A domestic wastewater with a flow of 1700 m3 / day will be treated in a biological treatment plant. Wastewater pre-settling tank effluent BOD value is 350 mg / L. If the volume of the biological reactor (ventilation reactor) is 500 m3, do you prefer a fully mixed or plug-flow reactor? Please explain the reasons.

explain the water footprint consumptions in Oman and consumers behavior

A vertical summit curve has tangent grades of +2.5% and -1.5% intersecting at station 12+460.12 at an elevation of 150m above sea level. If the length of the curve is 182m: a. Compute the length of the passing sight distance.

b. Compute the stationing of the highest point of the curve.

c. Compute the elevation of the highest point of the curve.

Q) Determine using the NRC formula, the BOD5 of the effluent from a single-stage, low-rate trickling filter that has a filter volume of 1,500 m3 , a hydraulic flow rate of 0.26 m3/s, and a recirculation ratio of 1.5. The influent BOD5 is 360 mg/L. Would the single stage be sufficient to achieve the WHO BOD efficacy? If not how can you improve the system efficiency and provide the necessary calculations?

Q) A. Design a set of three rectangular grit basins with proportional flow weir for a plant which has a max flow of 97,500 m3/day, an average flow of 75,000 m3/day and a minimum flow of 30,000 m3/day. Make the max depth equal to the width. The design velocity (Vh) is 0.5 m/s. B. Design a set of three parabolic channel for the same flow rates and design velocity in branch A above.

Abdul-Rahim Taysir

You are contracted to produce a map of University of Ghana covering the area shown in the image below. Explain how you will arrive the final map [Hint: your explanation should touch on how you will collect your data, perform selection, classification, simplification, symbolization and finally the map design]

Risk registers are a common part of professional practice in construction in identifying and analysing risk. Critically appraise the limitations of the risk register in effectively managing risks during the project delivery stage.

^{Briefly identify and discuss four ways clients (or their representatives) could try to reduce the adversarial (win-lose) nature of construction contracting}

Road engineering:

Explain with diagrams, the concept of the major and minor drainage system approach.

What are the methods by which the effect of punched holes can be considered in
the calculation?

Fixed load bending moment MD = 130 kN·m, live load bending moment ML = 140 kNNm
Rectangular short beams with width b = 400 mm and depth h = 600 mm are designed as follows:
Determine design suitability. Assume the coating thickness is 40 mm.(f ck = 27 MPa, f y = 300 MPa , tensile reinforcement 6-D22, shear reinforcement D10)

Explain why an increase in water-to-cement ratio for a fixed amount of cement results in lower concrete strength.

Explain the role that diffusion plays in both diffusion creep and dislocation creep; also explain how these types of creep can be designed against.

Discuss the cement hydration process and its importance in developing the strength of concrete. Explain how it works according to the stages (dormant,setting,hardening stages). Discuss the setting time, its importance in concreting, and a practical solution to delay the initial setting time. Explain how the cement fineness, water-to-cement ratio, and curing temperature can promote or hinder the hydration.