The Aquisafe project aims at mitigation of diffuse pollution from agricultural sources to protect surface water resources. The first project phase (2007-2009) focused on the review of available information and preliminary tests regarding (i) most relevant contaminants, (ii) system-analytical tools to assess sources and pathways of diffuse agricultural pollution, (iii) the potential of mitigation zones, such as wetlands or riparian buffers, to reduce diffuse agricultural pollution of surface waters and (iv) experimental setups to simulate mitigation zones under controlled conditions. The present report deals with (iii), providing a review of the potential of constructed wetlands to protect surface waters from diffuse agricultural pollution. Population growth and industrialization have lead to the demise of large majorities of natural wetland systems. Recent research continues to suggest the importance of these often saturated areas in the natural remediation of pollutants in water, as well as being aesthetically pleasing and acting as potential habitat for declining species. The drastic losses in wetland areas, combined with the realization of their importance, have stimulated recent attempts at wetland restoration and even construction of wetlands where they would not have naturally occurred. In terms of substance remediation, constructed wetlands were traditionally used for the treatment of point sources, such as urban or industrial waste water. Recently they have also become increasingly popular for the treatment of diffuse pollution from agriculture and urban storm runoff. Constructed wetlands have been shown to be efficient in the treatment of nutrients, organic matter and heavy metals. Few studies also show their potential against trace organics, such as pesticides and pharmaceutical residues and against pathogens. Retention efficiencies vary significantly among case studies. In agricultural settings the following design criteria should be considered: (i) Water residence time in wetlands is critical. Some studies concerning nutrient removal suggest that a constructed wetland should be about 5 % of the watershed area and assure water residence time of 7 days. (ii) Vegetation is important to slow down flow and increase sedimentation. Regular cutting and removal of plants is controversially discussed, since it may reduce their beneficial effect on wetland hydrology. (iii) Constant redox conditions are important to avoid release of sedimented or adsorbed pollutants. (iv) A combination of constructed wetlands with buffer strips showed very positive results.

Bei der Planung von Strategien für ein „Integriertes Wasser-Ressourcen-Management in urbanen Räumen" kommt der Berücksichtigung von niederschlagsbedingten Einflüssen auf die Qualität der als Ressource verfügbaren Gewässer eine zunehmende Bedeutung zu. Unter den Gewässereinleitungen aus urbanen Gebieten stellen Mischwasserüberläufe (engl. combined sewer overflows, CSO) aufgrund ihres dynamischen Charakters eine besondere Belastung für die Gewässer dar. Für eine integrierte Modellierung von Kanalnetz und Gewässer werden Mengen- und Qualitätsdaten von der Schnittstelle Mischwasserüberlauf benötigt. Ein Monitoring-Konzept für Mischwasserüberläufe in Berlin wurde im Rahmen des Projektes Monitor-1 vom KompetenzZentrum Wasser Berlin erstellt. Dieses dient der Vorbereitung einer Messphase im Folgeprojekt Monitor-2. Ein wichtiger Aspekt bei der Planung und Vorbereitung eines Monitorings ist neben der Bewertung möglicher Standorte die Auswahl geeigneter Messtechnik. Hierzu wurden umfangreiche Tests verschiedener Produkte aus dem Bereich Online-Messtechnik namhafter Hersteller an der TU Berlin an einem Versuchsstand analog zur DIN EN ISO 15839 durchgeführt. Mit den Tests sollten Fragestellungen zur Vorbereitung des Mischwassermonitorings geklärt werden. Daher wurde das Hauptaugenmerk nicht auf eine Standardisierung der Tests gerichtet, sondern versucht, die Mischwasseranforderungen nachzubilden. Getestet wurden Sensoren, die auf photometrischer Basis das UV- bzw. UV/VISSpektrum analysieren, sowie ionensensitive Sensoren. Ein Hauptaugenmerk lag dabei auf in situ einsetzbaren Sensoren. Im Wesentlichen wurden die Parameter Ammonium, Nitrat und CSB betrachtet. Für die Messung von Orthophosphat stehen am Markt derzeit keine kompakten Geräte zur Verfügung, daher wurden hier klassische Analysatoren (mit z. T. sehr kompakter Bauform) verglichen. Der Versuchsstand wurde mit Rohabwasser, Flusswasser und daraus hergestellten Mischungen beschickt. Alle Sensoren wurden parallel getestet, so dass eine gute Vergleichbarkeit der erzielten Ergebnisse gegeben ist. Neben Fragestellungen wie Genauigkeit, Ansprechverhalten bei plötzlich auftretenden Belastungspeaks bzw. Verdünnungen und verfügbaren Messintervallen wurden insbesondere die Aspekte Kalibrierung, Reinigung und Handhabbarkeit der Sonden bewertet. Der Einfluss der Kalibrierung wurde insbesondere bei den ionenselektiv arbeitenden Sonden untersucht. Dabei wurde der Fragestellung nachgegangen, wie die Sonden kalibriert werden müssen, um sowohl bei den zu erwartenden sehr niedrigen Konzentrationen im Gewässer als auch bei plötzlichem sprunghaftem Anstieg der Konzentration im Fall des Anspringens des Mischwasserüberlaufes die größtmögliche Genauigkeit zu bieten. Neben der Aufstockung mit Abwasser wurden Ammonium und Nitrat auch mit Chemikalien aufgestockt. Die Fragestellung der Datenerfassung und Weiterverarbeitung wurde mit untersucht. Zur Bewertung der Sonden wurden die Anforderungen in die Gruppen quantitative (=direkte aus den Versuchen bewertbar), qualitative (=Literatur- und Herstellerangaben sowie eigene Erfahrungen) und zusätzliche Kriterien(=Herstellerangaben zu Messeigenschaften) unterteilt. Die Ergebnisse aller Sonden lagen dicht beieinander. Eine wichtige Erkenntnis der Untersuchungen ist, dass die getestete Onlinemesstechnik grundsätzlich für den Einsatzzweck in Frage kommt. Zu beachten sind allerdings die jeweiligen Anforderungen und Hinweise der Hersteller zur geeigneten Platzierung der Geräte. Eine große Bedeutung zur Erzielung der gewünschten Genauigkeit kommt der Auswahl und richtigen Durchführung der geeigneten Kalibriermethode zu.

The overall project WellMa, which stands for well management, aims at the optimization of the operation and maintenance of drinking water abstraction wells. For this purpose, in addition to a statistical analyses of well data (report D 1.2) and first field investigations to compare various diagnosis methods (report D 1.3), a review of literature during the preparatory phase WellMa1 should answer the following questions: (1) Which processes affecting the well performance and conditions can occur? (2) Which correlation exists between well ageing and well characteristics? (3) How can such well ageing be recognized at an early stage? (4) What is the state of the practice to restore a good performance and condition? (5) What can be done during well design and construction to prevent well ageing? (6) How can well operation be adjusted to slow-down well ageing processes? Based on textbooks, standards and professional articles published in large number since the middle of the nineties, the state of the art was gathered and compared to current practice at BWB and Veolia to identify possibilities for improvement and specify the need for further investigations to be proposed for WellMa2. 1) Three well ageing types involving different processes could be identified. These are chemical, biological and physical clogging. They are closely linked to the characteristics of the exploited aquifer, such as the physical properties of the formation or the chemical composition of the groundwater. 2) The evaluation of these site-specific aquifer characteristics, the impacts from well design and the observed effects on the well performance and condition and their development with time of operation should be used to specify the individual ageing potential for each well site. 3) The early recognition of well ageing implies the need to monitor wells (1) regularly and (2) with comparable methods. As suitable indicators, the development of water levels and discharge rates to calculate the specific drawdown and specific capacity, the pump surveillance and the visible condition of the well interior could be identified. 4) Both, the assessment of the ageing potential and the monitoring of a reference value describing the state of the well lead to the specification of maintenance requirements. Generally, three strategies could be identified, ranging from sheer operation, over reactive maintenance to regular condition assessment and preventive treatment. Concerning the choice of maintenance method, key criteria must always be the well design, its state of construction, the well ageing type and location. Up to now, patterns linking well characteristics and the success of maintenance could not be identified. Thus, maintenance relies on practical experience and the willingness to discuss limitations and disadvantages of methods as open as the advantages on side of the rehabilitation companies. 5) For well design and construction, the technical standards were summarized, describing the necessary steps for proper dimensioning, drilling, choice of materials and final well development. Not only the avoidance of nonconformities and the careful evaluation of the advantages, but also the restrictions of different well design alternatives, e.g. for the accessibility of rehabilitation, assure an optimal well ageing prevention and well operation. 6) Furthermore, well operation could be identified as a key element and critical factor codetermining the lifetime, but at the same time the economic efficiency of a well. It is always a compromise between demand, technical possibilities and economic considerations, for which reason general standards or technical guidance are not available so far. They need to be developed individually considering present well ageing processes and the quantification of impacts. Comparing the state of the art with current practice at BWB and Veolia, room for improvement could primarily be identified for monitoring and subsequent data processing for both, operational parameters (to assess well performance and condition), and maintenance (to evaluate the success of applied treatments). Based on the recommendations derived on this state of the art review, within WellMa2 the effects of measures for preventing and treating well ageing shall be quantified so that the benefits can be assessed for future optimized well management.

The Aquisafe project aims at mitigation of diffuse pollution from agricultural sources to protect surface water resources. The first project phase (2007-2009) focused on the review of available information and preliminary tests regarding (i) most relevant contaminants, (ii) system-analytical tools to assess sources and pathways of diffuse agricultural pollution, (iii) the potential of mitigation zones, such as wetlands or riparian buffers, to reduce diffuse agricultural pollution of surface waters and (iv) experimental setups to simulate mitigation zones under controlled conditions.

The overall objective of MIA-CSO is to develop a model-based planning instrument for impact based CSO control. The objective of this study was to examine the potential and the drawbacks of different model coupling techniques that may be taken into account within the MIA-CSO project.

Riverbank filtration (RBF) denotes the process whereby river water is induced to infiltrate into a groundwater system by well operation adjacent to banks. In Central Europe, RBF has been common practice for 100 years to produce drinking water. Due to the easy implementation and little maintenance necessary, BF has been suggested to be a useful drinking water treatment for developing and newly-industrialised countries. Experience from Europe has demonstrated that RBF is suitable to remove a range of organic and inorganic contaminants while an exhaustion of cleaning capacity has not been observed. RBF systems can mitigate shock loads and are particularly known for the efficient removal of pathogens, suspended solids and algal toxins from surface water, all being water quality parameters of high relevance in developing and newly-industrialised countries. Another benefit of RBF operation is the storage capacity which may help to balance freshwater availability in areas experiencing high variations of precipitation and run-off. This report aims at evaluating the relevance and opportunities of RBF systems to provide safe water to these countries. In order to evaluate the relevance and opportunities of RBF systems to developing and newly-industrialised countries, the report is structured to address key considerations and (i) identify prerequisites for successful RBF operation based on the experience in Central Europe and the United States, (ii) assess the removal potential of RBF for various water contaminants based on available literature, the TECHNEAU investigations in India and NASRI data from Berlin and (iii) evaluate the sustainability and relevance of RBF operation with regard to the particular needs in developing and newly-industrialised countries.

The Aquisafe project aims at mitigation of diffuse pollution from agricultural sources to protect surface water resources. The first project phase (2007-2009) focused on the review of available information and preliminary tests regarding (i) most relevant contaminants, (ii) system-analytical tools to assess sources and pathways of diffuse agricultural pollution, (iii) the potential of mitigation zones, such as wetlands or riparian buffers, to reduce diffuse agricultural pollution of surface waters and (iv) experimental setups to simulate mitigation zones under controlled conditions. The present report deals with (ii), presenting existing diagnostic methods for agricultural diffuse pollution on a river basin scale. The report focuses on methods with low to moderate data requirements and analytical effort. Generally no numerical models but mostly GIS based approaches have been considered. The described methods were distinguished along two questions: 1. Does diffuse agricultural pollution play an important role in a given catchment? 2. Which areas within the catchment contribute highly to diffuse pollution of the receiving river, i.e. which areas are critical source areas (CSAs)? Question 1 can be answered by using nutrient measurements, mass balance approaches or land use based methods. For most catchments some nutrient measurements and land use data are available, which allow a first assessment whether diffuse pollution could play a role. For question 2, the identification of CSAs, a number of GIS-based methods was found in scientific literature. Since most available methods focus on nutrients and since spatial data on other contaminants, such as pesticides, are typically not available, the report outlines methods for the two critical nutrients nitrogen and phosphorus. Each method can be looked up separately, as they are summarized in a similar structure. Moreover Table 8 in Appendix G provides a quick overview of all the presented methods. All the described approaches focus on nutrients, as they are a major concern and often in the focus of research projects. In general the presented methods consider three aspects to assess the risk of pollution from an area within a river basin: 1. The source of nutrients on agricultural land is included through fertilizer application, livestock numbers or indirectly via land use. 2. Transport to the river is mainly assessed via soil type, land cover, elevation and distance to the river 3. In addition several methods take retention processes into account during transport to or within the river It is important that different contaminants show different behaviour. For instance, phosphorus is pre-dominantly particle-bound, enters rivers via soil erosion and can be retained by adsorption or plant export. Nitrate, the dominant form of nitrogen, is very well soluble, is lost mostly through leaching and most efficiently retained by denitrification. Consequently, methodologies for the assessment of CSAs for phosphorus and nitrogen were looked at separately. While many promising methods with limited data requirements and analytical efforts were identified in the report, few concepts (such as the Universal Soil Loss Equation for phosphorus) seem to be well established. Most literature concerns specific local or regional case studies. As a result, transferability to other catchments is questionable. The highest potential is seen in qualitative, multi-criteria methods (such as the scoring approach by Trepel and Palmeri, 2002), which can be adapted by the user depending on the diagnostic aim as well as local data availability. In summary, it is recommended to test several of the presented GIS methods on one or two catchments to gain experience in their handling and their transferability.

In rural areas, small wastewater treatment plants (SWWTP) are a cost-efficient solution to sewage disposal issues. In Europe, small WWTPs are defined as plants for treating domes- tic wastewater up 50 PE. In Germany, about 2.2 million SWWTPs are in operation or are being installed. In France about 10 to 12 million people are served by decentralised sys- tems. There are many different technical solutions on the market, ranging from artificial wetlands, reed bed filters to activated sludge systems. All systems available on the European market have to meet the EU-Certification EN 12566-3, which regulates a minimum standard of op- eration reliability and purification limits. Furthermore, additional guidelines have to be con- sidered, depending on national and regional specifications. There is still a lack of information about performance, operation reliability and maintainability of the different types of SWWTP under real operating conditions. These parameters are however, of particular importance to both customers and service providers. To fill this gap, during a duration time of 14 month in this study 12 different treatment systems were simultaneously compared and evaluated un- der real operating conditions. The study delivers now detailed information about the perfor- mances of different plant models with regard to purification capacity, effluent values, operat- ing expenditures, sludge treatment etc. The results will be published in a user guide. The study was performed at the Training and Demonstration Centre for Decentralised Sew- age Treatment (BDZ) in Leipzig with a special range of small wastewater treatment plant, already installed at BDZ for training purposes as well as two additional plants, which has been installed there especially for the compass study.

The intention of the work package 5.2 is to analyze the function and relevance of managed aquifer recharge (MAR) techniques with a main focus on Riverbank Filtration (RBF) to enable sustainable water resources management, especially in developing or newly industrialized countries. For this aim three RBF sites in Delhi were equipped with groundwater observation wells and sampled monthly for determination of surface and groundwater quality. This report includes information of more than 150 samples from surface- and groundwater, which were analyzed for a broad series of chemical and physicochemical parameters. For each sample, physicochemical parameters were determined in situ (pH, T, ORP, EC, DO) along with alkalinity, nitrite, ammonia and hydrogensulphide content by the Freie Universität Berlin (FUB) and the Indian Institute of Technology, Delhi (IITD). Additionally, water samples were collected and prepared under appropriate conditions for analysis of inorganic substances (major ions, heavy metals and other inorganic substances) and stable isotopes at FUB laboratories and microbiological parameters and organic contaminants at IIT laboratories. At FUB, in general all parameters were determined monthly except for some heavy metals for which the analysis is very time consuming and costly. For these metals, three sampling campaigns (monsoon, pre- and postmonsoon) were selected for analysis to get an overview of possible contaminations. Investigations on RBF are being performed at three different field sites within the National Capital Territory of Delhi (NCT), two of them on the banks of River Yamuna (Palla and Nizamuddin) and one of them at it’s major tributary in the Delhi stretch, called Najafgarh Drain (Najafgarh). At each of the field sites, at least five piezometers were constructed with varying depths and distances from the surface water. For each field site, groups of piezometers were built, to differentiate surface water and piezometers tapping shallow, medium and deep groundwater. For each parameter distribution and range of the values are shown with boxplots and compared to the German and the Indian drinking water standards. At the Palla field site positive effects during bankfiltration can be observed for several heavy metals like Pb, Al and Cu, while no significant changes or an increase in the concentration can be observed for Fe and Mn, respectively. Other substances like As, NO2- and Ammonia decrease during underground passage while no significant changes or an increase in the concentration can be observed for B and F, respectively. Only Fluoride exceeds the threshold for drinking water standard (Indian standard 1.5 mg/l) and must be considered as critical. At the Nizamuddin field site positive effects during bankfiltration can be observed only for one heavy metal (Al), while no significant changes can be observed for Pb and Cu and an increase in the concentration can be observed for Fe and Mn. Other substances like As, F and Ammonia increase during the underground passage while no significant changes or an decrease in the concentration can be observed for B and NO2-, respectively. At this field site elevated concentrations of several substances like As, Fe, Mn, F and NH4 will make a post-treatment necessary. At the Najafgarh field site the main constraints is the high salinity of the groundwater and the seasonal disavailability of fresh surface water. Due to the high mineralization of the groundwater a possible RBF site must be situated very close to the drain with shallow filter screens in order to obtain a high share of bank filtrate. The design and the potential capabilities of RBF facilities are currently subject to ongoing work and cannot evaluated finally. The sampling campaigns carried out so far are very useful to evaluate i) the seasonal changes in the surface water and ii) the depth dependent changes of the ambient groundwater. It needs to be taken into account that nitrogen species will promote the occurrence of problematic substances like ammonia, nitrite or nitrate due to a load with untreated sewage. Fluoride is expected to be no problematic substance.