@phdthesis{Okofo2023, author = {Okofo, Louis Boansi}, title = {Hydrogeological assessment for evaluating the feasibility of managed aquifer recharge in Northeastern Ghana}, doi = {10.26127/BTUOpen-6244}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-62444}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {In the Garu-Tempane area and Tamne River basin of north-eastern Ghana, granitic aquifers supply nearly 80\% of annually abstracted groundwater. Rapid and diffuse recharge enters the fractured and weathered Tamnean Plutonic Suite aquifers mainly granitoid, which are the dominant rock types in the study area. However, a greater challenge to the water supply in the area is posed by global climatic changes and overexploitation due to population growth. The semi-arid nature of the area together with the factors mentioned earlier has caused water scarcity, particularly in the dry season and these have affected the livelihoods of the farmers who depend mostly on the groundwater for irrigation and domestic purposes. A promising way to balance water resources in the region is using engineering technology such as managed aquifer recharge (MAR). MAR augments water levels in water-scarce areas and represents a key tool in water supply management. For this reason, a comprehensive hydrogeological characterization involving the hydrochemistry of the groundwater, groundwater recharge process and residence time using multi-environmental tracers, and a numerical groundwater flow model was developed. Based on the hydrochemistry results, the water quality index showed that the groundwater is very suitable for drinking. However, about 10.5 \% out of the 38 groundwater samples had elevated nitrate concentrations exceeding the permissible WHO drinking water limit. These are mainly agricultural areas, which might have influenced the elevated nitrate concentrations. Groundwater age dating using sulphur hexafluoride (SF6) and chlorofluorocarbons (CFCs) was used to date shallow groundwater in Ghana for the first time. The results proved that the mean residence time of groundwater was around 30 years, an indication of young groundwater and rapid groundwater renewability. The findings also showed different groundwater ages implying diffused flow systems occurring in the fractured granitic aquifer. Investigation of the groundwater recharge using stable isotopes of deuterium and oxygen-18 revealed that the main source of groundwater recharge is of meteoric origin. There were little or no contributions from the stream and ponds as they were subjected to evaporative fractionation during the dry season. The White Volta River samples and samples from two big rivers were depleted in heavy isotopes, which suggested a hydraulic connection between them and the groundwater. The numerical groundwater flow model was used to assess the feasibility of MAR and determine the maximum recharge and abstraction rates. The results showed that the aquifer had enough storage to accommodate enough volumes of floodwater without causing groundwater mounding. This shows that MAR is feasible in augmenting the water levels in the area when irrigation and domestic withdrawals are regulated.}, subject = {Managed aquifer recharge; CFCs; SF6; Numerical groundwater flow modelling; Northeastern Ghana; Schwefelhexafluorid; Fluorchlorkohlenwasserstoffe; Grundwasserstr{\"o}mungsmodell; Nordost-Ghana; Ghana (Nordost); Wasserversorgung; Grundwasser{\"u}berwachung; Grundwasserbildung; Grundwasseranreicherung; Numerische Str{\"o}mungssimulation}, language = {en} } @phdthesis{Abdallat2016, author = {Abdallat, Ghaida}, title = {Optimization of nitrogen removal in various vertical flow constructed wetland designs and application of treated wastewater for reuse in irrigation in Jordan}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-37987}, school = {BTU Cottbus - Senftenberg}, year = {2016}, abstract = {In arid countries, reclaimed water in irrigation is a widespread practice. Therefore, robust treatment designs are prerequisite to obtain effluent quality that conforms to the legal requirements for reuse and health standards. Vertical flow constructed wetlands (VFCWs) are attractive decentralized treatment plants in many countries and communities. VFCWs are capable of providing adequate treatment for organic and solids removal, even though there are limitations on nutrient and pathogen removal. Within this study, various VFCW systems were investigated, in Germany and Jordan, to optimize nitrogen removal using sustainable and low cost options to guarantee the safe reuse in Jordan. In Germany at Langenreichenbach research facility, two-stage VFCWs planted (Phragmites australis) and unplanted were evaluated and modified to compare the role of plants over two years. Generally, there was no significant role of plants on the treatment performance. Both systems showed high removal efficiency for TOC, BOD5, and TSS over the study period. During the first year of the study, effluent TN concentrations ranged from 60 - 61 mg/L in both systems as a result of high effluent NO3--N concentrations (50 - 52 mg/L). In the second year, the systems were modified, adopting a saturated layer in the 1st stage to enhance denitrification. Average effluent TN concentrations were reduced to 45 mg/L in both systems. In addition, during modifications, the E.coli removal was enhanced in both systems achieving 4 log reduction instead of 2 log reduction during the first year of the study. In Jordan at the Fuhais research facility, two VFCW systems were studied considering category-A (TN: 45 mg/L and NO3-N: 30 mg/L) in the Jordanian Standards for reuse in irrigation (JS 893/2006). Recirculating (ECO-1) and Multi-stage (ECO-2) VFCW designs have shown high removal efficiency of COD, TSS, and BOD5 over three years of monitoring. ECO-1 system combines simultaneous nitrification and denitrification by recycling portion of nitrified effluent into the recirculation tank. However, effluent TN and NO3--N concentrations were 55 and 44 mg/L, respectively, that the system conformed to the JS category-B (TN: 70 mg/L and NO3-N: 45 mg/L) during monitoring phase. Therefore, ECO-1 was modified by installing plastic media in the recirculation tank that attached growth increases the abundance and activity of microorganisms. TN concentration was reduced effectively of 40 mg/L, conforming to the JS category-A, whereas, NO3--N concentration was reduced to 37 mg/L, conforming to the JS category-B. However, over the study period, E.coli concentrations were conformed to the JS category-C (more than 1000 MPN/100 mL). ECO-2 consists of two unsaturated VFCWs in series; single-pass unplanted filter followed by planted filter (Phragmites australis). E.coli removal was relatively high before modification that the effluent conformed to the JS (category-B: 1000 MPN/100 mL), achieving 4.4 log reduction. The effluent TN and NO3--N concentrations did not conform to the JS of 77 and 76 mg/L, respectively, due to insufficiency of carbon source to promote denitrification (high BOD5 removal) during monitoring phase of the study. Thus, ECO-2 was modified adopting raw wastewater step-feeding strategy that a specific volume of raw wastewater was mixed with 1st stage effluent in the mixing tank. TN and NO3--N concentrations were reduced to 52 and 50 mg/L, respectively; conforming to the JS category-B. Whereas, E.coli removal was influenced by E.coli ingress from raw step-feeding, achieving 3.5 log reduction, conforming to the JS category-C. The short-term impact of irrigation with different water quality and quantity was investigated at the Fuhais site. Soil physicochemical and biological properties in three parallel experimental reuse plots were investigated. The plots were cultivated with lemon trees and were irrigated via a subsurface irrigation system. Moreover, each plot was divided into two subparts (A and B) whereby one part received 11 mm/day of irrigation water and the other received 6 mm/day. Using treated effluent and tap water showed the same trend of increased soli salinity (ECs). Significant difference in ECs, SAR, Mg+2, Ca+2, and Na+ were observed at 0-20 cm as a result of high evaporation and capillary rise that increased salts accumulation in the topsoil. However, using more water reduced the salts accumulation in sub soil layers due to continuous leaching. Whereas, results showed no significant variation in soil texture, structure, moisture, and infiltration rate among reuse plots and subparts. Additionally, results revealed an absence of total coliform, fecal coliform, and E.coli in the irrigated soils, indicating the effectiveness of using subsurface irrigation as a disinfection step for reuse.}, subject = {Constructed wetland; Nitrogen; Nitrification; Denitrification; Pflanzenkl{\"a}ranlage; Stickstoff; Nitrifikation; Denitrifikation; Jordanien; Pflanzenkl{\"a}ranlage; Abwasserreinigung; Denitrifikation; Wiederverwendung; Bew{\"a}sserung}, language = {en} } @misc{Ijioma2013, type = {Master Thesis}, author = {Ijioma, Uche}, title = {Determination of specific metabolic activities of anammox bacteria and their sensitivity to oxygen}, doi = {10.26127/BTUOpen-5582}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-55820}, school = {BTU Cottbus - Senftenberg}, year = {2013}, abstract = {The discovery of Anammox bacteria has bridged our knowledge gap in the nitrogen cycle. This is because it explained the direct conversion of nitrite and ammonium to nitrogen gas in many reducing natural environments. However, it has been found that the presence of oxygen is an important determinat factor for certain biochemical processes and distribution of organisms in the environment. In this work, two methodological approaches were used to investigate the specific metabolic activities of Anammox bacteria and their sensitivity to oxygen using a mixed biomass culture. Two laboratory-scale bioreactors were maintained and the biomass in the reactors served as the inoculum for the investigations. The molecular characterization of the biomass was done using the Fluorescence in situ hybridization (FISH) technique. The specific Anammox activity (SAA) and important inhibition kinetic parameter characterization were estimated while monitoring activities of the biomass using several batch experiments. The results of the biochemical characterization revealed that several microbial activities such as denitrification, nitrification, dissimilatory nitrate reduction to ammonium and Anammox processes were competing in the bioreactors. These were observed in the analysis of effluent recirculation of the feed solutions in the bioreactors, however, the Anammox process was predominant. An optimum sonication time top of eight minutes was established used to determine the average optical density to dry mass (OD: DM) ratio of 0.87 in the biomass. The FISH characterization estimated 60.4 \% ± 14.6\% (mean ± standard deviation) Anammox bacteria concentration in the biomass of Bioreactor 1. The Anammox bacteria were made up C. Kuenenia Stuttgartiensis (̴ 78\%) and the remaining C. Brocadia Fulgida. The maximum SAA of 0.025 mgNH4-N (TSSAnammox-1. d-1) and 5.4 mgNH4-N (1011 CellAnammox-1. d-1) for ammonium, and 0.04 mg N2-N (TSSAnammox-1. d-1) and 9.4 mgN2-N (1011 CellAnammox-1. d-1) for nitrogen gas were found in the biomass. While a binding affinity constant Ki = 0.07 mgO2 /l, maximum half inhibition concentration IC50 ̴ 0.2 mg O2 /l and KM = 50 mg/l were estimated for the inhibition kinetics of oxygen in the biomass. The low Ki value found in this study indicates that oxygen is an efficient inhibitor for Anammox activities and concentrations between 0.4 - 0.64 mg O2 /l can lead to complete inhibition of Anammox activity. However, this process is reversible. Finally, the implication of this inhibition kinetic results might be important in tracing the distribution of Anammox processes in natural environments where fixed nitrogen is present.}, subject = {Anammox bacteria; FISH; Specific anammox activities; Inhibition kinetics; IC50; Anammox-Bakterien; FISH; Spezifische Anammox-Aktivit{\"a}ten; Hemmungskinetik; IC50; Stickstoffkreislauf; Anaerobe Bakterien; Ammoniumverbindungen; Nitrite; Oxidation; Stickstoff; Biomasse}, language = {en} } @article{RiedelMeissnerKaschubowskietal.2024, author = {Riedel, Ramona and Meißner, Karsten and Kaschubowski, Arne and Benndorf, Dirk and Martienssen, Marion and Braun, Burga}, title = {Laundry isolate Delftia sp. UBM14 capable of biodegrading industrially relevant aminophosphonates}, series = {Microorganisms}, volume = {12}, journal = {Microorganisms}, publisher = {MDPI}, address = {Basel}, issn = {2076-2607}, doi = {10.3390/microorganisms12081664}, year = {2024}, abstract = {Phosphonates such as ethylenediaminetetra (methylenephosphonic acid) (EDTMP) and aminotris (methylenephosphonic acid) (ATMP) are used every day in water treatment processes or in household products. Their consumption is still increasing, regardless of the debates on their environmental impact. Here, the microbial characterisation and determination of the biodegradation potential of selected industrially relevant phosphonates for the isolate Delftia sp. UMB14 is reported. The opportunistic strain was isolated from a biofilm that was derived from a conventional washing machine using conventional detergents containing phosphonates. In antimicrobial susceptibility testing, the strain was only susceptible to sulfonamide, tetracycline, and chloramphenicol. Physiological and biochemical characteristics were determined using the BIOLOG EcoPlate assay. Most importantly, the strain was shown to convert D-malic acid and D-mannitol, as confirmed for strains of Delftia lacustris, and thus the new isolate could be closely related. Biodegradation tests with different phosphonates showed that the strain preferentially degrades ATMP and EDTMP but does not degrade glyphosate (GS) and amino (methylphosphonic acid) (AMPA). A specific gene amplification confirmed the presence of phnX (phosphonoacetaldehyde hydrolase) and the absence of PhnJ (the gene for the core component of C-P lyase). The presence of PhnCDE is strongly suggested for the strain, as it is common in Delftia lacustris species.}, subject = {Phosphonates; Biodegradation; PhnX; PhnJ; PhnCDE; Phosphonate; Biologischer Abbau; Mikrobieller Abbau; Waschmittel}, language = {en} } @phdthesis{Engelbrecht2019, author = {Engelbrecht, Steffen}, title = {Mikrobielle Stickstoffelimination mit kombinierter partieller Nitrifikation/ Anammox (PN/A) in membranbel{\"u}fteten hochsalinen und Niedrigtemperatur-Festbettreaktoren}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-48848}, school = {BTU Cottbus - Senftenberg}, year = {2019}, abstract = {Durch anthropogene Aktivit{\"a}t hat sich der N{\"a}hrstoffeintrag in die Umwelt stark erh{\"o}ht. Die Hauptquellen sind die Landwirtschaft, kommunales und industrielles Abwasser. Erh{\"o}hte Stickstofffrachten haben einen starken Einfluss auf den Stickstoffkreislauf. Das {\"U}berangebot an Stickstoff f{\"u}hrt zu Eutrophierung in Gew{\"a}ssern und somit zu einem weniger diversen, instabileren {\"O}kosystem. Die Stickstoffeliminierung aus Abw{\"a}ssern ist essentiell f{\"u}r den Schutz der {\"O}kosysteme. Das etablierte System der Nitrifikation/Denitrifikation ist aufgrund des hohen Sauerstoffbedarfs sehr energie- und somit auch kostenintensiv. Der Anammox-Prozess (anaerobe Ammonium Oxidation) ist eine potentielle Alternative zur konventionellen Stickstoffelimination. Anammox-Bakterien nutzen Ammonium und Nitrit als Elektronenakzeptor. Durch Nutzung der partiellen Nitrifikation in Kombination mit Anammox (PN/A) kann bis zu 60 \% der Bel{\"u}ftungsenergie eingespart werden. Trotz Erfolgen in der Teilstrombehandlung ist der Prozess noch nicht erfolgreich in der Hauptstrombehandlung eingesetzt worden. Die gr{\"o}ßten Herausforderungen sind die niedrigen Temperaturen, geringe Zulaufkonzentrationen und hohe Konzentrationen organischen Kohlenstoffs. Die vorliegende Arbeit konnte die Wirksamkeit von membranbel{\"u}fteten Biofilm Reaktoren unter Verwendung von synthetischem Abwasser bei niedrigen Temperaturen (18 - 8 °C) belegen. Die Innovation in diesem System ist die r{\"a}umliche Trennung von nitrifizierenden Bakterien und Anammox Bakterien. Die regelm{\"a}ßige mechanische Entfernung des Nitrifikanten-Biofilms erm{\"o}glichte einen langzeitstabilen Reaktorbetrieb. Diese Reaktorkonfiguration konnte auch erfolgreich f{\"u}r hochsaline Abw{\"a}sser (5 -30 g NaCl*L-1) bei einer Reaktortemperatur von 30 °C und auch unter Zugabe von TOC (40-100 mg TOC*L-1) genutzt werden. Weiterhin wurden Untersuchungen zur Aktivit{\"a}t von salzadaptierter Anammox-Biomasse und nicht adaptierter Biomasse in einem Bereich von 0 bis 50 g NaCl*L-1 durchgef{\"u}hrt. Bei Konzentrationen unter 30 g NaCl*L-1 konnten keine signifikanten Unterschiede im Abbauverhalten festgestellt werden. Allerdings war adaptierte Biomasse bei h{\"o}heren Salzkonzentrationen konkurrenzst{\"a}rker. Außerdem wurden Langzeitlagerungsversuche durchgef{\"u}hrt. Die Lagerungsbedingungen variierten in der Lagerungstemperatur, im Redoxpuffer und der N{\"a}hrstoffversorgung. Nach 106 Tagen bei 4 °C konnte die Anammox-Biomasse noch 91 \% ihrer urspr{\"u}nglichen Aktivit{\"a}t erhalten. Somit konnte eine einfache und kosteng{\"u}nstige Lagerungsmethode f{\"u}r Anammo-Bakterien entwickelt werden.}, subject = {PN/A; Niedrigtemperatur; Anammox; Mebranbel{\"u}fteter Biofilm-Reaktor; Hohe Salinit{\"a}t; PN/A; Low temperature; MABR; High salinity; N{\"a}hrstoffeintrag; Salzgehalt; Abwasser; Biofilmreaktor; Ammoniumoxidierer}, language = {de} } @article{MartienssenRiedelKuehne2024, author = {Martienssen, Marion and Riedel, Ramona and K{\"u}hne, Tom}, title = {Contribution of professional cleaning to indoor air and sewage pollution}, series = {Sustainable Chemistry}, volume = {5}, journal = {Sustainable Chemistry}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2673-4079}, doi = {10.3390/suschem5040019}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-71378}, pages = {275 -- 286}, year = {2024}, abstract = {In this study, several professional cleaning products were analyzed for their impact on local air and sewage contamination. The products were first analyzed for their content of potentially harmful ingredients, their biodegradability, and the potential for the mobilization of hazardous substances from the floorings that were cleaned. The contribution of the cleaning products to sewage pollution with environmentally hazardous substances was studied at full scale. All commercially available cleaning products studied were declared to be environmentally friendly (labeled with the EU Ecolabel). However, despite being labeled as "green" products, between 16 and 24 volatile harmful ingredients were identified. An optimized experimental product, produced completely from natural raw materials, also contained several harmful substances originating from the herbal raw materials themselves. During the field study, we identified a range of trace substances in the sewage. Eight of these substances (e.g., p-cymene, butanone, eucalyptol) significantly originated from the cleaning products. Several others may have originated from the cleaning products, but other sources were also possible. The flooring materials that were cleaned contained several harmful substances themselves. The release of some substances (e.g., toluene) into the sewage significantly increased during the cleaning process.}, subject = {Professional cleaning agents; Trace substances; Biodegradability; Sewage pollution; Environmental impact}, language = {en} } @phdthesis{Bryant2019, author = {Bryant, Isaac Mbir}, title = {Development of single-stage solar-supported hyper-thermophilic anaerobic reactor for biogas production and disinfection of black water : a pilot case study of Terterkessim slum, Elmina - Ghana}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-47814}, school = {BTU Cottbus - Senftenberg}, year = {2019}, abstract = {Rapid urbanisation in Ghana has resulted in individuals expanding the cities for abodes without considerations of the negative externalities these may have on the environment. One of the major challenges with rapid urbanisation is the formation of urban slums associated with lack of basic sanitation facilities. This has led to recurrent outbreak of cholera and typhoid fever. The use of a single-stage solar-supported hyper-thermophilic anaerobic biogas digester for the treatment of black water has not been investigated, hence this study. The performance of three seeding sludge under three different hyper-thermophilic temperatures (60°C, 65°C and 70°C) were tested in batch tests. The three seeding sludge were sewage sludge, sludge from maize silage and cow manure. The results from the batch tests showed cow manure at 65°C as the preferred seeding sludge and optimal hyper-thermophilic temperature. A 50 L single-stage laboratory-scale hyper-thermophilic continuous stirred tank reactor (HT-CSTR) was operated to treat only black water for 10 weeks using cow manure at 65°C as the seeding sludge and optimal hyper-thermophilic temperature. Afterwards, co-digestion of blended kitchen food waste and black water was also practised for 12 weeks. With a mean hydraulic retention time (HRT) of 23.3 days, a mean total COD removal of 86.3 \% was achieved. The reactor had an average COD volumetric loading rate of 6.22 kgCOD/(m3.d) and remained uninhibited. It also had organic loading rate of 0.3 kgVS/(m3.d) and a degradation performance (R) of 5.43 kgCOD/(m3.d). Treatment of only black water produced biogas with less methane content of 34.9 \% even though a stable pH of 6.9 was recorded both in the reactor and in the effluent. Co-digestion with kitchen food waste increased the percentage content of methane in the biogas by 77 \% from 34.9 \% to 61.8 \%. The effectiveness of the HT-CSTR to hygienise the effluent for agricultural purpose was assessed by spiking the reactor with 200 ml each of 2 x 109 CFU/ml Salmonella senftenbergensis and 8 x 108 CFU/ml Escherichia coli. The HT-CSTR was able to hygienise all bacteria of Salmonella senftenbergensis and E. coli. A simulation test confirmed that between 30 minutes and 1 hour, all the cells of Salmonella senftenbergensis and E. coli in the treatment system were killed at 65 °C. Eubacteria, Methanosarcina spp., Methanomicrobium spp. and Methanococcus spp. were identified in the seeding sludge at the hyper-thermophilic temperature of 65°C. The design, construction and performance of a pilot-scale reactor in Terterkessim slum in Elmina, Ghana was based on results from the laboratory-scale HT-CSTR. It achieved 97 \% removal of influent total COD and could produce about 2.52 Nm³CH₄/(kgCOD.d) which could be burned for at least 8 hours. The effluent cannot be used for cultivation of leafy vegetables such as cabbage since it had some concentrations of pathogens like Salmonella spp. and E. coli but can be used for cotton crop.}, subject = {Black water; Single-stage; Solar-supported; Hyper-thermophilic temperature; Methane yield; Schwarzwasser; Einstufig; Solar-beheizt; Hyperthermophil; Methanertrag; Abwasser; R{\"u}hrreaktor; Fermentation; Biogas; Methanproduktion}, language = {en} } @phdthesis{Coban2015, author = {Coban, Oksana}, title = {Microbial nitrogen transformations in constructed wetlands treating contaminated groundwater}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-35006}, school = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {Groundwater is the main source for potable water and domestic use in numerous countries around the world. However, water quality can be affected by pollution, which influences the natural environment and human health. One of the widespread pollutants in water is ammonia which is toxic to fish and causes eutrophication of lakes and wetlands. Constructed wetlands are promising in situ water treatment methods thanks to enhanced microbial growth within the plants' rhizospheres, which creates an effective contaminant degradation zone. The ammonia in constructed wetlands can be removed either via total nitrification with further denitrification or partial nitrification coupled with anaerobic ammonium oxidation (anammox). However, so far, the role of anammox in constructed wetlands as well as its correlation with other nitrogen transformations remains unclear. The quantification of nitrogen turnover processes in constructed wetlands is difficult due to the complexity of the wetland systems. Accordingly, the main aim of this research is to investigate pathways of ammonium removal in constructed wetlands treating contaminated groundwater. For this, several approaches were applied: a) physico-chemical parameters measurements; b) investigations of nitrogen stable isotope fractionation; c) stable isotope labelling approach; d) molecular biological methods. Also, seasonal and spatial variations in nitrogen transformations in several types of constructed wetlands (unplanted horizontal subsurface flow, planted horizontal subsurface flow, and floating plant root mat) were investigated. The application of the stable isotope approach combined with common physico-chemical investigations enabled us to identify key factors influencing efficiency of nitrogen removal in constructed wetlands, which was the plant presence as substrate for attachment and growth of microorganisms. Ammonium removal efficiencies were not different between investigated seasons (spring, summer, and autumn), what could be explained by the fact that throughout all investigated seasons the air temperature remained high (above 10°C). While plant uptake accounted for significant part of ammonium removal during spring and summer in planted constructed wetlands, isotope fractionation patterns revealed that nitrification-denitrification were prevailing processes in planted constructed wetlands throughout the year, occurring in a linear way along the flow path, and not depending on depth in the root zone. The research results also illustrated that in the planted horizontal subsurface flow constructed wetland, the functional genes of the nitrogen cycle were evenly distributed in a linear way along the flow path with prevalence at the superficial points. The same trend was observed for the nitrification and denitrification turnover rates using the isotope labeling techniques. Significant nitrate consumption under aerobic conditions diminishes nitrification rates and should therefore be taken into account when estimating nitrification turnover rates. This nitrate consumption was due to aerobic denitrification, the rate of which was comparable to that for anaerobic denitrification. Consequently, denitrification should not be considered as an exclusively anaerobic process. Phylogenetic analysis of hydrazine synthase (hzsA) gene clones indicated the presence of Brocadia and Kuenenia anammox species in the constructed wetland. Although anammox bacteria were detected by molecular methods, anammox activity could not be measured and hence this process appears to be of low importance in nitrogen transformations in these freshwater ecosystems. In conclusion, this research demonstrated that combination of physico-chemical measurements with stable isotope and molecular biological approaches is an effective tool for investigation of nitrogen transforming processes in constructed wetlands. Such information is not only valuable for understanding of the processes ongoing inside these wastewater treatment facilities but also necessary for further technological improvement of constructed wetlands.}, subject = {Constructed wetlands; Nitrogen; Nitrification; Denitrification; Anammox; Pflanzenkl{\"a}ranlagen; Stickstoff; Nitrifikation; Denitrifikation; Anammox; Grundwasser; Pflanzenkl{\"a}ranlage; Ammonium; Nitrifikation; Denitrifikation}, language = {en} } @article{BoellmannMartienssen2024, author = {B{\"o}llmann, J{\"o}rg and Martienssen, Marion}, title = {Seasonal variability of cultivable nitrate-reducing and denitrifying bacteria and functional gene copy number in fresh water lake}, series = {microorganisms}, volume = {12}, journal = {microorganisms}, number = {3}, publisher = {MDPI}, address = {Basel}, issn = {2076-2607}, doi = {10.3390/microorganisms12030511}, year = {2024}, abstract = {This study describes the seasonal course of denitrifying and nitrate-reducing bacteria in a dimictic mesotrophic lake (Lake Scharm{\"u}tzelsee, Brandenburg, Germany) within a three-year period from 2011 to 2013. The bacterial cell numbers were quantified by the fluorescence microscopy, most probable number (MPN) and PCR-dependent quantification of the chromosomal 16S rDNA and of the nirS and nirK gene copy number. The highest seasonal differences (up to three orders of magnitudes) have been measured usingMPNin the epilimnion. This variation was not reflected by PCR-dependent approaches or direct microscopical enumeration. At adverse conditions (low temperature and/or low nitrate concentrations), the differences between MPN and gene copy numbers increased by up to five orders of magnitudes and decreased to one magnitude at favourable environmental conditions. These results can be explained best by an increasing ratio of viable but not cultivable (VBNC) cells or dead cells at impairing conditions. In the hypolimnion, the courses of MPN and nir gene copy numbers were similar. This can be explained by a higher feeding pressure and therefore smaller amounts of dormant cells. In the pelagial in general, the total cell numbers enumerated by either microscopical or molecular approaches were similar. In the sediment, more than 99\% of the DNA was obviously not related to viable bacteria but was rather DNA in dead cells or adsorbed to particle surfaces.}, subject = {Denitrification; Nitrite reductase; Microscopical cell number; Hypolimnion; Dimictic lake; Denitrifikation; Nitrit-Reduktase; Mikroskopische Zellzahl; Dimiktischer See}, language = {en} } @article{AfitiriAfrifa2024, author = {Afitiri, Abdul-Rahaman and Afrifa, Ernest Kofi Amankwa}, title = {Households' willingness to use water from a solar water disinfection treatment system for household purposes}, series = {World}, volume = {5}, journal = {World}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2673-4060}, doi = {10.3390/world5040060}, pages = {1181 -- 1193}, year = {2024}, abstract = {The consumption of contaminated water contributes to the global burden of diarrhea and other water-borne diseases, especially among young children. While decentralized solar water disinfection treatment systems (hereafter SODIS) remain a viable option to have safe drinking water, our understanding of the effects of household water treatment before use on willingness to accept and adopt a SODIS is limited. In this study, a complementary log-log regression analysis of the compositional and contextual factors that systematically vary with willingness to accept and adopt a SODIS in the Sawla-Tuna-Kalba (STK) district of Ghana was carried out. Based on our findings, a greater proportion of households (97\%) are willing to accept and adopt a SODIS. Compositional and contextual factors such as age, marital status, education, religion, and geographical location significantly contribute to households' willingness to accept and adopt a SODIS in the STK district of Ghana. Households that treat their water before use (66\%, p < 0.05) are more likely to accept and adopt a SODIS compared to those that do not treat their water before use. The findings, therefore, suggest that scaling up SODIS in the STK district is sacrosanct and highlight the necessity to analyse compositional and contextual factors influencing willingness to accept and adopt SODIS. Our findings will inform policies and programs aimed at implementing SODIS in the study area to improve the health of communities that rely on poor-quality drinking water sources.}, subject = {SODIS; Disinfection; Willingness to accept; Adoption; Sawla-Tuna-Kalba district}, language = {en} }