Chapter 11, Problem

Determine the required solids retention time (SRT) of a completely mixed activated sludge aeration tank for a conventional activated sludge system treating a design flow rate of 34,560 m³/d, where the effluent standards are 30.0 mg/L for BODs and 30.0 mg/L for total suspended solids (TSS). Assume that the BOD5 of the effluent TSS is 70% of the TSS concentration. Assume the BODs concentration leaving the primary clarifier is 128 mg/L that the MLVSS concentration (X₂) is 2,500 mg/L. Assume the following values for the growth constants: Ks 100 mg/L BODS ⚫ Hm - 2.5 d 1 kd = 0.050 d 1 Y = 0.50 mg VSS/mg BODs removed Express your answer in days and round to the nearest 0.1.

For the gravity concrete dam shown in the figure, the following data are available: Unit weight of concrete (7)-2.4 ton/m Neglect Wave pressure, silt pressure, ice force and earth quake force) -0.65, (7)-1 ton/m' Solve on paper and sketch Find factor of safety against sliding and overturning (F.Sa & F.S), If heel and toe stresses (Pain & P) are 57.17ton/m2 and 84.53 ton/m² respectively. Solve in table on paper w.s.l 83m 10m 8m 80m

1. Find moments of inertia around horizontal and vertical centroid axes for given 6 cross sections. 30cm 4) "T 0cm 1116 5) 20cm 5cm 6)

1. Find moments of inertia around horizontal and vertical centroid axes for given 6 cross sections. 1) 30cm 5cm 10cm 20cm 2) 3)

An anchored sheet-pile bulkhead is shown in the figure below. Let L₁ = 2 m. L₂ =6 m. l₁ = 1 m = 17 kN/m². sat -18.86 kN/m², '=32°, and c=27 kN/m². Use the free earth support method. Anchor Sand = 0 Water table L Sand Ysat c' = 0 Clay = 0 1. Determine the theoretical depth of embedment, D. (Enter your answer to three significant figures.) D= m 2. Calculate the anchor force per unit length of the sheet-pile wall. (Enter your answer to three significant figures.) F= kN/m

Calculate the dry mass of activated sludge (✗a) produced in wastewater treatment system where the flow rate is 7,500 m³/day, the BOD concentration in the primary effluent (i.e., the BOD concentration in the wastewater going to the aeration basin) is 75 mg/L, the soluble BOD concentration in the liquid effluent of the secondary clarifier is 10 mg/L, and the system is operating with an SRT of 3 days. Assume true yield is 0.5 g VSS per g BOD and the decay rate (i.e., bч or kd) is equal to 0.1 days 1. Assume the system does not achieve nitrification and that the mass of cell debris, nonbiodegradable VSS, and influent inert TSS is negigible. Express your answer in kg/day and round to the nearest 0.1.

In a school, there are three clubs: Drama Club, Music Club, and debating Club. Some students are members of multiple clubs, while others are only members of one club. a. How would you represent this scenario using set notation and Venn Diagram?

Determine the required volume of a completely mixed activated sludge aeration tank for a conventional activated sludge system treating a design flow rate of 34,560 m³/d, where the effluent standards are 30.0 mg/L for BOD5 and 30.0 mg/L for total suspended solids (TSS). Assume that the BOD5 of the effluent TSS is 70% of the TSS concentration. Assume the BOD5 concentration leaving the primary clarifier is 128 mg/L that the MLVSS concentration (Xa) is 2,500 mg/L. Assume the following values for the growth constants: • K = 100 mg/L BOD5 • μm = 2.5 d−1 • kd = 0.050 d 1 Y = 0.50 mg VSS/mg BOD5 removed Express your answer in m³ and round to the nearest integer.

Determine the daily volume of methane and total gas produced in an anaerobic digester if the biosolids flow rate is 200 m³/d and the COD concentration going into the reactor is 5,000 g/m³. Assume yield is 0.05 g VSS/g COD, that there is 90% COD removal, and that methane is 50% of the total gas volume. Assume that actual gas production at the operating temperature is 0.4 L of CH4 per g of COD. Express your answer in m³/d and round to the nearest integer.