Fakultät 10 / :metabolon Institut
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The management of the liquid fraction of digestate produced from the anaerobic digestion of biodegradable municipal solid waste is a difficult affair, as its land application is limited due to high ammonium concentrations and the municipal waste that water treatment plants struggle to treat due to high pollutant loads. The amount of leachate and the pollutant load in the leachate produced by landfills usually decreases with the time, which increases the capacity of landfill leachate treatment plants (LLTPs) to treat additional wastewater. In order to solve the above two challenges, the co-treatment of landfill leachate and the liquid fraction of anaerobic digestate in an industrial-scale LLTP was investigated along with the long-term impacts of the liquid fraction of anaerobic digestate on biocoenosis and its impact on LLTP operational expenses. The co-treatment of landfill leachate and liquid fraction of anaerobic digestate was compared to conventional leachate treatment in an industrial-scale LLTP, which included the use of two parallel lanes (Lane-1 and Lane-2). The average nitrogen removal efficiencies in Lane-1 (co-treatment) were 93.4%, 95%, and 92%, respectively, for C/N ratios of 8.7, 8.9, and 9.4. The average nitrogen removal efficiency in Lane-2 (conventional landfill leachate treatment), meanwhile, was 88%, with a C/N ratio of 6.5. The LLTP’s average chemical oxygen demand (COD) removal efficiencies were 63.5%, 81%, and 78% during phases one, two, and three, respectively. As the volume ratios of the liquid fraction of anaerobic digestate increased, selective oxygen uptake rate experiments demonstrated the dominance of heterotrophic bacteria over ammonium and nitrite-oxidising organisms. The inclusion of the liquid fraction of anaerobic digestate during co-treatment did not cause a significant increase in operational resources, i.e., oxygen, the external carbon source, activated carbon, and energy.
In the degradation of ammonia (NH4+) to gaseous nitrogen (N2), the nitrification is one of the two reaction steps. The nitrification itself is divided in two steps and is performed by two different types of bacteria. Current literature has shown that there are types of bacteria, which have the genetic equipment to perform both steps in one bacteria. Nevertheless, in wastewater and landfill leachate treatment, ammonia-oxidizing organisms (AOO) and nitrite-oxidizing organisms (NOO) occur as a symbiosis. The intermediate of the two consecutive reaction steps (NO2-, nitrite) is toxic. For this reason, both steps are necessary for the two bacterial groups. To determine the ratio of AOO, NOO and heterotrophic bacteria (which use organic compounds as carbon and energy source) the oxygen uptake rate (OUR) with selective inhibition with N-allylthiourea (ATU) and azide is used. In the inflow of a pilot plant in one street a step by step increased amount of a process water out of a fermentation plant was added to the landfill leachate. For comparison, the other street was supplied only with landfill leachate with the same amount of nitrogen. As a result, comparable values for the different bacterial groups and reproducible results were measured and lead to a better understanding of the analysed nitrification sludge. Deeper understanding of the behavior of the different groups will result in a reduce risk of malfunctions and a more stable operation in the wastewater or landfill leachate treatment plant.
The whole site of the waste disposal centre Leppe in Lindlar has been modified by the project :metabolon into an authentic learning site for knowledge transfer. Addressing all age groups, the project offers insights into environmental knowledge and explains contexts of resources and material flows. The site conditions allow practical outlooks on future energy systems. Following the meta theme of “lifetime learning”, pupils and students are addressed by different modules, considering their individual learning levels.
Before transporting the landfill leachate to municipal wastewater treatment plant it has to be treated in a landfill leachate treatment plant, as it comprises high concentrations of ammonium. The elimination of ammonium load in the leachate is usually done by the combined processes of nitrification and denitrification with a specially adapted biocenosis in the activated sludge (AS). For each of the steps, specialized bacteria such as Nitrosomonas, Nitrobacter and Paracoccus are used to transfer the ammonia to gaseous nitrogen. The aim of this investigation was to find suitable process parameters for a complementary treatment of fermentation water from a biogas plant together with landfill leachate. The processed water of the biogas plant consists of a higher concentration of ammonium and carbon sources or easily degradable volatile fatty acids. It can save the usage of external carbon source (acetic acid) and additionally it could also compensate the missing volumes of leachate in times of low rain and low leachate flows. To maintain the high workload for the existing leachate treatment pilot plant (LTPP), a combined treatment of landfill leachate and process water is also of economic and of ecological interest. The long-term adaption process of the biocenosis needs to be done step-by-step. Innovative process monitoring is needed to prevent biocenosis collapse. In our study, we present our set-up, a closer look at the ongoing experiment and the long-term changes in the biocenosis.
Modern industrial biomass combustion plants are regulated by the power and/or combustion control. In this process, the implemented sensors collect the relevant measured data. The aim is to achieve ideal combustion with optimum efficiency and to minimize gas emissions. For this purpose, a group within the research project Metabolon developed new regulatory procedures in order to record the combustion process of a biomass combustion plant using a webcam. The recordings were evaluated automatically and were used for a better monitoring of the process. In addition, the webcam-based method aims, among other things, to provide private homes with a cost-effective variant as an alternative to industrial system solutions.
Mit Einführung der Deponieverordnung 2005 endete die Deponierung nicht-inerter Stoffe und biologisch aktiver Spezies. Im Zuge ihrer Durchsetzung traten neue Behandlungsmöglichkeiten dieser Stoffströme in das Zentrum der Betrachtung. Zu diesen Behandlungsmethoden zählt die anaerobe biologische Behandlung. Sie findet vor allem bei stark organisch geprägten Stoffströmen mit hohen Wassergehalten Anwendung (Kaltschmitt et al. 2009). Im Zuge der anaeroben Behandlung werden organische Kohlenstoffverbindungen hauptsächlich in CO2 und CH4 umgesetzt. Die anaerobe Behandlung reduziert so den organischen Anteil und das Volumen des Gärsubstrates. Im Gegenzug steigt der Wasseranteil des Gärsubstrates durch die Freisetzung von Zellwasser an. Verbindungen aus Phosphor und Stickstoff verbleiben im Gärsubstrat und machen es damit zu einem geeigneten Düngemittel für die Landwirt-schaft (Möller et al. 2009). Das Material unterliegt der Düngemittelverordnung, durch welche sowohl die Ausbringung als auch die Ansprüche an dessen Beschaffenheit geregelt werden. Um den anfallenden Gärrest für die Landwirtschaft nutzen zu können, muss daher eine Möglichkeit zur mittelfristigen Lagerung geschaffen werden (Raussen et al. 2008). Über das Verhalten im Zeitraum dieser Lagerung gibt es bisher nur wenige Untersuchungen. Grund hierfür ist vor allem die hohe Diversität des Presswassers. Dessen Eigenschaften werden durch die Betriebsparameter der Biogasanlage bestimmt und unterscheiden sich so deutlich von Anlage zu Anlage.
Die hier dargestellten Arbeiten sind Teil eines Forschungsvorhabens zur Untersuchung des Lagerungsverhaltens von Presswasser aus der Vergärungs- und Kompostierungsanlage Leppe. Diese verfügt über zwei Lagerungsbehälter mit einem Fassungsvermögen von je 3.500 m³. Bereits im Zuge der Planung wurde ein anaerober und aerober Betrieb vorgesehen. Neben den drei Rührwerken, mit denen die Durchmischung des Presswassers gewährleistet wird, sind zwei Injektionsbelüfter installiert.
Ziel der Untersuchungen war es, eine Datengrundlage zu schaffen, aufgrund derer über die Betriebsweise der Presswasserspeicher entschieden werden kann.
Die Messung des Chemischen Sauerstoffbedarfs (CSB) im Zulauf von Kläranlagen ist von zentraler Bedeutung für die Optimierung und Regelung der Abbauprozesse der Nitrifikation und Denitrifikation. Allerdings ist die Messung des CSB bislang sehr zeitaufwändig und kostenintensiv, da 24-Stunden Mischproben im Labor nasschemisch analysiert werden müssen.
Online-Messtechnik in Form von spektroskopischen Messgeräten (10.000 ̶ 20.000 €) oder nass-chemischen Online-Analysatoren (> = 50.000 €) sind insbesondere für kleine und mittlere Kläranlagen aus Kostengründen keine Alternative.
Eine extrem kostengünstige Alternative ist der im Folgenden beschriebene Softsensor für CSB im Kläranlagenzulauf, der auf Basis von Standardmesstechnik im Zulauf von kleinen und mittleren kommunalen Kläranlagen sowie mit zusätzlicher Online-Messtechnik für Trübung sowie Ammonium- und Nitratstickstoff (NH4-N und NO3-N) die aktuelle CSB-Konzentration bestimmt. Zur Entwicklung des Softsensors werden Regressionsmethoden aus dem Bereich des Machine Learning eingesetzt. Die Ergebnisse einer Entwicklungs- und Testphase an der Kläranlage Rospe in Gummersbach zeigen, dass die Werte des Softsensors sehr gut mit den Originaldaten übereinstimmen. Die Korrelationswerte beim Vergleich mit CSB-Messungen liegen bei der Regression mit Support Vector Regression bei 0,98 mit einem RSME von 2,45 mg/l.
Die Regelung heutiger, industriell genutzter Biomasse-Feuerungsanlagen erfolgt meistens über fest eingestellte Parameter. Bei Veränderungen des Brennstoffs dienen visuelle Beobachtungen der Mitarbeiter als Basis der Neueinstellung dieser Parameter. Das Ziel der Forschung besteht in der Optimierung solcher Regelungen durch den Einsatz von Kamerasystemen in Kombination mit einer automatisierten Regelung, die auf Basis von Flammenbild-Analysen funktioniert. Ein solches System wäre auch unabhängig von der Art des Brennstoffs.
This paper presents a series of flow and temperature measurements on the principal heat network of :metabolon in Lindlar, Germany. These measurements intend to show the behaviour of the system on specific production areas of :metabolon for future monitoring and optimisation purposes. Such measurements allow the analysis of the system’s heat flow through the network, which showed that losses exist, some areas. The results demonstrate successfully that the temperature and flow changes deserve more detailed and fixed monitoring in specific areas to help the user decide the optimum measuring point.
In this paper a closed-loop substrate feed control for agricultural biogas plants is proposed. In this case, multi-objective nonlinear model predictive control is used to control composition and amount of substrate feed to optimise the economic feasibility of a biogas plant whilst assuring process stability. The control algorithm relies on a detailed biogas plant simulation model using the Anaerobic
Digestion Model No. 1. The optimal control problem is solved using the state-of-the-art multi-objective optimization method SMS-EGO. Control performance is evaluated by means of a set point tracking problem in a noisy environment.
Results show, that the proposed control scheme is able to keep the produced electrical energy close to a set point with an RMSE of 0.9 %, thus maintaining optimal biogas plant operation.