Water and Wastewater Engineering: Design Principles and Practice 2nd. Edition by Mackenzie L. Davis | 9781260132274 | 1260132277 | Holooly

Water and Wastewater Engineering

Water and Wastewater Engineering: Design Principles and Practice

138 SOLVED PROBLEMS

Question: 27.8

Select a CBFP to dewater an anaerobic digester sludge. The sludge is primary plus waste activated sludge that has a solids concentration of 2.5% and a specific gravity of 1.02. The design sludge flow rate is 171.2 m³/d. The plant managers wish to operate on a two-shift basis, that is, 16 h/d to ...

Verified Answer:

a. Convert the sludge flow rate to units compatibl...

Question: 27.4

An aerobic digester for Omega Three (Examples 27-2 and 27-3) is being considered as an alternative to alkaline stabilization. Determine the volume of the digester and the required air flow rate to meet a Class B pathogen density (PSRP). The following data have been obtained for this analysis: ...

Verified Answer:

a. Check the requirements for volatile solids redu...

Question: 27.5

Determine the daily volume of methane and total gas produced in an anaerobic digester that is operated at 35°C under the following conditions: biosolids flow = 300 m³/d; bsCOD = 5,000 g/m³ . Assume Y = 0.04 g VSS/g COD and 95% bsCOD removal. ...

Verified Answer:

a. Use a steady-state mass balance to determine th...

Question: 20.7

Select an appropriate aerator and aerator configuration for the equalization basin volume calculated in Example 20-6. Assume that the aerators in Table 20-14 are available and that Figure 20-18 applies. ...

Verified Answer:

a. From Example 20-6, the required storage volume ...

Question: 20.6

Determine the equalization basin volume required for the following cyclic flow pattern. Provide a 25% excess capacity for equipment, unexpected flow variations, and solids accumulation. Evaluate the impact of equalization on the mass loading of BOD5 . ...

Verified Answer:

Design of the equalization basin volume. a. Becaus...

Question: 23-8

Estimate the volume of an extended-aeration oxidation ditch for carbonaceous BOD oxidation and nitrification for the city of Cartouche Lake using the following design data: Influent data Design flow rate = 14,200 m³/d bCOD = 205 mg/L NH3-N = 16.8 mg/L Total suspended solids (TSS) = 160 mg/L ...

Verified Answer:

a. Assume nitrification governs, and select the fo...

Question: 27.3

Design a pretreatment lime stabilization system for Omega Three (Example 27-2). Determine the volume of the reactor tank, mixer size (kW, rpm, turbine diameter), lime feed rate, and lime storage volume for two-week delivery. Assume the specific gravity of the sludge is 1.012, that lime has a bulk ...

Verified Answer:

a. From Example 27-2, the volume of sludge deliver...

Question: 27.7

Evaluate the feasibility of heating the digester designed for Omega Three (Example 27-6) with the methane produced in the digester. The proposed digester design and temperatures are given in the sketch below. Ignore the slope of the bottom of the digester in calculating the area of the bottom. The ...

Verified Answer:

a. Compute the heat requirement to raise the sludg...

Question: 27.6

An anaerobic digester for Omega Three (Examples 27-2, 27-3, and 27-4) is being considered as an alternative to alkaline stabilization or aerobic digestion. Determine the volume of the digester and the flow rate of methane. The following data have been obtained for this analysis: Temperature of ...

Verified Answer:

a. Using Equation 27-23, with the kinetic paramete...

Question: 23.17

Begin the design of a complete-mix BOD removal and nitrification stage for Tempe’s new BPR wastewater treatment plant. As a first step determine the SRT and volume of tank required for nitrification using the following design data: Influent data after primary settling Design flow rate = 90,000 m³/d ...

Verified Answer:

a. Assume that four identical process lines will b...

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