Deterioration models can be successfully deployed only if decision-makers trust the modelling outcomes and are aware of model uncertainties. Our study aims to address this issue by developing a set of clearly understandable metrics to assess the performance of sewer deterioration models from an end-user perspective. The developed metrics are used to benchmark the performance of a statistical model, namely, GompitZ based on survival analysis and Markov-chains, and a machine learning model, namely, Random Forest, an ensemble learning method based on decision trees. The models have been trained with the extensive CCTV dataset of the sewer network of Berlin, Germany (115,258 inspections). At network level, both models give satisfactory outcomes with deviations between predicted and inspected condition distributions below 5%. At pipe level, the statistical model does not perform better than a simple random model, which attributes randomly a condition class to each inspected pipe, whereas the machine learning model provides satisfying performance. 66.7% of the pipes inspected in bad condition have been predicted correctly. The machine learning approach shows a strong potential for supporting operators in the identification of pipes in critical condition for inspection programs whereas the statistical approach is more adapted to support strategic rehabilitation planning.

Combined sewer systems are one of the major sources of microbiological contamination in urban water bodies. However, identification of hotspots for pathogen emissions is not straightforward, especially in large and complex drainage systems. To determine the relevance of different CSO outlets for bathing water quality a simple tracer approach which uses wastewater volume as a proxy for pathogen emissions has been developed and tested for the city of Berlin, Germany. The approach reveals that the average wastewater ratio in CSO varies largely between different river outlets (0 to 15%). Hence, the outlets with the largest CSO volumes are not automatically the greatest wastewater emitters and assumed hotspots for pathogen contamination do not coincide with hydraulic hotspots. This is verified with own measurements that show enormous differences in pathogen concentrations between waste and stormwater of 4 orders of magnitude. As a result, wastewater which represents only 5% of the CSO volume contributes > 99% of the pathogen loadings to the river. The study highlights the relevance of wastewater volumes for the identification of point sources for the hygienic impairment of water bodies.

Das Ziel dieser Arbeit liegt in einer optimierten Betriebsführung der Ozonierung kommunalen Abwassers durch Identifizierung von organischen und mineralischen Ablagerungen auf Sensoroberflächen (Fouling). Als Grundlage dienen die über einen Zeitraum von sieben Monaten aufgenommenen Onlinedaten zweier (unterschiedlicher) photometrischer Sondentypen zur Einzelwellenlängenmessung des SAK254 (s::can – i::scan) und zur spektralen Messung im UV- und UV/VIS-Bereich (TriOS – OPUS, WTW – CarboVis 705 IQ). a über die Dauer des Untersuchungszeitraums sowohl eine Problemanalyse des Praktischen Betriebs als auch eine zusätzliche Versuchsreihe zur Überprüfung der spektralen Foulingauswirkungen durchgeführt. Dabei zeigten sich die für die jeweiligen Sondentypen unterschiedlich stark ausgeprägte Effekte. Die spezifische Beschaffenheit und Funktionsweise von Reinigungsmodul und Trübungskompensation wirkt in hohem Maß auf die Entwicklung und Auswirkung des Foulings ein und beeinflusst die Werte entsprechend stark. Während des Betriebs einer SAK254-Sonde ist die Identifizierung von Fouling durch einen Abgleich des tatsächlichen Ozoneintrags mit der erwarteten SAK254-Reduktion (und umgekehrt) möglich (E-delta SAK-Diagramm). Die Versuche der spektralen Untersuchung zeigten im niedrigeren Wellenlängenbereich um 254 nm ein stärkerer Zuwachs, als bei höheren Wellenlängen um 360 nm nm zu verzeichnen war. Dieser Umstand führt zu einer unzureichenden Trübungskompensation sowie einem Anstieg des gemessenen SAK254. Zur Lösung dieser Problematik wurde ein sondeninterner Abgleich der Spektren durchgeführt, um so die Trübungskompensation mittels Integration eines Korrekturfaktors zu optimieren. Zur Identifizierung von Fouling anhand eines E-delta SAK-Diagramms oder zur Optimierung der Trübungskompensation per Korrekturfaktor, sind jedoch weitere Versuche notwendig.

In recent decades, emerging contaminants (ECs) have surfaced as one of the key environmental problems threatening ecosystems and public health. Most emerging contaminants are present in low concentrations, and therefore often remain undetected and are also referred to as ‘micropollutants’. Despite this, many ECs raise considerable concerns regarding their impacts on human and environmental health. DEMEAU (Demonstration of promising technologies to address emerging contaminants in water and wastewater), a European Seventh Framework Programme (EU-FP7, 2013-2015) project, aimed to tackle ECs in drinking and wastewater by advancing the uptake of knowledge, prototypes, practices and removal technologies. The project followed a solutions-oriented approach using applied research and demonstration sites, and explored four promising technologies for EC removal and/or degradation: Managed Aquifer Recharge (MAR), Hybrid Ceramic Membrane Filtration (HCMF), Automatic Neural Net Control Systems (ANCS) and Advanced Oxidation Techniques (AOT). Furthermore, Bioassays (BA) were investigated as an effect-based monitoring tool. This article shares new findings for each approach and their potential for widespread integration in the drinking- and wastewater sector. Research results from DEMEAU demonstration sites show that opportunities for synergies among these developments offer the most promising and effective methods for tackling ECs in the water sector.

This study analyses reference and innovative POWERSTEP schemes for municipal WWTP in their environmental and economic impacts using life-cycle tools of Life Cycle Assessment and Life Cycle Costing. Based on hypothetical scenarios at defined boundary conditions for WWTP size, influent quality, and effluent discharge limits, multiple process schemes have been modelled in a mass and energy flow model with a benchmarking software for WWTPs. This process data forms the basis to calculate operational efforts, and it is amended by infrastructure data for material demand and related investment costs. In addition, specific data has been added based on results of the POWERSTEP project (e.g. for N2O emissions) or information from literature. The results show that innovative schemes with advanced primary treatment operate with a superior electricity balance compared to current state-of-the-art schemes for municipal wastewater treatment as a reference, increasing electrical self-sufficiency from 27-82% to 80-170%. The POWERSTEP schemes reach this goal without compromising effluent quality targets of the schemes, i.e. reaching the same effluent quality than before. Concentrated influent with high COD levels supports the POWERSTEP approach and enables highly energy efficient schemes. However, nitrogen removal has to be realized with mainstream anammox after enhanced carbon extraction from concentrated influent. This process is still under development, and its performance and stability should be further validated in full-scale references. Sidestream N removal, advanced control of COD extraction and partial bypass of primary treatment are other options to guarantee nitrogen removal after enhanced carbon extraction with conventional denitrification. In the life-cycle perspective, POWERSTEP schemes significantly decrease primary energy demand of WWTP operation by 29-134% compared to the reference. In favourable conditions, their superior electricity balance can fully compensate life-cycle energy demand for chemical production, sludge disposal and infrastructure, resulting in real energy-positive WWTP schemes. Greenhouse gas emissions can also be substantially reduced with POWERSTEP (- 6 to 43%) due to savings in grid electricity production. GHG benefits of POWERSTEP are smaller than energy benefits on a relative scale, because direct emissions such as N2O from biological N removal and mono-incineration also deliver a major contribution to overall GHG emission profiles, and they are not reduced with POWERSTEP. In contrast, POWERSTEP schemes with mainstream anammox will most likely increase N2O emissions, compensating a large part of the electricity-related benefits in GHG emissions. Total annual costs are in a comparable range for both reference and POWERSTEP schemes. While the latter decrease operational costs by 3-16% due to lower purchase of grid electricity, they require higher investment for primary treatment, increasing capital costs by 4-17%. Overall, effects of POWERSTEP on operational and capital costs off-set each other and result in a net increase of total annual costs of 2-7%, which is within the uncertainty range of this cost calculation. Higher electricity prices (> 0.12 €/kWh) will increase the positive impact of POWERSTEP on operating costs, resulting in fully costcompetitive eco-efficient WWTP schemes at power prices of 0.25 €/kWh. Final recommendations are derived on the way to develop eco-efficient WWTP schemes of the future.

The ETV programme is designed to provide an independent validation of the performance claims of technology suppliers by a qualified third party called “ETV verification body”. The "Statement of Verification" delivered at the end of the ETV process can be used as evidence that the claims made about the innovation are both credible and scientifically sound. With proof of performance credibly assured, innovations can expect an easier market access and/or a larger market share and the technological risk is reduced for technology purchasers. In the POWERSTEP project, 2 technologies were finally chosen after a section process (“quick scan”), Drum filters for primary treatment of raw wastewater (supplied by the company “Veolia Water Technologies Sweden – Hydrotech”) and the Biomethanation process for conversion of biogas or CO2 into biomethane, using a proprietary biocatalyst and reactor configuration (supplied by the company “Electrochaea”). The report summarizes the how the quick scan was carried out to select the above mentioned technologies, feedback from the two companies of the overall ETV process and their experiences as well as general feedback and recommendation to improve the ETV process in general from the POWERSTEP project point of view. It has to be mentioned that until the end of the POWERSTEP project (30th of June) the ETV verification process is not finished in both cases, so no results or feedback on the outcomes can be presented in this report.

This report analyses the legal framework for marketing of renewable energy produced at a wastewater treatment plant for three different countries (Germany, France, Denmark). Looking at the energy types of electricity (for self-supply or grid supply), heat and biomethane, the report describes taxes, fees, levies, and subsidy schemes which directly affect the potential revenues of the WWTP operator. The analysis shows that there are large differences between the countries that have a decisive impact on the economic attractiveness of the different options. While electricity use for self-supply is favored in case of high purchase costs for grid electricity (e.g. Germany), subsidy schemes for grid supply can also make this option economically relevant. In all countries, the grid injection of biomethane is a viable option which will be increasingly attractive for WWTP operators in the future. Reliable legal frameworks are required to offer stability for longterm investment at WWTP level, which is today often not the case due to the dynamic nature of the energy markets and policies.

The increasing application of plastic products during the last 60 years, entailed an undesirable plastic input to the environment. Small plastic particles (microplastic) are able to reach the water cycle by households and urban areas. Microplastics are defined as particles with smaller than 5 mm and could be subdivided into two groups. Primary microplastics are engineered materials used as product additives for cosmetics, peelings and cleaning agents. Secondary microplastics are produced from the embrittlement of common plastic products, due to physical, chemical or biological degradation processes.The project “Optimized materials and processes for the separation of microplastic from the water cycle” – OEMP founded by the German Bmbf intends the development of new restraining materials and separation processes of various microplastic particles (different in size, shape, type of plastic). Different entry pathways of the urban water cycle in city areas (effluent from wastewater treatment plants, combined sewer overflows, street drainage) are investigated for the purposes of optimized technical approaches, to ensure a sustainable water economy with high class standards in protection of the surface waters. Therefore, a proper assurance is needed, that examines the different technical and natural systems with regard to their retention qualities. An integrant is an evaluable methodology for sampling and analytics of microplastic, as well as a first benchmark of the purification processes, which are developed during the project OEMP. For the effluent of the wastewater treatment plant high performance filtration materials were developed. The first field tests are evaluated and show relevant reduction of suspended solids. The cloth filtration media and for sieve filtration show a removal efficiency of more than 70 % for the Materials down to 20 microns. Further test with pore size materials down to 6 microns will follow. The following figures explain the principle of the cloth filtration media and the sieve filtration. For the fine materials fare higher reduction rates are expected. To analyze the samples a thermal extraction method was developed as well as a sampling technique for high sampling volumes up to 2 m3 to measure the amount of microplastics in the frictions of 500, 100, 50, and 6 microns. Plastics and microplastics will be preserved in the environment for many years, therefore systematic studies in the field of urban water management are reasonable. To implement promising technics for separating microplastics from the effluent of wastewater treatment plant and mixes sewage water at existing infrastructure the municipality, the industry, the research and the citizen/consumer are requested to collaborate. The Project OEMP is founded by the German Bmbf: MachWas – Materialien für eine nachhaltige Wasserwirtschaft“

Bank filtration schemes for the production of drinking water are increasingly affected by constituents such as sulphate and organic micropollutants (OMP) in the source water. Within the European project AquaNES, the combination of bank filtration followed by capillary nanofiltration (NF) is being demonstrated as a potential solution for these challenges at pilot scale. As the bank filtration process reliably reduces total and dissolved organic carbon (TOC/DOC), biopolymers, algae and particles, membrane fouling is reduced resulting in a long term stability of operation of the NF. With the new developed membrane module for capillary NF a reduction of sulphate, selected micropollutants (depending on size & charge) and hardness can be achieved together with further removal of DOC. Dissolved iron and manganese concentrations in bank filtrate were not a problem for the capillary NF under anoxic conditions with a good cleaning concept including backwash with anoxic permeate, forward flush and chemical cleaning.

Bank filtration schemes for the production of drinking water are increasingly affected by constituents such as sulphate and organic micropollutants (OMP) in the source water. Within the European project AquaNES, the combination of bank filtration followed by capillary nanofiltration (capNF) is being demonstrated as a potential solution for these challenges at pilot scale. As the bank filtration process reliably reduces total organic carbon and dissolved organic carbon (DOC), biopolymers, algae and particles, membrane fouling is reduced resulting in long term operational stability of capNF systems. Iron and manganese fouling could be reduced with the possibility of anoxic operation of capNF. With the newly developed membrane module HF-TNF a good retention of sulphate (67–71%), selected micropollutants (e.g., EDTA: 84–92%) and hardness (41–55%) was achieved together with further removal of DOC (82–87%). Fouling and scaling could be handled with a good cleaning concept with acid and caustic. With the combination of bank filtration and capNF a possibility for treatment of anoxic well water without further pre-treatment was demonstrated and retention of selected current water pollutants was shown.