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Messverfahren zur Erfassung der potenziellen Ökotoxizität in anaeroben und aeroben Abbauprozessen
(2014)
In der vorliegenden Ausarbeitung werden die etablierten Verfahren zur Bestimmung der Ökotoxizität erläutert, mit dem Ziel weitere Bioaktivitätsparameter zur Charakterisierung der biologischen Prozesse bei der Forschungsgemeinschaft :metabolon zu integrieren.
Die Erfassung der Toxizität beruht bei den vorgestellten Methoden auf der Messung der Lumineszenz, der Sauerstoffverbrauchsrate oder der Zellzahl. In Abhängigkeit von den Eigenschaften der Schadstoffe sowie der biologischen Betriebsbedingungen der Behandlungsstufen ist die Auswahl der bestmöglichen Methode erforderlich.
In der vorliegenden Arbeit wurde eine HPLC-Methode mit der dazugehörigen Probenvorbereitung entwickelt, welche es ermöglicht Essigsäure und Acrylsäure in komplexen Matrizes wie Deponiesickerwasser zu bestimmen. Hauptaugenmerk lag dabei auf der Matrixreduzierung, die bei 96 % lag. Die Wiederfindung der Analyten Essigsäure und Acrylsäure liegt bei der beschriebenen Methode bei ca. 100 %.
Der vorliegende Bericht ist ein ökonomischer Vergleich
verschiedener Varianten der Überschussschlamm
(ÜSS)-Verwertung der Sickerwasseranlage
auf der Deponie des Entsorgungszentrums Leppe
mit dem aktuellen Entsorgungsweg. Als Vergleichsparameter
werden die Jahresvollkosten herangezogen.
Der derzeitige Entsorgungsweg über die kommunale
Kläranlage wird hierbei als Basisvariante
betrachtet und mit alternativen Behandlungs- und
Verwertungsmöglichkeiten verglichen. Hierbei werden
verschiedene Varianten mit unterschiedlichen
Ausführungen der Komponenten Lagerung, Entwässerung,
Trocknung, Transport und Verbrennung
gegenübergestellt.
Biogas, mit geringen Konzentrationen an Methan, entsteht unter anderem bei verschiedenen industriellen Prozessen. Wegen der Umweltschädlichkeit des Methans gilt es dessen Eintrag in die Umwelt zu vermeiden.
Das Ziel des vorgestellten Projektes war die Überprüfung eines umweltfreundlichen Verfahrens zur Reduzierung des Methans durch methanotrophe Bakterien. Die einzelnen Batchversuche liefen über 15 Stunden und zeigten eine starke Reduzierung des Methans von 18 auf 1 Vol.-%.
Mit Hilfe der Inline-ATR-FTIR-Spektroskopie im mittelinfraroten (MIR) Spektralbereich lassen sich gleich mehrere Prozessparameter für Biogasanlagen in Echtzeit und ohne Probenahme verfolgen. Die gemessenen Absorptionsspektren geben simultan Aufschluss über den Gehalt an flüchtigen organischen Säuren (FOS), die alkalische Pufferkapazität (TAC) und die Ammoniumstickstoff-Konzentration (NH4-N).
Dabei können unter Verwendung intelligenter Datenanalyseverfahren, wie z.B. Partial Least Squares (PLS), Regression oder Support Vector Regression (SVR) sowie in kontrollierter Laborumgebung, Vorhersagefehler (RMSECV) von 0.372 g/l (FOS: R2=0.971), 0.336 g/l (TAC: R2=0.996) und 0.171 g/l (NH4-N: R2=0.992) im Falle der PLS, bzw. 0.386, 0.259 und 0.110 g/l für die SVR erreicht werden.
Erste Inline-Messungen in einer Biomüllvergärungsanlage zeigen, dass die erwarteten Absorptionsbanden auch im Prozessbetrieb wiedergefunden werden können. Sie unterliegen jedoch einem ausgeprägten Temperatureinfluss, der bei der Quantifizierung dieser Prozessdaten berücksichtigt werden muss. Weiterführende Untersuchungen sind notwendig, um die Inline-Tauglichkeit des Messsystems unter Beweis zu stellen.
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.
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.
For use in a landfill, a laboratory reactor for safe and environmentally friendly biological utilization of low-concentration methane gas will be further developed. The current principle of denitrification-coupled aerobic methane oxidation will be replaced by methane oxidation under anaerobic conditions. Anaerobic methane oxidation offers the advantage that, in addition to methane, nitrate also undergoes biodegradation. Another advantage is that the oxygen content can be significantly lower. This reduces the risk of the formation of an explosive atmosphere in the reactor. Currently, the principle of anaerobic methane oxidation is known. However, organisms capable of doing so are not yet available as a pure culture. Therefore, several biomasses were probed for the ability of anaerobic methane oxidation. It was found that moor-heavy sediment, activated sludge from the leachate treatment plant and biomass from the local biogas plant oxidize methane after the natural carbon source (C source) was been removed.
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.