layer will be_____________(mm). (One-dimensional settlement is applicable. The density of water is 1000 kg/m³)