A continuous monitoring, using UV-VIS spectrometers, was carried out in Berlin from 2010 to 2012. It combined (i) continuous measurements of the quality and flow rates of combined sewer overflows (CSO) at one main CSO outlet downstream of the overflow structure and (ii) continuous measurements of water quality parameters at five sites within the urban stretch of the receiving River Spree. Locally, the collection of data aims at (i) characterizing CSO emissions, (ii) assessing the local dynamics and intensity of CSO impacts on the river and (iii) calibrating sewer and river water quality models being part of a planning tool for future CSO management in Berlin (Riechel et al., 2011). UV-VIS spectrometers are in-situ probes, which measure absorbance spectra ranging from UV to visual wavelengths. Concentrations, such as chemical oxygen demand (COD), are calculated from these spectra. Due to the varying composition of waste and river water a local calibration is required to enhance the measurement quality. According to Gamerith et al. (2011), manufacturer global calibration can lead to systematic error up to 50% for COD measurements.

Das vorgestellte modellbasierte Werkzeug bildet Mischwasserüberläufe aus dem Berliner Mischkanalsystem und deren kurzfriste Auswirkungen im Gewässer ab. Es soll für die Maßnahmenplanung und die Berechnung von Zukunftsszenarien verwendet werden. Das Werkzeug zeigt eine gute Übereinstimmung mit Messungen bezüglich des Verlaufes der Sauerstoffkonzentration im Gewässer und des Auftretens kritischer Bedingungen für die Fischfauna. Eine Szenarienuntersuchung für ein Extremjahr zeigt, dass durch die bis zum Jahr 2020 geplante Stauraumvergrößerung die Häufigkeit fischkritischer Bedingungen im Gewässer bereits um ein Drittel reduziert werden kann. Eine Reduktion um ein zusätzliches Drittel wäre durch weitergehende Maßnahmen im Bereich der Entsiegelung möglich. Die verbleibenden fischkritischen Bedingungen sind das Ergebnis von sehr starken Regenereignissen und können kaum verhindert werden. Eine durch Klimaveränderung erhöhte oder reduzierte Regenintensität im Sommer hätte starken Einfluss auf das Auftreten fischkritischer Bedingungen; die erwartete Temperaturerhöhung würde hingegen hauptsächlich die Sauerstoffsituation bei Trockenwetter verschlechtern.

Das vorgestellte modellbasierte Werkzeug bildet Mischwasserüberläufe aus dem Berliner Mischkanalsystem und deren kurzfristige Auswirkungen im Gewässer ab. Es soll für die Massnahmenplanung und die Berechnung von Zukunftsszenarien verwendet werden. Das Werkzeug zeigt eine gute Übereinstimmung mit Messungen bezüglich des Verlaufes der Sauerstoffkonzentration im Gewässer und des Auftretens kritischer Bedingungen für die Fischfauna.

Recent infrastructure studies underline the general deterioration of sewer systems and the risk reversing public health, environment and increasing costs (ASCE, 2009). Aging pipes have not been inspected, replaced or rehabilitated rapidly enough to prevent sewer deterioration and increasing system failures (Tuccillo et al., 2010). According to a need survey conducted by EPA (2008), total funding needs for replacement, rehabilitation and expansion of existing collection systems for a 20 year period in the USA is 82.7 billions $, i.e. 28% of the total need of public agencies for wastewater treatment and collection. In the last 30 years, most municipalities have invested in sewer system expansion and treatment plant upgrade but a relatively small component has been allocated to the improvement of sewer system condition.

In order to efficiently tackle odour problems from sewers which are connected with resident’s complaints and health risks, reliable online odour monitoring is necessary. Multi-gas sensor systems (electronic noses), which display a broad range of odorants, may substitute common online odour monitoring devices in the future. Four electronic noses with different configurations were tested over a period of 8 months at a sewer research plant of Berliner Wasserbetriebe. The objective was to analyse the applicability of four electronic noses for sewer odour management. 11 evaluation criteria were defined to evaluate the E-noses measurement behaviour, stability and their general practicability and handling. Generally it can be mentioned that the results are promising and the E-noses show good potentials. The E-noses which showed good results in predicting the odour concentration at the site have lack of some practical features. Whereas the systems which provide more possibilities (e.g. remote control, direct odour display) and have more complex gas preparation or measurements modes (like thermal desorption) showed lower capabilities to measure the actual odour at the site.

Data play an important role in water-related research. In the field of limnology, monitoring data are needed to assess the ecological status of water bodies and understand the bio-geochemical processes that affect this status. In wastewater management, measured or simulated data are the basis for planning and control of sewer networks. Given the importance of data in water-related research makes them a valuable resource, which should be handled in an adequate way. Based on experiences in data collection and data processing in water-related research this paper proposes – both from a computer scientist’s and an environmental engineer’s point of view – a set of rules for data handling: Rule 1: Protect raw data. Rule 2: Save metadata. Rule 3: Use databases. Rule 4: Separate data from processing. Rule 5: Use programming. Rule 6: Avoid redundancy. Rule 7: Be transparent. Rule 8: Use standards and naming conventions. Applying these rules (i) increases the quality of data and results, (ii) allows to prepare data for long-term usage and make data accessible to different people, (iii) makes data processing transparent and results reproducible, and (iv) saves – at least in the long run – time and effort. With this contribution the authors would like to start a discussion about best data handling practices and present a first checklist of data handling and data processing for practitioners and researchers working in the water sector.

Theoretically the Berlin River Spree could be under pressure from depressions in dissolved oxygen (DO) and high concentration of fish toxic ammonia following overflows of the combined sewer system. However, monitoring results indicate that the Spree is only under pressure from depressions in dissolved oxygen (DO). Consequently, a sewer model, a river water quality model and an impact assessment tool were calibrated and validated for representation of DO depressions. The three elements are joined in a planning tool, which will be used to test the effect of CSO management approaches for the current situation and with altered boundary conditions to account for expected climate change.