Conversion Of Organic Nitrogen Research Articles

Characterization and genome sequence of N,N-dimethylformamide degradation in Paracoccus sulfuroxidans DM175A1-1 isolated from activated sludge of wastewater.

N,N-dimethylformamide (DMF) is an organic solvent with stable chemical properties and high boiling point. Based on its good solubility, DMF is widely used in synthetic textile, leather, electronics, pharmaceutical and pesticide industries. However, the DMF pollutes the environment and does harm to human liver function, kidney function, and nerve function. Herein, an efficient DMF-degrading strain, DM175A1-1, was isolated and identified as Paracoccus sulfuroxidans. This strain can use DMF as the sole source of carbon and nitrogen. Whole-genome sequencing of strain DM175A1-1 revealed that it has a 3.99-Mbp chromosome a 120-kbp plasmid1 and a 40-kbp plasmid2. The chromosome specifically harbors the dmfA1 and dmfA2 essential for the initial steps of DMF degradation. And it also carries the some part of genes facilitating subsequent methylotrophic metabolism and glutathione-dependent pathway. Through further DMF tolerance degradation experiments, DM175A1-1 can tolerate DMF concentrations up to 10,000 mg/L, whereas the majority of Paracoccus strains could only show degradation activity below 1,000 mg/L. And the efficiency of organic nitrogen conversion to NH3-N in DMF can reach 99.0% when the hydraulic retention time (HRT) is controlled at 5 days. Meanwhile, it showed a significant degradation effect at a pharmaceutical enterprise in Zhejiang Province with high concentration of DMF wastewater. This study provides a new strain Paracoccus sulfuroxidans DM175A1-1 which shows a significant influence on DMF degradation, and reveals the characterization on its DMF degradation. It lays the foundation for the application of biological method in the efficient degradation of DMF in industrial wastewater.

Transformation of organic to inorganic nitrogen in NH4+-illite-bearing and Ga-Al-REE-rich bituminous coals: Evidence from nitrogen isotopes and functionalities

Nitrogen is one of the most important elements and mainly occurs as organic forms in coal, and in a few cases, in an inorganic form. Organic nitrogen in coal is mainly derived from the proteins of plants and micro-organisms but sources of inorganic nitrogen remain controversial. One hypothesis for the source of inorganic nitrogen is the organic matter of coal, but this lacks strong evidence. In the Daqingshan Coalfield of Inner Mongolia, northern China, an igneous intrusion in the east of the coalfield led to a coal rank increase from the Hailiushu through the Datanhao mines to the Adaohai mine from the west to east, with NH4+-illite being detected in the coals from the Datanhao and Adaohai mines. These coals are highly enriched in Ga, Al, and rare earth elements (REE). This study aims to explore the transformation of organic to inorganic nitrogen in these coals by means of nitrogen isotopes, element distribution in NH4+-illite, and nitrogen functional groups.The analysis of NH4+-illite by Electron Probe Microanalysis (EPMA) indicates partial substitution of nitrogen during the transition from kaolinite to NH4+-illite. Thermal metamorphism has resulted in the organic nitrogen isotope (δ15No) values in coals from the Adaohai Mine being more positive than those in the Datanhao and Hailiushu mines. 15N is more enriched in NH4+-illite than in the associated organic matter. The distribution of nitrogen functional forms showed a decrease in pyrrolic nitrogen (N-5) and an increase in pyridinic nitrogen (N-6) from coals in the Hailiushu to Datanhao and Adaohai mines. Ammonium quaternary nitrogen (N-Q) was detected in the NH4+-illite-bearing samples. This study provides significant evidence for the conversion of organic nitrogen to inorganic nitrogen in coals as a result of thermal metamorphism.

Application of immobilized biological fillers for the hydrolytic acidification and denitrification of sulfide-containing tannery wastewater

This study investigated the application of immobilized biological fillers in the hydrolytic acidification (HA) and denitrification (DN) of actual sulfide-containing tannery wastewater (TWW) through pilot-scale systematic experiments, which provided technical insights for the engineering application of immobilized bio-filler in practical TWW treatment. HA fillers and DN fillers could effectively realize the enrichment and maintenance of functional flora even under long-term inhibition of high sulfide concentration. The HA fillers demonstrated efficient conversion of organic nitrogen. At a hydraulic retention time (HRT) in the range of 3–6 h, the HA reactor achieved an average organic nitrogen conversion concentration of about 100 mg/L, accounting for 56.2 %-68.5 % of the total organic nitrogen in the TWW. Under this condition, the highest average organic nitrogen conversion and mean chemical oxygen demand (COD) degradation efficiencies were achieved, at 32.95 mgNH4+-N/(L·h) and 179.42 mgCOD/(L·h), respectively. Free ammonia (FA) may contribute to pH stabilization in the HA reactor. Denitrification fillers could utilize the endogenous organic matter in the actual TWW hydrolyzed acidified solution, and realize stable biological nitrogen removal effect with no additional carbon source. The denitrification rate reached 76.3 mg NO3--N/(L·h) and the ΔC/ΔN of the denitrification ranged from 3 to 4.

Root-associated bacteria strengthen their community stability against disturbance of antibiotics on structure and functions

Antibiotics affect bacterial community structure and functions in soil. However, the response and adaptation of root-associated bacterial communities to antibiotic stress remains poorly understood. Here, rhizobox experiments were conducted with maize (Zea mays L.) upon exposure to antibiotics ciprofloxacin or tetracycline. High-throughput sequencing analysis of bacterial community and quantitative PCR analysis of nitrogen cycling genes show that ciprofloxacin and tetracycline significantly shift bacterial community structure in bulk soil, whereas plant host may mitigate the disturbances of antibiotics on bacterial communities in root-associated niches (i.e., rhizosphere and rhizoplane) through the community stabilization. Deterministic assembly, microbial interaction, and keystone species (e.g., Rhizobium and Massilia) of root-associated bacterial communities benefit the community stability compared with those in bulk soil. Meanwhile, the rhizosphere increases antibiotic dissipation, potentially reducing the impacts of antibiotics on root-associated bacterial communities. Furthermore, rhizospheric effects deriving from root exudates alleviate the impacts of antibiotics on the nitrogen cycle (i.e., nitrification, organic nitrogen conversion and denitrification) as confirmed by functional gene quantification, which is largely attributed to the bacterial community stability in rhizosphere. The present study enhances the understanding on the response and adaptation of root-associated bacterial community to antibiotic pollution.

Reconceptualization of the mechanism of thermal hydrolysis pretreatment to enhance the anaerobic conversion of sludge organic nitrogen: Decisive role of organic nitrogen occurrence

The occurrence state of organic nitrogen (ON) is the key to affect anaerobic biotransformation of sludge. ON in sludge was chemically classified as PA (easily accessible part), PB (moderately accessible) and PC (hardly accessible) according to the modified CNCPS method. The components of them were analyzed by PY-GCMS, and it was identified that PA was extracellular amino acids, peptides and proteins; PB was genetic material, cell wall peptidoglycans and intracellular proteins; PC was ON that cross-linked with complex macromolecules. The conversion characteristics of PA, PB and PC in sludge and their relationship with anaerobic digestion (AD) performance were investigated after thermal hydrolysis pretreatment (THP) at different temperatures (100–180 °C). With the increase of THP temperature, the hydrolysis of PA and the conversion of PB to PA were promoted. At 180-THP, part of PA was converted to PC due to thermochemical reactions. In the fast degradation stage of AD of ON (ON-fast), PA is the main component of degradation; while in the slow degradation stage (ON-slow), the degradation of ON is mainly dominated by PB. Therefore, THP can significantly increase the proportion of ON-fast and reduce the ON fraction in the digestate (ON-hard). Moreover, PA and PB, rather than PC, were identified as dominant in ON-hard with or without THP for the first time, overturning the traditional view (remaining ON after AD was that cross-linked with complex macromolecules). This is due to that PA and PB are the main ON that make up microbial cells. The findings upgraded our perspective on conversion of ON of sludge during AD and inspire the shifted focus from “degrading PC” to “PC accumulation” for later use, through targeted enhanced PA degradation.

Assessment of nitrogen and phosphorus in the soil of longitudinal direction affected by in-situ oxidation remediation

ABSTRACT The application of in-situ chemical oxidative remediation for contaminated soils has attracted extensive attention, but the effects of remediation processes on soil physical and chemical properties are rarely studied. Herein, a ferrous-activated persulphate oxidation system for remediating dibutyl phthalate (DBP)-polluted soil was simulated in the soil column to explore the effects of in-situ oxidative remediation on soil properties in the longitudinal direction. The DBP content in the soil column was used as an indicator of oxidation strength and the correlation between N, P, soil particle size and oxidation strength was analysed. The experiment results showed that the settling performance of polluted soil after remediation improved and the distribution of the soil particle size at 128 nm disappeared after oxidation, indicating that the suspended solids in the experimental soil were mainly fine clay particles. The oxidation system can promote the conversion of organic nitrogen to inorganic nitrogen and migration characteristics of nitrogen and phosphorus, to aggravate the loss of TN and TP in the soil. The average soil particle size (d 50), TN, NH4-N, available phosphorus (Ava-P), exchangeable phosphorus (Ex-P) and organic phosphorus(Or-P) were significantly correlated with oxidation strength; and stable pH in the soil column (pH = 3), showing that the changes in the longitudinal direction of d 50 (smaller), TN, NH4-N, Ava-P, Ex-P, and Or-P resulted from the weakening of the longitudinal oxidation strength in the direction of the soil column.

Effective reinforcement ozone oxidation degradation of N,N-dimethylformamide with cobalt doping micro electrolysis composite

Here we report a novel cobalt doping iron carbon micro electrolysis composite Fe-Co-AC (FCA) that exhibits excellent catalytic performance for the remove of N,N-Dimethylformamide (DMF). The catalytic effects of FCA micro electrolysis (ME), only ozone oxidation (O3), and micro electrolysis synergetic ozonation (ME-O3) on the degradation of DMF were carried out. The results proved that the ME-O3 could obtain high •OH radical yield, showing eminent catalytic efficiency. This is attributed that Co doping optimizes the electron transport path in the material, improves the micro electrolysis synergetic catalytic ozonation performance. Additionally, the relative contribution of reactive oxygen species (ROS) and related reactions were qualitatively evaluated, and the reaction mechanism of ROS generation and pollutant removal was explored. According to the conversion of organic nitrogen and the detection of intermediate, the possible degradation paths of DMF were speculated. The column experiments showed that the ME-O3 process has a certain potential in practical application.

The effect of calcium superphosphate addition in different stages on the nitrogen fixation and ammonification during chicken manure composting

Nitrogen losses through ammonia (NH3) emission were an unavoidable issue during chicken manure composting. Calcium superphosphate can be added to effectively limit the emission of NH3. The results show that adding calcium superphosphate in the heating, high temperature and cooling stages reduces ammonia emission by 18.48 %, 28.19 % and 0.91 % respectively. Furthermore, adding calcium superphosphate at high temperature stage increased the ammonium nitrogen content (NH4+-N), reducing the conversion of organic nitrogen (HON) to NH4+-N. Network analysis indicated that adding calcium superphosphate during the high temperature stage reduced NH3-related microorganisms and effectively inhibited ammonification. Moreover, the results of qPCR of the ammonification gene gdh and structural equation model (SEM) verify that adding calcium superphosphate at the high temperature stage reduced ammonification and drove ammonification-related bacterial communities to decrease ammonia emissions. Adding superphosphate at high temperature can effectively increase the nitrogen content and reduce gas pollution during composting.

Combined application of microbes immobilized carbon reactor and the reactive struvite system for the management of tannery deliming wastewater.

This present study investigated the removal of COD and ammoniacal nitrogen (NH4+-N) from tannery deliming wastewater (TDLWW) through microbesimmobilized carbon consisted a bioreactor (MICCR) and reactive struvite crystallization process. Initially, 90% of the organic content of TDLWW was removed using a MICCR reactor at 24 h retention time. Nanoporous carbon (NPC) was used as the carrier matrix for the MICCR reactor. SEM and AFM images of NPC used in the MICCR reactor identify different microorganisms on its surface. The microbial profile of NPC used in the MICCR was analyzed, and the relative abundance is phyla Firmicutes, 25.64%; Proteobacteria, 43.68%; Bacteroidetes, 6.58%; Cyanobacteria, 2.22%; Actinobacteria, 2.34% reason for organic removal. The removal of organics follows the pseudo-second-order rate kinetics with the rate constant of 1.75×10-3L COD-1 h-1. For the reactive struvite crystallization, MgO and Na2HPO4.2H2O were taken as the precipitating agents. The optimum molar ratio for the maximum conversion of NH4+-N into struvite was obtained as 1:1.4:1.4 (NH4+-N:MgO:Na2HPO4.2H2O). The volume of struvite precipitate was 48.5mL/L of TDLWW, and the dry weight was 8.89 g/L. More than 93% of NH4+-N was converted as the struvite fertilizer. The conversion of NH4+-N into struvite follows the pseudo-first-order rate kinetics with the rate constant of 1.67×10-2 min-1. Despite the conversion of NH4+-N into struvite, COD removal was observed, which confirms the conversion of organic nitrogen into struvite. The struvite was evaluated using SEM, XRD, TGA, DSC, and FT-IR spectroscopic analysis. Hence, the integrated MICCR and the reactive struvite crystallization process can be applied to manage tannery deliming wastewater.

Transformation characteristics of nitrogen, sulfur and chlorine during microwave-assisted hydrothermal treatment of excavated waste

The removal effect of nitrogen, sulfur and chlorine from the excavated waste utilizing the microwave-assisted hydrothermal method was investigated in this work. Speciation changes of nitrogen, sulfur and chlorine in hydrochars with different treatment times were determined by X-ray photoelectron spectroscopy analysis. Results showed that 90% chlorine, 65% nitrogen and 63% sulfur were removed from the excavated waste after treatment at 230 °C for 100 min, while 82% energy and 85% carbon element were recovered at the same time. The conversion of organic nitrogen, sulfur and chlorine into the corresponding water-soluble inorganic forms was enhanced by the combined microwave irradiation and hydrothermal reaction, which promoted the migration of Cl, S, N into the liquid phase. However, some original and generated species of nitrogen, sulfur and chlorine remained in the hydrochars due to the polymerization of organic forms and the adsorption of inorganic forms. These findings suggested that the efficient purification of nitrogen, sulfur and chlorine in excavated waste could be obtained using the microwave-assisted hydrothermal treatment without additives, which provided a reference for the recycling and cleaning utilization of excavated waste.

Characteristics and mechanisms of nitrogen transformation during chicken manure gasification in supercritical water

Supercritical water gasification (SCWG) is a clean and efficient method for the energy utilization of biomass waste. Studying the behavior of nitrogen in feedstock during the SCWG process is essential because of its significant potential impact on the environment. In this study, the characteristics and mechanisms of nitrogen transformation during chicken manure gasification in supercritical water were investigated in autoclave reactors. The results revealed that temperature plays an important role in raw material conversion and product distribution, especially for nitrogenous components. In particular, the carbon gasification efficiency was 92.66 % at 700 °C, 10 wt%, and K2CO3 as catalysts, implying that the chicken manure was nearly completely converted. NOx was not identified in the gaseous products. As the temperature increased, nitrogen in the raw material was mainly transferred to the liquid. This process is accompanied by the conversion of organic nitrogen to inorganic nitrogen, which is mainly present as NH3-N in liquids. Finally, the migration pathways of nitrogenous intermediates were investigated. The hydrolysis of proteins and amino acids in the initial phases creates conditions for the Maillard reaction, forming nitrogenous heterocyclic compounds (NHCs). Most NHCs gradually ring-opened and eventually converted to CO2, H2, NH3, and other gases. Only a small number of NHCs undergo a series of polymerization reactions at lower temperatures to form nitrogenous carbon precursors that are challenging to gasify. This study provides a theoretical foundation for the targeted removal of nitrogen components during the SCWG of high-nitrogenous biomass.

Microwave irradiated ammonia nitrogen removal from anaerobically digested liquid dairy manure: A response surface methodology and artificial neural network-based optimization and modeling

Anaerobic digestion (AD) is a commonly adopted technology to treat liquid dairy manure. However, an increase in ammonia nitrogen (NH3-N) concentrations in anaerobically digested liquid dairy manure (DLDM) has been observed due to the conversion of organic nitrogen to NH3-N during AD. The removal and recovery of NH3-N from DLDM has therefore gained increased attention among researchers to ensure environmental sustainability along with making better uses of manure N fertilizer values. In this study, 150 mL of DLDM was treated under different operating conditions using a modified domestic microwave and the key operational parameters viz. pH, irradiation time (min), and microwave power output (W) were optimized and modeled via response surface methodology (RSM) and RSM-artificial neural network (ANN). The role of operational parameters on the performance of the treatment process was first evaluated using RSM. Afterward, the RSM was combined with ANN to predict the NH3-N removal from DLDM. Although all the operational parameters at a linear level along with the interactive effect of irradiation time, microwave power output, and pH at a quadratic level significantly influenced NH3-N removal from the waste stream (p < 0.001). The results also revealed that pH acted as the primary factor affecting NH3-N removal during the microwave irradiated treatment process. Under the optimal conditions (pH: 10.8, irradiation time: 4.1 min, and microwave power output: 625 W), the NH3-N removal efficiency of 86.71 ± 1.85% was observed and found to be in line with the computational values from both the RSM and RSM-ANN models, while the recovery efficiency was found to be 77.98 ± 3.71%. Furthermore, a statistical comparison between the models demonstrated the RSM-ANN model has a greater prediction capability than the RSM model. The high NH3-N removal efficiency obtained under the optimal conditions indicates the effectiveness of the process and will further encourage the application of microwave irradiation to treat DLDM in pilot and full-scale processes.

Quantum chemistry simulation and kinetic analysis of organic nitrogen transfer during oil shale pyrolysis

The nitrogen in oil shale would cause the generation of heteroatomic compounds during the pyrolysis, causing fuel instability, viscosity increase, glue formation and discoloration. To explore the formation mechanism of the nitrogenous substances, the relevant reaction paths and the corresponding kinetic analysis during the pyrolysis were constructed and conducted in this paper. Through quantum chemical transition state theory combing with density functional theory, the energy of reactants, transition states and intermediates involving in the reaction was obtained. Moreover, the energy distribution diagrams were also constructed to further clarify the formation mechanism of typical organic nitrogen product. In the exist of some functional groups like hydroxy, the N-containing rings such as pyrrole and pyridine are more easily to be opened, generating NH3 and NO. Five kinds of pathways constructed by this paper were chosen as the representational paths for revealing the micro theoretical mechanism of organic nitrogen conversion in oil shale. The results could provide reliable theoretical basis for investigating the conversion mechanism of nitrogen in oil shale pyrolysis and further reducing the NOx emission in the future.

Hydrodynamic zones and the influence of microorganisms on nitrogen transformation in the diverging area of branched rivers

Diverging area is widespread in river networks, and understanding its biogeochemical process characteristics is of great significance to river ecological restoration and environmental quality improvement. Microbial communities affected by hydrodynamics play an important role in biogeochemical processes, but their relationship in diverging area is little known. Here, the composition of microbial community and its feedback to hydrodynamics and nitrogen conversion in the diverging area of river networks were first studied by coupling ecological theory, biogeochemical theory, microbial DNA sequencing and mathematical model of water environment. The results showed that there were five hydrodynamic zones with significant velocity differences in the diverging area, namely low velocity zone, maximum velocity zone, stagnant zone, separation zone, and deflection zone. According to the flow velocity grouping, there were significant differences in the microbial diversity and abundance among low velocity group, maximum velocity group and stagnant group had significant differences (p < 0.05, stress = 0.1207). In the low velocity group, Firmicutes was the dominant phylum which had a highest abundance and may promot the conversion of organic nitrogen into ammonia nitrogen. In the maximum velocity group, Bdellovibrionota was the dominant phylum which had a highest abundance and may promot the conversion of nitrate and nitric oxide to nitrogen. In the stagnant zone, Methylomirabilota was the dominant phylum which had a highest abundance and may promot the conversion of nitrogen into nitrate and ammonium. In addition, dissolved oxygen was the most sensitive environmental factor for shaping microorganisms and nitrogen conversion in the diverging area of the river networks by canonical correlation analysis. The denitrifying bacteria Rhodocyclaceae, was shown to negatively correlated with the flow velocity. This research improves the scientific basis for the study of the ecosystem in river networks, which will guide the construction of river ecological projects.

Improvement of fish production and water quality in a recirculating aquaculture pond enhanced with bacteria-microalgae association

Intensive aquaculture plays an essential role in meeting human beings' growing demand for aquatic products. Recirculating pond has been considered as an effective approach for water and energy saving, but its wastewater also causes severely impair to aquatic animal health in some extent due to residual noxious nitrogen compounds (such as ammonia and nitrite) which are derived from mineralisation and break-up of uneaten feed and fish faeces. In order to purify water efficiently, biological processes are combined with recirculating pond such as using biological filtration, adding probiotics and so on. In this study, a field experiment was conducted to evaluate the potential of a closed recirculating aquaculture pond enhanced with bacteria-microalgae association in improving fish production and water quality. The results showed that the concentrations of total nitrogen (TN), total ammonia-N (TAN) and nitrite-N in the group of bacteria-microalgae with biofilm carriers were reduced by 29.15%, 51.28% and 33.48%, respectively, compared with treatment without any bioaugmentation. Meanwhile, the fish production was significantly improved (13.3%). Microbial community analysis (qPCR and high-throughput sequencing of 16 s and 18 s rRNA genes) suggested that the application of bacteria-microalgae with biofilm carries reduced the abundance of chiA gene (83.19%) which convert organic nitrogen into ammonia-N and increased the abundance of ammonia-monooxygenase (amoA) gene carried by ammonia-oxidizing bacteria (330.75%) and copper-containing nitrite reductase (nirK) gene (464.44%), indicating that the conversion of organic nitrogen to inorganic nitrogen was reduced and the denitrification process was increased. At the initial period, most of nitrogenous compounds were assimilated by microalgae. Along with the experiment, the bacteria community relative to nitrification and denitrification was also increased in bacteria-microalgae with biofilm carriers group compared with CK, such as Delftia (500%) and Acidovorax (450%) in ammoxidation process.

Degradation difference of fluoroquinolones by vacuum ultraviolet (VUV) and VUV/Fe2+ processes: Performance, mechanism, and influencing factors

Vacuum UV (VUV) has attracted much attention because it effectively splits water to produce hydrogen peroxide (H2O2) and reactive oxygen species (ROS) in situ. So far, the formation and consumption pathways of H2O2 and its role in the generation of ROS in VUV and VUV/Fe2+ processes are not clear. Herein, added Fe2+ utilized in-situ generated H2O2 by VUV irradiation to accelerate the degradation and mineralization of three fluoroquinolones. The H2O2 and hydroxyl radical (HO•) generated in situ under VUV irradiation were in a dynamic equilibrium state of mutual transformation, and H2O2 played an important role in VUV and VUV/Fe2+ processes. The fluorescent molecular probe experiments proved that both HO• and hydroperoxyl radical (HO2•) existed in VUV and VUV/Fe2+ processes. Radical quenching experiments confirmed that HO• and HO2• were the main ROS, and their contributions to norfloxacin (NOR) degradation were also quantified. Besides, organic and inorganic intermediate by-products of NOR degradation by VUV and VUV/Fe2+ were detected, and degradation pathways of NOR were also proposed. Added Fe2+ accelerated defluorination effect and the conversion of organic nitrogen to inorganic nitrogen during NOR degradation under VUV irradiation. Effects of initial pH, dissolved oxygen, dissolved organic matter and coexisting ions on VUV and VUV/Fe2+ were also compared. Moreover, energy consumption values of VUV/Fe2+ were always lower than that of VUV, and the average energy-saving rate of VUV/Fe2+ was 37.12%. Based on the satisfactory results achieved by VUV and VUV/Fe2+ in real waters, application strategies for VUV and VUV/Fe2+ were also proposed.

Efficient conversion of organic nitrogenous wastewater to nitrate solution driven by comammox Nitrospira

A bacterium capable of complete ammonia oxidation (comammox) has been widely found in various environments, whereas its industrial application is limited due to the difficulty of cultivation and/or enrichment. We developed a biological system to produce a high-quality nitrate solution for use in hydroponic fertilizer. The system was composed of two separate reactors for ammonification and nitrification and was found to have a stable and efficient performance in the conversion of organic nitrogen to nitrate. To determine the key microbes involved and better understand the system, the microbial communities in the reactors were analyzed by 16S rRNA gene sequencing in combination with a shotgun metagenomic analysis. Canonical ammonia-oxidizing bacteria, which can only catalyze the oxidation of ammonia to nitrite, were detected with negligible relative abundances, while a comammox Nitrospira-related operational taxonomic unit (OTU) dominated the nitrification reactor. Furthermore, the comammox-type ammonia monooxygenase was found to be 500 times more highly expressed than the canonical one by quantitative PCR, indicating that comammox was the main driver of the stable and efficient ammonia oxidation in the system. A microbial co-occurrence analysis revealed a strong positive correlation between Nitrospira and several OTUs, some of which, such as Anaerolinea OTU, have been found to co-exist with comammox Nitrospira in the biofilms of water treatment systems. Given that these OTUs were abundant only on microbe-attached carriers in the system, their co-existence within the biofilm could be beneficial to stabilize the Nitrospira abundance, possibly by physically preventing oxygen exposure as well as cell spillage.

Photocatalytic Transformations of 1H-Benzotriazole and Benzotriazole Derivates.

Benzotriazoles are a new class of organic emerging pollutants ubiquitously found in the environment. The increase of their concentration to detectable values is the consequence of the inability of the Conventional Waste Water Plants (CWWPs) to abate these products. We subjected 1H-benzotriazole (BTz), tolyltriazole (TTz), and Tinuvin P (TP, a common UV plastic stabilizer) to photocatalytic degradation under UV-irradiated TiO2 in different conditions. The principal photoformed intermediates, the relationship between the degradation rate and the pH, the degree of mineralization, and the fate of the organic nitrogen were investigated. Under the adopted experimental conditions, all the studied substrates were rapidly photocatalytically transformed (the maximum degradation rates for BTz and TTz were (3.88 ± 0.05) × 10−2 and (2.11 ± 0.09) × 10−2 mM min−1, respectively) and mineralized (the mineralization rate for BTz and TTz was 4.0 × 10−3 mM C min−1 for both substrates). Different from the 1,2,4-triazole rings that are not completely mineralized under photocatalytic conditions, 1H-benzotriazole and tolyltriazole were completely mineralized with a mechanism that involved a partial conversion of organic nitrogen to N2. The photocatalytic process activated by UV-irradiated TiO2 is an efficient tool to abate 1H-benzotriazole and its derivatives, avoiding their release in the environment.

Effects of Wood Ash-Based Alkaline Treatment on Nitrogen, Carbon, and Phosphorus Availability in Food Waste and Agro-Industrial Waste Digestates

Handling of food waste and agro-industrial waste digestates, and fly and bottom wood ashes represents an economic and environmental problem for society and industries where they are produced due to the requirement of large capacity storage facilities with special conditions. Since both materials contain important nutrients for crops, two different blending combinations were examined as potential slow-release fertilizers to enhance the circular economy. High share of biomass ashes were selected aiming the chemical alkaline stabilization of the digestates. The concentrations of nitrogen, carbon, and phosphorus in the water-soluble extract of the blends, which was obtained by adding ten parts of milli-Q® per each part of sample and subsequent solid–liquid separation, were measured during a 10-h incubation at 22 °C and 100 rpm. The volatilization of ammonia was the main route of losing nitrogen, with the greatest rate of volatilization at the time of blending and approximately 50 mg NH3-N/kg blend/hour by the end of the incubation. The hydrolysis taking place at alkaline pH was found responsible of the conversion of organic nitrogen to ammoniacal nitrogen and of the increase of the amount of water-soluble carbon, which rose progressively during the incubation. The release of CO2 was prevented by the high pH (> 10) of the blends. The drop in the concentration of water-soluble orthophosphate at the time of preparing the mixtures was driven by adsorption onto the ashes. The desorption of some of the orthophosphate was found to be inversely related to the amount of ashes added to the digestates.Graphic

Determination of nitrogen mineralization in an open dumpsite soil treated with poultry manure in Anyigba, Nigeria.

Nitrogen mineralization is the process of conversion of organic nitrogen to a useful form for plant use. A pot experiment was conducted at Soil and Environmental Management Department of Kogi State University Anyigba to determine nitrogen's mineralization rate in an open dumpsite soil treated with organic manure. About 1.6kg of soil sample was collected from Fallow land where no fertilizer history has been recorded and at three different dumpsite soil (Ate-Iji dumpsite (DS1), Ijebu-Ode dumpsite (DS2) and Iyale road dumpsite (DS3) ) in Anyigba at a depth of 0-15cm and was put inside a pot, which was replicated three times. The spacing between pots was 8m×5m range in completely randomized design (CRD). The soil's physicochemical properties were determined, 20g of poultry manure was added to each pot at a constant rate excluding the control pots (fallow land soil). The soil was stirred, and water was added at regular interval. The mineralization rate of nitrogen was determined after 14days, 28days and 56 days of treatment application. Nitrate (NO3-N), ammonium (NH4+–N) and nitrite (NO2-N) was calculated from total nitrogen. The data was analyzed, and treatments mean separated using Least Significant Difference (LSD). Poultry manure had a significant influence on the mineralization rate of nitrogen. DS3 soil gave the highest mineralization values for all the nitrogen forms. Highest values of 184.5mg/kg of NH4+ was recorded after 14days of mineralization in DS3 soil, while the highest value of 470.8mg/kg of NO2 -was recorded after 14days of mineralization in DS3 soil and the highest value of 634.5mg/kg of NO3- was recorded after 14days of mineralization compared to other dumpsite soil. The fallow land which serves as control gave the lowest mineralization values for all the nitrogen forms, and this indicated that organic manure has a greater impact in nitrogen mineralization in soil when applied to the soil within 28 days