Thermal alkaline pretreatment (TAP) of waste activate sludge (WAS) was carried out in pilot-scale over a year to investigate its seasonal effects on anaerobic digestion and its impact on dewaterability, sludge liquor quality and formation of soluble refractory COD (sCODref). Temperature of TAP was set at 65–70 °C and pH was increased by initial dosing of sodium hydroxide [NaOH] (50% w/w, 1–2.5 mL/L sludge) as alkali agent following 2–2.5 h reaction time. Pilot digesters were fed with primary sludge (PS) and hydrolyzed WAS (HWAS) and compared to a reference digester fed with PS and untreated WAS. Biogas yield increase due to TAP of WAS showed a sinusoidal trend throughout the year with maximum in summer (+42%), minimum in winter (+3%) and average of +20%, indicating a strong seasonal effect on TAP efficiency. Ammonium [NH4+-N], orthophosphate [PO43--P] and sulphate [SO42-] in sludge liquor increased by 34.6%, 17.0% and 21.6% with TAP, respectively. Centrifugation tests showed no significant difference in dewaterability of both digestates with respect to total solids of sludge cake. Normalized capillary suction time of digestate increased due to TAP, indicating a lower capability for water release. Furthermore, detected sCODref after batch aerobic biodegradation tests showed an increase of 30.3% with TAP. Hence, implementation of TAP of WAS in full-scale will potentially lead to an increase of 0.8–1.1 mg/L of sCODref in effluent of six wastewater treatment plants (WWTP) in Berlin. In conclusion, TAP of WAS leads to increase in biogas production with a slighter negative impact on effluent COD quality than high-temperature thermal hydrolysis.

This document contains the synergies and common activities of five H2020 projects that started in the summer of 2019: The five projects are digital-water.city, Score Water, Fiware4Water, Naiades and aqua3S. The first four were funded by the SC5-11-2018 call and the latter by the H2020-SU-SEC-2018-DRS-03. All these five projects have a common theme: Digital Water, with a variety of case studies and approaches, but also with several similarities in challenges, scope and goals.
Following a suggestion by EASME that supervises the SC5-11-2018 projects, the synergies and clustering activities were included in the Grant Agreement of each project, resulting in the contractual obligation to report about them in a common deliverable (this document). Thus a Synergy group was born: DigitalWater2020 (DW2020).

DW2020 is organised along four thematic areas/task forces:

Task Force 1: Ontologies,

Task Force 2: Sensors demonstration,

Task Force 3: Business models and

Task Force 4: Communication,

each with its own task force leader.

Additionally a fifth task force (Task Force 0: Management) has been created, to coordinate the efforts and activities overall.
This document is the first DW2020 report, in common for all the projects, describing their synergies and cooperation, which started early in 2020 and is scheduled to continue until the end of the projects (and hopefully beyond). It contains a brief presentation of each project, details about the structure and activities of each Task Force, as well the planned events for 2020-21 and the next steps. So far the synergies and cooperation among these five projects has been very successful. It gave to all the chance to interact, to exchange knowledge, to cooperate for specific challenges and to help each other. We are already discussing future steps that will lead to DW2020 being “alive” after the end of the five projects.

Thermal hydrolysis (TH) increases the anaerobic biodegradability of waste activated sludge (WAS), but also refractory organic and nutrient return load to a wastewater treatment plant (WWTP). This could lead to an increase in effluent chemical oxygen demand (COD) of the WWTP. The aim of this study was to investigate the trade-off between increase in biogas production through TH and anaerobic digestion and increase in refractory COD in dewatered sludge liquors at different temperatures of TH in lab-scale. WAS was thermally hydrolyzed in temperature range of 130e170 C for 30 min to determine its biomethane potential (BMP). After BMP test, sludge was dewatered and sludge liquor was aerated in Zahn-Wellens test to determine its non-biodegradable soluble COD known as refractory soluble COD (sCODref). With increasing temperature in the range of 130e170 C, BMP of WAS increased by 17e27%, while sCODref increased by 3.9e8.4%. Dewaterability was also enhanced through relative increase in cake solids by 12 e30%. A conversion factor was defined through mass balance to relate sCODref to volatile solids of raw WAS. Based on the conversion factor, expected increase in effluent CODs of six WWTPs in Berlin were predicted to be in the range of 2e15 mg/L after implementation of TH at different temperatures. It was concluded that with a slight decrease in temperature, formation of sCODref could be significantly reduced, while still benefiting from a substantial increase in biogas production and dewaterability improvement.

In Berlin wird Trinkwasser ohne aufwändige technische Aufbereitung über naturnahe Verfahren gewonnen. Ca. 80% des geförderten Rohwassers stammen aus Uferfiltration oder künstlich angereichertem Grundwasser (Möller & Burgschweiger 2008). Nach der Entfernung von Eisen und Mangan über Belüftung und Filtration wird im Routinebetrieb grundsätzlich auf eine chemische Desinfektion verzichtet. Zur Gewährleistung der hygienischen Sicherheit haben die Wasserschutzgebiete und hier insbesondere die engere Schutzzone (Zone II) daher eine wichtige Bedeutung. Deren Ausdehnung reicht von der Fassungsanlage bis zu der Linie, von der aus das genutzte Grundwasser 50 Tage im Grundwasserleiter fließt, bevor es über Brunnen zum Wasserwerk gefördert wird (DVGW 2006). Durch die Einhaltung dieser 50-Tage-Richtlinie wird v.a. der Schutz vor mikrobiellen Verunreinigungen angestrebt. Die Aufenthaltszeit des Wassers in der Untergrundpassage kann direkt durch Markierungsversuche ermittelt werden. Da solche Tracer-Untersuchungen zeitlich und technisch aufwändig sind, wurde im Rahmen verschiedener gemeinsamer Forschungsprojekte der Berliner Wasserbetriebe und des Kompetenzzentrums Wasser Berlin geprüft, mit welchen einfachen, kostengünstigen Methoden die Fließzeiten und die Auswirkungen sich ändernder klimatischer Randbedingungen im Betrieb der Grundwasseranreicherung und der Trinkwasserbrunnen überwacht werden können (Sprenger et al. 2016). Dabei wurden unter anderem kontinuierlich messende Temperatur-Druck-Sonden eingesetzt, sowie Geräte zur Quasi-Echtzeitmessung mikrobiologischer Parameter. Parallel wurde für einen Wasserwerksstandort in Berlin ein vereinfachtes numerisches Modell erstellt, mit dem Anreicherungsszenarien in Abhängigkeit der Temperatur des angereicherten Wassers gerechnet und bewertet werden können. Außerdem wurde der Einfluss der Wassertemperatur auf betriebliche Parameter der Oberflächenwasseraufbereitung untersucht. Die Untersuchungen sind ebenfalls Grundlage für risikobasierte Bewertungsansätze für hydraulische und mikrobiologische Parameter und die Ableitung betrieblicher Maßnahmen gegen eine Unterschreitung der 50-Tage-Verweilzeit.

Nitrogen and phosphorus budgets were compiled for the littoral (29 km2) and pelagic (329 km2) of ancient, deep, clear, and hard water Lake Ohrid (Albania and North Macedonia), to assess the importance of the littoral in nutrient retention. P originates mainly from domestic point sources (73%), for N this is karst seepage (50%). Total littoral loads are estimated at 1700 kg P and 23,200 kg N km-2 (area of littoral) yr-1; net littoral retention is 31% ± 13% for P and 40% ± 16% for N, largely in the dense charophyte belt. P retention is mainly due to detritus burial, but also due to coprecipitation; N retention is due to both detritus burial and denitrification. A Monte Carlo plausibility analysis balanced the budget by increasing nonconnected domestic household inputs (from 20% to 27% of external load), and decreasing pelagic sediment P burial by 27% and littoral denitrification by 25%. Scenario projections for 2100 corresponding to SRES A2 and B1 were linked to an AQUASIM lake ecosystem model. Under B1, the changes were small compared to the present. A2, however, led to a major reduction in precipitation, an increase in evapotranspiration, a reduction in river outflow (to ~20%), a doubling in P-loading, a drop in lake level of ~1.5 m, and a decline in the extent of the charophyte belt. Areal loading of the littoral would increase accordingly, but water transparency would not decline much. Also, the littoral vegetation will witness a shift in species composition, and an increase in filamentous Cladophora cover.

Combined sewer overflows (CSOs) are of major environmental concern for impacted surface waterbodies. In the last decades, major storm events have become increasingly regular in some areas, and meteorological scenarios predict a further rise in their frequency. Consequently, control and treatment of CSOs with respect to best practice examples, innovative treatment solutions, and management of sewer systems are an inevitable necessity. As a result, the number of publications concerning quality, quantity, and type of treatments has recently increased. This review therefore aims to provide a critical overview on the effects, control, and treatment of CSOs in terms of impact on the environment and public health, strict measures addressed by regulations, and the various treatment alternatives including natural and compact treatments. Drawing together the previous studies, an innovative treatment and control guideline are also proposed for the better management practices.

Die energetischen Potenziale in kommunalen Kläranlagen werden nur unzureichend ausgeschöpft und bleiben in Klimaschutzmaßnahmen häufig unberücksichtigt. Kläranlagen gehören jedoch zu den größten kommunalen Stromverbrauchern und haben dadurch einen signifikanten CO2-Fußabdruck. Im Vorhaben REEF 2W, das von der EU im Rahmen des Programms INTERREG 2 gefördert wird, wird mit Blick auf öffentliche Infrastrukturen von Städten und Gemeinden ein Entscheidungstool zur strategischen Planung entwickelt. In diesem Tool können neue Technologien in die bestehende Anlagensituation integriert werden, um eine höhere Energieeffizienz und eine Verbesserung der Nutzung von nachwachsenden Rohstoffen zu erzielen. Dies soll durch Kombination und Integration der Sektoren Abfall- und Abwasserbehandlung erreicht werden. Das Projekt untersucht im Rahmen der Toolentwicklung die Ressourcenströme und notwendigen technischen Infrastrukturen. Ein Kernstück bildet dabei die Co-Fermentation von Klärschlamm und Bioabfall während deFaulungsprozesses, wodurch sich die Wärme- und Energieerträge (Strom oder Gas) beträchtlich steigern lassen können. Daneben werden neue Wege zur Nutzung des anfallenden Faulgases aufgezeigt, z. B. Gasaufbereitung und Einspeisung ins Gasnetz sowie Power-to-Gas Technologie. Ziel des Excel-basierten Entscheidungstools ist es letztlich, verschiedene innovative Technologiekombinationen energetisch, wirtschaftlich und ökologisch mit dem aktuellen Status zu vergleichen.