BOD Values Research Articles

Water quality evaluation by WQI and ICOs for the rivers of Joya de los Sachas and Francisco de Orellana

A monitoring program enabled the evaluation of water quality and the simulation of the pollution dynamics of the rivers in the Joya de los Sachas and Francisco de Orellana cantons in Ecuador. For this assessment one used the WQI (water quality index) and the pollution indices ICOMO (organics contamination), ICOSUS (suspended solids), ICOMI (mineralization), ICOTRO (trophy system), and ICOpH (pH Index). The mathematical model operates with several input parameters, including dissolved oxygen, fecal coliforms, the biochemical oxygen demand (BOD5), turbidity, total solids, total phosphorus, pH, total nitrogen, suspended solids, alkalinity, conductivity, temperature, and the concentrations of nitrates, nitrites, and phosphates. WQI values were obtained from ICO pollution indices. The pollution of the Sacha area is significant, WQI = 0.292, which represents an advanced degree of pollution, since increased BOD values correspond to a high load of organic pollutants. They can originate from household, agricultural, industrial, and soil erosion waste. Likewise, the Sacha River has an ICOSUS = 0.16, which renders water treatment difficult, without impacting human health. Calculated WQI values reveal that the water quality of the Sacha, Basura and Coca rivers is low, being highly contaminated. In contrast, the Huamayacu, Jivino Rojo, Jivino Negro, and Jivino Blanco rivers are commonly polluted.

PbO2/rGO Electrode as a Superior and Efficient Anode in Electrocatalytic Degradation of Safranine-O

The electrocatalytic degradation method with PbO2/rGO electrode (anode) was chosen to treat Safranine-O waste because it was cheap and environmentally friendly. This research aimed to study the electrocatalytic efficiency of PbO2/rGO working electrode in Safranine-O removal. In this research, rGO and PbO2/rGO electrodes were synthesized and applied to Safranine-O removal through electrochemical degradation. The characterization results of the morphology of rGO are in the form of a layered structure and have the atomic composition of C (82.87%) and O (17.13%). The characterization results of PbO2/rGO are uniform particles with gaps/pores that appear relatively large. The rGO particles in the form of sheets (layers) seem to be distributed on the surface of PbO2. PbO2/rGO electrode has the atomic composition of C (87.24%), O (9.03), and Pb (3.73). The application of PbO2/rGO anode to the electrochemical degradation of Safranine-O showed good performance. It was able to perform dye removal (DE%), as well as a decrease in BOD and COD values up to >95% within 10 minutes at a concentration of 20 ppm. Application on real waste also showed the ability of dye removal, COD, and BOD reduction up to >95%. Coating or modifying the PbO2 anode with rGO can reduce the dissolution of Pb2+ ions in the solution during the electrochemical degradation. This study concluded that the PbO2/rGO electrode has improved the efficiency in Safranine-O degradation. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Real-time water quality monitoring along the lower stretch of River Ganges and its connected drains using sensors and Water Quality Index

ABSTRACT In this study, water quality is measured using a Real-Time Water Quality Monitoring System for a total of 84 times at 14 locations, in which four drains discharged sewage directly to river Ganges at Bihar, five locations on river Ganges at West Bengal, two tributaries of river Ganges at West Bengal and three drains discharged wastewater directly to river Ganges at West Bengal. In Bihar, four major drains discharged 377.98 MLD wastewater into the river Ganges which in turn released 8985.17 kg of BOD per day. In West Bengal, three major drains had a total flow of 1630.88 MLD that discharged 11563.77 kg of BOD per day to the River Ganges. The average Water Quality Index of the river Ganges was observed as 64.55 and that of drains of West Bengal and Bihar were recorded as 309.78 and 775.56, respectively. The average BOD to COD ratio of less than 0.6 indicated wastewater from drains of Bihar and West Bengal was nonbiodegradable. DO and pH values were recorded compliant with the bathing water quality standard at all river locations, however, the average BOD value at five monitoring points of the river Ganges and its tributaries was slightly above the bathing water quality standard.

Ultrasound Evaluation of the Optic Nerve Sheath as a Predictor of Severity and Complications

Objectives: Ultrasonography has the potential advantage of being a repeatable tool, safe at the bedside and low cost, without risks of radiation and side effects. Emerging as a tool with potential to promote the optimization of the prognosis of neurosurgical patients. Methods: 31 participants diagnosed with expansive brain injury were selected, all over 18 years of age, after signing the free consent form and clarification, the postoperative evaluation was carried out at the time of hospital discharge and 3 months after surgery on an outpatient basis. The ultrasound evaluation of the optic nerve sheaths was performed by a team member, who was blind to the clinical and radiological information and using the same GE VERSANA ACTIVE ultrasound device. Results: During the preoperative analysis of 31 patients, 41.9% were male (n=13) and 58.06% female (n=16), with a mean age of 50.64 +- 16.29. Regarding the functional analysis with KPS, it was found that 58% of patients (regardless of sex) had results >=70, equivalent to 18 patients. Regarding the diameter of the optic nerve sheath performed by ultrasound, the value of the preoperative BOD was greater than 6.1 mm, the value greater than 6.2 mm determined unfavorable prognosis in 3 months. Discussion: In the present study, the cutoff point of the BNO measurement for favorable or unfavorable prognosis was 6.1 mm, and when we correlated this variable with the analyzed KPS variable, we can observe that they correlate, mainly with outcome, getting an unfavorable result.

Multiannual oceanographic studies in the coastal area of Karadag Nature Reserve and Koktebel Bay (northern Black Sea) in 2004–2021

The study presents the results of the first multiannual oceanographic monitoring in the coastal area of Karadag Nature Reserve and adjacent water areas in May and September in the period from 2004 to 2021. Significant and unprecedentedly high increasing trends were detected for salinity in May. Increasing trends in nitrate concentration in Koktebel Bay were noted both for May and for September. The five-day biochemical oxygen demand (BOD5), ammonium and phosphate concentrations demonstrated mostly negative trends for the measurements in May and positive trends in September. Significant decreasing trends in phytoplankton biomass were noted in September, which fit in the range of the larger-scale phytoplankton trends reported in the literature. The position of the extrema of nutrients in the long-term-average and trend slope maps was confined to the areas of increased hydrodynamic and anthropogenic activity. Multivariate analysis showed significant negative correlations of the quantitative phytoplankton characteristics with salinity, which were explained by the effect of the freshened and nutrient-enriched Azov plume. The absence of significant correlations with nutrients was attributed to the non-conservative and stochastic character of the nutrient inflow on the yearly scale and time lag between the nutrient supply and the phytoplankton growth. The large percentage of occurrences of low BOD5 values at any station indicates the unpolluted status of the area under research, which is confirmed by the low trophic index values and appearance of probability distributions of the nutrient concentrations.

Performance Evaluation of Advanced Wastewater Treatment Technologies in Herbal Processing and Extraction Industry

"Due to enormous quantities with hazards and complexity in nature is a big challenge for effective treatment of wastewater from pharmaceutical processes including herbal extraction through conventional methods of distillation. The situation is further aggravated in countries facing high rising population, urbanization, and industrialization resulting in the generation of industrial wastes. The study has been carried out in the herbal extraction industry by conducting stage-wise sampling of ETP based on the conventional method and further coupled with ozonation as an advanced treatment to comply with regulatory standards. Additionally, the same process was studied that implementing the best available technology (BAT) by providing ETP with advanced technology modules such as MBR (membrane bioreactor) + RO + O3 has not only resulted in compliance with standards but also reuse of treated wastewater into the process and utilities has been proved to be techno-economically a viable and sustainable option. Modifying existing aeration tanks and advanced oxidation through ozone injection post-biological treatment has resulted in COD and BOD reduction of 96.42% and 99.0% respectively. Whereas in the case of MBR + RO + O3, the values of pH, BOD, COD, TSS, and sulfide have been observed as 8.32, 2.0 mg.L-1, 14.0 mg.L-1, 1.0 mg.L-1 and 0.0 mg.L-1 respectively and 98% recovery of treated effluent, thus saving 44 KL.day-1 of freshwater resulting into significant financial benefits of Rupees 12.59 acs annually, which otherwise was outsourced through tankers."

Effectiveness of Apuwood Plants (Pistia Stratiotes) Using the Phytoremediation Method in Reducing Bod Levels in Ciprat Langitan Magetan Batik Waste

The batik industry generally consists of residue, residual dye water, residual wax and batik pelorodan water. The characteristics of batik liquid waste include high levels of Biological Oxygen Demand, Chemical Oxygen Demand, and Total Suspended Solids. Batik industry waste is considered dangerous, because its characteristics can pollute waters such as turbidity in river water. The aim of this research is todetermine the effectiveness of using apu wood plants (Pistia Stratiotes) in reducing the BOD value in Ciprat Langitan Simbatan Magetan batik waste.The method used in this research is experimental, with analysis using Quasi Experimental and using a Pretest-posttest Control Group Design.The results of measuring BOD levels with phytoremediation treatment of apu wood plants on the 3rd day were 114 mg/l, on the 6th day it was 71 mg/l and on the 9th day it was 53 mg/l. The percentage of effectiveness in reducing BOD levels on day 3 was 9.78%, on day 6 it was 45.31% and on the last day it was 58.20%. There was a reduction in BOD levels with phytoremediation using apu wood plants. The effectiveness of the apu wood plant in reducing BOD levels was found with an exposure time of 9 days. Apart from that, a long-standing treatment of more than 9 days can be used to measure the effectiveness of apu wood plants in reducing the BOD levels of batik liquid waste.

Industrial Wastewater Efficiency Assessment of Al-Dora Refinery Plant in Baghdad by Decreasing BOD5 and COD Concentrations

In petroleum refineries, cooling towers, steam engines, and vacuum distillation all require a large volume of water. Before being dumped into the water bodies, it is then transported to an industrial water treatment facility. One of the study's objectives is to verify how well different processing units in the industrial wastewater treatment plant at the cycle refinery remove concentrations of chemical and biological oxygen demand (COD) and BOD. Five samples of industrial wastewater were collected before and after each treatment unit and one sample of wastewater was drained as a final product to the Tigris River. Over the summer, the BOD5 values after each processing unit were 180.8, 175.2, 111, 43, and 37 ppm. Winter readings were 106.8, 99.6, 81.2, 33.8, and 31 ppm, with summer and winter complete elimination rates of 79% and 71%, respectively. The reason for higher BOD5 concentrations in summer than in winter is due to higher temperatures that lead to evaporation and increased concentrations of BOD5 and COD pollutants. While COD concentrations were during the summer after each processing unit 399.6, 383.2, 187.2, 72.8, and 55.4 ppm, in winter they were 324.4, 310.2, 115, 46, and 42.6 ppm with a total removal rate of 86% in summer and 87% in winter. It was found that the refinery's water-drained treatment method, which includes a high proportion of BOD5 and COD concentrations in the main treatment plant, is effective. The water that flowed from the treatment plant into the river was within the national standard of the river water.

Kajian Penambahan Bakteri Probiotik Lokal Dengan Interval Waktu Inkubasi 8 Jam Terhadap Perubahan Kadar BOD dan COD Pada Air Buangan Industri Tahu

Tofu has become one of the most popular foods among the people of Indonesia. This encourages the existence of a growing tofu manufacturing industry. However, the growth of this industry also results in a lot of waste being generated. If the waste is not treated properly, it can cause pollution because it contains very high BOD and COD levels. One of the ways that researchers do is by utilizing local probiotic bacteria to help reduce BOD and COD levels. Data analysis in this study is in the form of statistical analysis, where statistical data will be presented with graph/diagram methods that show the results of differences in BOD and COD values in Tofu Industry Wastewater before and after treatment. Based on the results of the study, there was a significant decrease in BOD and COD levels due to the addition of local probiotic bacteria. The efficiency of the largest decrease in BOD levels was 79.88% in the sample variation with a probiotic content of 75% when the incubation time interval was 32 hours. Meanwhile, the largest decrease in COD levels also occurred in the same sample variation with an efficiency of 74.76%.

Alkoxide-based solvent dyeing: a feasible strategy for pollution minimization and sustainable approach for the reactive dyeing of cellulosic materials

This study aimed to evaluate the feasibility of substituting the conventional inorganic alkalis (Na2CO3) with different organic alkoxide5s to explore the potential of replacing aqueous dyeing medium with environmentally friendly solvents like ethanol (EtOH). The study aimed to assess the dyeing characteristics, such as exhaustion, fixation, fastness qualities, physical properties, and environmental implications when EtOH and water were present, while also examining the impact of alkoxides. Time-gated Raman spectra provide insights into the allomorphic forms of cellulose-II after the alkoxide pretreatment, which significantly influences the overall reactivity of cellulose fibers and their dye absorption capabilities. Notably, organic alkoxide pretreated dyeing demonstrated improved color strength, exhaustion, and fixation efficiency compared to Na2CO3 pretreatment, as one of the work’s key findings. For instance, the conventional dyed fabric exhibits 3.4 times lower color strength than alkoxide-based (RR239 + C2H5ONa 3 g/L + EtOH) dyeing, showing substantial potential for upscaling at commercial level as it requires no chemical auxiliaries (such as NaCl and Na2CO3). Importantly, the alkoxide pretreatment does not significantly alter the physical, mechanical and fastness properties of the fabrics, which are comparable to both the pristine and aqueous dyed fabrics, as confirmed by scanning electron microscopy experiments. The effluent’s color intensity resulting from dyeing with C2H5ONa + EtOH (3 g/L) is approximately 24 times lower (250 Pt/Co) in comparison to the aqueous dyeing using 40 g/L of NaCl and 20 g/L of Na2CO3 in an aqueous medium (6154 Pt/Co). Apart from the color intensity, alkoxide pretreatment and EtOH-based dyeing drastically reduce the COD, BOD, TDS, TSS and total hardness values, which could have cost-saving implications for wastewater treatment plants (WWTPs).

Assessing environmental pollutionfrom shrimp farming activities in Soc Trang province

The study aimed to evaluate the level of environmental pollution from shrimp farming in coastal areas of Soc Trang province. A total of 10 shrimp farming households and 50 neighbouring households were interviewed about emissions and environmental sanitation conditions. At the end of the shrimp season, pond water samples were collected from 5 semi-intensive ponds and 5 intensive ponds, bottom sediment samples were collected from 5 semi-intensive ponds to evaluate the level of pollution. Interview results indicated that wastewater and bottom sediment from shrimp farming are the main causes of declining surface water quality and reducing the number of wild fish; pollution levels are likely to increase in the future. The pH, total suspended solid (TSS), BOD5, and chemical oxygen demand (COD) values of pond water samples are suitable for shrimp farming (except TSS of water samples in Cu Lao Dung and Long Phu); total Kjeldahl nitrogen (TKN) and total phosphorus (TP) contents fluctuate widely between sampling ponds. The metal content in the bottom sediment is lower than the allowable discharge threshold of sediment quality standards. Solid waste generated in farming areas has not been properly collected and treated. To sustainably develop the shrimp industry, local authorities need to encourage shrimp farmers to apply proper waste treatment technologies in addition to state management solutions.

Investigation and Evaluation of Aquiferous Zones Within Orlu and Its Environs, Using a Geo-electrical and Physiochemical Approach

This study investigated the suitability of drinking water in Orlu, Nigeria, facing challenges due to limited surface water availability and environmental deterioration. To solve the problem of the availability of portable water, electrical resistivity surveys using a Schlumberger array were conducted to identify potential groundwater resources. Twelve locations were assessed, revealing resistivity values indicative of potential aquifers. Following the geophysical survey, the physicochemical properties of water samples collected from various locations were analyzed. Parameters including pH, dissolved oxygen (DO), total dissolved solids (TDS), and minerals were evaluated against WHO and Nigerian drinking water standards. The analysis indicated generally good water quality across the sampling sites. pH levels were within the recommended range, and DO concentrations met the minimum requirements. Similarly, TDS and BOD values suggested low levels of organic matter and dissolved solids. Mineral content also remained below WHO-permissible limits. A Water Quality Index further confirmed that the water quality within the study area can be graded from good to excellent in quality. These findings suggest that the groundwater resources identified in the study hold promise for providing safe drinking water in Orlu and its environs.

Oil spill dispersant formulation from Palmitoyl-DEA and methyl ester sulfonate

Surfactants are chemical compounds that can interact with solvents to reduce surface tension. Palmitoyl-Diethanolamide surfactant (Palmitoyl-DEA) and methyl ester sulfonate (MES) can be applied in dispersing oil in seawater as Oil Spill Dispersant (OSD). An OSD formulation derived from a mixture of two surfactant solutions, namely Palmitoyl-DEA and MES, was found. Diethanolamide non-ionic surfactant solution and anionic methyl ester sulfonate surfactant solution in various concentrations were mixed according to their respective ratios at 50℃ for 60 minutes. The OSD product obtained was then analyzed for density, surface tension, and emulsion stability. OSD products at a concentration of 4% MES and 2% DEA with a 2:1 ratio obtained the best analytical results. The OSD product has excellent density, surface tension, and emulsion stability (> 80%). Furthermore, testing of OSD products was carried out for oil pollution in seawater. The results of simulation tests using OSD products for handling petroleum pollution in seawater (15 mL/L) show an excellent ability to disperse oil (> 90%). The oil and OSD dispersed in seawater showed a more significant increase in COD and BOD values.

Kajian Kualitas Air Laut dan Sebaran Indeks Pencemaran di Pesisir Utara Kecamatan Palang-Tuban pada Musim Kemarau

The northern coastal area of ​​Palang Sub-District is a densely populated area in the Tuban district with high differentiation of economic activities. The large population and heterogeneous community activities on the northern coastal of Palang Sub-District have the potential to become a source of pollution which results in a decrease in seawater quality. The research aim is to analyze seawater quality on the north coast of Palang Sub-District based on seawater quality parameters and the spatial distribution of the pollution index. It is hoped that this research can help local governments to monitor and control water pollution in the area. Sea water sampling was carried out in the dry season for 2 days at high and low tide conditions. This research analyzes the concentration values ​​of BOD, COD, NO3-, TSS, detergent, oil & grease, pH, temperature, and Total coliform compared to seawater quality standards of PP RI No. 22 of 2021 Appendix VIII on Marine Biota. The spatial distribution of the water quality pollution index is the result of interpolation using the Inverse Distance Weighted (IDW) method from the results of measuring test parameters. The Pearson Correlation statistical test was carried out to determine the level of correlation between the parameters selected in determining water quality. The results of the research show a decline in the quality of the northern coastal waters of Palang-Tuban District with several parameter concentration average values ​​exceeding the quality standards, namely pH = 6.9 (QS = 7.0-8.5); TSS = 29.2 ppm (QS= 20 ppm); Nitrate = 0.4 ppm (QS = 0.06 ppm), BOD5 = 54.8 ppm (QS= 20 ppm), COD = 112.5 ppm (QS= 100 ppm). The water quality status shows that the water conditions are moderately polluted (ST1A), lightly polluted (ST1B-ST5B), and good conditions (ST4C & ST5C). Controlling and reducing the pollution load entering coastal waters needs to be carried out to prevent the quality of coastal waters from decreasing further. One of them is by creating wastewater treatment at every fishing port and fish auction.

Metagenomic landscape of sediments of river Ganga reveals microbial diversity, potential plastic and xenobiotic degradation enzymes

The Ganga is the largest river in India, serves as a lifeline for agriculture, drinking water, and religious rites. However, it became highly polluted due to the influx of industrial wastes and untreated sewages, leading to the decline of aquatic biodiversity. This study investigated the microbial diversity and plastic-xenobiotic degrading enzymes of six sediment metagenomes of river Ganga at Prayagraj (RDG, TSG, SDG) and Devprayag (KRG, BNG, BRG). The water quality parameters, higher values of BOD (1.8–3.7 ppm), COD (23–29.2 ppm) and organic carbon (0.18–0.51%) were recorded at Prayagraj. Comparative analysis of microbial community structure between Prayagraj and Devprayag revealed significant differences between Bacteroidetes and Firmicutes, which emerging as the predominant bacterial phyla across six sediment samples. Notably, their prevalence was highest in the BRG samples. Furthermore, 25 OTUs at genus level were consistent across all six samples. Alpha diversity exhibited minimal variation among samples, while beta diversity indicated an inverse relationship between species richness and diversity. Co-occurrence network analysis established that genera from the same and different groups of phyla show positive co-relations with each other. Thirteen plastic degrading enzymes, including Laccase, Alkane-1 monooxygenase and Alkane monooxygenase, were identified from six sediment metagenomes of river Ganga, which can degrade non-biodegradable plastic viz. Polyethylene, Polystyrene and Low-density Polyethelene. Further, 18 xenobiotic degradation enzymes were identified for the degradation of Bisphenol, Xylene, Toluene, Polycyclic aromatic hydrocarbon, Styrene, Atrazene and Dioxin etc. This is the first report on the identification of non-biodegradable plastic degrading enzymes from sediment metagenomes of river Ganga, India. The findings of this study would help in pollution abatement and sustainable management of riverine ecosystem.

Factors affecting the performance of a pharmaceutical wastewater treatment plant: Characterization of effluent and environmental risk

Pharmaceutical industries produce a huge volume of emerging pollutants (EPs) that pose a threat to the aqueous environment. Biological processes have shown their inefficacy in treating many pharmaceutical products. The study assessed physicochemical parameters, EPs, heavy metals in pharmaceutical industrial wastewater, and the removal efficiency (RE) of an aerobic biological treatment plant. The study also assessed the contamination levels and risk using several indices, such as the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), heavy metal pollution index (HPI), heavy metal evaluation index (HEI), and risk quotients index (RQs). The study found that the treated water quality was poor, having antibiotics, nonsteroidal anti-inflammatory drugs, and others, along with several transformation products (TPs) and heavy metals, which were unsafe for consumption with high environmental risk. The analysis results showed that the RE for TSS, BOD5, COD, TDS, and EC were found to be 91.80%, 86.81%, 72.29%, 72.20%, and 65.60%, respectively, where the values of BOD5, COD, NO3−, and PO43− in the effluent were still higher than the permissible limits of the ECR (2023). However, the RE for heavy metals was in the order of Cu (84.62%) > Fe (65.04%) > Mn (63.3%) > Zn (60.58%) > Cd (53.85%) > Ni (54.12%) > Pb (42.42%) > Cr (38%), where Cr and Cd concentrations were still higher than the permissible limit of DoE (2019). The Pearson correlation and PCA suggested that EC, TDS, TSS, DO, BOD5, and COD were the most correlating and contributing variables. This study argued that metal-ligand behaviors mainly affect the removal efficiency of the treatment plant by lowering the removal rate of heavy metals and pharmaceutical products.

Physicochemical characterization of university campus’ wastewater for internal treatment system installation (Casablanca, Morocco)

Today, protecting water resources and their sustainable use has become an obligation of people and organizations. Wastewater management and reclamation are the most important solutions to protect these resources. This study aims to determine the wastewater physicochemical quality of the Faculty of Sciences Ben M'Sick (FSBM) (Casablanca, Morocco) to establish the appropriate system for their treatment and internal reclamation. The results show that averages of FSBM's wastewater temperature vary between 17.64 and 19.55 °C, 7.18 and 8.18 for pH, and 2.47 and 3.98 mS.cm-1 for electrical conductivity.. The COD, BOD5, and TSS average values oscillate respectively between 967.44-1,151.08 mg.L-1, 70.5-119.05 mg.L-1, and 223.64-1,659.74 mg.L-1, and those of total phosphorus between 2 and 3.99 mg.L-1. The determination of the biodegradability degree of the discharge, through the calculation of COD/BOD5, BOD5/COD, TSS/BOD5, COD/TP, COD/NH4+ ratios, and oxidizable matters (OM,) reveals that the FSBM's wastewater has a heterogeneous character with a high load of oxidizable matter difficult to biodegrade. Despite its low biodegradability, the FSBM’s wastewater could be treated using a biological treatment system, preceded by a physicochemical treatment to eliminate non-biodegradable chemical substances. Such a choice of wastewater treatment system requires prior experimental investigations and laboratory tests.

Modification of antibacterial and self-cleaning composite membrane using thermo-responsive hydrogel for fish ball industrial wastewater treatment

Membrane technology is commonly used to treat wastewater in the food industry. However, membrane fouling remains a major problem. This research aims to study the development of composite membranes with antibacterial properties and self-cleaning ability to solve the membrane fouling problem for fish ball industrial wastewater treatment. Polyethersulfone (PES) membrane was modified with poly(N-isopropyl acrylamide) (PNIPAM), sodium acrylate (SA), and [2-(methacryloyloxy)ethyl]trimethylammonium chloride (DMC), followed by adsorbing silver nanoparticles (AgNPs) onto the membrane surface. The results demonstrate that PNIPAM-SA and PNIPAM-DMC hydrogels at 100-0, 90-10, and 80-20 concentration ratios exhibit thermo-responsive properties. This thermo-responsive effect facilitates the self-cleaning of the membrane at 40 °C (higher than LCST). PES/PNIPAM-SA (80-20) membrane modified with AgNPs exhibited the highest antibacterial properties. For BSA filtration, it was found that the PES/PNIPAM-SA/Ag membrane had a flux that was twice as high as that of the PES/PNIPAM-DMC/Ag membrane. For the filtration of fish ball industrial wastewater, the PES/PNIPAM-SA/Ag membrane is capable of reducing COD, BOD, TKN, and TSS values by 96.64%, 98.13%, 74.68%, and 70.48% respectively. The wastewater quality of permeate passed the standard requirements. Membranes with self-cleaning and antibacterial properties are good candidates to develop for use in further wastewater treatment.

Prediction of the biodegradation of chemicals using OECD QSAR Toolbox software

Introduction. The development of integrated approaches to testing, assessment of the hazard and exposure risk of chemicals on human health and the environment is one of the priorities of preventive toxicology. An integrated approach involves various combinations of methods in silico, in chemico, in vitro, ex vivo, in vivo for hazard assessment. In the Russian Federation, in silico methods are often perceived with skepticism, mainly due to the lack of their legal status, weak methodological base and insufficient training of specialists. In order to expand the methodological base, the possibility of predicting the stability of chemicals in biotic conditions using the OECD QSAR Toolbox software was studied.
 Material and methods. The OECD QSAR Toolbox software version 4.4.1., OECD guidelines on the assessment of biodegradation of chemicals.
 Results. The world community and the OECD have developed and implemented a three-level system for chemicals biodegradation testing, which includes tests for readily biodegradation (OECD Guidelines 301 A, 301 B, 301 C, 301 D, 301 E, 301 F, 306, 310), tests to determine the potential biodegradability (OECD Guidelines 302 A, 302 B, 302 C, 304 A) and model systems tests (OECD Guidelines 303 A, 303 B).
 To test the capabilities of the program, 24 endpoints were selected. They are the determination of biodegradability (%) by BOD, DOC, CO2, CH4 releases in OECD tests 301 A, 301 B, 301 C, 301 D, 
 302 C, 302 B, biodegradability (%) in sediments and soil, bioconcentration factors for more than 100 organic chemicals of various structures.
 The parameters were calculated using the analog method, followed by mandatory interpretation of the data obtained by an expert. When predicting the biodegradability of chemicals, it is necessary to perform a series of calculations using different tests (OECD tests 301 A, 301 B, 301 C, 301 D, 301 E, 302 B are preferred) and grouping methods followed by a comprehensive assessment of the results obtained, taking into account not only the structural similarity of substances and analogues, but also the quality of the experimental data used. When predicting biodegradability by BOD values, it is advisable to use the OECD 301 C test. The proportion of tested substances whose biodegradability could be estimated by BOD values is about 50% in the OECD 301 C test, which is primarily due to the presence of a significant amount of experimental data. The calculation of bioconcentration factors seems to be promising. For about 45% of the tested substances, it was possible to calculate bioconcentration coefficients with good correlation with experimental data. Biodegradation in soil (% and half-life) can be predicted only for a very limited range of compounds (10% of the tested substances), which is due to the difficulty of selecting structurally similar analogues with experimental data. The method is not applicable for predicting the biodegradation of salts, organometallic compounds, polymer molecules and mixed products.
 Conclusion. The Russian Register of Potentially Hazardous Chemical and Biological Substances has developed a methodological guide for predicting the stability of chemicals in biotic conditions using the OECD QSAR Toolbox software. The document presents algorithms for calculating biodegradability (%) according to OECD tests 301, 302, 303; BOD, bioconcentration factors and biodegradability (%) in soil.

Spatiotemporal Variation Analyses of Water Quality, Fish Ecological Guilds, and the Longitudinal Connectivity in Musim Stream

The main objectives of this study were to analyze the spatiotemporal variations of water quality, fish ecological guilds and longitudinal connectivity in the weirs of Musim Stream. Fish were collected at 44 sites during spring and fall seasons for the analysis of trophic guilds, tolerance guilds, and the ecological stream health, based on FAI model. Total 33 species were observed in the stream and the dominant species were <i>Zacco platypus</i> and <i>Squalidus qracilis majimae</i>. Mean values of BOD and COD, as an indicator of organic matter pollution, showed high in the drought spring and low in fall (post-monsoon season). Also, TP showed same pattern with the BOD and COD pattern. The hierarchical clustering, based on the fish compositions, classified as three groups (up-stream, mid-stream and the down-stream). Based on the NMDS (Non-metric Multidimensional Scaling) analysis of fish abundance, high similarity was observed between S1-S5 sites, which were consistent with the results of hierarchical cluster analysis. Fish ecological guilds in the upper stream showed a high similarity between the insectivore and sensitive species, while in the middle and lower reaches, high similarity was found between the omnivore and intermediate species. Evaluations of longitudinal connectivity, based on the structural and hydrological characteristics of the weir, indicated all disconnections by the weirs, except for S15, in the spring. Stream ecological health, based on the FAI model, was significantly (<i>p</i> < 0.05, n=37) influenced by the height of overflow (<i>Hu1</i>). Overall, our study suggests that the longitudinal connectivity, based on the weir structures, flow regime and fish swimming capacity, were blocked off by the weirs in the stream. The results provide valuable insights for securing river management strategies and served as the fundamental data for stream restoration in the future.