Bei der Verwertung von Grünabfällen werden holzige Anteile teilweise separiert und als Brennstoff abgegeben. Die bei der thermischen Nutzung von diesen und anderen biogenen Brennstoffen anfallende Holzasche wird u.a. Betreibern von Kompostierungsanlagen zur Zumischung bei der Kompostierung angeboten. Da Holzaschen unterschiedliche Verwertungs- und Entsorgungswege gehen können, wird empfohlen, nur qualitätsgesicherte Holzasche anzunehmen.

This report summarizes relevant available knowledge on the removal of micropollutants from WWTP effluent in natural treatment systems such as constructed wetlands (polishing). Five studies were found investigating removal of various micropollutants in eight different full scale systems located in Spain, southern France, Korea and Sweden (all being different configurations of free water surface wetlands), demonstrating good removal (>80%) for more than 15 micropollutants compounds under summer conditions, e.g. diclofenac, ketoprofen, naproxen, ibuprofen, galaxolide, atenolol, ciprofloxacin, triclosan, glyphosate, ofloxacin and metoprolol. Hydraulic retention times (HRT) ranged from 0.25 to 30d. At HRT of 0.25d, only naproxen and atenolol were removed by >80% in summer, highlighting the importance of HRT for system performance. Another important factor influencing the removal is temperature and season with lower removal in winter. However, in warm climates (e.g. two studies in northern Spain and one study in southern France), reduction of removal efficiencies in winter is less pronounced with values for removal of the majority of investigated pharmaceuticals in winter still being >60%. In 4 FWS wetlands sampled during winter at sub-zero temperatures in Sweden, though, removal was mostly below 50%. A variety of removal mechanisms simultaneously occur in natural treatment systems and are relevant to varying extent for each compound and system type. Important removal mechanisms are biodegradation (e.g. for naproxen, ibuprofen), photodegradation (e.g. for diclofenac, ketoprofen, sulfamethoxazole) and adsorption (e.g. for galaxolide, tonalide). The relevance of plant uptake and phytodegradation as removal mechanisms is not fully understood; however, a few studies demonstrate the translocation of pharmaceuticals (e.g. carbamazepine) to plant tissue. For biodegradation, redox conditions are an important parameter influencing microbial degradation pathways. Design guidelines for eco-engineered treatment systems targeting the removal of micropollutants are not available to date. In addition, data necessary to dimension ecoengineered treatment systems that target the reduction of micropollutants in WWTP effluent (e.g. kinetic data such as removal rates and its dependence on temperature) is lacking. For the development of design guidelines for eco-engineered systems targeting the removal of micropollutants, removal rates for each system type and compound and their dependence from temperatures needs to be determined for all compounds of interest. Furthermore, more research is necessary for a deeper understanding of processes in eco-engineered systems, especially the relevance of the different removal mechanisms and conditions for removal for each individual micropollutant of interest. Nevertheless, eco-engineered treatment systems are a promising technology for polishing of WWTP effluent, including further removal of micropollutants.

The present study provides an overview of geogenic contamination, its occurrence, impacts and possible treatment options for drinking water production. Natural background and anthropogenic contamination can be differentiated using an algorithm based on the frequency distribution of measured substance concentrations. Case studies for geogenic contaminants such as ammonium, fl uoride, chloride, sulfate and uranium are discussed based on the origin, occurrence, controlling factors and treatment options. It is suggested that, in case of occurrence of geogenic contaminants, water must be treated or alternative sources need to be found, e.g., managed aquifer recharge, prior to the distribution as drinking water.

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.

Combined sewer overflows (CSO) after heavy rainfall can cause acute depletions of dissolved oxygen (DO) in the Berlin River Spree. A planning instrument for CSO impact assessment has been developed in the framework of the research project MIA-CSO at the Kompetenzzentrum Wasser Berlin. This instrument couples the sewer model InfoWorks CS, the water quality model Hydrax/QSim and an impact assessment tool. Within this thesis it is tested for various CSO management strategies and climate change scenarios. The coupled sewer-river-model InfoWorks CS-Hydrax/QSim was validated for the years 2010 and 2011. Simulation results for the critical parameters discharge and DO concentrations in the Berlin River Spree agree well with measurements. Although not all observed DO deficits can be simulated accurately, the very good representation of processes related to the oxygen budget allows assessing relative changes in boundary conditions, e.g. from different CSO control strategies. The conducted scenario analysis indicates that the coupled sewer-river-model reacts sensitively to changes in boundary conditions (temperature, rainfall, storage volume and other CSO control strategies, etc.). Based on the simulation year 2007 - representing an extreme year with regards to CSO volume and critical conditions in the river - sewer rehabilitation measures planned to be implemented until 2020 are predicted to reduce total CSO volumes by 17% and discharged pollutant loads by 21-31%. The frequency of critical DO conditions for the most sensitive local fish species (<2 mg/L) will decrease by one third. For a further improvement of water quality after the year 2020, the reduction of impervious surfaces emerges as a very effective management strategy. A reduction of the impervious connected area by 20% results in a decrease in the frequency of critical DO conditions by another third. The studied increase in surface air and water temperature as part of the climate change scenarios leads to a significant aggravation of DO stress due to background pollution in the Berlin River Spree, while acute DO depletions after CSO are barely affected. However, changes in rain intensity have a considerable effect on CSO volumes, pollutant loads and the frequency of critical DO concentrations. The extended sensitivity analysis shows that a general reduction of discharged pollutant loads by 60% based on the sewer status 2020 can prevent critical DO conditions in the Berlin River Spree, even for the exceptionally rain intense year 2007. Further, it has been shown that the entry and biodegradation of organic carbon compounds is the most important process for acute DO depletions after CSO. However, mixing of oxygen free spill water with the Berlin River Spree provokes an additional impairment of DO conditions. In the framework of this thesis, CSO impacts under different management strategies or climate change conditions are only assessed for a part of the Berlin combined sewer system and for one exemplary year. Before applying the presented instrument for planning specific measures it is proposed to expand the model area and simulated time period.

Within the context of continuously increasing CO2 concentrations in the atmosphere, as well as diminishing reserves of fossil fuels, finding new ways for autarkic and “climate friendly” energy production becomes more and more important. The development of emerging subsurfaces activities like Carbone Capture and Storage, and Hydraulic Fracturation might offer new options to tackle all three of the mentioned challenges. But, carbon capture and storage (CCS) and unconventional gas exploration (“hydro-fracking”) have in common that they impact parts of the subsurface and may thus potentially have an effect on fresh water aquifers. The combination of all the most recent studies about GCS and Hydro-fracking, allows the identification of a broad panel of key parameters that can assess and indicate a groundwater contamination resulting from emerging subsurface activities. Strong emphasis needs to be put on the fact that numerous new monitoring, verification and accounting tools are being developed worldwide threw researches programs. However, actually, it seems that the most efficient monitoring and early warning network should be based on the combined used of the most suitable (site-specific) geophysics and geochemicals tools.