Im BMBF-Forschungsprojekt KURAS wurde eine Methode vorgeschlagen, mit der Maßnahmen der Regenwasserbewirtschaftung für konkrete Stadtquartiere ausgewählt und platziert werden können. Hinsichtlich der möglichen Ziele geht die Methode über die wasserwirtschaftliche Wirkung hinaus und betrachtet zusätzlich Effekte auf Umwelt (Grundwasser und Oberflächengewässer, Biodiversität) und Bewohner (Stadtklima, Freiraumqualität, Gebäudeebene) sowie den Aufwand an Kosten und Ressourcen.

This study aimed at characterizing the groundwater flow pattern in a semi-arid agricultural area in northern India crossed by an intermittent monsoon-controlled watercourse, the Najafgarh drain. More specifically, it focused on studying the impact of groundwater recharge from the riverbed to the regional aquifer using hydrogeochemical and isotopic data. Significant hydrogeochemical zonation was observed between the northern, central and southern sides of the drain, linked to different mineralization processes and mixings. Northward from the drain, groundwater was mainly brackish (4.1–23.4 mS/cm), due to dissolution of evaporites (halite and anhydrite). Southward from the drain, mostly fresh groundwater was found (from 0.5 to 2.3 mS/cm), revealing notable cation exchange processes. In the vicinity of the drain (central area), mineralization was intermediate (0.7–4 mS/cm) and groundwater showed low geochemical evolution, supposing a distinct origin. Stable isotopes of water (d18O, d2H) confirmed that central groundwater was not a simple mixing between northern and southern groundwater masses, but had a significant component of infiltrated surface water from the drain. Potentiometric data supported these findings and confirmed the contribution of the drain to the recharge of the aquifer, setting up a hydraulic barrier between north and south, despite surface water availability limited to the monsoon season and low hydraulic conductivity of the riverbed. This study demonstrates the value of the geochemical and isotopic analysis of groundwater to characterize groundwater flow pattern in peri-urban agricultural areas, especially surface water–groundwater interactions.

Spree und Havel sind langsam fließende Gewässer, deren Wassermenge besonders durch die Reduzierung des Braunkohletagebaus am Oberlauf der Spree seit 1990 kontinuierlich zurückgeht. Die Berliner Wasserbetriebe leiten in diese Vorfluter das biologisch gereinigte Abwasser (Klarwasser) ein, das die Gewässersituation in Bezug auf Keime, NährstofFe und organisehe Spurenstoffe beeinflusst. Maßnahmen an der Quelle zur Vermeidung oder Verminderung des StofFeintrages in den Wasserkreislauf, eine Abwasserreinigung mit Ozonung, Pulverkohle sowie Membranfiltration könnten hier eine verbesserte Entfernung bewirken. Die Berliner Wasserbetriebe und das Kompetenzzentrum Berlin haben gemeinsam mit der TU Berlin zur Spurenstoff- und Keimentfernung das Verfahren der Ozonung von gereinigtem Abwasser durchgeführt. Das Ziel der Ozonung ist es, die Spurenstoffe möglichst weitreichend zu entfernen. Gleichzeitig lag der Fokus darauf, neben den Indikatororganismen für Fäkalverunreinigungen auch Krankheitserreger, besonders die Viren zu untersuchen, und zu bewerten. Es ist besteht das Interesse eine zukunftsweisende und kompakte Technologie, die alle Ziele umfasst, zu realisieren.

In der Debatte um Strategien des Phosphorrecyclings zeichnet sich immer mehr ab, dass ein Ende der bodenbezogenen Verwertung von Klärschlamm nicht zielführend ist, wenn Schlämme für dieses Recyclingverfahren qualitativ geeignet sind.

In view of existing and future challenges, such as the results of climate change and the changing manner of water usage, the overriding target of the joint research project KURAS (Concept for urban stormwater management and wastewater systems), sponsored by the German Federal Ministry for Education and Research, was to formulate recommendations for the operation, expansion and adjustment of urban wastewater and stormwater infrastructures to the future. To this end planning methods have been developed in KURAS, in which a consequent evaluation of measures interlink with local requirements and challenges. The basic methods were elaborated within the project for the topics wastewater systems and management of stormwater and applied for Berlin case studies at quarter and catchment area level. For both topic areas it shows that an integrated, scale overlapping planning of measures for stormwater management and wastewater management can achieve an increased level of usage. The methods developed in KURAS are suitable for supporting such a planning. A standard employment necessitates additional solutions of a technical as well as regulatory nature.

Ozone process control in secondary effluent used for elimination of trace organic compounds (TrOCs) requires the use of surrogates, such as the relative reduction of UV absorption at 254 nm (DUVA254) to adapt the ozone dose to a varying water quality. In the present study, a closed-loop process control based on two online UVA254 measurements was successfully implemented and tested under realistic conditions with ozone doses from 0.2 to 1.05 mg-O3/mg-DOC at a pilot scale ozonation system with subsequent coagulation filtration at a municipal wastewater treatment plant (DOC ~ 13 mg/L, UVA254 ~27m-1, and nitrite peaks of up to 1.6 mg-N/L). It could be shown that measuring the UVA254 at the ozonation effluent was superior to the measurement of UVA254 at the filter effluent in terms of response time due to changes in water quality, whereas online measurement at the filter effluent showed a better agreement with laboratory data and a reduced maintenance interval due to less particles. Additional online nitrite measurement is not necessary as the ozone consumption by nitrite directly impacts DUVA254.

Deterioration modelling can be a powerful tool to support utilities in planning efficient sewer rehabilitation strategies. However, the benefits of using deterioration models are still to be demonstrated to increase the confidence of utilities toward simulation results. This study aims at assessing the performance of a statistical deterioration model to estimate the current condition and predict the future deterioration of the network. The quality of prediction of the deterioration model GompitZ has been assessed using the extensive dataset of 35,826 inspections of the city of Braunschweig in Germany. The performance of the statistical model has been compared with the performance of a simple model based only on the condition of observed sewers. Results show that the statistical model performs much better than the simple model for simulating the deterioration of the network. The findings highlight the relevance of using modelling tools to simulate sewer deterioration and support strategic asset management.

UV/Vis spectrophotometers have been used for one decade to monitor water quality in various locations: sewers, rivers, wastewater treatment plants (WWTPs), tap water networks, etc. Resulting equivalent concentrations of interest can be estimated by three ways: i) by manufacturer global calibration; ii) by local calibration based on the provided global calibration and grab sampling; iii) by advanced calibration looking for relations between UV/Vis spectra and corresponding concentrations from grab sampling. However, no study has compared the applied methods so far. This collaborative work presents a comparison between five different methods. A Linear Regression (LR), Support Vector Machine (SVM), EVOlutionary algorithm method (EVO) and Partial Least Squares (PLS) have been applied on various data sets (sewers, rivers, WWTPs under dry, wet and all weather conditions) and for three water quality parameters: TSS, COD total and dissolved. Two criteria (r2 and Root Mean Square Error RMSE) have been calculated - on calibration and verification data subsets - to evaluate accuracy and robustness of the applied methods. Values of criteria have then been statistically analysed for all and separated data sets. Non-consistent outcomes come through this study. According to the Kruskal-Wallis test and RMSEs, PLS and SVM seem to be the best methods. According to uncertainties in laboratory analysis and ranking of methods, LR and EVO appear more robust and sustainable for concentration estimations. Conclusions are mostly independent of water matrices, weather conditions or concentrations investigated.