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"Waterworks Simulation methods."
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Hydraulic modeling and GIS
\"Hydraulic Modeling and GIS is a best practices guide for developing a sustainable hydraulic model and maintenance strategy that makes optimal use of your GIS. This book addresses GIS-centered concepts and applications that will help you understand and improve hydraulic model structures, advanced spatial analysis, network connectivity and topology, hydraulic model development and maintenance strategies, and GIS database design. Hydraulic Modeling and GIS is a practical handbook for GIS managers, engineers, and decision makers in the water and wastewater utility industry\"-- Provided by publisher.
Book
Preparation of sustainable non-combustion filler substrate from waterworks sludge/aluminum slag/gypsum/silica/maifan stone for phosphorus immobilization in constructed wetlands
In this study, an artificial wetland filler matrix capable of effectively fixing phosphorus was prepared using a non-combustion process to save energy. To evaluate the adsorption performance of this filler, adsorption experiments were performed and the phosphorus adsorption mechanism characterization was studied. An alkaline environment was found to be conducive to the increase of adsorption capacity, but excessive alkalinity was not conducive to adsorption. Static adsorption experiments showed that the phosphorus removal rate could reach 95% in the simulated phosphorus-containing wastewater after adsorption completion. The adsorption process is closely simulated by the pseudo-second-kinetic adsorption model. The isothermal adsorption experiment data were consistent with the Langmuir and the Freundlich adsorption isotherms. The characterization results showed a large number of micropores and adsorption binding sites inside and on the surface of the filler. Speciation analysis on the adsorbed phosphorus revealed that chemisorption by calcium in this filler was the dominant adsorption mechanism. The research results of this study provide the basis and reference for the development of high-efficiency phosphorus removal filler in constructed wetlands.
Journal Article
Hybrid Genetic Algorithm and Tabu Search for Solving Preventive Maintenance Scheduling Problem for Cogeneration Plants
Preventive Maintenance (PM) is a periodic maintenance strategy that has great results for devices in extending their lives, increasing productivity, and, most importantly, helping to avoid unexpected breakdowns and their costly consequences. Preventive maintenance scheduling (PMS) is determining the time for carrying out PM, and it represents a sensitive issue in terms of impact on production if the time for the PM process is not optimally distributed. This study employs hybrid heuristic methods, integrating Genetic Algorithm (GA) and Tabu Search (TS), to address the PMS problem. Notably, the search for an optimal solution remained elusive with GA alone until the inclusion of TS. The resultant optimal solution is achieved swiftly, surpassing the time benchmarks set by conventional methods like integer programming and nonlinear integer programming. A comparison with a published article that used metaheuristics was also applied in order to evaluate the effectiveness of the proposed hybrid approach in terms of solution quality and convergence speed. Moreover, sensitivity analysis underscores the robustness and efficacy of the hybrid approach, consistently yielding optimal solutions across diverse scenarios. The schedule created exceeds standards set by waterworks experts, yielding significant water and electricity surpluses—16.6% and 12.1%, respectively—while simultaneously matching or surpassing total production levels. This method can be used for power plants in private or public sectors to generate an optimal PMS, save money, and avoid water or electricity cuts. In summary, this hybrid approach offers an efficient and effective solution for optimizing PMS, presenting opportunities for enhancement across various industries.
Journal Article
Direct dosage of reactivated carbon from waterworks into the activated sludge tank for removal of organic micropollutants
The thermal reactivation of granular activated carbon is a substantial ecological and economic benefit in the process of drinking water treatment. A significant amount of abraded carbon, which is similar to powdered activated carbon (PAC), is produced that can be brought to application at wastewater treatment plant level for the removal of micropollutants in a powdered activated carbon–activated sludge (PAC–AS) system. This excess carbon derived as a by-product from the reactivation process in a waterworks was applied directly into the activated sludge tank and has been elevated in this study by monitoring the removal efficiencies for benzotriazole, carbamazepine, diclofenac, metoprolol and sulfamethoxazole in the effluent of a semi-technical wastewater treatment plant of 39 m3. A simulation-derived sampling strategy was applied to optimize the recovery rates of the micropollutants. Flow-proportional, 72-hour composite sampling was considered best. The elimination rates obtained for a 10 g PAC·m−3 dosage were 73% for benzotriazole, 59% for carbamazepine, 60% for diclofenac, 67% for metoprolol and 48% for sulfamethoxazole. The obtained results underline the importance of appropriate sampling strategies, which can be derived from hydraulic modeling.
Journal Article
Modeling integrated urban water systems in developing countries: case study of Port Vila, Vanuatu
Developing countries struggle to provide adequate urban water services, failing to match infrastructure with urban expansion. Despite requiring an improved understanding of alternative infrastructure performance when considering future investments, integrated modeling of urban water systems is infrequent in developing contexts. This paper presents an integrated modeling methodology that can assist strategic planning processes, using Port Vila, Vanuatu, as a case study. 49 future model scenarios designed for the year 2050, developed through extensive stakeholder participation, were modeled with UVQ (Urban Volume and Quality). The results were contrasted with a 2015 model based on current infrastructure, climate, and water demand patterns. Analysis demonstrated that alternative water servicing approaches can reduce Port Vila’s water demand by 35 %, stormwater generation by 38 %, and nutrient release by 80 % in comparison to providing no infrastructural development. This paper demonstrates that traditional centralized infrastructure will not solve the wastewater and stormwater challenges facing rapidly growing urban cities in developing countries.
Journal Article
Analysis of Contaminant Co-Occurrence in Community Water Systems
The current framework for U.S. Environmental Protection Agency regulation of water quality in community drinking water supplies produces sequential rules for either single contaminants or small groups of similar contaminants. For both substantive and pragmatic reasons, some water industry experts have advocated the development of a more holistic regulatory process in which rules are promulgated less frequently but for larger contaminant classes. Such a framework would require the expansion of existing regulatory evaluation technologies to account for joint occurrence distributions of multiple contaminants. This article presents an analysis, using two national contaminant databases, of the joint distributions of seven contaminants (arsenic, nitrate, uranium, manganese, magnesium, calcium, and sulfate) in community water system source waters. Inferences are based on a flexible Bayesian hierarchical modeling structure with numerous features desirable for empirical exploration of multicontaminant regulations, including the simultaneous estimation of spatial heterogeneity in contaminant levels and covariations among contaminants, applicability to sparse data collected over a large spatial scale, and coherent assimilation of information provided by censored observations. The model is used to estimate a family of joint distributions for the contaminants indexed by water system characteristics, with empirically appropriate complexity given the resolution of the available data. The resulting distributions provide insights about the nature of, and uncertainty about, contaminant co-occurrence patterns, quantify the impact on national assessments of jointly modeling the contaminants, and facilitate identification of critical classes of water systems where uncertainty is highest.
Journal Article
Assessment of risk of infection due to Cryptosporidium parvum in drinking water
The risk of infection of Cryptosporidium via drinking water was assessed using Monte Carlo simulation with the field survey data of the Sagami River watershed. The levels of Cryptosporidium in this river were found to follow the lognormal distribution. From the counted data, the median level of the Miyayama sampling point was estimated to be 5.7 oocysts per 100L. To calculate the annual risk of infection due to Cryptosporidium in drinking water, the Cryptosporidium level of Miyayama sampling point was used as the water source of the waterworks. The 95% percentile of the annual risk of infection was found to be 10−2.60. If the daily risk was eliminated when the level of Cryptosporidium in treated water exceeded 1 oocyst per 20L, the 95% percentile of the annual risk was reduced by about 1 log. To reduce the 95% value of the annual risk lower than 10−4, the risk of days with levels of Cryptosporidium in treated water exceeding 1 oocyst per 80L should be eliminated.
Journal Article
A long-term plan for water pipeline rehabilitation considering preventive maintenance
Water pipelines deliver water of daily-life demand to customers. However, pipelines tend to be damaged after years of use. Thus, many waterworks are now faced with the major task of water pipeline rehabilitation. However, budgets for pipeline replacement are limited. The present study aims to propose a long-term plan for water pipeline rehabilitation under limited rehabilitation budgets that utilizes a damage occurrence model. Especially, this study attempts long-term rehabilitation planning by efficiently allocating a budget for pipeline rehabilitation. First, a simulation model is used to obtain the failure rate curve which uses reliability theory and data analysis for pipeline leakage accidents, and Monte Carlo simulation is applied to the simulation model. Secondly, in order to set the best planning, several cases with changed annual replacement rate are applied to this study. Finally, the simulation model is applied to key pipelines. The key pipelines are vital pipelines located in central districts. Thus, the replacement of key pipelines is considered to be the priority. From these steps, this study is expected to provide desirable alternative plans for water pipelines when the budget for replacement is limited.
Conference Proceeding