Photocatalytic Degradation of 4,4'-Isopropylidenebis(2,6-dibromophenol) on Magnetite Catalysts vs. Ozonolysis Method: Process Efficiency and Toxicity Assessment of Disinfection By-Products

Flame retardants have attracted growing environmental concern. Recently, an increasing number of studies have been conducted worldwide to investigate flame-retardant sources, environmental distribution, living organisms’ exposure, and toxicity. The presented studies include the degradation of 4,4′-isopropylidenebis(2,6-dibromophenol) (TBBPA) by ozonolysis and photocatalysis. In the photocatalytic process, nano- and micro-magnetite (n-Fe₃O₄ and μ-Fe₃O₄) are used as a catalyst. Monitoring of TBBPA decay in the photocatalysis and ozonolysis showed photocatalysis to be more effective. Significant removal of TBBPA was achieved within 10 min in photocatalysis (ca. 90%), while for ozonation, a comparable effect was observed within 70 min. To determine the best method of TBBPA degradation concentration on COD and TOC, the removals were examined. The highest oxidation state was obtained for photocatalysis on μ-Fe₃O₄, whereas for n-Fe₃O₄ and ozonolysis, the COD/TOC ratio was lower. Acute toxicity results show noticeable differences in the toxicity of TBBPA and its degradation products to Artemia franciscana and Thamnocephalus platyurus. The EC₅₀ values indicate that TBBPA degradation products were toxic to harmful, whereas the TBPPA and post-reaction mixtures were toxic to the invertebrate species tested. The best efficiency in the removal and degradation of TBBPA was in the photocatalysis process on μ-Fe₃O₄ (reaction system 1). The examined crustaceans can be used as a sensitive test for acute toxicity evaluation.

Microbial community composition and glyphosate degraders of two soils under the influence of temperature, total organic carbon and pH

Glyphosate can be degraded by soil microorganisms rapidly and is impacted by temperature and soil properties. Enhanced temperature and total organic carbon (TOC) as well as reduced pH increased the rate of 13C315N-glyphosate conversion to CO2 and biogenic non-extractable residues (bioNERs) in a Haplic Chernozem (Muskus et al., 2019) and in a Humic Cambisol (Muskus et al., 2020). To date; however, the combined effect of temperature and TOC or pH on microbial community composition and glyphosate degraders in these two soils has not been investigated. Phospholipid fatty acid [PLFA] biomarker analysis combined with 13C labeling was employed to investigate the effect of two soil properties (pH, TOC) and of three temperatures (10 °C, 20 °C, 30 °C) on soil microorganisms. Before incubation, the properties of a Haplic Chernozem and a Humic Cambisol were adjusted to obtain five treatments: (a) Control (Haplic Chernozem: 2.1% TOC and pH 6.6; Humic Cambisol: 3% TOC and pH 7.0), (b) 3% TOC (Haplic Chernozem) or 4% TOC (Humic Cambisol), (c) 4% TOC (Haplic Chernozem) or 5% TOC (Humic Cambisol), (d) pH 6.0 (Haplic Chernozem) or pH 6.5 (Humic Cambisol), and (e) pH 5.5 for both soils. All treatments were amended with 50 mg kg-1 glyphosate and incubated at 10 °C, 20 °C or 30 °C. We observed an increase in respiration, microbial biomass and glyphosate mineralization with incubation temperature. Although respiration and microbial biomass in the Humic Cambisol was higher, the microorganisms in the Haplic Chernozem were more active in glyphosate degradation. Increased TOC shifted the microbiome and the 13C-glyphosate degraders towards Gram-positive bacteria in both soils. However, the abundance of 13C-PLFAs indicative for the starvation of Gram-negative bacteria increased with increasing TOC or decreasing pH at higher temperatures. Gram-negative bacteria thus may have been involved in earlier stages of glyphosate degradation.

Obsessive-compulsive symptoms in anxiety and depressive disorders: Influence of recent and/or traumatic life events

INTRODUCTION

A high prevalence of obsessive-compulsive symptoms (OCSs) in anxiety-depressive disorders ranging from 30 to 67% has been described.

OBJECTIVE

This study aims to assess the presence and persistence of OCSs in an outpatient sample of subjects with anxiety and depressive disorders, as well as its relationship with recent life events (RLEs) and/or traumatic experiences (TEs).

METHOD

We conducted a prospective, observational, analytical study of 200 subjects with DSM-5 diagnoses of anxiety and/or depression. Participants were included by consecutive sampling and were evaluated at baseline and after 6-12 months (mean 8.5 months) of follow-up. The severity of the symptoms was assessed through the Hamilton Anxiety Scale (HARS) and Hamilton Scale for the evaluation of depression (HRSD-17), and comorbidity was assessed through the International Neuropsychiatric Interview (MINI). The Revised Inventory of Obsessions and Compulsions (OCI-R), the Recent Vital Changes Questionnaire (CVSV), and the Diagnostic Scale for Post-Traumatic Stress (PDS) were also administered.

RESULTS

54% of the sample presented OCSs, and 30.5% presented one or more TEs throughout life. At the baseline visit, the presence of OCSs was associated with the severity of depressive symptoms (p=0.028), the presence of TEs (p<0.01), symptoms of post-traumatic stress disorder (p<0.01) and the number of RLEs (p<0.01). Response rate at follow-up was 38%, and persistence of OCSs was found in 60.5% of patients, independent of depressive or anxious symptoms, but was associated with the number of RLEs (p<0.01).

CONCLUSION

The presence of OCSs in patients with anxiety and depressive disorders is frequent and persistent. Anxious-depressive patients with a history of TEs and RLEs had higher OCS levels. These findings highlight the importance of early detection and the use of therapeutic strategies focused on resilience to stress and trauma.

Dissolved organic carbon drives nutrient cycling via microbial community in paddy soil

Microbial mediated iron cycling drives the biogeochemical cycling of carbon, nitrogen, sulfur, and phosphorus. However, the fate of the microbial community and the relative metabolic pathways in paddy soil after the addition of biogas slurry are poorly understood. In this study, the response of functional genes was investigated by growing one-season rice in paddy soils in a pot experiment. Seven treatments were prepared: 1) control (CK); 2) organic carbon (OC); 3) fertilizer (F); 4) 5% of biogas slurry (B05); 5) 10% of biogas slurry (B10); 6) 15% of biogas slurry (B15); 7) 20% of biogas slurry (B20). In the biogas slurry treatments, Geobacter increased more than in the other treatments during rice growth, which were structured by TOC. Particularly, in the B10 treatment, the relative abundance of Geobacter was 1.6 and 14.8 times higher than that of CK at the heading and mature stages, respectively. At the heading stage, the addition of biogas slurry and OC shifted the microbial phosphorus-transformation communities differently. There were no significant differences in the carbon, nitrogen, and sulfur metabolic pathways between the two treatments. At the mature stage, the carbon: nitrogen: phosphorus balance was significantly influenced by the regulation of functional gene expression and metabolic activities. These findings provide insight into the key factors affecting carbon, nitrogen, sulfur, phosphorus, and iron during rice growth after carbon inputs.

Petroleum hydrocarbon pollution in sediments from the Gulf and Omani waters: Status and review

This review presents the spatio-temporal distribution of petroleum hydrocarbons including total petroleum hydrocarbon (TPH), total organic carbon (TOC), total aliphatics, unresolved complex mixture (UCM), polycyclic aromatic hydrocarbons (PAHs), and total aromatic hydrocarbons in marine sediments of the Gulf (Iraq, Iran, Kuwait, Saudi Arabia, Bahrain, Qatar, United Arab Emirates and Oman). The TPH ranged between 0.134 and 48,018 μg g^-1 dw where 10-15 μg g^-1 dw was considered as a background concentration. The TOC levels were between 0.04 and 14.96% with a mean concentration of 1.154 ± 0.523%. Total aliphatic hydrocarbon levels were reported between 0.1 and 76 μg g^-1, the 2005 levels that had the largest spatial coverage were between 0.1 and 4.4 μg g^-1. The unresolved complex mixture was very variable post Gulf War but by 2005 most of the Gulf War artifacts had decreased and the levels were between 1.5 and 73.5 μg g^-1. The ƩPAHs in bottom sediments by 2005 were between 0.3 and 3450 ng g^-1. The total aromatics were limited in spatial extent and varied between 1.0 and 14,000 μg g^-1. Most of the locations with elevated contamination levels were near point sources, e.g. oil facilities and ports, and these sites could be categorized as chronically contaminated by oil. This review highlights the paucity of the data both in terms of the spatial extent and temporal coverage, and with several Gulf states undergoing large-scale coastal developments and offshore oil exploration, it will be prudent to undertake regular monitoring of the petroleum hydrocarbons to ensure effective ecosystem functioning as well as seafood and drinking water safety in the Gulf region. The spatial distribution also highlights the lack of uniformity in assessments and the need to support marine pollution assessments in the Gulf countries.

New Insights into the Host-Pathogen Interaction of Mycoplasma gallisepticum and Avian Metapneumovirus in Tracheal Organ Cultures of Chicken

Respiratory pathogens are a health threat for poultry. Co-infections lead to the exacerbation of clinical symptoms and lesions. Mycoplasma gallisepticum (M. gallispeticum) and Avian Metapneumovirus (AMPV) are two avian respiratory pathogens that co-circulate worldwide. The knowledge about the host-pathogen interaction of M. gallispeticum and AMPV in the chicken respiratory tract is limited. We aimed to investigate how co-infections affect the pathogenesis of the respiratory disease and whether the order of invading pathogens leads to changes in host-pathogen interaction. We used chicken tracheal organ cultures (TOC) to investigate pathogen invasion and replication, lesion development, and selected innate immune responses, such as interferon (IFN) α, inducible nitric oxide synthase (iNOS) and IFNλ mRNA expression levels. We performed mono-inoculations (AMPV or M. gallispeticum) or dual-inoculations in two orders with a 24-h interval between the first and second pathogen. Dual-inoculations compared to mono-inoculations resulted in more severe host reactions. Pre-infection with AMPV followed by M. gallispeticum resulted in prolonged viral replication, more significant innate immune responses, and lesions (p < 0.05). AMPV as the secondary pathogen impaired the bacterial attachment process. Consequently, the M. gallispeticum replication was delayed, the innate immune response was less pronounced, and lesions appeared later. Our results suggest a competing process in co-infections and offer new insights in disease processes.

Distribution of black carbon and PAHs in sediments of Peninsular Malaysia

Concentrations, sources and interactions between black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were investigated in 42 sediment samples collected from riverine, coastal and shelf areas in Peninsular Malaysia. The concentrations of BC measured by benzene polycarboxylic acid (BPCA) method and PAHs showed broad spatial variations between the relatively pristine environment of the East coast and developed environment of the West and South coast ranging from 0.02 to 0.36% dw and 57.7 ng g^-1 dw to 19,300 ng g^-1 dw, respectively. Among diagnostic ratios of PAHs, the ratios of Ant/(Ant+Phe) and LMW/HMW drew the clearest distinctions between the East coast versus the West and South coast sediments indicating the predominance of petrogenic sources in the former versus pyrogenic sources in the latter. PAHs significantly correlated with BC and total organic carbon (TOC) in the sediments (p < 0.05) having similar correlation coefficients. BC accounted for 6.06 to 30.6% of TOC in sediments.

Multivariate Analysis of Sediment Toxicity in an Ocean Ecosystem: A Southern California Bight Case Study

Contaminated sediments can negatively affect aquatic organisms and beneficial uses of coastal regions. Monitoring programs typically collect many indicators of sediment toxicity, yet multivariate approaches that comprehensively evaluate data across heterogeneous spatial environments are frequently not performed. In this paper, we explore a multivariate approach to show that a list of suspected drivers of sediment toxicity to native Mytilus galloprovincialis (mussel) and Eohaustorius estuarius (a marine amphipod) population can be narrowed down without excluding samples, and that redundancies in sampling sites can be identified and isolated. Using a 153 × 28 data matrix assembled from a southern California-wide bight monitoring program, we demonstrate by this approach that Port of Los Angeles (PLA) and San Diego Bay (SDB) contained the most toxic sediments in the bight in 2008, the nature of which was unique to each locality. (Note: Little toxicity was observed here in 2013 and 2018.) In PLA sediments, mussels were more affected than amphipods, with higher survivability associated with low Hg and Sn levels. Conversely, amphipods had higher mortality than mussel embryos in SDB sediments, with higher survivability associated with low Be and Co levels. Nitrogen, organic content, and finer sediment particles were not related to the survivability of these organisms.

Increases in organic carbon and nitrogen concentrations in boreal forested catchments - Changes driven by climate and deposition

Brownification, caused by increasing dissolved organic carbon (DOC) concentrations is a threat to aquatic ecosystems over large areas in Europe. The increasing concentrations of DOC in northern boreal streams and lakes have attracted considerable attention with proposed important drivers such as climate, deposition and land-use, and complex interactions between them. Changes in total organic N (TON) concentrations have received less attention, even though carbon and nitrogen losses are highly related to each other. We used long-term (1990-2019) monitoring records of 12 small data-rich headwater forested catchments in a large gradient of climate and deposition. We found that total organic carbon (TOC) concentrations were significantly increasing in almost all study catchments. The mean air temperature and change in sulphate concentrations had a strong, significant correlation to TOC change-%. Both explained, alone, more than 65% of the change in TOC concentrations, and, together, up to 83% of the variation. Sulphur deposition has already decreased to low levels, our results indicate that its importance as a driver of TOC leaching has decreased but is still clearly detected, while the impact of climate warming as a driver of TOC leaching will be even more pronounced in the future. A positive correlation was found between drainage-% and increases in TON, suggesting also importance of land management. TON trends were tightly connected to changes in TOC, but not directly linked to decreasing S deposition.

ZnO nanoparticles for photodegradation of humic acid in water

Humic acid (HA) is the most important precursor of toxic disinfection byproducts upon chlorination. Removing HA from water body is therefore critical in drinking water acquisition. In this research, ZnO nanoparticles are employed for photocatalysis under UV light at neutral pH to remove HA from a water environment. Almost 100% degradation of HA was achieved using 0.3 g/L of ZnO in 180 min with UV-A and UV-C light. Under identical experimental conditions, total organic carbon (TOC) removals reach 67% and 21% with UV-A and UV-C light, respectively. A higher degree of mineralization of HA is achieved with UV-A light although the degradation of HA is slightly better with UV-C light. This indicates that ZnO/UV-A has relatively low selectivity to degrade different compounds, including various intermediates from HA degradation. The use of UV-A light is therefore recommended for ZnO as it possesses higher mineralization ability. Negligible TOC is observed on the ZnO surface after photocatalytic reactions. In contrast, the adsorption of HA in dark conditions reaches 42% in 180 min. This strongly indicates that the adsorption of HA plays an important role in the photocatalytic degradation of HA, but it is not the main process for HA removal.

Evaluating and improving the reliability of the UV-persulfate method for the determination of TOC/DOC in surface waters

The UV-persulfate oxidation method is widely used for determining the total organic carbon concentration of aqueous samples (denoted for convenience as UVP-TOC). However, for some surface water samples, the measurement of TOC by this method can be unreliable, deviating significantly from the true carbon content. In this study, the performance of the UVP-TOC method has been investigated by comparing the results from the analysis of a variety of aqueous samples that included two kinds of surface water samples and related surface water model substances: bovine serum albumin (BSA), sodium alginate (SA), humic acid (HA), tannic acid (TA), benzoic acid (BA) and citric acid (CA), with those from a high-temperature combustion method (elemental analysis); the latter providing the true carbon content value. By comparing the above data, it was found that the UVP-TOC method significantly underestimated the TOC value of the surface water samples, and it was also found that the model components BSA (protein) and HA (humic substances, HS) had a substantial influence on the TOC underestimation, while the SA (polysaccharide), TA (complex organic molecule) and CA/BA (small molecules) had little effect. The results showed that the agglomeration within and between BSA and HA molecules was an important reason for the inaccurate UVP-TOC values of BSA and HA. A further limitation was that for BSA, surfactants (e.g. sodium dodecylbenzene sulfonate, SDBS) and other surfactant-like substances, foam was formed during the CO₂ removal purging process by N₂ that seriously interfered with the determination of TOC. The study provides new information and insight into the causes of inaccuracies in the UVP-TOC analysis of surface waters and possible approaches to improve the accuracy.

Pollutants removals and energy consumption in electrochemical cell for pulping processes wastewater treatment: Artificial neural network, response surface methodology and kinetic studies

Response surface methodology (RSM) and artificial neural network (ANN) were used for modelling the electrocoagulation removal of pollutants from wastewater from pulping processes. The Design of Experiment based on central composite design was used to investigate the combine effects of pH (5.4-9.0), time (10-45 min) and current density (j) (9-39 mA/m²), on the removal efficiency of the Chemical Oxygen Demand (COD), Total Dissolve Solids (TDS) as well as Turbidity while Energy consumption (EC) was estimated per kg [COD] removed. The kinetics of the process was modelled with pseudo first and second order models. The removability of the COD, TDS and Turbidity were found to be 76.4, 57.0 and 97.13% with Energy consumption of 2.72 kWh/kg_[COD] at optimal pH 6.83, current density of 22.06 mA/m², and reaction time of 45 min. The ANN model gave a better fitting of the electrocoagulation process than the RSM, considering the R² of 0.999 and MSE of 0.00753 obtained for the former. The pseudo first order model gave a better analysis of the kinetic data. The characterization of the sludge produced showed the potential of its use as adsorbent for organic or mineral contaminants and recovery of aluminium and other metals. Thus, electrocoagulation with monopolar aluminium electrodes displayed effective and a viable alternative for the pollutants removal from pulp processing wastewater.

Degradation of simulated Direct Orange-S (DO-S) textile effluent using nonthermal atmospheric pressure plasma jet

One of the major environmental issues of textile industries is the discharge of large quantities of textile effluents, which are source of contamination of water bodies on surface of earth and quality of groundwater. The effluents are toxic, non-biodegradable, carcinogenic and prodigious threats to human and aquatic creatures. Since textile effluents can be treated efficiently and effectively by various advanced oxidation processes (AOPs). Among the various AOPs, cold atmospheric pressure plasma is a promising method among many prominent techniques available to treat the effluents. In this paper, we report about the degradation of simulated effluent, namely Direct Orange-S (DO-S) aqueous solution, using nonthermal atmospheric pressure plasma jet. The plasma treatment of DO-S aqueous solution was carried out as a function of various operating parameters such as potential and treatment time. The change in properties of treated DO-S dye was investigated by means of various analytical techniques such as high-performance liquid chromatography, UV-visible (UV-Vis) spectroscopy and determination of total organic content (TOC). The reactive species present in the samples were identified using optical emission spectrometry (OES). OES results confirmed that the formation of reactive oxygen and nitrogen species during the plasma treatment in the liquid surface was responsible for dye oxidation and degradation. Degradation efficiency, as monitored by color removal efficiency, of 96% could be achieved after 1 h of treatment. Concurrently, the TOC values were found to decrease with plasma treatment, implying that the plasma treatment process enhanced the non-toxicity nature of DO-S aqueous solution. Toxicity of the untreated and plasma-treated dye solution samples was studied using Escherichia coli (E. coli) and Staphylococcus (S. aureus) organisms, which demonstrated that the plasma-treated dye solution was non-toxic in nature compared with untreated one.

Optimization of the adsorption of total organic carbon from produced water using functionalized multi-walled carbon nanotubes

This study investigated the removal of Total Organic Carbon (TOC) from produced water by batch adsorption process using adsorbents developed from Multi-Walled Carbon Nanotubes (MWCNTs). The MWCNTs, synthesized by catalytic chemical vapour deposition method using kaolin-supported tri-metallic (iron-cobalt-nickel) catalyst were purified by H2SO4/HNO3 and then functionalized with 1-pyrenebutanoic acid N-hydroxyl succinimidyl ester (PSE). The raw, purified and functionalized MWCNTs were characterized by High Resolution Scanning Electron Microscopy (HRSEM), High Resolution Transmission Electron Microscopy (HRTEM), Brunauer-Emmett-Teller (BET) and Fourier Transform Infrared Spectroscopy (FTIR). In the results, HRSEM/HRTEM revealed the structure, purity and also confirmed the attachment of the PSE molecule onto the nano-adsorbent(s). The BET surface areas of MWCNTs, PMWCNTs and FMWCNTs were 970.17, 869.25 and 831.80 m2/g, respectively while the FTIR established the existence of surface functional groups. The functionalized MWCNTs (FMWCNTs) nano-adsorbent showed superior performance efficiency (93.6%) than the purified MWCNTs (PMWCNTs) (79.2%) as examined under the same batch adsorption condition: 0.02 g adsorbent dosage, 10-90 min contact time and 30 °C solution temperature probably, due the improved wettability resulted from incorporation of PSE. Subsequently, Central Composite Design (CCD) was applied to optimize the process parameters for the sorption of TOC onto FMWCNTs. The CCD in the response surface methodology predicted 260 mg/g adsorption capacity of FMWCNTs in the removal of TOC at the optimum condition of 49.70 min contact time, 34.81 °C solution temperature, and 0.02 g adsorbent dosage. The kinetics data were best described by pseudo-second-order model and thermodynamic parameters suggested that the process was feasible, spontaneous and exothermic. It can be inferred from the various analysis conducted that the developed FMWCNTs nano-adsorbent is effective for removal of TOC from oil-produced water and may be explored for removal of organic contaminants from other industrial wastewater.

Obsessive-compulsive symptoms in anxiety and depressive disorders: Influence of recent and/or traumatic life events

INTRODUCTION

A high prevalence of obsessive-compulsive symptoms (OCSs) in anxiety-depressive disorders ranging from 30 to 67% has been described.

OBJECTIVE

This study aims to assess the presence and persistence of OCSs in an outpatient sample of subjects with anxiety and depressive disorders, as well as its relationship with recent life events (RLEs) and/or traumatic experiences (TEs).

METHOD

We conducted a prospective, observational, analytical study of 200 subjects with DSM-5 diagnoses of anxiety and/or depression. Participants were included by consecutive sampling and were evaluated at baseline and after 6-12 months (mean 8.5 months) of follow-up. The severity of the symptoms was assessed through the Hamilton Anxiety Scale (HARS) and Hamilton Scale for the evaluation of depression (HRSD-17), and comorbidity was assessed through the International Neuropsychiatric Interview (MINI). The Revised Inventory of Obsessions and Compulsions (OCI-R), the Recent Vital Changes Questionnaire (CVSV), and the Diagnostic Scale for Post-Traumatic Stress (PDS) were also administered.

RESULTS

54% of the sample presented OCSs, and 30.5% presented one or more TEs throughout life. At the baseline visit, the presence of OCSs was associated with the severity of depressive symptoms (p=0.028), the presence of TEs (p<0.01), symptoms of post-traumatic stress disorder (p<0.01) and the number of RLEs (p<0.01). Response rate at follow-up was 38%, and persistence of OCSs was found in 60.5% of patients, independent of depressive or anxious symptoms, but was associated with the number of RLEs (p<0.01).

CONCLUSION

The presence of OCSs in patients with anxiety and depressive disorders is frequent and persistent. Anxious-depressive patients with a history of TEs and RLEs had higher OCS levels. These findings highlight the importance of early detection and the use of therapeutic strategies focused on resilience to stress and trauma.

Yield loss during bleaching of pulp of Pinus radiata previously delignified with oxygen

The pulp bleaching process removes or transforms the chromophore groups in the pulp, so that the final product reaches a desired brightness. However, this chemical treatment inevitably results in yield loss. Therefore, the objective of this work was to quantify the yield loss caused during the bleaching of kraft pulp of Pinus radiata delignified with oxygen. The material was submitted to three distinct ECF sequences (D₀(EPO)D₁D₂, D₀(EPO)D₁P, and Z/EDP). At the end of each bleaching stage, the pulp brightness and the loss of gravimetric yield of the process were determined, and the generated filtrates were collected. From these filtrates, the pollutant load of the effluent was determined by measuring the content of total dissolved solids, the chemical oxygen demand, the concentration of total organic carbon carbon, and the adsorbable organic halogens. Among the whole sequences, the Z/EDP sequence had the lowest gravimetric yield, the highest pollutant load in the collected filtrate, and lowest potential for adsorbable organic halogens generation. There was good correlation between the loss of yield from the bleaching process and the organic load of the generated effluent; and among the techniques studied, the quantification of total organic carbon was the most appropriate method for the indirect quantification of the yield loss during the bleaching process of the studied material.

Ten-years monitoring of MSWI bottom ashes with focus on TOC development and leaching behaviour

In Switzerland MSWI bottom ash has to comply with the legal threshold value for TOC of < 2 wt-% in order to be landfilled. However, TOC contents of this magnitude lead to elevated DOC emissions and associated emissions of ammonium and Cu (aq). Since 2008 the Canton of Zürich therefore pursues a strategy to lower TOC contents in bottom ash by 2020 to 0.5 wt-%. To observe the development of TOC and other constituents, bottom ash has been monitored from 2008 to 2018. Monitoring results indicate that TOC contents < 0.5 wt-% in bottom ash lead to DOC eluate concentrations < 20 mg/l. DOC concentrations of this magnitude are close to Swiss legal criteria for discharge of landfill leachate into surface waters (10 mg/l). The emission results have been obtained by batch eluate tests according to Swiss Waste Legislation. Such laboratory tests only partially simulate real conditions occurring on landfills. To approximate landfill conditions, column tests with recent bottom ashes combined with tests on simple emission forecasting complete the study. The comparison of results from batch and column tests shows similar cumulative concentrations, indicating that batch tests are suitable to evaluate bottom ash quality. The tested modelling approach, based on constant conditions and exponential decrease in concentration, proved adequate to simulate column progressions. The modelled emission forecasts for DOC lies within 33% of column test results. Further, the model demonstrates the differences in flow regime between eluate tests and landfills and promotes better understanding of temporal aspects and the influence of landfill relevant parameters on pollutant mobilisation.

Aquatic testing guidelines insufficiently control the influence of dilution water toc and hardness on cationic polymer toxicity - A proposal to improve standardized test procedures

Cationic polymers (CPs) are widely used chemicals for wastewater treatment applications and in various "down-the-drain" household products. The aquatic toxicity of CPs results from an electrostatic interaction with negatively charged cell surfaces. These effects are greatly mitigated by the binding affinity of CPs to total organic carbon (TOC) in surface water. Consequently, baseline aquatic toxicity tests of CPs using clean lab water (TOC < 2 mg/L) typically overestimate toxicity and risk which is greatly mitigated at higher environmentally relevant OC levels. However, the point at which mitigation begins is not well defined and low-level TOC in lab water may influence the baseline toxicity outcome. Similarly, divalent cations, quantified as water hardness, may modulate the electrostatic binding between OC and CP. Although standard guidelines define limits for lab water hardness and TOC, the consequences of variability within those limits on test outcome is unknown. We investigated the impact of part-per-billion (ppb) additions of TOC to lab water at different hardness levels on CP acute toxicity to Daphnia magna and Raphidocelis subcapitata. In both species, the acute toxicities of CPs with different molecular weight and charge density varied by > 10-fold in response to slight changes in TOC and water hardness, although parameters were maintained within guideline limits. When determining the baseline aquatic toxicity of CPs, the lab water should be standardized at the lowest biologically tolerable hardness and TOC at a reliably measurable level (>1 - < 2 mg/L) to reduce variability and increase the reliability of the toxicity estimate.

Performance and energetic analysis of hydrodynamic cavitation and potential integration with existing advanced oxidation processes: A case study for real life greywater treatment

The current work is a "first of a kind" report on the feasibility and efficacy of hydrodynamic cavitation integrated Advanced Oxidation Processes (AOP's) towards treatment of a real life greywater stream in form of kitchen wastewater. The work has been carried out in a sequential manner starting with geometry optimization of orifice plate (cavitating device) followed by studying the effects of inlet pressure, pH, effluent dilution ratio on degradation of TOC and COD. Under optimized conditions of pH 3, 4 bar pressure, TOC and COD reduction of 18.23 and 25% were obtained using HC for a period of 120 min. To improve the performance of HC, further studies were carried out by integrating H₂O₂and O₃with HC. Using 5 g/h optimum dosage of H₂O₂, 87.5% reduction in COD was obtained beyond which it started decreasing. Moreover, integrating O₃(57.5% reduction in COD) increased the treatment cost. However, a hybrid process (HC + H₂O₂ + O₃) yielded 76.26 and 98.25% reductions in TOC and COD within60 min.The energetics of all the processes and the treatment costs were studied in detail and it was concluded that combined process of HC + H₂O₂ + O₃surpassed by far the performances of HC + H₂O₂and HC + O₃.

Supercritical water oxidation of p-aminonaphthalenesulfonic acid and enhancement by Fenton agent

The introduction of Fe²⁺ into supercritical water oxidation (SCWO) and the formation of Fenton reagent with oxidant H₂O₂ form a new environment, namely, supercritical Fenton oxidation (SCFO) environment. p-Aminonaphthalenesulfonic acid was selected as the typical organic pollutant to explore the effects of temperature, oxidant multiple, reaction time and Fenton conditions on the TOC removal rate. SCFO showed the superiority in the degradation of organic matter compared with the SCWO. The oxidative degradation kinetics of p-aminonaphthalenesulfonic acid in SCFO environment was further explored. Under SCFO condition, the oxidative degradation of p-aminonaphthalene sulfonic acid was consistent with first-order reaction kinetics. The results showed that the activation energy E_a and pre exponential factor k ₀ were 39.937 kJ·mol^-1 and 1.94 × 10⁴ s^-1 respectively.

Study of organic pollution in superficial sediments of Meliane river catchment area: aliphatic and polycyclic aromatic hydrocarbons

Organic contaminants can be accumulated in aquatic systems even at trace concentrations with potential threats to the environment and human health. The present study has been performed to evaluate the effects of organochlorines and polyaromatic hydrocarbons on surface sediments of the Meliane river catchment. Their determination provides an essential scientific approach for a better understanding of the expected sources and the processes of bioaccumulation. The concentrations of saturated hydrocarbons in extractable organic matter of the dry sediment were found ranging from 0.58 to 3 83 μg kg^-1 and PAHs content ranged from 63 to 131 μg kg^-1. These results indicated the adherence of Oued Meliane to the pollution of the Tunis Gulf. The fraction of saturated hydrocarbons extracted from the sediments of Oued Meliane included a majority of organic compounds of biogenic nature with a small oil input. In addition, characterization with the TAR index and the LMW/HMW index confirmed that terrigenous inputs in this fraction are more abundant than aquatic inputs. The characterization of PAHs fraction has shown its pyrolitic origin with a predominance of high molecular weight PAHs.

Mercury accumulation in soil from atmospheric deposition in temperate steppe of Inner Mongolia, China

Mercury (Hg) is a toxic and persistent pollutant and has long-term impacts on ecological systems and human health. Coal-fired power plants (CFPPs) are the main source of anthropogenic Hg emission, and the emitted atmospheric Hg is deposited to the surrounding environments which causes soil pollution. To assess the effects of atmospheric Hg from CFPPs in China on the temperate steppe, Hg contents in the topsoil and subsoil were analyzed for samples collected from 80 sites in central Inner Mongolia during 2012-2015. The average content of Hg in topsoil and subsoil were 14.9 ± 10.4 μg kg^-1 and 8.9 ± 5.8 μg kg^-1, respectively. The principal components analysis (PCA) indicated that the soil organic matter content and atmospheric deposition were the main factors determining soil Hg content in Inner Mongolia. We used the power plant impact factor (PPIF) to evaluate the impacts of the surrounding CFPPs. The PPIF results showed the most positive correlation with Hg content in topsoil at more than 400 km distances, indicating that the contribution of the long-range transport of Hg emitted from CFPPs is regional in scale. Considering the potential of Hg accumulation in soil, long-term and regional measurements of soil Hg and stricter emission-limit standards for power plants should be implemented to control soil Hg pollution in China.

Spatial and Temporal Variations of Arsenic Distribution in a Tropical Estuary Along the West Coast of India

Arsenic (As) contamination was studied and reported for the first time in the sediments of the Cochin estuary. Surface sediment samples were collected from twenty-seven stations encompassing the entire estuary constituting south, central and north estuary. The total As concentration varied from 0.01 mg/kg to 9.28 mg/kg and undetected to 23.37 mg/kg during the pre and post-monsoon. The degree of contamination assessed in terms of geochemical indices such as contamination factor (CF), geoaccumulation index (I_geo) and enrichment factor (EF) unraveled the As contamination to be meager. The application of risk index factor and sediment quality guidelines showed that the As concentration in the estuary is below the background concentration. Pearson correlation analysis of As with iron and TOC exhibited significant weak and poor correlations with these variables.

Contamination and spatial distribution of parabens, their metabolites and antimicrobials in sediment from Korean coastal waters

Synthetic antimicrobials known as parabens, triclosan (TCS), and triclocarban (TCC) are emerging environmental contaminants. Limited studies on these contaminants have been conducted in coastal environments. In our study, parabens, their metabolites, TCS, and TCC were measured in sediment collected along the Korean coast, to investigate contamination status, spatial distribution, and potential health risks to coastal environments. Methyl paraben and 4-hydroxybenzoic acid were detected in all sediment samples, suggesting widespread contamination. Total concentrations of parent parabens, their metabolites, TCS, and TCC ranged from 0.19 to 11.2 (mean: 2.40) ng/g dry weight, 9.65 to 480 (mean: 120) ng/g dry weight, and < limit of quantification (LOQ)-6.10 (mean: 0.41) ng/g dry weight, and from < LOQ-41.0 (mean: 2.78) ng/g dry weight, respectively. The overall contamination of parabens and antimicrobials in sediment was different from that reported for persistent organic pollutants due to different contamination sources among chemical groups. Significant correlation was found among target contaminants in sediment, suggesting the existence of a common source. Total organic carbon (TOC) was significantly correlated with the concentrations of target contaminants, implying a major factor for coastal distribution of parabens and antimicrobials. The concentrations of parabens and TCS measured in sediment did not exceed a hazard quotient (HQ), implying low potential health risks associated with exposure to these contaminants. This is the first study to report the nationwide distribution of parabens, their metabolites, and antimicrobials in the coastal environments of Korea.

Influences of nitrite on paracetamol degradation in dielectric barrier discharge reactor

The frequent detection of paracetamol in natural water increased environmental concerns. The dielectric barrier discharge (DBD) technology is an effective paracetamol removing method, however, this research showed that the removal of paracetamol using DBD technology at 30 min dropped from 100% to 53.3% as the initial paracetamol concentration increased from 10 mg/L to 100 mg/L, due to the formation of more competitive intermediate products at higher paracetamol concentration. The removal of TOC was found to be much slower than that of paracetamol, as paracetamol was removed completely after 5 min treatment, the removal rate of TOC was 46.3% after 20 min treatment under 500 W discharge power and 50 mL/min air flow rate. The orthogonal experiment showed that the removal of TOC was significantly influenced by the treatment time, discharge power and recirculating flow rate, while less influenced by the discharge frequency. In the removal process of paracetamol, nitrite ion that generated during DBD treatment reacted with paracetamol to form an intermediate product of 3-nitro-4-acetamidophenol. The presence of nitrite ion retarded the removal of 3-nitro-4-acetamidophenol and thus the TOC, however, the nitrate ion did not. The degradation of paracetamol followed a sequence of 3-nitro-4-acetamidophenol, nitrosophenol/acetamide, N-methylacetamide, acetamide and small molecule organic acids in the DBD reactor, and these intermediates were finally oxidized to CO₂, H₂O and NO₃^-.