2023 CIVL 237 design project

CIVL 237 Biological Treatment Processes, Fall 2023 Design Project Overview Students will work in pairs to design a biological treatment facility for a proposed resort area. A group of investors is developing a plan for the resort area and they need information about the wastewater treatment facilities that will be required. Design conditions and effluent requirements The resort is proposed to be constructed near Grass Valley, CA. The resort’s groundwater will serve as the drinking water supply, and it has high alkalinity (120 mg/L as CaCO 3 ), moderate water hardness (150 mg/L as CaCO 3 ), and low pH (≈ 6.5). Wastewater flow rates and composition is likely to be representative of typical unit flows and water quality concentrations. According to data from other nearby communities, the untreated wastewater temperature range is likely to be 10-20°C. Based on watershed standards developed using the TMDL process, it is anticipated that the NPDES permit will have the following effluent standards : BOD 5 = 10 mg/L Soluble-P = 0.70 mg/L TSS = 10 mg/L Minimum alkalinity = 50 mg/L as CaCO 3 Ammonia-N = 1 mg/L pH = 6.5 – 8.5 Nitrate-N = 8 mg/L Process description and resources Students will design a membrane bioreactor (MBR) treatment system that incorporates biological nitrogen and phosphorus removal using the University of Cape Town (UCT) process. Note that Table 8-23 in the textbook contains a process description for designing an activated sludge process that incorporates nitrogen removal. Example 8-7, PART B may be helpful although it only incorporates nitrogen removal and not phosphorus removal. Example 8-13 demonstrates design for phosphorus removal although it is for a conventional process and not for an MBR. This project is based loosely on the work of Sayi-Ucar et al. 2015 although the reactor in that study was located in a hot climate (i.e., SRT is low). The following is a schematic of the UCT process using membrane separation for solids: For convenience, I will refer to the “S” recycle as a multiplier of influent flow, Q , with a multiplier of IR S . The “A” recycle will be assigned a multiplier of Q that is IR A . The nitrate mass balance for the UCT process is:

− ¿ − N e = NO x 1 + IR A NO 3 ¿ Design calculations Students will identify design criteria and perform design calculations, as described below: 1. Consult a reliable internet source to identify a design elevation. 2. Calculate the design flow using the proposed development information for the resort (see the spreadsheet) and typical wastewater unit flow rates from the textbook. Use metric units. Use a peaking factor of 4.0 to calculate the design flow, which represents a sustained peak flow with capacity for future development. Fill out Table 1 provided. 3. Identify the design composition of the untreated wastewater using typical concentration values (“medium strength”) in the textbook. Fill out Table 3 provided. 4. Perform design calculations to calculate the parameters list in Tables 7 through 11. List assumptions used in the calculations in Table 6. Make sure to list all assumptions and sources of data (including table numbers from text and/or pages in text and lecture notes)—this part of the project is very important. The design calculations can be done by hand or using software (Excel, Matlab, etc.). In using the spreadsheet, feel free to add cells but do not delete cells or move content. 5. Write out the equations that you use and provide handwritten sample calculations. Print the hand calculations to a pdf for submittal. 6. Print the Excel tables to a pdf for submittal. The tables are arranged with page breaks for easy pdf printing. Submittal Answer the following questions (5 pts each). State each question and place your answer immediately below. Use 12 pt font, double-spacing, and 1-inch margins. Number the pages. The Excel printouts and hand calculations can be in separate documents. 1. What is a membrane bioreactor (MBR) and how does it work? Be brief—no more than four sentences. In your explanation explain how the MBR would work as it is applied to the UCT process. 2. Why is the MBR used as a treatment technology? What advantages does it offer over conventional activated sludge treatment systems? 3. What are the motivations for using wastewater treatment technologies that removal nitrogen and phosphorus? How might your make a MBR design more efficient (using less energy and providing better treatment)? 4. What are some potential operational problems with the MBR that you have designed? As a designer, how might you mitigate those potential problems? 5. What are some of the limitations of the design? Consider missing information, assumptions, and uncertainty in your response (e.g., consider data that could be collected to verify assumptions). Include print outs of your Excel spreadsheets, hand calculations (sample calcs), and a reference list that includes the textbook, 10 State Standards, and any other references that were used. (75 pts) Grading