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- SENSITIVITY ANALYSIS: INFLUENCE OF INFLUENT VARIABLES ON A WRP MODEL
- Wang, Xiaolong
- 2015, 2015-07
Balancing between cost and effluent quality at the Calumet water reclamation plants (WRP) is important. Influent quality has strong effects on...
Show moreBalancing between cost and effluent quality at the Calumet water reclamation plants (WRP) is important. Influent quality has strong effects on effluent quality. In this study, based on a simulation model, the influence of influent parameters on effluent ammonia concentration is identified by sensitivity analysis methods. Nine sensitivity analysis methods, including two mathematical methods, five statistical methods, and two graphical methods, are presented. Using different sensitivity analysis, most results presented all main effects have stronger effects than interactions among input variables on the output. Water temperature is always the most important parameter; the most important interaction effect is between water temperature and SS. Key words: Sensitivity analysis; water reclamation plants; design of experiments; simulation model; influent water quality; effluent ammonia
M.S. in Environmental Engineering, July 2015
- WASTEWATER COLLECTION SYSTEM MODELING: TOWARDS AN INTEGRATED URBAN WATER AND ENERGY NETWORK
- Wang, Xiaolong
Wastewater collection systems, among the oldest features of urban infrastructure, are typically dedicated to collect and transport wastewater...
Show moreWastewater collection systems, among the oldest features of urban infrastructure, are typically dedicated to collect and transport wastewater from users to water resource recovery facilities (WRRFs). Since the 1970s, wastewater engineers and scientists have come to understand that wastewater collection systems can bring benefits for urban water and energy networks, including thermal energy recovery and converting pipelines to bioreactors. However, there is little knowledge about the temporal and spatial changes of collection systems parameters that are important for these applications. Furthermore, the vast majority of existing studies of these applications have focused on laboratory or extremely small-scale systems; there have been few studies about beneficial applications associated with large-scale systems. The purpose of this study is to increase our understanding of how urban wastewater collection systems can bring potential benefits to urban water and energy systems. Models describing wastewater hydraulics, temperature, and water quality can provide valuable information to help evaluate thermal energy recovery and wastewater pretreatment feasibility. These kinds of models, and supporting data from a case study, were used in this study; sizes of the theoretical wastewater collection systems range from 2.6 L/s to 52 L/s, and the sample locations of the case study had flows ranging from 2.3 L/s to 24.5 L/s. A cost-benefit analysis of wastewater source heat pumps was used to evaluate the thermal energy recovery feasibility for different sizes of wastewater collection systems. Results show that the large collection system can support a large capacity heat pump system with a relatively low unit initial cost. Small collection systems have a slightly lower unit operating cost due to the relatively high wastewater temperature. When the heat pump system capacity design was based on the average available energy from the collection system, larger systems have lower payback times; the lowest payback time is about 3.5 years. The wastewater quality model was used to describe the dissolved oxygen (DO) and organic matter concentrations changes in the collection system. The model provides a framework for predicting pretreatment capability. Model results show that DO concentration is the limiting parameter for organic matter removal. Larger collection systems can provide more organic matter removal because they provide relatively longer retention times, and they offer the potential for greater DO reaeration. The model can also be used to identify environmental conditions in sewer pipelines, providing information for potential issues predication.