Water Turbidity Research Articles

Physico-chemical and microbiological parameters of natural, industrial recycled water and its treatment

Background: Under conditions of anthropogenic impact, the chemical composition of water in surface rivers and groundwater bodies is subjected to pollution, which leads not only to a decrease in water quality, but also to an increase in the number of pathogenic and opportunistic bacteria. Aim: The purpose of this work is to study the physicochemical and microbiological parameters of natural and industrial recycled water before and after treatment with coagulants based on activated aluminum alloys. Materials and methods: As natural waters were analyzed: natural waters from water intake “Almaty SU”, “Medeu” tract, Zhaiyk river, from the well of experimental metallurgical production of IMOB. As recycled water was analyzed water taken from the water treatment unit of deep oil refining production. Turbidity was measured using HACH 2100Q turbidimeter and 2100Qis turbidimeter (USA). Cell morphology of microorganism cultures was studied by light microscopy using a MicroOptix MX-1150 (T) stereoscopic-sotrinocular microscope. Results: An effective and technologically simple method of obtaining aluminum polyoxychloride with the content of the main substance from 33 to 41.0% by Al2O3 and basicity from 55.1 to 66.5% has been developed. The method consists in dissolution of aluminum alloy activated by metal-activators (indium, gallium, tin) in the amount of 0.5–1.0 wt.% of each in 3% HCl. Physico-chemical and microbiological parameters of natural and industrial recycled water have been studied. The efficiency of the obtained aluminum polyoxychloride for treatment and conditioning of drinking water and industrial recycled water was evaluated. Conclusion: Unique alloys with high energy characteristics based on aluminum containing indium, gallium, tin from 0.5–1.0 wt.% have been created. The alloy has high activity in various oxidizing media (water, hydrochloric acid). A technologically simple method of obtaining aluminum polyoxychloride has been developed. Chemical and microbiological composition of natural and industrial recycled water has been studied. Coagulants based on activated aluminum alloys are effective in the processes of conditioning and purification of natural and recycled water from toxic compounds, have bactericidal activity, the level of gram-negative bacteria is reduced to 73%, gram-positive bacteria to 84% and to 96% of other groups of microorganisms. Fungi and yeasts (Mucor, Fusarium) were not detected after water treatment. Efficiency of water turbidity reduction reaches 90–99%, permanganate oxidizability up to 93%.

Polarization-Enhanced Underwater Laser Range-Gated Imaging for Subaquatic Applications.

Laser range-gated underwater imaging technology, by removing most of the backscattering noise, can effectively increase image contrast and extend the detection range. The optical signal captured by a range-gated imaging system primarily comprises reflected light from the object and backscattered light from the surrounding water. Consequently, surfaces with low reflectivity or highly turbid water environments substantially constrain the applicability of the range-gated imaging system. To enhance the detection capability of underwater laser range-gated imaging, this paper proposes the incorporation of underwater polarized light imaging technology as an enhancement method. Based on polarization differences, backscattered light and reflected light from an object can be distinguished. Experimental results indicate that, compared to images obtained using a conventional range-gated laser imaging system, those captured with a polarization-enhanced system exhibit an increase of up to 47% for the corresponding Enhancement Measure Evaluation (EME) index. The proposed approach, which integrates polarization imaging with range-gated laser imaging, has the potential to broaden the applicability of underwater laser imaging scenarios, such as deep-sea exploration and military applications.

A smart, multi-configuration, and low-cost system for water turbidity monitoring

Measuring the amount of suspended sediment in rivers is important for a better understanding of phenomena like soil erosion or floods. Since such phenomena are not spatially homogeneous, a distributed measurement approach is required to obtain fine-grained and realistic models. We designed and implemented a low-cost, flexible, and smart suspended sediment concentration monitor. The system only uses components that are easy to find and assemble. This, together with the reduced costs, enables the use of multiple instances for distributed monitoring. The system can operate according to different configurations, fixed or mobile, and using a variety of connection technologies, to possibly cover the various necessities that arise from the diverse installation sites. Each measuring unit automatically retrieves its operational parameters, easing the configuration of a possibly large distributed measurement system.

Study on the coupling enrichment process mechanism of volatile oil of Alpiniae officinarum rhizoma from oil-bearing water

The aim of this study is to study the demulsification of oil-bearing water in Alpiniae officinarum rhizoma by the combination of chemical demulsification and membrane separation. Oil-bearing water of A. officinarum rhizoma was demulsification by two methods of inorganic salt-membrane separation and span-membrane separation, and the influence of process parameters was systematically studied by single factor analysis. Then the chemical demulsification process was optimized by orthogonal design (three factors and three levels). The membrane flux and enrichment rate before and after demulsification were measured. The results showed that the membrane flux and enrichment rate of the inorganic salt-membrane separation and demulsification were 2.03 times and 1.18 times higher than those of the undemulsification, and the span-membrane separation was 1.34 times and 1.18 times of that of undemulsification, respectively. The turbidity, viscosity, pH, and particle size of oil-bearing water before and after demulsification were measured, and the correlation between demulsification process, physicochemical properties, membrane flux, and enrichment rate was analyzed. The results indicate that inorganic salt and span change the membrane flux and enrichment rate by decreasing turbidity and increasing particle size. The chemical composition and relative content of volatile oil were similar before and after demulsitioning by GC-MS. The highest relative content was 1,8-eucalyptine (20.05∼51.42%), followed by α-terpineol (11.13∼12.66%), camphene (2.74∼6.75%), camphor (2.29∼4.74%), etc. The results showed that the composition of volatile oil of A. officinarum rhizoma collected by the two demulsification methods remains unchanged, and the inorganic salt-membrane separation was more suitable for the demulsification application of oil-bearing water of A. officinarum rhizoma.

Prevalence of Intestinal Parasitosis Caused by Nematopsis sp (Protozoa: Apicomplexa) in Litopenaeus vannamei and its Relationship with Water Turbidity, in a Fattening Farm

Objective: This research aims to calculate the prevalence of intestinal parasitosis caused by Nematopsis sp (Protozoa: Apicomplexa) on white shrimp (Litopenaeus vannamei) and relate it to water turbidity, in a fattening farm. Methods: The work was carried out on the western coast of the state of Falcón (Venezuela), where the animals (for clinical and laboratory analysis) and the turbidity data of the pool water were obtained. For the turbidity analysis, the Secchi disk was used, which allowed the measurement to be recorded in centimeters of transparency. The shrimp were captured by random sampling in the lagoons and immediately transferred to the laboratory for clinical study, subsequently data on prevalence, correlation (R), and coefficient of determination (R2) were obtained. Results: Once the analyses were carried out, a correlation coefficient (R) of 0.319951628 was obtained, indicating the low dependence (weak positive connection) between the related variables (the prevalence of diseases and the levels of turbidity in the water). In the evaluation of the R2, the value of 0.102369044 was obtained, which indicated that in only 10.23% of the infected animals, there was an influence of turbidity on the prevalence of infected animals. Conclusion: The prevalence values obtained in this study are consistent with those reported in other research in Latin America. In turn, the related data demonstrated that water turbidity could be related (weakly) to the presence of the parasitic protozoan Nematopsis sp, however, their statistical relationship is very scarce.

Innovative upcycling gabions with coal bottom ash for nonpoint source pollution control against climate change

Climate change accelerates extreme temperature fluctuations and rainfall volatility, and shifts in rainfall patterns, rapidly increasing nonpoint source pollution originated from turbid water and soil erosion. The climate changes also pose serious threats to the agricultural environment and food security. This study innovates the conventional control facilities of turbid water and soil erosion in the sloping field, using coal bottom ash as a harmful waste of thermal power generation. Typical gabion and side modified gabion are designed in consideration with geographical characteristics. The adsorption capacity of coal bottom ash for turbidity, suspended solids (SS), total nitrogen (T-N), and total phosphorus (T-P) were increased as the amounts of coal bottom ash increase. At the rate of 20-g coal bottom ash, the turbidity, SS, T-N, and T-P were absorbed by 84.0%, 80.2%, 40.2%, and 53.2%, respectively. The typical gabion (TG) and side modified gabion (SMG) installed in the sloping field also decreased the turbidity, SS, T-N, and T-P by up to 98.1%, 99.4%, 77.6%, and 84.0%, respectively, during the natural rainfall events. The use of coal bottom ash cannot only be an effective upcycling way to control nonpoint source pollution but also be an ecofriendly approach against climate change.

Performance of different rice genotypes cultivated under submergence and normal growing conditions

Abstract Submergence negatively affects the plant growth and yield of rice genotypes, which in turn results in huge financial loss. Thus, identification of submergence tolerance rice genotypes is needed for sustainable rice cultivation in flood-prone areas. Keeping this in view, a two-year (2019 and 2020) field study was undertaken at Rice Research Farm of Bihar Agricultural College, Bihar Agricultural University, Sabour, Bhagalpur to investigate and compare the yield responses of rice genotypes under submergence and normal growing conditions. Twenty-five days old seedlings of 25 rice genotypes were transplanted in a randomized complete block design in two replicates, which were allowed to grow under normal practice for the next 25 days. Thereafter, the 50-day old plants were completely submerged with turbid water of 1.5 m height for the next 18 days. After de-submergence, all the recommended agronomic practices were adopted during the rest of the crop period. Under submergence, higher grain yield was recorded under all the genotypes during 2020 as compared to 2019 mainly due to higher temperature and lesser rainfall during 2020. Under submergence conditions, Jalmagna, Nona Bokra and Swarna Sub 1 were the best performers having produced average yields of 3,167, 2,786 and 2,741 kg/ha, respectively. Whereas under normal growing practice, Swarna Sub 1, Jalmagna and Sudha were the first three best performing genotypes producing average yields of 5,063, 4,565 and 4,456 kg/ha, respectively. Therefore, Jalmagna should be preferred for cultivation in the flood-prone regions of the state, however in non-flooded areas; Swarna Sub 1 may be cultivated.

Antibacterial bio pores as a river flow filter for the development of "Ndeso Park" water tourism

The realization of the full potential of natural resources in each village for the benefit of the local community has been observed as a significant challenge. The national village-owned enterprises program encourages villages to optimize the utilization of their existing natural and human resources with the objective of fostering their economic independence. The program entails the optimization of the national village-owned enterprises program in the tourism sector, specifically in the context of Taman Ndeso. The objective of this community service activity is to provide technological assistance and address the issue of river water filtration as a pool water source. The impetus for this activity is the declining tourism activities at Taman Ndeso due to the presence of turbid water in the pool, which was deemed unsuitable for use. The activity is realized through the construction of a water purification filtration system to produce clean and healthy water. The antibacterial biopores are applied as filtration technology. This technology is designed to capture bacteria from river water that flow into the pond. This research adopted the direct exploration method, which was divided into a number of stages, including planning and preparation, implementation, evaluation, and reporting. The research outcome manifests into the restoration of the Taman Ndeso water tourism pool, which will be capable of attracting tourists and reviving village income to the maximum extent possible, with the management of the village-owned business entity.

Using Artificial Neural Networks to Predict Operational Parameters of a Drinking Water Treatment Plant (DWTP)

The scope of the present study is the estimation of key operational parameters of a drinking water treatment plant (DWTP), particularly the dosages of treatment chemicals, using artificial neural networks (ANNs) based on measurable in situ data. The case study consists of the Aposelemis DWTP, where the plant operator had an estimation of the ANN output parameters for the required dosages of water treatment chemicals based on observed water quality and other operational parameters at the time. The estimated DWTP main operational parameters included residual ozone (O3) and dosages of the chemicals used: anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas (Cl2(g)). Daily measurable results of water sample analysis and recordings from the DWTP Supervisory Control and Data Acquisition System (SCADA), covering a period of 38 months, were used as input parameters for the artificial neural network (1188 values for each of the 14 measurable parameters). These input parameters included: raw water supply (Q), raw water turbidity (T1), treated water turbidity (T2), treated water residual free chlorine (Cl2), treated water concentration of residual aluminum (Al), filtration bed inlet water turbidity (T3), daily difference in water height in reservoir (∆H), raw water pH (pH1), treated water pH (pH2), and daily consumption of DWTP electricity (El). Output/target parameters were: residual O3 after ozonation (O3), anionic polyelectrolyte (ANPE), poly-aluminum chloride hydroxide sulfate (PACl), and chlorine gas supply (Cl2(g)). A total of 304 different ANN models were tested, based on the best test performance (tperf) indicator. The one with the optimum performance indicator was selected. The scenario finally chosen was the one with 100 neural networks, 100 nodes, 42 hidden nodes, 10 inputs, and 4 outputs. This ANN model achieved excellent simulation results based on the best testing performance indicator, which suggests that ANNs are potentially useful tools for the prediction of a DWTP’s main operational parameters. Further research could explore the prediction of water chemicals used in a DWTP by using ANNs with a smaller number of operational parameters to ensure greater flexibility, without prohibitively reducing the reliability of the prediction model. This could prove useful in cases with a much higher sample size, given the data-demanding nature of ANNs.

Structural Characteristics of Phytoplankton Communities and Its Relationship with Environmental Factors in Different Habitats of Hedi Reservoir

To explore the characteristics of phytoplankton communities and their relationship with environmental factors in different habitats of Hedi Reservoir, the inflow rivers, estuaries, and reservoir area of Hedi Reservoir were investigated in February （recession period）, April （flood period）, July （flood period）, and December （recession period） of 2022. During the investigation, 231 species of phytoplankton that belong to seven phyla were identified, and the cell density of phytoplankton ranged from 2.94 × 106 - 8.04 × 108 cells·L-1. Phytoplankton cell density in flood periods were higher than that in recession periods, and that was higher in estuaries and the reservoir area than that in inflow rivers. Meanwhile, the cell density of phytoplankton in the estuarine and reservoir area was dominated by Cyanobacteria throughout the year, especially Raphidiopsis raciborskii, whereas the cell density of phytoplankton in inflow rivers was dominated by Cyanophyta, Chlorophyta, and Bacillariophyta. In the inflow river area, the dominant species of cyanobacteria were Microcystis aeruginosa, Limnothrix redekei, Pseudanabaena circinalis, and Merismopedia punctata； the dominant species of Chlorophyta were Chlorella vulgaris and Crucigenia tetrapedia； and the dominant species of Bacillariophyta were Chlorella vulgaris and Melosira granulate. The highest biodiversity （Shannon-Wiener Index, Pielou index, and Margalef index） were observed in the inflow river area of Hedi Reservoir. The correlation analysis （Pearson） indicated that the environmental factors that were significantly correlated to phytoplankton communities included water temperature, dissolved oxygen, pH, conductivity, nitrogen, and phosphorus concentration. The RDA analysis indicated that phytoplankton communities in the inflow river area were mainly affected by pH and total nitrogen concentration, which were majorly affected by water temperature and pH in the estuarine area and chiefly affected by turbidity and pH in the reservoir. The pH affected the changes in phytoplankton communities in all three different habitats, whereas the inflow river area was significantly affected by total nitrogen concentration, and the estuarine and reservoir were significantly affected by water temperature and turbidity, respectively.

A photonic sensor system for real‐time monitoring of turbidity changes in aquaculture

AbstractObjectiveThe objective of this study was to test the compatibility and performance of a developed photonic sensor system, which can serve as a dependable and practical device for continuous monitoring of turbidity changes in aquaculture tanks.MethodsThe fabricated photonic sensor system consisted of an integrated data logger and sensor probe. The sensor probe exhibited a precise emission of infrared light at a wavelength of 850 nm. Moreover, the sensor evaluates the ambient light across the red‐green‐blue spectrum. To ensure accuracy and reliability, the entire system underwent a thorough calibration process, referencing nephelometric turbidity unit values acquired through a specialized handheld turbidimeter. Rigorous trials were systematically conducted in 600‐L seawater tanks featuring tubular sea cucumber Holothuria tubulosa and Gilt‐head Sea Bream Sparus auratus to ensure the sensitivity and robustness of the photonic sensor system to the aquaculture environment.ResultA calibration curve revealed a significant correlation between the infrared channel values of the sensor (photon counts) and the turbidity values measured by the turbidimeter. The photonic sensor effectively captured turbidity changes in the aquaculture tanks, with significant differences observed between the tanks. The sensor performance was evaluated in trials with Gilt‐head Sea Bream, which showed sensitivity to high turbidity changes. The photonic sensor system accurately reflects turbidity changes continuously using its own active light source, independent of ambient light intensity, which is essential for turbid water conditions or for taking measurements in total darkness.ConclusionThe photonic sensor is a reliable tool for the continuous and accurate monitoring of turbidity changes in aquaculture systems. However, there are specific usage limitations under low‐turbidity conditions that can be improved in further studies.

Physiological responses of the Asian green mussel (<i>Perna viridis</i>) in highly turbid waters

In order to simulate conditions induced by climate change, the filtration rates and pseudofaeces production of Perna viridis from two distinct size categories were investigated at progressively increasing total suspended solid concentrations. Filtration rates of smaller mussels increased with increasing total suspended solid concentration. For larger mussels, filtration rates increased with increased concentration up to 800 mg L–1, after which filtration rate dropped sharply. Pseudofaeces production also increased with increasing total suspended solid concentration up to 600 mg L–1, beyond which no further significant increase was observed for large mussels, and there was a considerable decline for small mussels. The results show that the mussels of different sizes have different filtration rates with smaller mussels ranging from 0.11 to 2.62 mg min–1 and in larger mussels from 0.21 to 4.83 mg min–1. Pseudofaeces production ranged from 0.08 to 0.67 mg min–1 for small mussels and from 0.02 to 1.42 mg min–1 for larger mussels. These results may imply that smaller mussels are more vulnerable to siltation and high sediment load compared to larger individuals. In the natural environment, this situation can be caused by more frequent and severe typhoons resulting from climate change.

Remote sensing of turbid coastal and estuarine waters with VIIRS I (375 m) and M (750 m) bands

ABSTRACT The Visible Infrared Imaging Radiometer Suite (VIIRS) is a visible, near and shortwave, to thermal infrared multispectral scanning instrument operational on three polar orbiting satellites, Suomi-NPP, JPSS-1, and JPSS-2. In the present paper, the processing of VIIRS using ACOLITE is introduced, using the Dark Spectrum Fitting (DSF) algorithm for processing of the visible to shortwave infrared bands. ACOLITE now includes support for processing both the imaging (I) and moderate (M) resolution bands at 375 m and 750 m spatial resolution, respectively. In most conditions encountered in the present study, the SWIR bands (either I or M) are automatically selected by the DSF for performing the aerosol correction. The processing is evaluated for turbid water remote sensing via autonomous hyperspectral radiometry from four sites across coastal and estuarine waters: two sites in Belgium and one each in France and Argentina. Through analysis of hundreds of matchups between the satellite and in situ measurements, a generally good performance is found for both I and M bands, especially for bands with the largest water signal, i.e. bands between 490 and 670 nm, where on average relative differences of 10–15% were found. Reflectance biases are generally less than 0.01, with a negative sign in the green and red bands and a positive sign in the blue and NIR bands. Similar matchup results are found for the I and M red and NIR bands, with a slightly higher scatter for the NIR bands. An additional comparison with OCSSW/l2gen processing of the M band data is performed for various configurations. Overall, DSF performance is better in the visible bands, whereas l2gen outputs are more closely aligned with the in situ measurements in the NIR. On average, negative biases are found for all l2gen configurations, up to −0.02 in the blue bands. Using either the SWIR1 + 2 or SWIR1 + 3 bands for the aerosol correction gives the best performance for l2gen processing. For the three VIIRS instruments separately, the average spectral differences with in situ measurements are comparable, with the most important deviation occurring at the Suomi-NPP shortest blue bands, where DSF processing gives a larger positive bias, up to nearly 0.02. For these bands, results from l2gen correspond more closely across the three instruments – although with significant negative biases for all three sensors up to −0.02 – presumably due to the use of system vicarious calibration gains in that processor. An operational network of autonomous hyperspectral instruments provides validation data for any overpassing optical imaging satellite in its commissioning or operational phase and eliminates the need for spectral interpolation or band shifting. In the case of VIIRS specifically, the hyperspectral instruments provide adequate data for the validation of the 20, 40 and 80 nm wide bands. With three operational wide-swath instruments, which provide largely interoperable data, a high frequency of observations is available, especially for study areas at higher latitudes. The novel exploitation of the I bands is now possible, thanks to the free and open source availability of ACOLITE. The advantage of the higher resolution I band data, combined with multiple VIIRS overpasses per day, is demonstrated for mapping turbidity in nearshore regions with high spatial variabilty and for detecting under-resolved floating algae.

Quality and noodle-making performance of wheat flour with varied gluten strengths altered by addition of various arabinoxylans.

This study examined the effects of adding different types of arabinoxylans (AXs) to wheat flour with varying gluten strengths on flour quality and noodle-making performance, with the aim of utilizing AXs as health-enhanced ingredients. Three flours (Goso, Hojoong, and Joongmo) with low, medium, and high gluten strengths were used, along with two water-extractable AXs (E1 and E2) and one water-unextractable AX (U) with diverse molecular weights and viscosities. The addition of 2% AXs increased the water and sucrose solvent retention capacity values and decreased the gluten performance index values for all flours, with a notable effect on Goso flour by U. The dough development time was prolonged in all flours, necessitating more water for development. The sodium dodecyl sulfate sedimentation volume increased with the addition of AXs, especially with E2 and U. Pasting properties remained unaffected, suggesting a minimal impact on starch-related properties. However, noodles made with E2 and U showed deteriorated quality in terms of fresh noodle texture, weight gain, cooking water turbidity, and cooked noodle texture, in contrast to noodles made with E1 alone. Additionally, adjusting the water amount when adding U altered the textural properties, approaching that of noodles without added AXs. Overall, the impact of AXs on flour and noodle quality varied depending on their molecular weights, viscosities, and the gluten strength of the flour. Additionally, AXs could be successfully utilized by adjusting the water amount for the production of health-enhancing noodles. PRACTICAL APPLICATION: Arabinoxylans, as health-promoting ingredients, can be utilized in noodle production by optimizing the water amount and mixing time.

A 14,000‐Year Sediment Record of Mercury Accumulation and Isotopic Signatures From Lake Malaya Chabyda (Siberia)

AbstractEurasian permafrost soils contain large amounts of organic carbon (OC) and mercury (Hg), sequestered by vegetation during past and present interglacial periods. Lake sediment archives may help understand past OC and Hg dynamics and how they interact with climate‐related variables. We investigated Hg accumulation, OC dynamics, and Hg and OC stable isotopes in a 14,000‐year sediment record from Lake Malaya Chabyda (Central Yakutia, Russia). Sediment Hg was correlated to OC (p value < 0.01), with lower OC and Hg accumulation rates (OCAR, HgAR) during the cold Younger Dryas (YD, 12,900–11,700 cal BP), when the lake level was low. Elevated sediment Δ200Hg (0.05‰ ± 0.11‰), representing dominant HgII deposition, and low δ13C, indicates low lake primary productivity during the YD. During the early Holocene, Δ200Hg and Δ199Hg decreased, while δ13C, δ202Hg, OCAR, and HgAR increased, suggesting enhanced algal primary productivity in deeper, more turbid waters. From 4,100 cal BP to present, Hg/OC ratios and HgAR increased at constant OCAR, indicating an additional Hg source to the lake. Analysis of Hg isotopes suggests direct Hg0 uptake into lake waters, potentially driven by primary production and efficient Hg burial. Our observations suggest that the gradual climate warming since the Last Glacial Termination and into the early Holocene led to enhanced OC and Hg burial in northern lakes and watersheds. Late Holocene enhanced Hg burial, but not OC, is possibly related to a renewed increase in lake primary productivity. Continued global warming may lead to further Hg sequestration in northern aquatic ecosystems.

The Development of Remotely Operated Underwater Vehicle for Plastic Waste Detection with Raspberry Pi

Abstract Underwater Plastic waste has had a serious impact on the environment. Unfortunately, Detecting and collecting underwater plastic waste is still a challenge, especially in Indonesia because of its position in the water, and the water turbidity. In previous research, a computer algorithm for detecting underwater plastic waste has been developed with Yolov3. To improve the research, we developed a Remotely Operated Underwater Vehicle (ROUV) with Raspberry Pi through the Research and Development (R&D) method. This ROUV is like a submarine that operates in the water and is integrated with a camera and computer algorithm to detect plastic waste. To get close to the real condition, we created an artificial water environment in a pond with various turbidity (from 20 to 200 Nephelometric Turbidity Unit). We use 30 pieces of plastic waste in several colors: white, red, black, and transparent. The plastic waste dipped in the water and was then detected by the ROUV camera. The result shows that the effective threshold for object detection is around 100 Nephelometric Turbidity Unit (NTU). Below 100 NTU, although the number of detected plastic images decreases as the turbidity increases, the visibility and contrast still allow for reasonably good object detection. The average confidence value for detection at turbidity levels below 100 NTU is 77%. At high turbidity conditions, the detection model may require adjustment or retraining with data that reflects those turbidity conditions.

Synergistic flocculation performance and underlying mechanisms of a novel bioflocculant flocan with coagulant iron salt

Flocculation is an integral part of wastewater treatment units and various flocculants have been employed to strengthen the flocs formation and produce clean water. Natural polysaccharides have been employed as eco-friendly bioflocculants for the treatment of turbid water. In the study, flocan is a named exopolysaccharide (EPS) isolated from a coastal mudflat with a high yield of 8.3g/L. Flocan consisted of glucose, mannose, galactose, and glucuronic acid in a molar ratio of 2:3:1:1, along with pyruvate modifications. As the bioflocculant agent, flocan exhibited more than 85% removal efficiency in kaolin suspension in terms of a concentration of 10mg/L at pH 3. The addition of iron salts with flocan showed high flocculation efficiency in acidic kaolin suspension (99.37%) and acidic coal wastewater (99.44%). The carboxyl/hydroxyl groups and branched structure of flocan provided ionic interactions and promoted higher bridging between bioflocculants and negatively charged particles. Coagulants FeCl3 enhanced the flocculating activity via neutralizing and stabilizing the residual negative charge of functional groups. Treatment with EDTA decreased the ionic interactions and reversed the flocculation significantly. Compared with the current bioflocculants, the superior production, low dosage, and excellent flocculating activity implied that flocan showed great potential in acidic wastewater treatment industrially. The coagulants/bioflocculants combination appears to be a promising and sustainable technology for wastewater flocculation.

Substantiation of the technology for reducing dilution by changing the direction of water flow in the dredge section

The global demand for gold was considered, as well as the ratio of placer gold to ore. It is revealed that there is an increase in the cost of gold mining. This is due to the fact that deposits with simple mining and geological conditions are currently depleted. The dredge method of developing placer deposits is considered. To reduce the cost, the problem of diluting the tailings of ephel dumps was considered. As a solution, a technology for reducing dilution by changing the direction of water flow is proposed. Modeling was carried out and patterns were identified between variables affecting the technological process. This technology can significantly reduce water turbidity, which has a positive effect on the environmental situation in the dredging area. The justification of the technology is given. Also, to justify the effectiveness of the proposed technology, a calculation example is considered. The given example allows us to identify water contamination under various technology options.

Production and characterization of efficient bioflocculant in high-turbidity drinking water treatment: Identification of flocculation-related genes

Bioflocculants are eco-friendly water treatment agents produced by bioflocculant-producing strains that are valuable in drinking water turbidity removal. The major challenges in the application of bioflocculants include low flocculation efficiency, high production costs, and unclear flocculation-related genes. In this study, Pseudomonas sp. ZC-41 a highly efficient bioflocculant-producing strain, was isolated from activated sludge to produce polysaccharide-based bioflocculant MBF-ZC with 94.12% flocculation efficiency under more economical culture conditions, which can solve the problem of low flocculation efficiency. Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed MBF-ZC contained hydroxyl, carboxyl, and amine groups, crucial for flocculation via adsorption bridging effects as the main flocculation mechanism. The 2393 differentially expressed genes (DEGs) in the transcriptome of strain ZC-41 were classified into five co-expression modules, and the turquoise module was associated with flocculation efficiency and bioflocculant yield. Nineteen flocculation-related genes were identified by combining functional pathways related to sugars. In addition, response surface methodology was optimized to achieve the efficiency of 93.57% for turbidity removal from high-turbidity water by bioflocculant. The results not only provide a solid theoretical foundation to solve the challenges of bioflocculants, but also enrich strategies for high-turbidity drinking water treatment.

Effects of temperature on fish aggression and the combined impact of temperature and turbidity on thermal tolerance

Deforestation can increase light penetration and runoff entering adjacent freshwaters leading to increased average water temperature, stronger diel temperature fluctuations, and increased water turbidity. Changes in temperature extremes (particularly upper peaks) are important for fishes as their body temperature and rate of oxygen consumption varies with environmental temperature. Here, we compare effects of diel-fluctuating versus stable water temperature regimes on the behaviour and upper thermal tolerance (measured as Critical Thermal Maximum, CTmax) of the Bluntnose Minnow, Pimephales notatus. Fish were acclimated to either a static 18°C, static 24°C or a diel-fluctuating treatment of low to high (18-24°C) for a total of 10 weeks. Activity level and aggression were measured for 6 consecutive weeks during the acclimation period. Activity level remained high across treatments and over time. However, fish from the diel-fluctuating treatment exhibited a significant increase in aggression over the day as temperatures increased from 18°C to 24°C. Following acclimation, upper thermal limits of fish from each treatment were measured under two conditions: clear water (<2 NTU) and turbid water (25 NTU). This was to evaluate effects of acute turbidity exposure that might arise with heavy rain on deforested streams. CTmax was lowest in fish acclimated to static 18°C and highest in fish acclimated to static 24°C; fish acclimated to diel 18-24°C showed an intermediate CTmax. Exposure to acute turbidity during CTmax trials significantly lowered CTmax across all treatments, highlighting the importance of multiple-stressor studies in evaluating upper thermal tolerance of fishes.