Answer Happy

Consider a residential neighborhood in Aurora, Colorado with 321 single family residential units. Wastewater accumulates in a wet well that discharges through a force main that conveys the wastewater to a gravity sewer manhole at higher elevation (Figure 1).* Assume the force main is cement lined cast iron with Hazen-Williams coefficient C = 120, with length L = 4321 ft and diameter d= 18 in. GRAVITY SEWER MANHOLE A ELEVATION WET WELL Figure 1: Wet well, force main, and gravity sewer manhole (not to scale). Part A Using Aurora's standard assumptions of 2.77 people/unit, water demand of 101 gpcd, and peak hour peaking factor of 4.5, what is the peak hour water demand for this neighborhood? [gpd] Part B Assume wastewater flows are 70% of water demand. What is the peak wastewater flow? [gpd] Part C The allowable velocity range is 5-10 ft/s. What is the corresponding discharge range? [gpd] Is this large enough to handle the peak wastewater flow? Part D If AELEVATION = 124 ft, what is the static head for pump design? [ft] Part E The dynamic head for pump design is H= KQ1.85. Using units of [ft] for H and [gpd] for Q, what are the magnitude and units on K?
Part F Determine operating point for your pump. i. Plot the static head, dynamic head, and system curve (i.e., total head) versus discharge up to the maximum discharge from Part C. ii. Assume you are using a pump described by the following equation: h = 240ft - (1,000,000) where again with units of [ft] for H and [gpd] for Q. Plot this pump curve on the same axes. iii. Does this operating point provide sufficient head and discharge to clear the wet well? Part G True or false: A single pump, as specified in Part F, is sufficient for this design. Explain briefly (<12 words).