Toxicity Assessment Of Effluents Research Articles

Photo-Fenton like catalyst system with CuCOFe2O4@AC nanoparticles for ciprofloxacin removal from aqueous solutions and effluent toxicity assessment by Escherichia coli and Enterococcus faecalis bacteria

In this study, the removal of the antibiotic ciprofloxacin (CIP) from aqueous solutions was investigated using the Photo-Fenton like (PFL) process and CuCOFe2O4@AC (CAC) magnetic nanoparticles as catalysts. First, CAC nanoparticles were synthesized and their characteristics were determined by XRD, VSM and FESEM, EDS, Mapping, FTIR. The removal efficiency of CIP in each of the nanomaterial processes, including UV, H2O2, CAC, UV+H2O2, CAC+H2O2 (Fenton like), and UV+CAC+H2O2 (PFL), were 1.0%, 7.97%, 61.37%, 6.0%, 73%, and 84%, respectively. Therefore, the PFL process was optimized as a suitable process, and the optimal conditions were determined as follows: H2O2 concentration of 2500 mg/L, pH of five, CAC dose of 600 mg/L, CIP concentration of 15 mg/L, and contact time of 50 min. The removal efficiency of CIP was achieved at 95.99%. The kinetic studies on the PFL process for the removal of CIP shown that the first order kinetic model exhibits better compatibility with the obtained results compared to other investigated kinetic models. Furthermore, the synergistic effect of the PFL process was equivalent to 1.8 times the individual processes. The results of microbiological tests in treated wastewater samples and control sample indicate the non-toxicity of residual pharmaceuticals wastewater on E. coli and E. faecalis bacteria. Due to the non-toxicity of the wastewater and the ability to recover nanoparticles using magnetism, as well as the possibility of recycling the nanoparticles, this technique can be effectively used as a suitable process in pharmaceutical industry wastewater treatment.

Anaerobic treatment removing tetrabromobisphenol A and biota safety: How do tropical aquatic species respond to effluent toxicity over short- and long-term exposures?

Wastewater containing tetrabromobisphenol A (TBBPA), a commonly used flame retardant found in wastewater, can present significant toxic effects on biota, yet its impact on tropical freshwater environments is not well understood. This study explores the effectiveness of two independent anaerobic treatment systems, the acidogenic reactor (AR) and the methanogenic reactor (MR), for the ecotoxicity reduction of TBBPA-rich wastewater in four tropical freshwater species. Despite presenting good physicochemical performance and reduced toxicity of the influent for most species, AR and MR treatments remain acute and chronic toxicity. Overall, MR exhibited greater efficacy in reducing influent toxicity compared with AR. TBBPA bioaccumulation was observed in Chironomus sancticaroli after short-term exposure to 100% MR effluent. Multigenerational exposures highlighted changes in the wing length of C.sancticaroli, showing decreases after influent and AR exposures and increases after MR exposures. These findings underscore the need for ecotoxicological tools in studies of new treatment technologies, combining the removal of emerging contaminants with safeguarding aquatic biota. PRACTITIONER POINTS: Acidogenic and methanogenic reactors reduced the acute and chronic toxicity of wastewater containing tetrabromobisphenol A. Both treatments still exhibit toxicity, inducing short- and long-term toxic effects on four native tropical species. The aquatic species Pristina longiseta was most sensitive to effluents from acidogenic and methanogenic reactors. TBBPA concentrations recovered from Chironomus sancticaroli bioaccumulation analysis ranged from 1.07 to 1.35 μg g-1. Evaluating new treatment technologies with multiple species bioassays is essential for a comprehensive effluent toxicity assessment and ensuring aquatic safety.

Current Trends on Role of Biological Treatment in Integrated Treatment Technologies of Textile Wastewater.

Wastewater discharge is a matter of concern as it is the primary source of water pollution. Consequently, wastewater treatment plays a key role in reducing the negative impact that wastewater discharge produce into the environment. Particularly, the effluents produced by textile industry are composed of high concentration of hazardous compounds such as dyes, as well as having high levels of chemical and biological oxygen demand, suspended solids, variable pH, and high concentration of salt. Main efforts have been focused on the development of methods consuming less water or reusing it, and also on the development of dyes with a better fixation capacity. However, the problem of how to treat these harmful effluents is still pending. Different treatment technologies have been developed, such as coagulation-flocculation, adsorption, membrane filtration, reverse osmosis, advanced oxidation, and biological processes (activated sludge, anaerobic-aerobic treatment, and membrane bioreactor). Concerning to biological treatments, even though they are considered as the most environmentally friendly and economic methods, their industrial application is still uncertain. On the one hand, this is due to the costs of treatment plants installation and, on the other, to the fact that most of the studies are carried out with simulated or diluted effluents that do not represent what really happens in the industries. Integrated treatment technologies by combining the efficiency two or more methodologies used to be more efficient for the decontamination of textile wastewater, than treatments used separately. The elimination of hazardous compounds had been reported using combination of physical, chemical, and biological processes. On this way, as degradation products can sometimes be even more toxic than the parent compounds, effluent toxicity assessment is an essential feature in the development of these alternatives. This article provides a critical view on the state of art of biological treatment, the degree of advancement and the prospects for their application, also discussing the concept of integrated treatment and the importance of including toxicity assays to reach an integral approach to wastewater treatment.

Acetaminophen Removal from Water by Microalgae and Effluent Toxicity Assessment by the Zebrafish Embryo Bioassay

In this work, zebrafish embryo bioassays were performed to assess the efficiency of microalgae in the removal of acetaminophen from water. Chlorella sorokiniana (CS), Chlorella vulgaris (CV) and Scenedesmus obliquus (SO) were the strains used for water treatment. Toxic effects on zebrafish embryo caused by effluents from microalgae treatment were compared with those observed under exposure to experimental solutions with known concentrations of acetaminophen. The three microalgae strains allowed for the reduction of acetaminophen concentration and its toxic effects, but CS was the most efficient one. At the end of the batch culture, a 67% removal was provided by CS with a reduction of 62% in the total abnormalities on the exposed zebrafish embryo. On the other hand, toxic effects observed under exposure to effluents treated by microalgae were alike to those determined for acetaminophen experimental solutions with equivalent concentration. Thus, it may be inferred that microalgae biodegradation of acetaminophen did not involve an increased toxicity for zebrafish embryo.

Sewage Effluent Toxicity Assessment: Comparison between Whole Effluent Toxicity (WET) and the Japanese Pollutant Release and Transfer Register (PRTR) Data

Sewage Effluent Toxicity Assessment: Comparison between Whole Effluent Toxicity (WET) and the Japanese Pollutant Release and Transfer Register (PRTR) Data

Optimizing the photocatalytic process of removing diazinon pesticide from aqueous solutions and effluent toxicity assessment via a response surface methodology approach

Diazinon is one of the most dangerous environment pollutants. In this study, the optimization of removing diazinon from contaminated aqueous solutions was evaluated by advanced oxidation process along with the evaluation of effluent toxicity by Escherichia coli bacteria. The design of the experiments was based on the response surface methodology. Iron oxide nanoparticles and iron oxide/titanium oxide were produced by co-precipitation and col–gel, respectively. The features of produced nanoparticles were investigated by scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) techniques. In this study, the toxicity tests of effluent were performed by the activity of dehydrogenase enzyme reducing Alamar Blue method. Based on statistical analyzes (R2 = 0.996), the values of optimal pH, contact time, and nanoparticle concentration were obtained at 6.75, 65 min, and 550 mg/L in the removal of diazinon, respectively. In this case, the efficiency of removing diazinon was 94.15%. By analyzing the effluent, eight by-products due to the degradation of diazinon were determined with the probability of correct detection above 50%. Based on the Alamar Blue reduction test (ABR), the effective concentrations of 50% (EC50) and the no observed effect concentration (NOEC) for E. coli were obtained 2340 and 18 mg/L, respectively. Based on the results, it was found that the photochemical process TiO2/Fe3O4 has high efficiency on the removal of diazinon and there is a significant relation (p value < 0.05) between dehydrogenase activity of E. coli bacteria and reduction of Alamar Blue.

Optimization of photochemical decomposition acetamiprid pesticide from aqueous solutions and effluent toxicity assessment by Pseudomonas aeruginosa BCRC using response surface methodology

Contamination of water resources by acetamiprid pesticide is considered one of the main environmental problems. The aim of this study was the optimization of acetamiprid removal from aqueous solutions by TiO2/Fe3O4/SiO2 nanocomposite using the response surface methodology (RSM) with toxicity assessment by Pseudomonas aeruginosa BCRC. To obtain the optimum condition for acetamiprid degradation using RSM and central composite design (CCD). The magnetic TiO2/Fe3O4/SiO2 nanocomposite was synthesized using co-precipitation and sol–gel methods. The surface morphology of the nanocomposite and magnetic properties of the as-synthesized Fe3O4 nanoparticles were characterised by scanning electron microscope and vibrating sample magnetometer, respectively. In this study, toxicity assessment tests have been carried out by determining the activity of dehydrogenase enzyme reducing Resazurin (RR) and colony forming unit (CFU) methods. According to CCD, quadratic optimal model with R2 = 0.99 was used. By analysis of variance, the most effective values of each factor were determined in each experiment. According to the results, the most optimal conditions for removal efficiency of acetamiprid (pH = 7.5, contact time = 65 min, and dose of nanoparticle 550 mg/L) was obtained at 76.55%. Effect concentration (EC50) for RR and CFU test were 1.950 and 2.050 mg/L, respectively. Based on the results obtained from the model, predicted response values showed high congruence with actual response values. And, the model was suitable for the experiment’s design conditions.

Whole effluent toxicity assessment at a wastewater treatment plant upgraded with a full-scale post-ozonation using aquatic key species

Ozonation as final wastewater (WW) polishing step, following conventional activated sludge treatment is increasingly implemented in sewage treatment for contaminant degradation to prevent surface water pollution. While the oxidative degradation of chemicals has been extensively investigated, the in vivo toxicological characteristics of ozonated whole effluents are rarely a matter of research.In the present study, whole effluents were toxicologically evaluated with an in vivo test battery before and after full-scale ozonation and subsequent sand filtration on site at a treatment plant. One aquatic plant (duckweed, Lemna minor) and five invertebrate species of different systematic groups (Lumbriculus variegatus, Chironomus riparius, Potamopyrgus antipodarum, Daphnia magna) were exposed to the effluents in a flow-through-designed test system with a test duration of 7–28d.None of the considered toxicity endpoints correlated with the pollutant elimination. A tendency towards an increased toxicity after ozonation was apparent in three of the test systems showing [statistically] significant adverse effects in the L. variegatus toxicity test (decrease in reproduction and biomass). After sand filtration, adverse effects were reduced to a similar level like after conventional treatment. Solely the Daphnia reproduction test revealed beneficial effects after ozonation in combination with sand filtration.Results of the test battery indicate the formation of adverse oxidation products during WW ozonation. L. variegatus appeared to be the most sensitive of the five test species. Sand filtration effectively removes or detoxifies toxic oxidation products, as toxic effects were subsequently reduced to the level after conventional treatment.

Biodegradability and toxicity assessment of bleach plant effluents treated anaerobically

As part of an experimental project on the treatment of bleach plant effluents the results of biodegradability and toxicity assessment of effluents from a bench-scale horizontal anaerobic immobilized bioreactor (HAIB) are discussed in this paper. The biodegradability of the bleach plant effluents from a Kraft pulp mill treated in the HAIB was evaluated using the modified Zahn-Wellens test. The inoculum came from a pulp mill wastewater treatment plant and the dissolved organic carbon (DOC) was used as the indicator of organic matter removal. The acute and chronic toxicity removal during the anaerobic treatment was estimated using Daphnia similis and Ceriodaphnia silvestrii respectively. Moreover, the evaluation of chromosome aberrations (CA), micronucleus frequencies (MN) and mitotic index (IM) in Allium cepa cells were used as genotoxicity indicators. The results indicate that the effluents from the anaerobic reactor are amenable to aerobic polishing. Acute and chronic toxicity were reduced by 90 and 81%, respectively. The largest CA and MN incidence in the meristematic cells of A. cepa were observed after exposure to the raw bleach plant effluent. The HAIB was able to reduce the acute and chronic toxicity as well as chromosome aberrations and the occurrence of micronucleus.

Assessment of Peracetic Acid Disinfected Effluents by Microbiotests

Bioassays were performed by commercially available kits on peracetic acid (PAA) solutions, at different concentrations, and on secondary effluents (from two different wastewater treatment plants) after disinfection at bench-scale, considering both samples containing residual active PAA and the same samples where residual PAA was quenched. Four indicator organisms were used: Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Selenastrum capricornutum. The experiments lead to conclude that Thamnocephalus platyurus is a very sensitive organism, probably not adequate to perform a reliable toxicity assessment of effluents for monitoring purposes. The presence of specific organic compounds deriving from human metabolism and urban pollution, even at very low concentrations, can affect the results of bioassays, especially those performed on Vibrio fischeri. PAA is toxic for bacteria and crustaceans even at concentrations lower than the ones commonly used in wastewater disinfection (2-5 mg/L), while its effect on algae is smaller. The toxic effect on bacteria was expected, as PAA is used for disinfection, but its possible influence on biological processes in the receiving aquatic environment should be considered. Toxicity on crustaceans would confirm the fact that discharging disinfected effluents could raise some environmental problems.

Direct toxic assessment of treated fertilizer effluents to Oreochromis niloticus, Clarias gariepinus and catfish hybrid ( Heterobranchus bidorsalis x Clarias gariepinus )

Acute static bioassay was employed to assess the toxicity of various ranges of effluent from the National Fertilizer Company of Nigeria (NAFCON) plant to three fish species: Oreochromis niloticus , Clarias gariepinus and hybrid ( Heterobranchus bidorsalis x C. gariepinus ) from the coastal estuaries of the Niger Delta area, Nigeria. The lethal concentration values at 24, 48 and 72 h were 72.05, 30.81 and 15.26% for O. niloticus and 26.18, 10.32 and 19.84% for the hybrid, respectively. No mortality was recorded for C. gariepinus . The median lethal time for O. niloticus at 70% and hybrid at 50% of the different samples was 18.14 and 6.02hrs, respectively. Ammonia appeared to be the major toxic component. The safe concentrations of the effluents ranged between 1.53% and 77.21% for O. niloticus , and 3.15 and 5.50 % for the hybrid. Although the ranges of treated effluents discharged from the plant met set standards and can be classified as non-toxic, yet they caused mortalities to exposed species. This underscores the merit of direct toxicity assessment of effluents over the traditional physicochemical method which does not adequately protect the environment. Key words: Toxicity assessment, fertilizer effluents, Oreochromis niloticus, Clarias gariepinus , catfish hybrid.

Policy, Principle, and Practice in Industrial Pollution Control: Views from the Regulatory Interface

There has been much criticism of the system for the control of industrial pollution, but not much is known about the views of the regulators and the industry. The objective of this study was to explore the attitudes at this regulatory interface towards the current and proposed regulatory system and make recommendations for improvements. The methodology involved a questionnaire survey sent to over 700 key personnel. Statistical analysis revealed similarities and significant differences between the views of industry and the regulator on the effectiveness of the current regime. Weaknesses related to the derivation and enforcement of standards were identified. The Environmental Quality Standards system was acknowledged to be flawed by both operators and regulators who agreed it should be improved by the expansion of listed chemicals, the introduction of sediment environmental quality standards and direct toxicity assessment of effluents. This paper concludes that these measures should be incorporated into the regulatory system, together with more rigorous enforcement of environmental performance standards including serious sanctions for non-compliance. In the longer term, a reappraisal of the regulatory system is required in order to establish an appropriate framework to ensure that environmental policy commitments are implemented.

Toxicity assessment of effluents in the Netherlands: implementation, problems and prospects

For many years ecotoxicologists worldwide have been working on the implementation of their knowledge in the hazard assessment of industrial effluents. Chemical analyses and risk assessment of complex effluents are often problematic. Among ecotoxicologists there is little doubt about the usefulness of toxicity tests or toxicity data as complementary tools to the routine chemical risk assessment and control. In the Netherlands the use of aquatic toxicity data from the literature is now being incorporated into a scheme for the risk assessment of effluents when granting consent-to-discharge (permit) effluents. Despite the potential advantages of the use of toxicity tests in whole-effluent-toxicity assessments, they are used infrequently in the Netherlands. An analysis has been made of the possible causes of the delay in implementation of ecotoxicological knowledge and tools in the hazard assessment of effluents in the Netherlands. It is concluded that implementation of whole effluent toxicity tests cannot to be improved or speeded up by more ecotoxicological research at this moment. A more intensive dialogue between ecotoxicologists and all parties involved in granting consents to discharge effluents is essential for the implementation process. To encourage increased toxicity assessment ecotoxicologists need to provide information through educational forums and technical support.