Rapid assessment of toxicity of chlorinated aqueous solution by dissolved oxygen depletion and optical density bioassays

Background: Chlorination of wastewater effluent with high levels of residual organic matter has been suspected to the production of toxic and hazardous disinfection by-products (DBPs) including trihalomethane (THM) compounds. Methods: In this study, two rapid techniques including dissolved oxygen depletion (DOD) and optical density (OD) bioassays were used to evaluate the chloroform toxicity of aqueous solution. The activated sludge was collected from aeration tank of a full-scale municipal wastewater treatment plant and used as a biological inoculum. In order to achieve an active and stabilized mixed culture of bacteria, the test cultures were transferred to a fresh nutrient broth culture media every day. The influence of chloroform on DOD and OD bioassays was examined at chloroform initial concentrations of 10-1000 μg/L. Results: It was revealed that the application of chloroform at concentrations of 100 and 1000 μg/L showed moderate and extreme toxicity, respectively, and reduced bacterial activity. The estimated chemical concentration with 50% inhibition of bacterial activity for DOD and OD bioassays was 457 and 961 μg/L, respectively. Conclusion: According to the results, the wastewater effluent should use bioassays in order to evaluate the effects of DBPs where the wastewater effluent is disinfected by chlorine compounds. Keywords: Trihalomethanes, Chloroform, Disinfection, Wastewater, Biological assay, Oxygen, Inhibitio

Combination of hydrodynamic cavitation with oxidants for efficient treatment of synthetic and real textile wastewater

In this study, the degradation of direct red 89 (DR89) dye from synthetic wastewater was assessed by lab-scaled hydrodynamic cavitation (HC) combined with different oxidants such as periodate (PI), persulfate (PS), and oxalic acid (OA). The degradation tests were carried out by combining the three oxidants in the absence of HC, and using HC with only one of the oxidants (HC/OA, HC/PS, and HC/PI) or with all combined (HC/PS/OA/PI). In all processes, the degradation constants followed first-order reaction kinetics, being the highest one that of the HC/PS/OA/PI process, equal to 2.01 × 10− 1 min− 1 . The degradation of DR89 was affected by pH, initial dye concentration, and reaction time. The degradation efficiency increased when pH decreased obtaining the best results at pH 3.0 due to favorable conditions for the generation and persistence of radical species. The degradation of the dye improved with increasing dose of OA, PS and PI. The best results were achieved using dosages of OA, PS, and PI of 100.0, 125.0, and 150.0 mg L− 1 , respectively. The quenching experiments revealed the presence of • OH, SO4 •− , IO3 • , O2 •– , and 1 O2 in the HC/PS/OA/PI process, while • OH, SO4 •− and IO3 • were the dominant responsible radicals. The rate constants of the individual processes were used to calculate the value of the synergetic coefficient of HC/PS/OA/PI process. At the optimum conditions, the calculated synergetic coefficient was 15.39. The effectiveness of the HC/PS/OA/PI process in the removal of color and COD from real textile wastewater was also investigated and exhibited the 96.23 ± 1.92 % and 93.84 ± 0.94 % reduction of color and COD after 70 min reaction time, respectively. The results showed that the combined process can be a useful technology for the treatment of textile wastewateThe authors thank the Isfahan University of Medical Sciences of Iran (Project No. 198124 and Ethics code: IR.MUI.RESEARCH. REC.1398.500) for financial support of this wor

Proposal of upgrading Isfahan north wastewater treatment plant: An adsorption/bio-oxidation process with emphasis on excess sludge reduction and nutrient removal

There is a rising challenge in managing the activated sludge process due to excess sludge disposal from the wastewater treatment plant and inadequate effluent quality due to the stricter standard of effluent quality. Hence, the incorporation of oxic-settling-anoxic process and ultrasonic waves in the return sludge line was proposed to assess the excess sludge reduction and nutrient removal in the adsorption/bio-oxidation activated sludge process as a proposal upgrading. The results indicated that sludge production from adsorption/bio-oxidation process could be reduced using oxic-settling-anoxic and ultrasonic by 50% at each studied mixed liquor suspended solids level. Compared to the adsorption/bio-oxidation process, the total and soluble chemical oxygen demand removal efficiencies in adsorption/bio-oxidation process with oxic-settling-anoxic and ultrasonic slightly decreased suggesting a lysis phenomenon. During the operation of adsorption/bio-oxidation process with oxic-settling-anoxic and ultrasonic, the total Kjeldahl nitrogen removal efficiency improved in A and B stages, with 38.3 ± 8.1% and 83.1 ± 6.5% versus 36.8 ± 14.5% and 75.1 ± 7.3%, respectively. According to the stoichiometric calculations, in B stage of adsorption/bio-oxidation process with oxic-settling-anoxic and ultrasonic, the soluble available ultimate biochemical oxygen demand and net NO3 produced for denitrification were 69.5 and 43.8 mg/L, respectively. Overall, the experimental data revealed that the adsorption/bio-oxidation process with oxic-settling-anoxic and ultrasonic produced lower excess biological sludge and better total Kjeldahl nitrogen removal efficiency compared to the adsorption/bio-oxidation system alone

Electron flow of biological H2 production by sludge under simple thermal treatment: Kinetic study

Mixed culture sludge has been widely used as a microbial consortium for biohydrogen production. Simple thermal treatment of sludge is usually required in order to eliminate any H2-consuming bacteria that would reduce H2 production. In this study, thermal treatment of sludge was carried out at various temperatures. Electron flow model was then applied in order to assess community structure in the sludge upon thermal treatment for biohydrogen production. Results show that the dominant electron sink was acetate (150–217 eˉ meq/mol glucose). The electron equivalent (eˉ eq) balances were within 0.8–18% for all experiments. Treatment at 100 °C attained the highest H2 yield of 3.44 mol H2/mol glucose from the stoichiometric reaction. As the treatment temperature increased from 80 to 100 °C, the computed acetyl-CoA and reduced form of ferredoxin (Fdred) concentrations increased from 13.01 to 17.34 eˉ eq (1.63–2.17 mol) and 1.34 to 4.18 eˉ eq (0.67–2.09 mol), respectively. The NADH2 balance error varied from 3 to 10% and the term eˉ(Fd↔NADH2) (m) in the NADH2 balance was NADH2 consumption (m = −1). The H2 production was mainly via the Fd:hydrogenase system and this is supported with a good NADH2 balance. Using the modified Gompertz model, the highest maximum H2 production potential was 1194 mL whereas the maximum rate of H2 production was 357 mL/h recorded at 100 °C of treatment

Magnetized Activated Carbon Synthesized from Pomegranate Husk for Persulfate Activation and Degradation of 4-Chlorophenol from Wastewater

The compound 4-chlorophenol (4-CP) is known to be a highly toxic compound having harmful effects on human health and the environment. To date, the removal of 4-CP by advanced oxidation processes (AOPs) has attracted tremendous attentions. The persulfate-based AOPs show higher oxidation, better selectivity, wider pH range, and no secondary pollution compared to the traditional Fenton-based AOPs. Carbon materials with low cost and chemical stability are useful for the activation of persulfate (PS) to produce reactive species. Herein, we magnetized activated carbon synthesized from pomegranate husk (MPHAC). By using 4-CP as a model organic pollutant, tests of the activation of PS via MPHAC for the removal of 4-CP were performed. Batch processes were carried out to study the influence of different parameters (initial solution pH, catalyst dose, PS dose, and initial 4-CP concentration) on the adsorption of 4-CP on PHAC with ferric oxide (Fe3O4-PHAC). The results show that under the obtained optimal conditions (MPHAC dose: 1250 mg/L, PS dose: 350 mg/L, solution pH 5, an initial 4-CP concentration of 100 mg/L, and a contact time of 60 min), a 4-CP removal factor of 99.5% was reached by the developed MPHAC/PS system. In addition, it was found that reusing MPHAC in five successive cycles is feasible because the catalyst in the last cycle kept exhibiting a high potential for 4-CP absorption, indicating the economically viable procedure. Therefore, this study provides a comprehensive understanding on the degradation of 4-CP by the magnetized activated carbon persulfate system

Efficiency of Constructed Wetland Vegetated with Cyperus alternifolius

The treatment of municipal wastewater from Yazd city (center of Iran) by constructed wetland vegetated with Cyperus alternifolius was assessed. Two identical wetlands with a total working volume of 60 L and 10 cm sandy layer at the bottom were used. First wetland (W1) was control and had no Cyperus alternifolius plant. Second wetland (W2) had 100 Cyperus alternifolius shrubs with 40 cm height. Influent wastewater was provided from Yazd's septic tanks effluents and after a 4-day retention time in wetlands, reactors effluent was sampled for parameters analysis. Results show that chemical oxygen demand (COD), –N, –N, and –P in W1 were reduced to 72%, 88%, 32%, and 0.8%, and in W2, these parameters were removed in values of 83%, 81%, 47%, and 10%, respectively. In both wetlands, the highest and lowest removal efficiencies were related to COD and phosphorus, respectively. Also, the removed phosphorus can be released to stream when the soil saturated or influent phosphorus decreased and when the plant died. After a 4-day-retention time, the W2 wetland showed a statistically significantly lower COD and –N in comparison with W2 wetland

The unfinished agenda of communicable diseases among children and adolescents before the COVID-19 pandemic, 1990-2019: a systematic analysis of the Global Burden of Disease Study 2019

BACKGROUND: Communicable disease control has long been a focus of global health policy. There have been substantial reductions in the burden and mortality of communicable diseases among children younger than 5 years, but we know less about this burden in older children and adolescents, and it is unclear whether current programmes and policies remain aligned with targets for intervention. This knowledge is especially important for policy and programmes in the context of the COVID-19 pandemic. We aimed to use the Global Burden of Disease (GBD) Study 2019 to systematically characterise the burden of communicable diseases across childhood and adolescence. METHODS: In this systematic analysis of the GBD study from 1990 to 2019, all communicable diseases and their manifestations as modelled within GBD 2019 were included, categorised as 16 subgroups of common diseases or presentations. Data were reported for absolute count, prevalence, and incidence across measures of cause-specific mortality (deaths and years of life lost), disability (years lived with disability [YLDs]), and disease burden (disability-adjusted life-years [DALYs]) for children and adolescents aged 0-24 years. Data were reported across the Socio-demographic Index (SDI) and across time (1990-2019), and for 204 countries and territories. For HIV, we reported the mortality-to-incidence ratio (MIR) as a measure of health system performance. FINDINGS: In 2019, there were 3·0 million deaths and 30·0 million years of healthy life lost to disability (as measured by YLDs), corresponding to 288·4 million DALYs from communicable diseases among children and adolescents globally (57·3% of total communicable disease burden across all ages). Over time, there has been a shift in communicable disease burden from young children to older children and adolescents (largely driven by the considerable reductions in children younger than 5 years and slower progress elsewhere), although children younger than 5 years still accounted for most of the communicable disease burden in 2019. Disease burden and mortality were predominantly in low-SDI settings, with high and high-middle SDI settings also having an appreciable burden of communicable disease morbidity (4·0 million YLDs in 2019 alone). Three cause groups (enteric infections, lower-respiratory-tract infections, and malaria) accounted for 59·8% of the global communicable disease burden in children and adolescents, with tuberculosis and HIV both emerging as important causes during adolescence. HIV was the only cause for which disease burden increased over time, particularly in children and adolescents older than 5 years, and especially in females. Excess MIRs for HIV were observed for males aged 15-19 years in low-SDI settings. INTERPRETATION: Our analysis supports continued policy focus on enteric infections and lower-respiratory-tract infections, with orientation to children younger than 5 years in settings of low socioeconomic development. However, efforts should also be targeted to other conditions, particularly HIV, given its increased burden in older children and adolescents. Older children and adolescents also experience a large burden of communicable disease, further highlighting the need for efforts to extend beyond the first 5 years of life. Our analysis also identified substantial morbidity caused by communicable diseases affecting child and adolescent health across the world. FUNDING: The Australian National Health and Medical Research Council Centre for Research Excellence for Driving Investment in Global Adolescent Health and the Bill & Melinda Gates Foundation

National, sub-national, and risk-attributed burden of thyroid cancer in Iran from 1990 to 2019

An updated exploration of the burden of thyroid cancer across a country is always required for making correct decisions. The objective of this study is to present the thyroid cancer burden and attributed burden to the high Body Mass Index (BMI) in Iran at national and sub-national levels from 1990 to 2019. The data was obtained from the GBD 2019 study estimates. To explain the pattern of changes in incidence from 1990 to 2019, decomposition analysis was conducted. Besides, the attribution of high BMI in the thyroid cancer DALYs and deaths were obtained. The age-standardized incidence rate of thyroid cancer was 1.57 (95% UI: 1.33–1.86) in 1990 and increased 131% (53–191) until 2019. The age-standardized prevalence rate of thyroid cancer was 30.19 (18.75–34.55) in 2019 which increased 164% (77–246) from 11.44 (9.38–13.85) in 1990. In 2019, the death rate, and Disability-adjusted life years of thyroid cancer was 0.49 (0.36–0.53), and 13.16 (8.93–14.62), respectively. These numbers also increased since 1990. The DALYs and deaths attributable to high BMI was 1.91 (0.95–3.11) and 0.07 (0.04–0.11), respectively. The thyroid cancer burden and high BMI attributed burden has increased from 1990 to 2019 in Iran. This study and similar studies’ results can be used for accurate resource allocation for efficient management and all potential risks’ modification for thyroid cancer with a cost-conscious view

Global burden of chronic respiratory diseases and risk factors, 1990–2019: an update from the Global Burden of Disease Study 2019

Background: Updated data on chronic respiratory diseases (CRDs) are vital in their prevention, control, and treatment in the path to achieving the third UN Sustainable Development Goals (SDGs), a one-third reduction in premature mortality from non-communicable diseases by 2030. We provided global, regional, and national estimates of the burden of CRDs and their attributable risks from 1990 to 2019. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated mortality, years lived with disability, years of life lost, disability-adjusted life years (DALYs), prevalence, and incidence of CRDs, i.e. chronic obstructive pulmonary disease (COPD), asthma, pneumoconiosis, interstitial lung disease and pulmonary sarcoidosis, and other CRDs, from 1990 to 2019 by sex, age, region, and Socio-demographic Index (SDI) in 204 countries and territories. Deaths and DALYs from CRDs attributable to each risk factor were estimated according to relative risks, risk exposure, and the theoretical minimum risk exposure level input. Findings: In 2019, CRDs were the third leading cause of death responsible for 4.0 million deaths (95% uncertainty interval 3.6–4.3) with a prevalence of 454.6 million cases (417.4–499.1) globally. While the total deaths and prevalence of CRDs have increased by 28.5% and 39.8%, the age-standardised rates have dropped by 41.7% and 16.9% from 1990 to 2019, respectively. COPD, with 212.3 million (200.4–225.1) prevalent cases, was the primary cause of deaths from CRDs, accounting for 3.3 million (2.9–3.6) deaths. With 262.4 million (224.1–309.5) prevalent cases, asthma had the highest prevalence among CRDs. The age-standardised rates of all burden measures of COPD, asthma, and pneumoconiosis have reduced globally from 1990 to 2019. Nevertheless, the age-standardised rates of incidence and prevalence of interstitial lung disease and pulmonary sarcoidosis have increased throughout this period. Low- and low-middle SDI countries had the highest age-standardised death and DALYs rates while the high SDI quintile had the highest prevalence rate of CRDs. The highest deaths and DALYs from CRDs were attributed to smoking globally, followed by air pollution and occupational risks. Non-optimal temperature and high body-mass index were additional risk factors for COPD and asthma, respectively. Interpretation: Albeit the age-standardised prevalence, death, and DALYs rates of CRDs have decreased, they still cause a substantial burden and deaths worldwide. The high death and DALYs rates in low and low-middle SDI countries highlights the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for tobacco control, enhancing air quality, reducing occupational hazards, and fostering clean cooking fuels are crucial steps in reducing the burden of CRDs, especially in low- and lower-middle income countries

Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin