Schütz, P. , Gutierrez, O. , Busquets, S. , Gunkel, M. , Caradot, N. (2023): The use of a low-cost monitoring dataset for sewer model calibration.

6th IWA International Conference on eco-Technologies for Wastewater Treatment. 26.6 - 29.6 2023. Girona, Spain

Abstract

Urban wastewater management and the associated modelling has become indispensable today. Reliable calibration is essential for these models, and water level data is used as a standard. However, data collection can be limited due to high sensor costs and harsh conditions in the sewer. A novel solution is collecting data using low-cost temperature sensors, placing one in the stream, the other at the crest of the weir. In the case of dry weather, the sensor measures the air phase, whereas, in the case of Combined Sewer Overflow (CSO), the discharged storm and wastewater is measured. Autocalibration was performed using OSTRICH for a SWMM model in Berlin, with water level and fictional temperature data, and various number of measuring sites. Results showed that calibration using temperature data was as good as using water level data, with promising outcomes achieved by using one measuring site, offering a cost-effective alternative for water utilities.

Abstract

The management of urban wastewater systems and the associated modelling of these systems has become indispensable in today's world. In order for these models to represent reality as accurately as possible, a reliable calibration is essential. Water level data is used as a standard, but due to expensive sensors and harsh conditions in the sewer, data can only be collected at a few key points of the system. One novel solution, that has experienced an upswing in recent years, is collecting data using low-cost temperature sensors. Two sensors are needed; one is placed in the stream; the other is placed at the crest of the weir. In the case of dry weather, the sensor measures the air phase, whereas, in the case of Combined Sewer Overflow (CSO), the discharged storm and wastewater is measured. The start and end of a CSO event can be determined via the merging of measured temperature values in both points of the overflow structure. Due to this method, the duration of CSO events in a sewer system can be detected.

In this work, the potential benefits of this novel method for model calibration are assessed. Therefore, autocalibration runs with water level data and fictional temperature data were carried out via OSTRICH for a SWMM model located in Berlin. Furthermore, calibration runs with a different number of measuring sites were performed, to evaluate the amount of necessary measuring sites for a reliable calibration. In order to be able to compare the different approaches, a calibration period of 19 events was first required for the respective datatype. Next, a validation period which consisted of 18 events was carried out and evaluated by the R² of three water level measuring sites for both approaches to ensure comparability. It was revealed that the calibration with duration data based on temperature sensors was able to achieve results as good as the conventional approach using water level data. Due to low spatial distribution of the measuring sites in the model, it could not be finally answered if more measuring sites would yield to even better results. However, already with one measuring site, promising calibration outcomes could be achieved and thus, offers an alternative for water utilities and practitioners.

Abstract

Eine aktuelle Planung eines wassersensiblen Stadtkonzeptes für ein Berlin Stadtumbau- und Neubaugebiet wurde modelltechnisch geprüft. Durch die konsequente Umsetzung von Low Impact Development (LID) konnte das 76 ha große Gebiet fast vollständig abgekoppelt werden. Bezogen auf das Kanaleinzugsgebiet entspricht dies einer Abkopplung von 16 %, die wiederum zu einer Reduktion von Mischwasserüberläufen von 23 % führt. Die wasserwirtschaftliche Wirksamkeit wird zwar bei mangelnder Pflege eingeschränkt, der Effekt auf Mischwasserüberläufe bleibt aber nahezu identisch. Der große Effekt von realistischen LID-Umsetzungen und die Robustheit dieses Effektes gegenüber Maßnahmenausfällen stellt eine Empfehlung für die zunehmende Transformation von Entwässerungssystemen zu wassersensiblen Entwürfen dar.

Abstract

Appropriate collection and disposal of medicine-related waste has been identified as one of the main ways to decrease the emission of active pharmaceutical ingredients (APIs) into the environment. Improvement to the take-back and treatment of collected pharmaceutical waste may be considered lowhanging fruit when one is considering measures to reduce API emissions. However, comparable information that would enable estimating the potential impact of these efforts has not been available. Directive 2004/27/EC, related to medicinal products for human use, mandates that EU member states implement appropriate collection schemes for unused or expired human-use medicinal products. However, it does not provide any guidelines on practical implementation of these schemes. Several studies have pointed out significant differences among Member States in this regard. In March 2019, the European Commission published the European Union Strategic Approach to Pharmaceuticals in the Environment. The actions specified therein cover all stages of the pharmaceutical life cycle, from design and production to disposal and waste management. It emphasizes such elements as sharing good practices, co-operating at international level, and improving understanding of the risks. This report is aimed at filling knowledge gaps and proposing good practices for take-back and disposal of unused human and veterinary medicines and other pharmaceutical waste. The report is targeted to e.g. ministries, environment and medicines agencies, supervisory authorities, municipalities, hospitals, NGOs, pharmacists, doctors, and veterinarians. For the report, current national practices for take-back and disposal of unused medicines and other pharmaceutical waste in Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, and Sweden were evaluated. The pharmaceutical waste originating from households, hospitals and other health care institutions, the pharmaceutical industry, and veterinary use was considered. The proportion of citizens who return unused pharmaceuticals via designated collection points varies greatly between Baltic Sea countries, from about 10% to 70%, with 16–80% disposing of them of as mixed household waste and 3–30% flushing them down the drain. The most commonly cited reason for improper disposal of medicines on households’ part is lack of information about their environmental impacts and how to get rid of them in an environmentally sound manner. Separate collection of unused household pharmaceuticals does not exist in Russia, and the collection mechanism functions poorly in Latvia, Lithuania and Poland. Information on the take-back schemes for unused human medicines is more readily available than is corresponding information on veterinary medicines. We identified, all told, 21 good practices and recommendations for take-back and disposal of unused pharmaceuticals and other pharmaceutical waste and for promoting the rational use of pharmaceuticals in the Baltic Sea region. Nevertheless, implementing them at national level requires particular consideration due to differences in national legislation and other characteristics of the EU Baltic Sea countries and Russia. The good practices identified in this report answer the call issued in the EU strategic approach for an efficient risk-reduction strategy.

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