The objective of this research project is to conduct a pilot study to define a standard procedural protocol to be applied during the calibration of numerical simulation models of urban drainage systems and treatment plants. The remarkable technological advances of recent decades have resulted in continued and steady improvements in the development of computational techniques useful for creating numerical models and simulations. They hold enormous potential in numerical models allowing a more realistic and detailed simulation of both the hydrological response of urban catchments (in terms of runoff volume and timing) and the buildup/wash-off processes, including relative propagation of pollutants through the sewage system. Such detailed numerical models are also useful for simulations of the physical, chemical and biological processes used in wastewater treatment.
Before they can be effectively used for resolving practical problems, numerical simulation models must necessarily be calibrated. Prerequisites for model calibration are the identification and definition of the numerical model parameters; more specifically, identifying those parameters that are most relevant for reproducing the processes intended for simulation. Estimation of the most appropriate model parameters is possible through onsite investigation (when dealing with directly measurable parameters). However, in most situations, these parameters are only conceptual representations of the basin/catchment’s abstract features and, as such, must necessarily be determined through a trial and error process wherein diverse and varied attempts are repeated until the desired outcome is obtained. Hence it is clear how the performance of simulation models, as increasingly refined and complex numerically as they are, essentially depends on the quality and accuracy with which the model calibration process was implemented. Manual calibration requires both extensive knowledge of the numerical formulation for the model and of the system to be modeled; however, although it may lead to good results when performed by an experienced operator, it provides no objective results/values (due to the degree of subjectivity surrounding the strategy used in estimating numerical model parameters) and can be very time-intensive (Duan et al., 1994 - Yapo et al., 1998 - Gupta, 1998). Another issue relates to the likelihood that a high number of calibration parameters interacting with one another may lead to unpredictable results when they are modified simultaneously, thus making it difficult to perform a full sensitivity analysis of the model.
To cope with these issues, we have identified the following as dual objectives:
1. Define the standard operating procedures for identifying the most significant parameters and all the necessary steps for implementing numerical models for urban waste water treatment and management. In this way, guidelines and criteria for observation are prescribed on the basis of the characteristics (hydraulic, land use) of the system being modeled;
2. Develop an automatic calibration procedure for estimating model parameters. In this way, quantifiable advantages are obtained both in terms of a higher model calibration speed (decreased time consumption) and a reduction in the degree of subjectivity inherent to the manual calibration procedure.
The two procedures above will be supported by evidence from field experiments in which several urban catchments are identified for use as a laboratory for implementing the following phases:
a. Collection and analysis of the existing sewage system and treatment plants working plans/projects to undergo modeling;
b. Precise altitude-profile survey of the existing sewage system for identifying possible differences between the current conditions and the original sewage system project;
c. Installation of area-velocity flowmeters in segments of the sewage network in order to continuously record flow data in the pipe system that is significant for calibrating and validating the numerical simulation model;
d. Installation of automatic water samples both inside the different segments of the sewage network and in the treatment plants in order to obtain wastewater samples for laboratory analysis. Samples are collected during periods deemed significant and are analyzed for pollutants. The classification is necessary for calibrating and validating the numerical simulation models on build-up and wash-off phenomena and treatment processes.
e. Implementation of the sewer system blueprint in the numerical model chosen in conformity with the standardized methodology used in modeling;
f. Verification of the model’s ability to accurately simulate the behaviour of urban drainage systems and treatment plants.
The ultimate objective is to test, evaluate, validate and disseminate a new, standardized, methodological approach capable of providing an operational tool for dealing with design, management and rehabilitation of drainage networks and treatment plants. The goal is to do this in both an innovative way with a long-term view of sustainable development and protection of water resources.
- R. Perin , A. Coccolo, M. Nicolini, D. Goi: “L.E.D.R.A. (Leading Eco - Engineering Developing for River Assessment) PROJECT - FASE 1”. Rassegna Tecnica FVG, n.1 - anno 2013
- M. Trigatti , R. Perin , M. Nicolini , D. Goi, “Preliminary Analysis of stormwater runoff and pollutant washoff in an industrial district”, Prooceedings of 13th Specialized Conference on Watershed and River Basin Management, 9-12 September 2014, San Francisco (USA).
- R. Perin , G. Peressi : “Modelli di formazione e di propagazione dei deflussi di piena a scala di bacino idrografico: il caso del Rio Costa”. Quaderni Tecnici di Ingegneria - Ordine degli Ingegneri della Provincia di Udine (2015)
- M. Trigatti , R. Perin , M. Nicolini , D. Goi, “Quality stormwater modeling in small suburban catchments: a case study” Prooceedings of International Conference on Sustainable Water Management; 29 November to 3 December 2015 at Murdoch University, Perth, Western Australia.
- M. Trigatti , R. Perin , M. Nicolini , D. Goi, “Using EPA-SWMM in quality stormwater modeling: calibration and design strategies”. In: M.R. Boni, P. Sirini, A. Chiavola, A. Polettini, R. Pomi, P. Viotti, A. Rossi. Book of Abstracts, (2016), X International Symposium on Sanitary and Environmental Engineering, SIDISA 2016. Rome, 19-23/06/2016, 145, ISBN: 978-88-496-391-1.
- M.Trigatti, R. Perin, M. Nicolini, D. Goi, “Stormwater quantity and quality for sustainable management of runoff in an industrial district. Preliminary analysis and modelling of first foul flush effect”, Journal of Multidisciplinary Engineering Science and Technology (JMEST), Vol. 3 Issue 7, July – 2016; ISSN: 2458-9403. (http://www.jmest.org/vol-3-issue-7-july-2016/)