scholarly journals Enhanced biodegradation of ciprofloxacin by enrich nitrifying sludge: assessment of removal pathways and microbial responses

2021 ◽  
Author(s):  
Shengjun Li ◽  
Yifeng Xu ◽  
Chuanzhou Liang ◽  
Ning Wang ◽  
Shaoxian Song ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
Parent Compound ◽  
Continuous Exposure ◽  
Fluoroquinolone Antibiotics ◽  
Microbial Responses ◽  
Positive Linear Correlation ◽  
Enhanced Biodegradation ◽  
Metabolic Degradation ◽  
Series Of Experiments

Abstract Antibiotics are mostly collected by sewage systems, but not completely removed within wastewater treatment plants. Their release to aquatic environment poses great threat to public health. This study evaluated the removal of a widely used fluoroquinolone antibiotic ciprofloxacin in enriched nitrifying culture through a series of experiments by controlling ammonium concentrations and inhibiting functional microorganisms. The removal efficiency of ciprofloxacin at an initial concentration of 50 μg L−1 reached 81.86 ± 3.21% in the presence of ammonium, while only 22.83 ± 8.22% of ciprofloxacin was removed in its absence. The positive linear correlation was found between the ammonia oxidation rate (AOR) and ciprofloxacin biodegradation rate. These jointly confirmed the importance of the AOB-induced cometabolism in ciprofloxacin biodegradation with adsorption and metabolic degradation pathways playing minor roles. The continuous exposure of AOB to ciprofloxacin led to decreases of ammonia monooxygenase (AMO) activities and AOR. The antibacterial effects of ciprofloxacin and its biodegradation products were further evaluated and the results revealed that biodegradation products of ciprofloxacin exhibited less toxicity compared to the parent compound, implying the potential application of cometabolism in alleviation of antimicrobial activity. The findings provided new insights into the AOB-induced cometabolic biodegradation of fluoroquinolone antibiotics.

scholarly journals Secondary Effects of Hypochlorite Treatment on the Emerging Pollutant Candesartan: The Formation of Degradation Byproducts and Their Toxicological Profiles

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3422
Author(s):  
Giovanni Luongo ◽  
Lorenzo Saviano ◽  
Giovanni Libralato ◽  
Marco Guida ◽  
Antonietta Siciliano ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Parent Compound ◽  
Antihypertensive Agents ◽  
Parent Drug ◽  
Degradation Pathway ◽  
Hplc Method ◽  
Chlorination Process ◽  
Emerging Pollutant ◽  
Ecotoxicity Tests ◽  
First Time

In recent years, many studies have reported the frequent detection of antihypertensive agents such as sartans (olmesartan, valsartan, irbesartan and candesartan) in the influents and effluents of wastewater treatment plants (WWTPs) and in the superficial waters of rivers and lakes in both Europe and North America. In this paper, the degradation pathway for candesartan (CAN) was investigated by simulating the chlorination process that is normally used to reduce microbial contamination in a WWTP. Twelve isolated degradation byproducts (DPs), four of which were isolated for the first time, were separated on a C-18 column by employing a gradient HPLC method, and their structures were identified by combining nuclear magnetic resonance and mass spectrometry and comparing the results with commercial standards. On the basis of these results, a mechanism of formation starting from the parent drug is proposed. The ecotoxicity of CAN and its DPs was studied by conducting a battery of ecotoxicity tests; bioassays were performed using Aliivibrio fischeri (bacterium), Daphnia magna (planktonic crustacean) and Raphidocelis subcapitata (alga). The ecotoxicity results shed new light on the increased toxicity of DPs compared with the parent compound.

Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems

2011 ◽  
Vol 39 (6) ◽  
pp. 1832-1837 ◽  
Author(s):  
Kartik Chandran ◽  
Lisa Y. Stein ◽  
Martin G. Klotz ◽  
Mark C.M. van Loosdrecht
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
N2o Emissions ◽  
Ammonia Oxidizing Bacteria ◽  
N2o Production ◽  
Nitrogen Emissions ◽  
Greenhouse Gas Inventories ◽  
Nitrogen Concentrations

Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO2−) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N2O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O2) is associated with N2O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N2O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N2O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N2O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N2O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

An advanced oxidation process using ionized gas for wastewater treatment

2010 ◽  
Vol 62 (2) ◽  
pp. 451-456 ◽  
Author(s):  
Eun Ju Lee ◽  
Paul Gene Chung ◽  
Dong Heui Kwak ◽  
Lee Hyung Kim ◽  
Min Jeong Kim
Keyword(s):  
Wastewater Treatment ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Wastewater Treatment Plants ◽  
Electricity Consumption ◽  
Advanced Oxidation ◽  
Ionized Gas ◽  
Water And Wastewater Treatment ◽  
Organic Matters ◽  
Series Of Experiments

This study on removing non-degradable materials in wastewater focused primarily on advanced oxidation methods such as ozone, ozone/UV and ozone/H2O2. Wastewater treatment using an ionized gas from plasma has been actively progressing. The ionized gas involves reactive species such as O2+, O2− cluster, O radical and OH radical. Since the ionized gas method has such outstanding characteristics as relatively simple structures, non-calorification, non-toxicity and low electricity consumption, it evidently of interest as a new process. A series of experiments were conducted to demonstrate the feasibility of ionized gas as a useful element for the diminution of nondegradable organic matters. On the other hand, a large amount of organic matters were changed to hydrophilic and the compounds containing aromatic functional group gradually decreased. The results implied that the ionized gas has been able to degrade the non-biodegradable organic matters. Therefore, the oxidation process by using an ionized gas process could be considered as an effective alternative unit in water and wastewater treatment plants.

Molecular analysis of ammonia-oxidizing bacterial populations in aerated-anoxic Orbal processes

2002 ◽  
Vol 46 (1-2) ◽  
pp. 273-280 ◽  
Author(s):  
H.-D. Park ◽  
J.M. Regan ◽  
D.R. Noguera
Keyword(s):  
Fragment Length Polymorphism ◽  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
Phylogenetic Analyses ◽  
Amoa Gene ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonia Monooxygenase ◽  
Anoxic Zone ◽  
Bacterial Populations ◽  
Nitrosomonas Oligotropha

Aerated-anoxic processes operate under the principle that small additions of oxygen to an anoxic reactor induce simultaneous nitrification and denitrification. In these systems, ammonia oxidation in the anoxic zone can easily account for 30–50% of the total nitrification in the reactor, even though the dissolved oxygen concentration is usually below detection limit. To investigate whether the nitrification efficiency in aerated-anoxic processes was due to the presence of specialized ammonia-oxidizing bacteria (AOB), an analysis of the AOB population in an aerated-anoxic Orbal process and a conventional nitrogen removal process was carried out using phylogenetic analyses based on the ammonia monooxygenase A (amoA) gene. Terminal restriction fragment length polymorphism (TRFLP) analyses revealed that Nitrosospira-like organisms were one of the major contributors to ammonia oxidation in a full-scale aerated-anoxic Orbal reactor. However, the relative populations of Nitrosospira-like and Nitrosomonas-like AOB were not constant and appeared to have seasonal variability. Cloning and sequence comparison of amoA gene fragments demonstrated that most of the AOB in the aerated-anoxic Orbal process belonged to the Nitrosospira sp. and Nitrosomonas oligotropha lineages. The abundance of Nitrosospira-like organisms in aerated-anoxic reactors is significant, since this group of AOB has not been usually associated with nitrification in wastewater treatment plants.

scholarly journals Amoxicillin in Water: Insights into Relative Reactivity, Byproduct Formation, and Toxicological Interactions during Chlorination

2021 ◽  
Vol 11 (3) ◽  
pp. 1076
Author(s):  
Antonietta Siciliano ◽  
Marco Guida ◽  
Giovanni Libralato ◽  
Lorenzo Saviano ◽  
Giovanni Luongo ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Parent Compound ◽  
Treatment Plant ◽  
Parent Drug ◽  
Degradation Pathway ◽  
Hplc Method ◽  
Consistent Finding ◽  
Byproduct Formation

In recent years, many studies have highlighted the consistent finding of amoxicillin in waters destined for wastewater treatment plants, in addition to superficial waters of rivers and lakes in both Europe and North America. In this paper, the amoxicillin degradation pathway was investigated by simulating the chlorination process normally used in a wastewater treatment plant to reduce similar emerging pollutants at three different pH values. The structures of 16 isolated degradation byproducts (DPs), one of which was isolated for the first time, were separated on a C-18 column via a gradient HPLC method. Combining mass spectrometry and nuclear magnetic resonance, we then compared commercial standards and justified a proposed formation mechanism beginning from the parent drug. Microbial growth inhibition bioassays with Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus were performed to determine the potential loss of antibacterial activity in isolated degradation byproducts. An increase of antibacterial activity in the DPs was observed compared to the parent compound.

scholarly journals Agreement between Theory and Measurement in Quantification of Ammonia-Oxidizing Bacteria

2005 ◽  
Vol 71 (10) ◽  
pp. 6325-6334 ◽  
Author(s):  
Gulnur Coskuner ◽  
Stuart J. Ballinger ◽  
Russell J. Davenport ◽  
Rheanne L. Pickering ◽  
Rosario Solera ◽  
...  
Keyword(s):  
Ammonia Oxidation ◽  
Wastewater Treatment Plants ◽  
Process Variable ◽  
Confocal Scanning Laser Microscopy ◽  
Ammonia Oxidizing Bacteria ◽  
Cell Numbers ◽  
Oxidation Rates ◽  
Cell Counts ◽  
Confocal Scanning Laser ◽  
Log Normal

ABSTRACT Autotrophic ammonia-oxidizing bacteria (AOB) are of vital importance to wastewater treatment plants (WWTP), as well as being an intriguing group of microorganisms in their own right. To date, corroboration of quantitative measurements of AOB by fluorescence in situ hybridization (FISH) has relied on assessment of the ammonia oxidation rate per cell, relative to published values for cultured AOB. Validation of cell counts on the basis of substrate transformation rates is problematic, however, because published cell-specific ammonia oxidation rates vary by over two orders of magnitude. We present a method that uses FISH in conjunction with confocal scanning laser microscopy to quantify AOB in WWTP, where AOB are typically observed as microcolonies. The method is comparatively simple, requiring neither detailed cell counts or image analysis, and yet it can give estimates of either cell numbers or biomass. Microcolony volume and diameter were found to have a log-normal distribution. We were able to show that virtually all (>96%) of the AOB biomass occurred as microcolonies. Counts of microcolony abundance and measurement of their diameter coupled with a calibration of microcolony dimensions against cell numbers or AOB biomass were used to determine AOB cell numbers and biomass in WWTP. Cell-specific ammonia oxidation rates varied between plants by over three orders of magnitude, suggesting that cell-specific ammonia oxidation is an important process variable. Moreover, when measured AOB biomass was compared with process-based estimates of AOB biomass, the two values were in agreement.

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