Die Klärschlammbewirtschaftung in Österreich befindet sich im Umbruch. Künftig soll die Phosphorrückgewinnung forciert werden, gleichzeitig verliert die landwirtschaftliche Ausbringung immer weiter ...an Bedeutung. Aktuelle politische Konzepte fokussieren sich primär auf die (wenigen) größeren Kläranlagen, allerdings haben auch die (vielen) kleinen Anlagen einen Bedarf an tragfähigen Lösungen für die Zukunft. Um einen Überblick über die aktuelle Praxis der Klärschlammbewirtschaftung unter spezieller Berücksichtigung von Kleinkläranlagen und kleinen Kläranlagen zu schaffen, wird in diesem Beitrag am Beispiel von Oberösterreich ein Inventar aller Kläranlagen im Land erstellt und darauf aufbauend anlagenspezifisch der Klärschlammanfall dargestellt und wichtige derzeit gängige Verwertungspfade genauer beleuchtet. Die präsentierten Erkenntnisse sollen dazu beitragen, die Fachwelt sowie die politischen Entscheidungsträger in Bezug auf die Bedürfnisse der „kleineren“ Kläranlagen zu sensibilisieren, damit auch diese bei der Entwicklung von geeigneten und tragfähigen Zukunftskonzepten der Klärschlammbewirtschaftung Berücksichtigung finden.
Zusammenfassung
Natur-basierte Systeme (NBS) sind Schlüsseltechnologien in der Siedlungswasserwirtschaft für die urbane Wasserwirtschaft sowie die Abwasserreinigung. Die Entwicklung von NBS begann in ...den 1960er-Jahren mit bepflanzten Bodenfiltern (auch Pflanzenkläranlage genannt) und führte zur Entwicklung und Anwendung diverser NBS für die Wasseraufbereitung und Versickerung, wie Grüne Dächer, vertikale Begrünungen und Regenwasserversickerungsanlagen. Ein Vorteil von NBS ist ihre Multifunktionalität. Diese inkludiert unter anderem Schutz vor Überflutungen, Stadtentwässerung, Biodiversität, Kühlung und Schutz vor Schadstofftransport in Grund- sowie Oberflächengewässer und die Eingliederung in die Kreislaufwirtschaft. Um die Umsetzung sowie den Nachweis der multiplen Funktionen zu sichern, ist eine integrative Planung beim Einsatz von NBS essenziell.
Zusammenfassung
Im Rahmen des EU-finanzierten Netzwerkprojekts COST Action Circular City wurde die Anwendung von naturbasierten Lösungen (NBS) im Kontext der Kreislaufwirtschaft in Städten ...untersucht. Dabei steht die Minimierung des Inputs von notwendigen Ressourcen wie Wasser, Nährstoffen, Biomasse, lebenden Organismen und Energie im Vordergrund. Die Hauptergebnisse sind das Circular-City-Rahmenwerk (Framework) und dessen grafische Umsetzung als Online-Toolbox. Das Rahmenwerk beschreibt einen Technologie-Katalog mit NBS-Einheiten und -Interventionen, mit denen die Bewältigung der urbanen Herausforderungen der Kreislaufwirtschaft möglich ist, sowie eine Methodik zur Definition von Input- und Output-Ressourcenströmen. Das Online-Tool besteht aus einer Toolbox sowie einem Tool zur Quantifizierung der Ressourcenströme. Meist wird bei der Implementierung von NBS deren Potenzial zur Förderung der Multifunktionalität in der Regel nicht voll ausgeschöpft. Eine sektorübergreifende Zusammenarbeit ist dafür im Planungsprozess unerlässlich. Zirkuläres Denken unterstützt dabei eine bessere und multifunktionale Planung mehrerer städtischer Herausforderungen.
One of the burning problems of our industrial society is the high consumption of water and the high demand for clean drinking water. Numerous approaches have been taken to reduce water consumption, ...but in the long run it seems only possible to recycle waste water into high quality water. It seems timely to discuss alternative water remediation technologies that are fit for industrial as well as less developed countries to ensure a high quality of drinking water throughout Europe.
The present paper discusses a range of phytoremediation technologies to be applied in a modular approach to integrate and improve the performance of existing wastewater treatment, especially towards the emerging micro pollutants, i.e. organic chemicals and pharmaceuticals. This topic is of global relevance for the EU.
Existing technologies for waste water treatment do not sufficiently address increasing pollution situation, especially with the growing use of organic pollutants in the private household and health sector. Although some crude chemical approaches exist, such as advanced oxidation steps, most waste water treatment plants will not be able to adopt them. The same is true for membrane technologies.
Incredible progress has been made during recent years, thus providing us with membranes of longevity and stability and, at the same time, high filtration capacity. However, these systems are expensive and delicate in operation, so that the majority of communities will not be able to afford them. Combinations of different phytoremediation technologies seem to be most promising to solve this burning problem.
To quantify the occurrence and the distribution of micropollutants, to evaluate their effects, and to prevent them from passing through wastewater collection and treatment systems into rivers, lakes and ground water bodies represents an urgent task for applied environmental sciences in the coming years.
Public acceptance of green technologies is generally higher than that of industrial processes. The EU should stimulate research to upgrade existing waste water treatment by implementing phytoremediation modules and demonstrating their reliability to the public.
Today about 2.4 billion people in rural and urban areas do not have access to adequate sanitation services. Within 20 years, it is expected that an additional 2 billion will live in towns and cities, ...mainly in developing countries, demanding sanitation. Still over 90% of sewage in developing countries is discharged untreated, polluting rivers, lakes and coastal areas. Conventional sanitation concepts, based on flush toilets, a water wasting technology, are neither an ecological nor economical solution in both industrialized and developing countries. The water-based sewage systems were designed and built on the premises that human excreta are a waste; suitable only for disposal and that the environment is capable of assimilating this waste.
A sanitation system that provides Ecological Sanitation (EcoSan) is a cycle—a sustainable, closed-loop system, which closes the gap between sanitation and agriculture. The EcoSan approach is resource minded and represents a holistic concept towards ecologically and economically sound sanitation. The underlying aim is to close (local) nutrient and water cycles with as less expenditure on material and energy as possible to contribute to a sustainable development. Human excreta are treated as a resource and are usually processed on-site and then treated off-site. The nutrients contained in excreta are then recycled by using them, e.g., in agriculture.
EcoSan is a systemic approach and an attitude; single technologies are only means to an end and may range from near-natural wastewater treatment techniques to compost toilets, simple household installations to complex, mainly decentralised systems. These technologies are not ecological per se but only in relation to the observed environment. They are picked from the whole range of available conventional, modern and traditional technical options, combining them to EcoSan systems.
The paper presents an introduction to EcoSan principles and concepts including re-use aspects (available nutrients and occurring risks), and case studies of EcoSan concepts in both industrialized and developing countries.
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•Decentralized low load greywater treatment applied in a touristic infrastructure.•High organic micropollutant contamination was measured in the influent greywater.•Most of standard ...parameters and organic micropollutants efficiently removed.•The technology effluent is suitable for several water reuse applications.•Correlation between the removal of some micropollutants and HRT.
A horizontal flow wetland (HF) was integrated, in a cascading vertical set-up (vertECO), in a Mediterranean tourist facility for decentralized treatment of real low load greywater streams. 15 different plant species were tested in LECA substrate at three different hydraulic retention times (HRTs: 1.9, 1.4 and 1.0 days) with additional aeration improving degradation processes. Beyond standard parameters, several organic micropollutants (14 pharmaceutical organic compounds and 12 endocrine disruptive compounds) were monitored over a 22 month period. The removal efficiency for standard parameters was very high, on average more than 90% for many parameters (COD, BOD5, TSS, VSS and turbidity) and more than 80% for TOC. BOD5 removal could be correlated with the temperature, while TN, TKN and NH4+-N showed the highest removal efficiency at the lowest HRT. The effluents consistently met the standards for various reuse applications, at all three HRTs, according to Spanish Legislation (RD, 1620/2007) and EU draft. In terms of organic micropollutants, influent greywater was characterized by high concentrations and variability (for example up to 256.1 ± 875.3 µg L−1 for acetaminophen, 88.7 ± 424.5 µg L−1 for ibuprofen). More than 95% of removal by vertECO was achieved for most of the compounds (acetaminophen, ibuprofen, salicylic acid, caffeine, estradiol, progesterone, testosterone, triclosan, methyl-, ethyl- and propylparaben) and more than 80% for diclofenac, atenolol and trimethoprim. On the other hand, hydrochlorothiazide, sulfamethoxazole and salbutamol could not be reduced by more than 30%. Statistically significant differences were found at different HRTs for acetaminophen, atenolol, ibuprofen, ethylparaben, TCPP and TBEP (p < 0.05). Conversely, most of the evaluated micropollutants were consistently removed without apparent influence from temperature.
Numerical models are a means to increase the understanding of the processes occurring in the “black box” constructed wetland. Once reliable models for constructed wetlands are available they can be ...also used for evaluating and improving existing design criteria. The paper shows simulation results for outdoor experimental subsurface vertical flow constructed wetlands using CW2D, a multi-component reactive transport module developed to simulate transport and reactions of the organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The surface area of the experimental vertical flow bed was 20 m
2. The organic load applied was 27 g COD m
−
2
d
−
1
(corresponding to a specific surface area of 3 m
2 per person). The aim of the work is to calibrate the model for temperature dependency that has been implemented in CW2D. Water temperature during the investigation period varied between 4 °C and 18 °C. The measured effluent concentrations during summer could be simulated using the standard CW2D parameter set when the flow model was calibrated well. However, the increasing effluent concentrations at low temperatures could not be simulated with the standard CW2D parameter set where temperature dependencies are considered only for maximum growth, decay, and hydrolysis rates. By introducing temperature dependencies for half-saturation constants for the hydrolysis and nitrification processes it was possible to simulate the observed behaviour. The work presented is a step on the way to validate the CW2D module. Model validation is a necessary step before numerical simulation can be finally used in practice, e.g. for checking existing design guidelines.
Constructed wetlands (CWs) provide a natural way for simple, inexpensive, and robust wastewater treatment. Detailed understanding of CW functioning is difficult, because a large number of physical, ...chemical, and biological processes occur in parallel and influence each other. For this reason, CWs have long been seen as "black boxes" where wastewater enters and treated water leaves the system. Numerical models describing the biochemical transformation and degradation processes in CWs are promising tools to better understand CW functioning. The first part of this paper reviews published mechanistic models for CWs. Horizontal flow systems can be simulated when only water flow saturated conditions are considered; six models have been reviewed whereby a series or network of completely stirred tank reactors is most frequently used to describe the hydraulics. For modeling vertical flow CWs with intermittent loading, transient variably saturated flow models are required. Due to the intermittent loading, these systems are highly dynamic, adding to the complexity of the overall system. Five models of different complexity have been reviewed; three use the Richards equation to describe variably saturated flow, whereas the two others use simplified approaches. In the second part of the paper, the multicomponent reactive transport module CW2D is demonstrated. Simulation results for CWs treating domestic wastewater, combined sewer overflow, and surface water are presented. In general, a good match between simulation results and measured data could be achieved if the hydraulic behavior of the system could be described well. Based on the experience from these examples, the need for further model development is determined.
The Agenda 2030 of the United Nations stipulates an ambitious set of 17 Sustainable Development Goals (SDGs). They were globally agreed upon and demand coherent, context-specific implementation at ...the national level. To address the complexity of challenges therein, the Agenda is designed to be integrated, indivisible, and universal. The numerous multifaceted interactions in-between the SDGs and with corresponding measures pose a complex challenge for decision-makers implementing them worldwide that requires support for a comprehensive discourse in the science-society-policy arena. Research on the interactions between the SDGs has been flourishing and can help to understand where policy options might be most successfully located. A catalytic effect on several other goals is, e.g., often attributed to SDG 6 on water and sanitation. However, beyond the where to locate policy options, it is similarly important to understand how potential policy options would affect the SDGs and their targets. We developed eleven options and 85 measures as context-specific pathways to advance the SDG 6 Targets in Austria. As a country in the Global North and with a generally far-established water and sanitation infrastructure and management, this responds to the Agenda's demand for universal applicability and can serve as an example to illustrate potential challenges beyond basic infrastructure provision and management. The proposed options cover resources-oriented sanitation, blue-green-brown infrastructure, efficient use and integrated management of water resources, maintenance and restoration of ecological functions of inland waters, reduction of diffuse discharge of nutrients and problematic substances as well as trace substances, water, sanitation and hygiene in public spaces, groundwater protection, development cooperation as well as co-design and co-creation. Their effects on the SDG 6 Targets are evaluated using a 7-point-scale. The evaluation method is simple and practicable, and fosters discourse on the entire water cycle amongst the expert group applying the method. The evaluated effects on the targets are found to be unanimously positive or neutral, but trade-offs might arise when including other SDGs in the assessment, making an expansion of the evaluation necessary for coherent implementation. The results can be used as a baseline to support follow-up discussions with stakeholders and decision-makers.
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•Eleven options and 85 measures illustrate context-specific ways to advance SDG 6.•The evaluation method is simple, practicable, and fosters a holistic discourse.•The evaluated effects on the targets are unanimously positive or neutral.•The results can propose a baseline for follow-up discussions with stakeholders.•Effects on other SDG targets and interactions within targets should be included.
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