Hilde Lemmer

Aerobic biodegradation of the sulfonamide antibiotic sulfamethoxazole by activated sludge applied as co-substrate and sole carbon and nitrogen source

Potential aerobic biodegradation mechanisms of the widely used polar, low-adsorptive sulfonamide antibiotic sulfamethoxazole (SMX) were investigated in activated sludge at bench scale. The study focused on (i) SMX co-metabolism with acetate and ammonium nitrate and (ii) SMX utilization when present as the sole carbon and nitrogen source. With SMX adsorption being negligible, elimination was primarily based on biodegradation. Activated sludge was able to utilize SMX both as a carbon and/or nitrogen source. SMX biodegradation was enhanced when a readily degradable energy supply (acetate) was provided which fostered metabolic activity. Moreover, it was raised under nitrogen deficiency conditions. The mass balance for dissolved organic carbon showed an incomplete SMX mineralization with two scenarios: (i) with SMX as a co-substrate, 3-amino-5-methyl-isoxazole represented the main stable metabolite and (ii) SMX as sole carbon and nitrogen source possibly yielded hydroxyl-N-(5-methyl-1,2-oxazole-3-yl)benzene-1-sulfonamide as a further metabolite.

FISH Handbook for Biological Wastewater Treatment

The FISH Handbook for Biological Wastewater Treatment provides all the required information for the user to be able to identify and quantify important microorganisms in activated sludge and biofilms by using fluorescence in situ hybridization (FISH) and epifluorescence microscopy. It has for some years been clear that most microorganisms in biological wastewater systems cannot be reliably identified and quantified by conventional microscopy or by traditional culture-dependent methods such as plate counts. Therefore, molecular biological methods are vital and must be introduced instead of, or in addition to, conventional methods. At present, FISH is the most widely used and best tested of these methods. This handbook presents all relevant information from the literature and, based on the extensive experience of the authors, advice and recommendations are given for reliable FISH identification and quantification. The overall purpose of the book is to help scientists, consultants, students, and plant operators to get an overview of important microorganisms in biological wastewater treatment and to explain how FISH can be used for detecting and quantifying these microbes. A proper and reliable identification of dominant microorganisms is of great importance for research and new developments in the wastewater treatment industry, and it is important for optimization and troubleshooting of operational problems in present wastewater treatment plants. The book encompasses an overview of dominant microorganisms present in the wastewater treatment systems, which oligonucleotide probes (gene probes) to select for detection of these microbes by FISH, how to perform FISH (detailed protocols), how to quantify the microbes, and how to solve common problems of FISH. The book addresses several functional groups: nitrifiers, denitrifiers, polyphosphate-accumulating organisms, glycogen-accumulating organisms, bacteria involved in hydrolysis and fermentation, filamentous bacteria from bulking sludge, and scum-forming bacteria. A comprehensive collection of FISH-images showing dominant representatives of these groups helps readers to use FISH in the context of wastewater treatment. ISBN: 9781843392316 (Print) ISBN: 9781780401775 (eBook)

Chemotaxonomy and physiology of some actinomycetes isolated from scumming activated sludge

Summary From 14 sewage treatment plants in southern Germany, Berlin and Switzerland sufferingfrom scum production in the aeration tank, 14 strains of nocardioform actinomycetes have been isolated. 11 strains belonged to the Rhodococcus rhodochrous group and fell into three different species. 2 strains belonged to the Gordona aurantiaca group, 1 strain was identified as Nocardia amarae . Physiological tests revealed marked differences between the strains indicating that specific scum control methods are needed depending on the actinomycete strain responsible for scumming. Some Rhodococcus strains were susceptible to heavy metals such as FeCl 3 . Growth of Nocardia amarae could be limited by supernatant of the anaerobic digester. No connection of scum production with the nitrogen and phosphorus content of the influent was found as is often assumed in the literature. The dependence of scum production on the grease and oil content of the influent is discussed. Since the isolated actinomycetes were found to have the ability to synthesize lipidic cell material from proteins and carbohydrates, there is no indication of a strong relation.

Population density and enzyme activities of heterotrophic bacteria in sewer biofilms and activated sludge

Abstract The heterotrophic activity of different wastewater biocenoses is assessed. The biofilms originate from a sewer discharging domestic wastewater and from a sewer discharging trade wastewater with chromium and nickel contamination. The activated sludge was taken from the aeration tank from the high load stage (F:M ratio 0.8 kg kg −1 d −1 ) and from the low load stage (F:M ratio 0.1 kg kg −1 d −1 ) of a two-stage municipal wastewater treatment plant. We determined the population density of heterotrophic saprophytes, polymer degrading bacteria, ammonifying bacteria as well as of nitrate reducers and denitrifiers. Enzyme activities were determined as relative substrate turnover rates for esterase, α- and β-glucosidase, for phosphatase and for l -alanine-aminopeptidase. The population density of heterotrophic saprophytes was one order of magnitude higher in the high load stage compared to the low load activated sludge. The sewer biofilms showed one to two orders of magnitude higher counts per g dry weight for the heterotrophic bacteria as compared to the activated sludges. The turnover rates of esterase and l -alanine-aminopeptidase were higher than those of α- and β-glucosidase and phosphatase. The sewer biofilms are highly active biocenoses both with respect to population densities as with respect to enzyme activities. Their heterotrophic activity is comparable with the one in high load activated sludge. Even the bacteria in the biocenosis which is exposed to high concentrations of chromium and nickel showed a high activity.

Denitrification in a methanol-fed fixed-bed reactor. Part 1: Physico-chemical and biological characterization

In a municipal two-stage biological wastewater treatment plant with full nitrification, methanol-fed post-denitrification was investigated in a succeeding sand filter system originally designed for the retention of suspended solids in the secondary effluent. Temperature, pH, redox potential, concentration of oxygen and nitrogen-compounds and gas production were determined in situ in the filter bed. In addition, biological parameters such as volatile solids, biofilm thickness, and nitrate elimination efficiency of denitrifying bacteria isolates were determined. The data characterize the microbial processes underlying denitrification in the filter cells and support operation optimization by avoiding detrimental effects on denitrification efficiency such as accumulation of biomass, pH drop and accumulation of undesired intermediates such as nitrite and nitrous oxide.

Scum in Activated Sludge Plants: Impact of Non‐filamentous and Filamentous Bacteria

Excessive scum production is a widespread phenomenon in present activated sludge wastewater treatment. The question how foaming is initiated and stabilized is still unanswered. Hydrophobic wastewater ingredients and surface active material such as synthetic surfactants are discussed among others as major causative agents for scum production. Focusing on biological impacts non-filamentous bacteria isolated from scum turned out to contribute to flotation by both cell surface hydrophobicity and emulsification activity, depending on the prevailing substrate and milieu conditions. The biological characterization of scum based on microscopic sludge investigation of conspicuous microorganisms resulted in a significant shift of filamentous and non-filamentous organism populations with Gram-positive bacteria prevailing in present nutrient removal plants as compared to the situation ten years ago. Their hydrophobic cell surface is supposed to support adherence and stabilization of interfaces and thus promote sludge flotation. In scum six types of filamentous bacteria turned out to be numerous: Microthrix parvicella and nocardioform actinomycetes, both of them being enriched in the scum fraction, moreover Nostocoida limicola and Eikelboom types 0041/0675, 1851, and 0092. Possible interactive mechanisms between non-filamentous and filamentous scum bacteria and their selection factors are discussed in order to contribute to a better understanding of scum formation and to provide efficient troubleshooting measures. Schaum in Belebungsanlagen: Einfluss nicht-fadiger und fadiger Bakterien Starke Schaumbildung ist gegenwartig ein weit verbreitetes Phanomen in Klaranlagen nach dem Belebungsverfahren. Die Frage nach Entstehung und Stabilisierung dieser Schaume ist nach wie vor ungeklart. Hydrophobe Abwasserbestandteile und oberflachenaktive Stoffe wie etwa Tenside werden unter anderem als wichtige Ursache der Schaumbildung diskutiert. Die Suche nach biologischen Einflussen ergab, dass aus Schaum isolierte Bakterien ohne Fadenbildung sowohl durch Oberflachenhydrophobierung als auch durch die Bildung stabiler Emulsionen zur Flotation beitragen, abhangig von den vorherrschenden Substrat- und Milieubedingungen. Die biologische Charakterisierung von Schaum, basierend auf mikroskopischen Untersuchungen auffalliger Organismen in belebtem Schlamm, ergab in Anlagen mit Stickstoff- und Phosphorentfernung eine deutliche Verschiebung hin zu Gram-positiven Bakterien – Fadenbakterien und solche, die nicht fadig wachsen – im Vergleich zu den vor etwa 10 Jahren ublichen Anlagen zur reinen Elimination von Kohlenstoffverbindungen. Die hydrophobe Oberflache dieser Organismen scheint der Adhasion an und Stabilisierung von Grenzflachen und damit der Flotation forderlich zu sein. In Schaum wurden sechs wichtige Fadenorganismen festgestellt: Microthrix parvicella und nocardioforme Actinomyceten, die beide in der Schaumfraktion angereichert werden, des Weiteren Nostocoida limicola und die zunachst noch mit Nummern benannten Fadenbakterien Eikelboom Typ 0041/0675, 1851 und 0092. Mogliche Interaktionen zwischen nicht-fadigen und fadigen Schaumbakterien sowie ihre Selektionsfaktoren werden diskutiert. Damit wird angestrebt, dem Praktiker uber ein besseres Verstandnis der Schaumbildung effektive Bekampfungsmasnahmen an die Hand zu geben.

Vitamin content of four sludge fractions in the activated sludge wastewater treatment process

Abstract The content of the water-soluble vitamins thiamine, riboflavin and folic acid was determined in the dry solids and the water phase of activated sludge and digested sludge respectively, in municipal and industrial wastewater treatment plants. Thiamine and riboflavin were determined by fluorimetric detection. Folic acid was determined by means of microbiological assays. Dry solids of activated sludge from municipal wastewater treatment plants contained 1.1–6.6 mg kg−1 thiamine, 17.6–43.2 mg kg−1 riboflavin and 10–13 mg kg−1 folic acid with 1–6 μg l−1 thiamine and 9–25 μg l−1 riboflavin in the water phase. Dry digested sludge matter contained 0.9–6.0 mg kg−1 thiamine with a content of the water phase after filtration of 18–386 μg l−1, riboflavin was 3.2–10.8 mg kg−1 and 6–116 μg l−1, respectively, folic acid was 0.25–0.62 mg kg−1 in the dry solid matter, none was found in the water phase. Dry solids of activated sludge from industrial sewage treatment plants contained 1.9–29.1 mg kg−1 thiamine, the water phase after filtration contained 3–14 μg l−1, riboflavin was 21.3–41 mg kg−1 with 1–26 μg l−1 in the water phase, folic acid was 2 mg kg−1 in the dry solids of activated sludge. The vitamin content varies in different sludge fractions. The requirements of heterotrophic saprophytes for thiamine and riboflavin should usually be met by the vitamin content in the sludge. Before dosing the vitamin content should be monitored.

Effect of acclimation and nutrient supply on 5-tolyltriazole biodegradation with activated sludge communities

The corrosion inhibitor 5-tolyltriazole (5-TTri) can have a detrimental impact on aquatic systems thus implying an acute need to reduce the effluent concentrations of 5-TTri. In this study, 5-TTri biodegradation was enhanced through acclimation and nutrient supply. Activated sludge communities (ASC) were setup in nine subsequent ASC generations. While generation two showed a lag phase of five days without biodegradation, generations four to nine utilized 5-TTri right after inoculation, with biodegradation rates from 3.3 to 5.2 mg L(-1)d(-1). Additionally, centrifuged AS supernatant was used to simulate the nutrient conditions in wastewater. This sludge supernatant (SS) significantly enhanced biodegradation, resulting in removal rates ranging from 3.2 to 5.0 mg L(-1)d(-1) without acclimation while the control groups without SS observed lower rates of ⩽ 2.2 mg L(-1)d(-1).

Monitoring benzotriazoles: a 1 year study on concentrations and removal efficiencies in three different wastewater treatment plants

Benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) were monitored over 1 year in three wastewater treatment plants (WWTPs) with a membrane bioreactor (MBR-MH) and two conventional activated sludge systems (CAS-E, CAS-M). The influent/effluent concentrations and treatment stages removal efficiencies were monitored. 5-TTri was removed best (mean removal 80%) in the WWTP mainly by biodegradation followed by BTri (mean removal 45%) and 4-TTri (mean removal 15%) that showed a significant lower elimination. High removal fluctuations for all three benzotriazoles occurred over the four seasons with lowest removal during winter. All three WWTPs constituted a point source for BTs in the aquatic environment as concentration measurements in the receiving rivers upstream and downstream of the WWTP proved. While MBR-MH and CAS-M significantly increased the downstream concentrations, CAS-E only slightly increased the downstream concentrations as the receiving river was already contaminated with benzotriazoles from hydropower. 5-TTri was detected in lowest concentrations due to its good removal compared to BTri and 4-TTri that contribute to high effluent concentrations with the potential to accumulate due to insufficient self-purification.

Screening and monitoring microbial xenobiotics’ biodegradation by rapid, inexpensive and easy to perform microplate UV-absorbance measurements

BackgroundEvaluation of xenobiotics biodegradation potential, shown here for benzotriazoles (corrosion inhibitors) and sulfamethoxazole (sulfonamide antibiotic) by microbial communities and/or pure cultures normally requires time intensive and money consuming LC/GC methods that are, in case of laboratory setups, not always needed.ResultsThe usage of high concentrations to apply a high selective pressure on the microbial communities/pure cultures in laboratory setups, a simple UV-absorbance measurement (UV-AM) was developed and validated for screening a large number of setups, requiring almost no preparation and significantly less time and money compared to LC/GC methods. This rapid and easy to use method was evaluated by comparing its measured values to LC-UV and GC-MS/MS results. Furthermore, its application for monitoring and screening unknown activated sludge communities (ASC) and mixed pure cultures has been tested and approved to detect biodegradation of benzotriazole (BTri), 4- and 5-tolyltriazole (4-TTri, 5-TTri) as well as SMX.ConclusionsIn laboratory setups, xenobiotics concentrations above 1.0 mg L-1 without any enrichment or preparation could be detected after optimization of the method. As UV-AM does not require much preparatory work and can be conducted in 96 or even 384 well plate formats, the number of possible parallel setups and screening efficiency was significantly increased while analytic and laboratory costs were reduced to a minimum.