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The wet oxidation of pharmaceutical sludge for the treatment and production of value-added materials was investigated. The experiments were carried out in a stainless-steel autoclave reactor with chemical synthetic pharmaceutical sludge. The highest removal rate of total suspended solids (90.1%) and volatile suspended solids (98.4%) was achieved at 260 °C for 60 min with an initial oxygen pressure of 0.8 MPa. Simultaneously, the total chemical oxygen demand removal rate (78.7%) and the soluble chemical oxygen demand removal rate (81.6%) were obtained. The volatile fatty acid concentration—including acetic acid, propanoic acid, isobutyric acid and isovaleric acid—increased to 4819 mg/L with pH 12.56, which indicated the possibility of improving the quality of wet oxidized sludge solution as a potential carbon source by adding reagents. Scanning electron microscopy images showed that the sludge became a loose porous structure after wet oxidation, which is beneficial for dewatering performance. Energy dispersive spectroscopy images illustrate that carbon elements in sludge migrate from solid to liquid phases during the wet oxidation process. These results provide meaningful data for the design of further works and demonstrate that wet oxidation is a promising method for the treatment of pharmaceutical sludge, and the produced volatile fatty acids, including acetic acid and propanoic acid, are potential carbon sources for the biological treatment of wastewater. [ABSTRACT FROM AUTHOR]

Population growth and rapid industrial expansion has contributed to substantial amount of waste generation that subsequently lead to increased demand for landfill sites. Leachate is a harmful substance that leaks from the landfill site consisting of vast amounts of organic and inorganic pollutants, and collected at the bottom of the site. Thus, we explored the potential of optimizing ferrous sulfate heptahydrate or copperas and lime in the coagulation treatment of leachate. Different formulations of copperas to lime (80:20 and 60:40) were employed for leachate treatment. This study evaluated the effect of initial pH 3-8, coagulant dosage 1,000-6,000 mg/L and coagulation time 15-75 min on leachate treatment. Finding showed that the hybrid coagulant of 60C:40L successfully achieved optimum removal of turbidity, color and suspended solids of about 89%, 91% and 96%, respectively, at pH 5, coagulant dosage of 5,000 mg/L, coagulation time of 30 min, and sedimentation time of 60 min. It was also found that the Freundlich isotherm model was the best to describe the adsorption mechanism for the studied coagulant. The findings of this research are vital for the development of sustainable and cost-effective leachate treatment in the future. [ABSTRACT FROM AUTHOR]

The residual sludge in the secondary sedimentation tank of the municipal sewage treatment plant was taken as the treatment object, the synergistic effect of swirl cutting and ozone oxidation was used to investigate the sludge reduction effect and the effect of the process on sludge lysis cells. The results showed that the mixed decomposition of sludge (swirl cutter and ozone treatment) was better than ozone alone. The removal rates of mixed liquor suspended solids and mixed liquor volatile suspended solids were 85.6% and 91%, respectively, when the ozone dosage rate was 15 mg·O3·g-1 suspended solids (SS). A better sludge reduction effect could be achieved with a lower ozone dosage rate. By examining microscope images with different magnifications before and after sludge treatment, it can be established that the swirl cutting process can disintegrate the sludge floc, thereby making the sludge floc into smaller particles and allowing ozone to be in full contact with the sludge floc. The carbon release effect of the sludge was characterized by chemical oxygen demand dissolution rate, which continued to increase with increasing ozone dosage. Total nitrogen (TN), total phosphorus (TP), PO43--P, increased from 3.75 to 12.8 mg·L-1 and the concentration of polysaccharides increased from 7 to 37 mg·L-1. Three-dimensional fluorescence was used to look at the changes in dissolved organic matter in the liquid phase of sludge both before and after treatment. The synergistic effects of swirl cutting and ozone oxidation resulted in the oxidation and decomposition of fulvic acid and aromatic protein I into small molecules without fluorescent characteristics. [ABSTRACT FROM AUTHOR]

A comprehensive geochemical study was conducted in the Sibuti River estuary by considering water, suspended solids (SS), and sediment samples from 36 stations during southwest monsoon (SWM) and northeast monsoon (NEM). In this study, the distribution of in situ parameters, major ions, nutrients, trace metals, and isotopes (δD, δ18O) were analyzed in water samples, whereas sediments and SS were studied for trace metals. The distribution revealed that suspended solids were the major carrier of Cd, Zn, and Mn, whereas sediments worked as a major source of Co, Cr, Ba, Se, Cu, and Pb. Na-Cl water type and ion exchange dominated the lower part of the estuary during both seasons. However, the mixed mechanism of Ca–Cl, Ca–Mg–Cl, and higher weathering indicated reverse ion exchange in the intermediate and upper parts of the estuary. Isotopic signatures of δD and δ18O in estuarine water indicate that the precipitation over the Limbang area dominates during SWM, whereas higher evaporation was confirmed during NEM. The factor analysis revealed that seawater influence in the estuary majority controlled the water chemistry irrespective of seasons. Major ions were mainly regulated by the tidal influence during the low flow time of the river (SWM), whereas the mixing mechanism of weathering and seawater controlled the concentrations during NEM. Nutrients such as NO3, SO42−, NH3, and NH4+ mainly originated from the agricultural fields and nitrification along with ammonification were responsible for the recycling of such nutrients. Trace metals except Cd were found to be geogenic in nature and originating mainly from the oxidation of pyrites present in the sandstone and mudstones of the Sibuti Formation. Redox condition was catalyzed by microorganisms near the river mouth, whereas Al-oxyhydroxides and Fe-oxyhydroxides complexes in the intermediate and upper part under oxygenated conditions controlled the absorption of metals. Overall, the estuary was found to be absorptive in nature due to ideal pH conditions and was confirmed by the saturation index (SI) of minerals. [ABSTRACT FROM AUTHOR]

Bioaugmentation potential and phenol substrate affinity in a multi-carbon-source condition for three Acinetobacter strains (Acinetobacter towneri CFII-87, Acinetobacter johnsonii CFII-99A and Acinetobacter sp. CFII-98) were demonstrated. First, the phenol biodegradation ability of the strains was analyzed in batch experiments with phenol as the sole carbon source. All strains degraded phenol at 100 and 500 mg·L−1 initial concentrations; the maximum specific growth rates were 0.59 and 0.30 d−1 for A. towneri CFII-87, 0.50 and 0.20 d−1 for A. johnsonii CFII-99A, and 0.64 and 0.29 d−1 for A. sp. CFII-98, respectively. For the two tested phenol concentrations, no lag phase was observed for the A. towneri CFII-87 strain, A. sp. CFII-98 presented 4 h and 8 h lag phase, while A. johnsonii CFII-99A presented 3 h and 12 h lag phases. Phenol carbon source dependency of the strains was tested in a multi-carbon-source condition (on phenol-rich synthetic wastewater), both for individual strains and for a consortium prepared as an equal mixture of the three strains. The strains A. towneri CFII-87 and A. sp. CFII-98 and the consortia degraded phenol in 16 h while there was no other significant carbon source consumption during the 48 h trial, as shown by the constant non-phenolic residual chemical oxygen demand (COD) and volatile suspended solids (VSS) concentration after the depletion of phenol. The strain A. johnsonii CFII-99A, however, consumed phenol within 24 h and a further decrease in non-phenolic COD and increase in biomass was also observed upon the depletion of phenol. The highest specific phenol removal rate of 282.11 mg phenol·g VSS∙h−1 was observed in the case of the strain A. towneri CFII-87, followed by A. sp. CFII-98, the consortium and A. johnsonii CFII-99A with 178.84, 146.76 and 141.01 mg phenol·g VSS∙h−1, respectively. Two bacterial strains (A. towneri CFII-87, A. sp. CFII-98) presented a strong affinity to phenol, utilizing it as a primary carbon source, and thus, their use in the bioaugmentation of wastewater bioreactors indicated the viable potential to increase the phenol removal rate of these systems. [ABSTRACT FROM AUTHOR]

Detention ponds are effective structures for stormwater management in the urban drainage system of sponge cities. The pond size is taken as the decision variable, while the cost, total suspended solids (TSS), and catchment peak outflow (CPO) serve as the objectives for optimizing the detention pond volume. First, we randomly generated 10,000 pond areas and input them into the stormwater management model to simulate the time series of outflow and suspended solids concentration, thereby generating samples by combining the set of pond area, corresponding cost, TSS, and CPO. Then, two backpropagation neural network models (i.e., BPNN-TSS and BPNN-CPO) were trained, tested, and evaluated for predicting TSS and CPO, respectively. We employed them as surrogates and used the non-dominated sorting genetic algorithm-II to solve the optimization problem. The results showed: (1) The BPNN models accurately predicted TSS and CPO (determination coefficient 0.988~0.996, Nash–Sutcliffe efficiency 0.988~0.997), and efficiently substituted stormwater management model simulations for optimization purposes (residuals −18.49~28.10 kg and −0.45~0.29 m3/s). (2) For the Pareto solutions, the detention pond reduced TSS by 0~8.33% and CPO by 0~72.44% and delayed their peaks by 4~52 min; the reduction in TSS and CPO tends to grow as pond size increases, and CPO reduction exhibits a minor marginal effect. (3) The surrogate-based approach saves 90.03% runtime while preserving the quality of the Pareto solutions, verifying reliability. [ABSTRACT FROM AUTHOR]

This study uses several years of effluent quality data from 43 sites where online monitoring has been operational for many years resulting in the accumulation of high‐resolution data sets. The data show a highly repeatable, seasonal dependence of effluent turbidity on temperature. This has been modelled with simple techniques producing a generic model that is neither data hungry nor requires site calibration. Viscosity‐based mechanisms are proposed and discussed. These mechanisms differ from conventional assumptions of suspended solids peaks being solely flow related and or ascribed to 'spring sloughing'. The proposal is that the organic loading of the filter and the physical temperature effects on settlement velocity are both as influential as hydraulic loading in determining effluent suspended solids concentration. Application of the models enables improved design for new/upgraded units and more accurate capacity assessment of trickling filters and humus tanks enabling improved operational risk management of compliance failure. [ABSTRACT FROM AUTHOR]

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A polyextremophilic fungal strain, A. flavus QMS-8, previously isolated from the hypersaline soil taken from the rhizospheric region of the neem tree, Azadirachta indica (Meliaceae), was recognized as the proficient strain for decolorization of Acid Orange 52, a toxic dye employed in textile operations. A. flavus QMS-8 immobilized on Luffa cylindrica (Cucurbitaceae) attained 80.6% and consecutively complete dye degradation within a hydraulic retention time of 12–24 h in a stirred tank reactor even at salinities of 1–5% and environmental temperatures ranging in between 34 and 39 °C under optimized settings. The SEM micrographs revealed the attachment of fungal hyphae on L. cylindrica, while enzyme profiling demonstrated the participation of laccase (0.17 IU mL−1), manganese peroxidase (0.16 IU mL−1), and lignin peroxidase (0.06 IU mL−1) in the degradation of Acid Orange 52. The decolorized samples were assessed through a UV-Vis spectrophotometer and HPLC which did not provide any information about the formation of aromatic amines or any other metabolite. The values of biological oxygen demand, chemical oxygen demand, total dissolved solids, and total suspended solids were reduced from 2836, 3000, 3415, and 360 mg L−1 to 615, 1179, 916, and 145 mg L−1, respectively, and aligned closely with the established criteria set forth by the NEQ. Phytotoxicity and cytotoxicity assays of effluent treated in STR demonstrated a significant reduction in the toxic impact of dye on plants and microbial cells, suggesting that the luffa immobilized A. flavus QMS-8 employed in this study holds promise for mitigating the potentially harmful effects associated with Acid Orange 52. These results offer valuable insights into the efficacy and potential environmental benefits of the bioremediation approach for textile effluent investigated in this research. [ABSTRACT FROM AUTHOR]

Agricultural water bodies are multifunctional objects in the agricultural production cycle. Residual amounts of the active ingredients of pesticide agrochemicals can enter and contaminate a water body during some agro-technological tasks. The purpose of this study was to investigate the conditions for the extraction of residual amounts of xenobiotics from surface water containing suspended particles and to measure their content by chromatographic methods. To determine the optimal conditions for the extraction of target xenobiotics, the values of the lipophilicity parameters of their molecules were considered. The methodology for determining the content of lipophilic xenobiotics by chromatographic methods with mass-selective detection in surface water samples includes a step of separating suspended particles, the content of which in the samples under study was controlled by gravimetric analysis and varied within 135-1500 mg/m3. The target compounds were extracted using n-hexane and acetonitrile. The analytes in the acetonitrile concentrate were determined according to high-performance liquid and gas chromatography with mass-selective detectors (HPLC/MS/MS and GC/MS). The achieved limit of detection of xenobiotics was 0.02 μg/m3, the limit of quantification of xenobiotics was 0.10 μg/m3. To substantiate the possibility of applying the proposed methodology, the following indicators were investigated: linearity of analytical signals with the amount of analytes in the solution, correctness, convergence, and accuracy of measurement results. The linear concentration range of the method for the determination of xenobiotics of diverse groups is 0.10-1.00 μg/m3, characterised by a regression coefficient of the linear dependence of the measurement of individual compounds (R2) exceeding 0.99. The degree of analytes recovery (percentage of recovery r, %) was within 85-120%, which indicates the acceptability of the proposed xenobiotic extraction procedure. The error of the measurement results was calculated as the standard deviation (Sr, %), which did not exceed 6%. The findings of this study suggested that the developed methodology is suitable for monitoring the residual content of active ingredients of agrochemicals in surface waters and predicting the level of water pollution

Microplastics (MP) are perceived as a threat to aquatic ecosystems but bear many similarities to suspended sediments which are often considered less harmful. It is, therefore pertinent to determine if and to what extent MP are different from other particles occurring in aquatic ecosystems in terms of their adverse effects. We applied meta-regressions to toxicity data extracted from the literature and harmonized the data to construct Species Sensitivity Distributions (SSDs) for both types of particles. The results were largely inconclusive due to high uncertainty but the central tendencies of our estimates still indicate that MP could be marginally more hazardous compared to suspended sediments. In part, the high uncertainty stems from the general lack of comparable experimental studies and dose-dependent point estimates. We therefore argue that until more comparable data is presented, risk assessors should act precautionary and treat MP in the 1–1000 µm size range as marginally more hazardous to aquatic organisms capable of ingesting such particles.

Erosion, soil loss and consequent nutrient fluxes impair water quality and can degrade arable soils. Erosion rates in Sweden are generally low but episodic losses of suspended solids (SS) can affect water quality. Identifying critical source areas (CSAs) and “hot moments” is essential to reduce erosive losses from arable land. Here we use a distributed, dynamic high-resolution erosion model that simulates the sum of all transported material, i.e., erosion within the soil profile, on the soil surface and transport through drainage systems. We simulate monthly SS transport in six small agricultural catchments with varying soil texture over 8 years. Kling-Gupta Efficiency (KGE) was used as model performance statistics, and calibration (KGE = 0.45–0.78) and validation (KGE = 0.64–0.83) showed acceptable model performance for all catchments, with mean annual SS losses between 2.1 and 31.5 t km-2yr-1. Equifinality could be minimised by using more precise initial parameter values. We suggest that the model can be applied to comparable unmonitored catchments to identify erosion-sensitive periods and CSAs.

Gold mining generates major environmental impacts like landscape degradation, accumulation of waste rock dumps, and water contamination by suspended solids. Russia ranks third in the world in gold production, but the impact of gold mining has not been previously estimated for its vast northeastern part. This study provides a detailed overview of land-cover changes associated with gold mining in the Magadan region (northeast Russia) in the 21st century, where alluvial gold production has increased by a third in the last 20 years. A long-term series of Landsat and Sentinel-2 images obtained in July and August are used to compile two datasets of mining-impacted areas with totally removed vegetation for 2000–2002 and 2022. We calculated the NDVI difference and then discriminated mining-related vegetation losses from other bare areas, using additional data like the classification of landforms based on the digital surface model and the data on mining allotments. The total area of gold-mining sites was estimated as 41,206 ha in 2000–2002 and 72,602 ha in 2022, with an increase of 26,031 ha over the past 4–6 years. Moreover, this is a lower-boundary estimate, without taking into account man-made reservoirs and historical mines recovered by vegetation. The spatial distribution of mining sites has not changed significantly over the past two decades and has a maximum in the western part of the region. We found that the floodplains of the Berelekh and Debin Rivers (large tributaries of the Kolyma River) are most heavily impacted by gold mining with a removed vegetation canopy occupying 16.0% and 11.2% of their area. Along with the land degradation assessment, we found that 19,900 ha of historical gold-mining sites in the Berelekh River basin are recovered by vegetation, which is comparable in size to the areas impacted by mining over the past 20 years. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive review of the efforts utilized in the measurement of water quality parameters (WQPs) with a focus on total dissolved solids (TDS) and total suspended solids (TSS). The current method used in the measurement of TDS and TSS includes conventional field and gravimetric approaches. These methods are limited due to the associated cost and labor, and limited spatial coverages. Remote Sensing (RS) applications have, however, been used over the past few decades as an alternative to overcome these limitations. Although they also present underlying atmospheric interferences in images, radiometric and spectral resolution issues. Studies of these WQPs with RS, therefore, require the knowledge and utilization of the best mechanisms. The use of RS for retrieval of TDS, TSS, and their forms has been explored in many studies using images from airborne sensors onboard unmanned aerial vehicles (UAVs) and satellite sensors such as those onboard the Landsat, Sentinel-2, Aqua, and Terra platforms. The images and their spectral properties serve as inputs for deep learning analysis and statistical, and machine learning models. Methods used to retrieve these WQP measurements are dependent on the optical properties of the inland water bodies. While TSS is an optically active parameter, TDS is optically inactive with a low signal–noise ratio. The detection of TDS in the visible, near-infrared, and infrared bands is due to some process that (usually) co-occurs with changes in the TDS that is affecting a WQP that is optically active. This study revealed significant improvements in incorporating RS and conventional approaches in estimating WQPs. The findings reveal that improved spatiotemporal resolution has the potential to effectively detect changes in the WQPs. For effective monitoring of TDS and TSS using RS, we recommend employing atmospheric correction mechanisms to reduce image atmospheric interference, exploration of the fusion of optical and microwave bands, high-resolution hyperspectral images, utilization of ML and deep learning models, calibration and validation using observed data measured from conventional methods. Further studies could focus on the development of new technology and sensors using UAVs and satellite images to produce real-time in situ monitoring of TDS and TSS. The findings presented in this review aid in consolidating understanding and advancement of TDS and TSS measurements in a single repository thereby offering stakeholders, researchers, decision-makers, and regulatory bodies a go-to information resource to enhance their monitoring efforts and mitigation of water quality impairments. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of ENSO on water quality by looking at COD, SS, and Escherichia coli along the Crocodile River. Water samples were collected between 2016 and 2021 at three strategic sites on the river and were tested in an accredited laboratory. Python (version 3.8), Spyder and Microsoft Excel 2019 were used to analyze the data. The highest COD concentration (800 mg/L) was recorded at the White River site during El Niño, followed by 600 mg/L during the normal period, and 240 mg/L during the La Niña period. In 2019 during La Niña and the normal period, the E. coli levels were centered in one place at 60 cfu/100 mL, while in 2021 no E. coli levels were detected from the La Niña, El Niño, and normal periods. The suspended solids in this study were more prevalent in the White River (upstream) during the El Niño period. These analyses demonstrate that it is possible to evaluate the local effects associated with large-scale climate variability. [ABSTRACT FROM AUTHOR]

This study investigated the bacteriological and physicochemical quality of seawater and sediment samples collected from four sampling sites in the Gulf of Annaba (Northeastern Algeria) over a one-year period. Culture-based techniques were used to quantify and assess Fecal Indicator Bacteria (FIB) and potentially pathogenic bacteria. Additionally, various physicochemical parameters including temperature, pH, salinity, dissolved oxygen, and suspended solids were measured. The results revealed seasonal variations in the physicochemical variables, reflecting the influence of environmental conditions in the research area. The highest concentrations of FIB were observed in samples obtained from Sidi Salem and Rezgui Rachid, indicating a possible association with sewage contamination. Furthermore, the sediments collected from all sites exhibited higher levels of FIB and potentially pathogenic bacteria compared to the seawater samples, particularly during the summer and fall seasons. [ABSTRACT FROM AUTHOR]

In the present study, enhanced wet oxidation of excess sludge from pharmaceutical wastewater by NaOH as an alkaline homogeneous catalyst was investigated. The experiments were carried out in a stainless-steel batch autoclave reactor. The highest volatile suspended solids (VSS) removal rate, 95.2%, was achieved at 260 °C within 60 min with an initial oxygen pressure of 1.0 MPa and NaOH 0.5 g·L−1. Simultaneously, the chemical oxygen demand (COD) removal rate of 57.3% was reached. The increase in volatile fatty acids (VFAs) demonstrated that the degradation of sludge was greatly accelerated by NaOH. Interestingly, the production of acetic acid, an intermediate by-product generated from the oxidation of organic compounds, increased significantly. These results illustrated that NaOH is a promising catalyst for the utilization of wet oxidation liquid of excess sludge as a carbon source for the treatment of wastewater. [ABSTRACT FROM AUTHOR]

Introduction: The environment of the bay of Santiago de Cuba is home to 27 polluting sources; including 22 industries and facilities, 4 rivers and the Trocha river drainage, all causing the deterioration of the ecosystem, being the second most polluted bay in Cuba. Objective: To show the variability of the pollution of the Bay of Santiago de Cuba between the years 2006 and 2020. Materials and Methods: In 2006 and 2020, the samples were taken in the morning, always at the same time, on the surface and at a depth of one meter along the east shore and at the entrance of the Bay. The parameters pH, nitrites, nitrates, ammonium, phosphate, chemical and biochemical oxygen demands, dissolved oxygen, suspended solids and turbidity were sampled. The samples were analyzed in the laboratories of the Oriente Geomining Company of Hygiene and Epidemiology and in the National Company of Assistance and Technical Services of Santiago de Cuba. Results and Discussion: In 2006, the waters of La Estrella beach could be used as a bathing area and the rest of the Bay area's for recreational fishing, except for the area corresponding to the Flour Factory. In 2020, the figures obtained indicated pollution in the waters of the Bay at the entrance and in the interior, highlighting a high content of suspended solids. Conclusions: The characteristics of the waters of the Bay of Santiago de Cuba in 2020 deteriorated with respect to the reports made in 2006. [ABSTRACT FROM AUTHOR]

The produced water of oilfield binary flooding contains a large number of residual oil displacement agents such as polymers and surfactants. The interaction between oil displacement agents and water results in the enhanced stability of oil droplets and colloidal particles in the produced water. The treatment cost of traditional coagulation technology is high, the amount of sludge is large, and the quality of treated water is difficult to meet the requirements of reinjection indicators. This paper studies the influence of the process of sedimentation-aeration-biological contact oxidation-filtration on the turbidity, particle electronegativity and particle size distribution of the produced water from binary flooding. The result showed that the best process: gravity sedimentation for 12 h, aeration for 12 h under the condition of aerated water ratio of 30∶1, biological contact oxidation for 7 d, using fiber ball as filter material to filter the produced water from binary flooding. The field test has achieved good treatment effect, and the treated water quality meets the requirements of reinjection with oil content less than 5 mg/L, solid suspended solids less than 10 mg/L, and the median particle size of suspended solids less than 2 μm. [ABSTRACT FROM AUTHOR]

The process of wine making is well known to produce large amounts of wastewater with highly variable characteristics. The disposal of untreated winery wastewater is strictly prohibited since it adversely affects the recipient environment. Due to the variability in characteristics of winery wastewater, developing a treatment system which can handle high organic and inorganic loads, especially during the vintage season, is a complex challenge. This study investigated the theory, methodology and implementation of a wastewater treatment technology called shear enhanced flotation separation (SEFS) as a potential primary treatment stage towards the treatment of winery wastewater. Winery effluent was subjected to a coagulation process in a high shear environment, with and without the introduction of air, followed by flocculation. Upon successful optimization of operating parameters, a polymeric-based coagulant AB121 and polyelectrolyte flocculant AB796 yielded the highest reduction in turbidity (95%) with typical values of 630 NTU for the raw wastewater and 25 NTU for the SEFS-treated effluent. A substantial reduction in total suspended solids (97%) was achieved with average raw winery wastewater values of 2275 mg/L compared to the 50 mg/L obtained for the SEFS-treated effluent. Furthermore, a notable reduction (54%) in COD (from 11,250 mg/L to 5220 mg/L) using SEFS technology was achieved. [ABSTRACT FROM AUTHOR]

After coal mine wastewater is artificially injected into a groundwater reservoir transformed from a goaf, micron-sized suspended matter in the wastewater is purified by the broken rock mass in the goaf. Existing studies can only analyze the macroscopic changes in the content of suspended solids during the purification process, and it is difficult to explain the microscopic deposition mechanism of the suspended solids in broken rock. This paper studied the microscopic deposition behavior of micron-sized suspended solids inside the broken rock mass via numerical simulation using a coupled CFD-DEM method. In addition, indoor model tests were carried out to verify the accuracy and reliability of the model in comparison. The study results show that suspended solids' deposition behavior varies significantly under broken rock masses' different pore sizes (0.47 mm, 1.14 mm, 3.00 mm, and 5.33 mm). Within the goaf, the adsorption of suspended solids by the broken rock mass plays a dominant role. At the same time, suspended particles are mostly collected in the inlet area, and the difference in the number of deposited particles can reach 74% when comparing the first 50 mm range as well as the 50–100 mm range. The number of deposited particles at a flow rate of 0.02 m/s is 14% more than that at a flow rate of 0.06 m/s. This work offers new ideas for studying the purification mechanism of coal mine wastewater within a goaf. [ABSTRACT FROM AUTHOR]

The textile industry is one of the largest water-consuming industries, and it generates a significant amount of wastewater that needs to be treated before being discharged into the environment. To address this challenge, there has been a growing interest in the development of state-of-the-art technologies for wastewater treatment in the textile industry. Physical treatments such as sedimentation, flotation, and filtration are commonly used to remove suspended solids and organic matter from textile wastewater. Chemical treatments such as coagulation/flocculation and oxidation are effective in removing dyes and other colorants. Biological treatments such as aerobic and anaerobic treatments have been shown to be effective in treating organic matter and other pollutants. Moving Bed Biofilm Reactor (MBBR) technology has become increasingly popular in the textile industry for treating wastewater. This technology uses a combination of biological and physical processes to effectively remove pollutants from textile wastewater. The use of MBBR technology in textile industry wastewater treatment has several benefits. It is highly efficient in removing pollutants, including organic matter, color, and suspended solids. It can also handle high variations in flow and organic loads, making it suitable for the highly variable wastewater generated by the textile industry. The use of MBBR technology in the textile industry offers a cost-effective, efficient, and sustainable solution for treating wastewater, making it an increasingly popular option for textile manufacturers worldwide. [ABSTRACT FROM AUTHOR]

Biological ammonium removal in wastewater treatment plants requires large quantities of energy input and the addition of organic carbon for denitrification. Anaerobic ammonium oxidation coupled to Fe(III) reduction (termed the Feammox process) has been considered a novel pathway to remove nitrogen from wastewater mediated by microorganisms in recent years. In this study, a 40 L anaerobic sequencing batch reactor with 14-d cycle was operated at different COD/N input ratios (24:1, 15:1, 9:1, 6:1 and 3:1). After 5 cycles of operation, the ammonia removal rate was 91.1%, 87%, 91%, 95%, and 82.9%, respectively. It was found that heterotrophic anaerobic microorganisms could coexist and co-consume carbon with Feammox bacteria at low COD/N conditions (<9). At high COD/N conditions (>9), Feammox bacteria had lower priority in carbon consumption. Nitrogen gas could be the final product of the Feammox process in this reactor. The mixed liquor volatile suspended solids/mixed liquor suspended solids ratio of Feammox sludge in this study (0.71-0.76) was equivalent to that of conventional activated sludge. This study provided a new possible solution to remove nitrogen from fish processing wastewater. [ABSTRACT FROM AUTHOR]

Aquatic systems worldwide can exist in multiple ecosystem states (i.e., a recurring collection of biological and chemical attributes), and effectively characterizing multidimensionality will aid protection of desirable states and guide rehabilitation. The Upper Mississippi River System is composed of a large floodplain river system spanning 2200 km and multiple federal, state, tribal and local governmental units. Multiple ecosystem states may occur within the system, and characterization of the variables that define these ecosystem states could guide river rehabilitation. We coupled a long-term (30-year) highly dimensional water quality monitoring dataset with multiple topological data analysis (TDA) techniques to classify ecosystem states, identify state variables, and detect state transitions over 30 years in the river to guide conservation. Across the entire system, TDA identified five ecosystem states. State 1 was characterized by exceptionally clear, clean, and cold-water conditions typical of winter (i.e., a clear-water state); State 2 had the greatest range of environmental conditions and contained most the data (i.e., a status-quo state); and States 3, 4, and 5 had extremely high concentrations of suspended solids (i.e., turbid states, with State 5 as the most turbid). The TDA mapped clear patterns of the ecosystem states across several riverine navigation reaches and seasons that furthered ecological understanding. State variables were identified as suspended solids, chlorophyll a, and total phosphorus, which are also state variables of shallow lakes worldwide. The TDA change detection function showed short-term state transitions based on seasonality and episodic events, and provided evidence of gradual, long-term changes due to water quality improvements over three decades. These results can inform decision making and guide actions for regulatory and restoration agencies by assessing the status and trends of this important river and provide quantitative targets for state variables. The TDA change detection function may serve as a new tool for predicting the vulnerability to undesirable state transitions in this system and other ecosystems with sufficient data. Coupling ecosystem state concepts and TDA tools can be transferred to any ecosystem with large data to help classify states and understand their vulnerability to state transitions. Author summary: The Upper Mississippi River System in the USA is a large, complex ecosystem that extends from about St. Paul, Minnesota, to the confluence with the Ohio River near Cairo, Illinois, and up the Illinois River. The system benefits from a water quality monitoring program for which consistent data have been collected since about 1986. We used a set of mathematical tools called 'topological data analyses' to help identify common water quality conditions or 'states' of this important river system. We also explored when and why the states have changed over the past 27 years. The tools identified five common water quality states, distinguished by nutrients and clear waters or muddy and turbid waters. State changes were commonly detected as seasonal transitions in the higher latitude reaches. The state changes also showed that water quality had improved or declined gradually over many years, depending on the river reach. River reaches named Pool 4 and Pool 8 had become clearer over time. Pool 13 became muddier over time with several undesirable state changes to a turbid-state. Three other river reaches were consistently muddy. Our study is a good example of how these topological data analysis tools may help others managing ecosystems by improving communications about what states exist and which are desirable. Coupling these tools with long-term data can also alert ecosystem managers to the ongoing, complex changes and vulnerability to help prioritize ecosystem rehabilitation. [ABSTRACT FROM AUTHOR]

Proper filtration selection, sizing, maintenance, and performance of a filtration system are crucial for removing suspended solids in water, preventing clogging of emitters, and ensuring a high-performing microirrigation system throughout its lifespan. Filtration prevents the intake of particles larger than the pore size specified in a given filtration grade. Proper selection of the filter media ensures efficient solid–liquid separation. Strainer-type or screen filters have elements composed of a woven or nonwoven cloth of numerous weave types. The material and characteristics of the screen directly affect the fluid flow and filter performance. The aim of this study is to propose a method for determining the actual filtration grade of filters used for irrigation. An automatic flushing strainer-type filter was equipped with five filter element models, composed of woven and nonwoven materials, for evaluation. A new methodology was developed to assess the actual filtration grade based on the removal efficiency for suspended solids under controlled and repeatable conditions. The removal efficiency of each filter element was determined for particle size ranges defined according to the filtration grade declared by the manufacturer. The proposed methodology allowed for the assessment of the actual filtration grade of each model of filter element operated with water containing suspended particles of silica sand. The filtration grade declared by the manufacturer was confirmed for some of the filter elements, but it could be modified for others. The proposed methodology could be useful for assessing the actual filtration grades of screen, disk, and media filters. [ABSTRACT FROM AUTHOR]

To elucidate the effects of environmental heterogeneity on diversity, composition, and degree of overlap between free-living (FL) and particle-attached (PA) bacteria, we sampled large, shallow, eutrophic Lake Taihu, China across gradients spanning riverine inflow, cyanobacterial blooms, and the open limnetic area. Using high-throughput sequencing of the 16S rRNA gene, we show that (i) bacterial communities near riverine inflow had high α-diversity and a high degree of overlap between FL and PA lifestyles, (ii) communities in cyanobacterial blooms have reduced α-diversity within the PA lifestyle, and (iii) communities from the limnetic area had the lowest bacterial α-diversity within the FL lifestyle and a medium degree of overlap between the FL and PA lifestyles. Redundancy analysis showed that the variation of the FL bacterial community was shaped by suspended solids and total phosphorous, while the variation of the PA bacterial community was shaped by suspended solids, dissolved oxygen, and the percentage of organic matter in suspended solids. This study highlights the importance of environmental heterogeneity, riverine input, cyanobacterial blooms, and nutrient status on the spatial distribution patterns of FL and PA bacterial communities in freshwater lakes. [ABSTRACT FROM AUTHOR]

The present study assesses the water quality of Ciénaga La Pachita swamp (Cesar, Colombia) by characterizing the aquatic macroinvertebrates associated to the macrophyte Eichhornia crassipes (Pontederiaceae), also known as Buchón de Agua. The assessment also examines physical and chemical variables in different hydrological periods, estimates alpha and beta diversity indices, and determines the BMWP/Col and ASPT water quality indices. As a result, 1550 macroinvertebrates are collected, belonging to five classes, 11 orders, and 21 families. Alpha and beta diversity indices show medium diversity and the class Insecta is dominant. The order Coleoptera is the most diverse while the order Diptera is the most abundant, the Chironomidae family being the most dominant. A significant percentage of the families identified are significantly correlated with both dissolved oxygen and suspended solids. In conclusion, the Ciénaga La Pachita has a medium diversity of macroivertebrates associated to the radicular system of E. crassipes. [ABSTRACT FROM AUTHOR]

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Carbon dioxide‐enhanced water recovery (CO2‐EWR) is a promising strategy for managing reservoir pressure build‐up and mitigating the risk of fault activation resulting from CO2 injection in deep saline aquifers. CO2‐EWR can also be employed for supplying the required water for different applications after a treatment stage for the produced saline water. In this study, a brief review on CO2‐EWR technology and its necessities are first carried out. After that, the feasibilities, advantages, and challenges of various available treatment technologies that can potentially be used to treat high total dissolved solids (TDS) brine are comprehensively assessed. Based on comprehensive evaluation on technologies, a chain desalination process, consisting of pretreatment, main treatment, and post treatment, is proposed as a strategic path for the treatment of high TDS brine extracted from the Shenhua CCS site. It is concluded that coagulation‐flocculation and gravity filtration are needed as primary stages to remove suspended particles, while membrane distillation (MD) is selected as a suitable main treatment technology for high TDS Shenhua brine. Then, MD treatment is comprehensively discussed for a small‐scale treatment of extracted Shenhua brine assuming that the pretreated brine is free of suspended solids. After presenting the heat and mass transfer equations for direct contact membrane distillation (DCMD), a mathematical thermodynamic model is programmed in EES (Engineering Equation Solver) software to briefly analyze the performance parameters of DCMD. The results indicate that the designed DCMD, in the absence of auxiliary systems and considering the inherent temperature of extracted brine from different formations, has the capability of producing 15.1 kg m−2hr of freshwater from the extracted brine of the Shihezi formation layer. In the case of employing the auxiliary system of flat‐plate collector (FPC) combined with heat exchanger (HX) to heat up the extracted Shenhua brine to the desired temperature of 80°C, the amounts of produced flux are enhanced by 133%, 72%, and 45% for the brine extracted from Liujiagou, Shiqianfeng, and Shihezi formations, respectively. Using the yearly solar radiation model in TRNSYS software, the maximum solar radiation on the tilted surface at the location of Shenhua project in Inner Mongolia Autonomous Region of China reaches 3800 kJ m−2hr at 1 PM on April 1. Considering maximum solar radiation on the tilted surface, it is proved that a small‐surface FPC can supply the required energy to heat up the extracted brine from its inherent temperature to the desired temperature of 80°C. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Anaerobic digestion is a promising technology for treating and disposing of oily sludge, but the presence of oil in the sludge reduces methane production and sludge volume reduction. To overcome this limitation, this study creatively reports the use of magnetite to enhance methane production in oily sludge mesophilic anaerobic digestion and elucidates the underlying mechanism. Results show that the addition of magnetite increases methane production, with a 5% magnetite content leading to a 1.42-fold increase in cumulative methane output compared to the blank. Mechanistically, magnetite accelerates the release of organic matter, promotes oil degradation, increases volatile fatty acids (VFA) accumulation, and reduces the proportion of propionate. Additionally, magnetite alleviates pH decreases and increases the release of ammonia nitrogen and phosphate, resulting in effective sludge reduction, with volatile suspended solids (VSS) reduction ranging from 26.9% to 32.6%, higher than that of the blank. Moreover, magnetite accelerates electron transfer and increased the relative abundance of microorganisms associated with methane production, with the relative abundance of Methanosarcina increasing to 37.6~38.5% due to the presence of magnetite. This study provides a theoretical framework for effectively utilizing oily sludge through the application of magnetite. [ABSTRACT FROM AUTHOR]

This work investigated the role of an agnail device (manually made from a comb) on sludge size restriction and organic degradation in extended filamentous aerobic granular sludge-sequencing batch reactors (AGS-SBRs) with artificial wastewater. Two identical SBRs (R1 and R2) were employed in this experiment. Extended filamentous AGS with a large size was achieved in both SBRs by seeding the dewatering the sludge on day 40. R1 (the control) did not use the agnail aeration device, and the extended filamentous AGS system was finally disintegrated. However, R2 promptly employed the agnail device on days 56–59, the extended filamentous AGS size obviously decreased from 4.8 mm to 2.5 mm, and the dominant filamentous species, including Proteobacteria, Acidobacteria, and Choroflexi, gradually shrank at a low level, acting as a framework for AGS recovery. This was because enough nutrients diffused into the inside of small sludge for the filamentous living. Simultaneously, the sludge volume indexes (SVI5 and SVI30) sharply decreased from 155.8–103.9 to 51.7–46.6 mL/g, and the mixed liquid suspended solids (MLSSs) and extracellular polymeric substances (EPSs) in R2 both increased and were kept at 5816 mg/L and 69.1 mg/g·MLVSS, respectively. These contributed to enhancing the sludge's structural stability to avoid AGS failure. COD and NH4+-N in R2 were both degraded by simultaneous nitrification and denitrification (SND) processes throughout the experiment, which was not significantly influenced before or after the agnail aeration device was employed. These results indicate that the agnail device can effectively restrict AGS size and limit the extended filamentous overgrowth with nutrient diffusion into the sludge's interior, which can prevent AGS disintegration. In addition, this device had no significant influence on organic degradation. [ABSTRACT FROM AUTHOR]

Improper runoff management not only endangers human health but also threatens the ecosystem. Runoff often contains large amounts of organic and inorganic contaminants that create adverse impacts on the environment and cause a significant impediment to urban stormwater reuse. A bioretention system is a modern device that has been widely used; it is engineered to eliminate suspended solids and some other water-bound contaminants. Biochar, a carbon-rich byproduct produced from biomass pyrolysis, has proven to be effective in removing certain pollutants. This paper reviews the relevant applications of biochar filter media in bioretention systems and examines biochar's ability to remove E. coli, heavy metals, and nutrients. It also compares the performance of biochar produced under different operating conditions and provides further refinement of bioretention design parameters. Remarkably, biochar was reported as a promising adsorbent that is suitable to be amended to the bioretention system. Its high specific surface area, microporous carbonaceous structure, and negatively charged oxygen functional groups on the surface have created a strong affinity for mixed contaminant removal. More studies need to be conducted to encourage continuous quality improvement of the bioretention system. [ABSTRACT FROM AUTHOR]

The extensive nature of natural resource use in the Siret River basin in recent years has led to a significant depletion of its water resources and deterioration of the ecological state of surface waters. The following paper presents the results of assessing the degree of water pollution of the Siret River. A number of biotic water quality indices were used for this purpose. In particular, the Trent Biotic Index (TBI) and the Biological Monitoring Working Party Index (BMWP), both of which use the density ratio of different macroinvertebrate taxa in the aquatic communities, and the Pantlé and Bucca saprobility index, which uses the absolute density and saprobility of indicator species of aquatic organisms. A comprehensive assessment of the aquatic ecosystem of the watercourse was carried out using the water pollution index (WPI). The biological indices were calculated on the basis of data on zooperiphyton communities formed on an artificial fibre media of the «VIYA» type. The VIYA fibre carrier was used for more accurate determination of the species composition and quantitative characteristics of zooperiphyton communities in the studied river sections. The TBI index ranged from 5 to 6 (which corresponds to a water quality assessment of 'satisfactory'). The BMWP index ranged from 8 (very poor) to 32 (good), and the saprobicity index from 1.52 to 1.95 (good water quality). The WPI index at the control sites in the Siret River ranged from 4.6 (which corresponds to a water quality assessment of 'polluted') to 8.1 (which corresponds to a water quality assessment of 'extremely polluted'). Signifi- cant differences in the results of the assessment by different biotic indices indicate that these indices cannot be used as indicators for an exhaustive assessment of water quality using zooperiphyton. They can only be used as relative indicators for comparing the state of water pollution at different locations. The values of hydrochemical indicators of water quality at two observation posts of the river were analysed. The maximum permissible concentrations of nitrite ions, ammonium ions and suspended solids in the control sections of the river were found to be exceeded. [ABSTRACT FROM AUTHOR]

Background: Land use is a major factor determining stream water physicochemistry. However, most streams move from one land use type to another as they drain their watersheds. Here, we studied three land use scenarios in a tropical cloud forest zone in Mexico. We addressed three main goals, to: (1) assess how land use scenarios generate different patterns in stream physicochemical characteristics; (2) explore how seasonality (i.e., dry, dry-to-wet transition, and wet seasons) might result in changes to those patterns over the year; and (3) explore whether physicochemical patterns in different scenarios resulted in effects on biotic components (e.g., algal biomass). Methods: We studied Tropical Mountain Cloud Forest streams in La Antigua watershed, Mexico. Streams drained different three scenarios, streams with (1) an upstream section draining forest followed by a pasture section (F-P), (2) an upstream section in pasture followed by a forest section (P-F), and (3) an upstream forest section followed by coffee plantation (F-C). Physicochemistry was determined at the upstream and downstream sections, and at the boundary between land uses. Measurements were seasonal, including temperature, dissolved oxygen, conductivity, and pH. Water was analyzed for suspended solids, alkalinity, silica, chloride, sulfate, magnesium, sodium, and potassium. Nutrients included ammonium, nitrate, and phosphorus. We measured benthic and suspended organic matter and chlorophyll. Results: Streams presented strong seasonality, with the highest discharge and suspended solids during the wet season. Scenarios and streams within each scenario had distinct physicochemical signatures. All three streams within each scenario clustered together in ordination space and remained close to each other during all seasons. There were significant scenario-season interactions on conductivity (F = 9.5, P < 0.001), discharge (F = 56.7, P < 0.001), pH (F = 4.5, P = 0.011), Cl- (F = 12.2, P < 0.001), SO42- (F = 8.8, P < 0.001) and NH4+ (F = 5.4, P = 0.005). Patterns within individual scenarios were associated with stream identity instead of land use. Both P-F and F-C scenarios had significantly different physicochemical patterns from those in F-P in all seasons (Procrustes analysis, m12 = 0.05-0.25; R = 0.86-0.97; P < 0.05). Chlorophyll was significantly different among scenarios and seasons (F = 5.36, P = 0.015, F = 3.81, P = 0.42, respectively). Concentrations were related to physicochemical variables more strongly during the transition season. Conclusion: Overall, land use scenarios resulted in distinctive water physicochemical signatures highlighting the complex effects that anthropogenic activities have on tropical cloud forest streams. Studies assessing the effect of land use on tropical streams will benefit from assessing scenarios, rather than focusing on individual land use types. We also found evidence of the importance that forest fragments play in maintaining or restoring stream water physicochemistry. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to investigate the effect of increasing porosity on concrete porous pavement (PP) clogging control. The delay due to the clogging process has been observed in order to extend pavement service life and improve storm water management performance in long term. By adding pumice to the pervious concrete mix design, porosity and permeability increased; hence, additional porosity for the accumulation of suspended solids has been formed. The results showed that adding the pumice as part of the concrete aggregates produces positive effect on the initial permeability. Affected by clogging, permeability of the specimens in which pumice was added reduced only 26%, 10%, and 29%, showing that the procedure successfully delays clogging and extends service life of the PP. Although adding pumice reduces the compressive strength, it is still within the acceptable range. By comparison the observed data with the results of the permeability prediction models, it is demonstrated that the models properly predict permeability of the pavement over time, in more than 73% of the observed data and the results of the prediction models merely less than 10% difference observed. The rainfall-runoff simulation indicates that adding pumice as part of the permeable concrete aggregates results in delaying of the clogging and improving the performance of concrete increasing the service life of permeable pavements. [ABSTRACT FROM AUTHOR]

The present study collected anaerobic sludge from a paper mill operating a UASB reactor on agro-based raw material (wheat straw) washings for biogas production. After determining the sludge profile and methanogenic activity of anaerobic sludge, it was further used to determine the anaerobic biodegradability of RCF-based kraft paper mill effluent. The sludge profile of collected anaerobic sludge was found w.r.t. Suspended Solids (SS) 60 g.L-1, Volatile Suspended Solids (VSS) 23 g.L-1, Inorganic content 62% & Organic content 38%. The presence of effective microbes in anaerobic sludge was confirmed by SEM (Scanning Electron Microscope). Degradation of organic matter present in effluent by anaerobic digestion leads to the production of biogas (methane & CO2), a renewable energy source. The sludge profile and methanogenic activity findings supported the anaerobic treatment of kraft paper mill effluent and were positive. The methanogenic activity of anaerobic sludge was determined as 0.832 gCOD.gVSS-1xDay, and the average anaerobic biodegradability of RCF-based kraft paper mill effluent was found to be 71.5%. [ABSTRACT FROM AUTHOR]

We have developed a MoS 2 /graphene oxide sponge that can selectively remove ultrafine suspended solids from actual wastewater. We skillfully use the chemical adsorbed CaCO 3 to improve the electropositivity of sponge surface, thus significantly improving its ability to remove electronegative nano-pollutants. In addition, the functionalized sponge can trigger reactions such as Fenton to simultaneously remove organic pollutants and heavy metal ions from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Resource utilization of animal manure can be used to reduce environmental pollution in the recycling of nutrients from the manure. Solid-liquid separation can serve as one of the pretreatment to improve the utilization efficiency for cost saving. However, existing treatments cannot fully meet the large-scale production in recent years, such as the high energy consumption, and low separation efficiency for sewage with a high viscosity and small solid particles, such as waterfowl feces and biogas slurry. Single-factor experiments were carried out to determine the effects of the centrifugal separation time, mesh number, and centrifugal separation speed on the separation effect of waterfowl feces. The quadratic general rotary unitized design was used to implement an optimization test. The optimal combination of parameters was obtained after the analysis of the data and consideration of the actual operating conditions. The data were analyzed by Excel 2016, Origin 2021, and Design Expert 12. The results showed that the treatment was achieved in better solid removal with the shorter hydraulic retention time of subsequent biochemical treatment. The content of pollutants in the waterfowl feces showed a trend of gradual decrease with the increase of screen mesh. The reason was that the aperture size decreased, as the number of sieve meshes increased. The larger solid particles were passed through to be trapped in the filter bag. The better performance of solid-liquid separation of waterfowl feces was achieved with the increase in centrifugal separation speed, due to the retention effect of the screen and stronger centrifugal action. The solids removal effect cannot be significantly enhanced under the action of low-speed centrifugation when the centrifugal separation speed continued to increase. The separation effect of free water was mainly achieved, where the adsorbed water was not strong enough to detach from the inter-particle adsorption. The thickness of the filter cake in the filter bag gradually increased, as the separation time increased. The solid particles were retained, whereas, the liquid also had sufficient time to separate through the filter cake. But the excessive separation time led to the clogging of the screen pores, where the liquid was difficult to pass through the filter cake. After the centrifuge separation optimization test and verification, the optimal separation effect was obtained, when the centrifuge separation time, mesh number, and centrifugal separation speed were set as 3 min, 120 mesh (aperture size 0.13 mm), and 700 r/min, respectively. At the same time, the removal rates of total solid (TS), volatile solids (VS), chemical oxygen demand (COD), NH4 + -N, and total phosphorus (TP) were 50.20%, 57.59%, 5.39%, 4.39%, and 5.76%, respectively. The separation effects (removal rates of TS and VS were 53.21% and 58.61%) were comparable to the separation effect of a high-speed centrifuge after the field operation of the prototype. The treatment cost was reduced by nearly 22% for one ton of sewage, indicating the feasible low-speed differential centrifugal separation. This finding can provide a promising scheme for the removal of suspended solids from the waterfowl feces in engineering popularization. [ABSTRACT FROM AUTHOR]

Granular sludge processes are frequently used in domestic and industrial wastewater treatment. The granule buoyant density and biomass density are important parameters for the design and operation of granular sludge reactors. Different methods to measure the granule density include the pycnometer method, the Percoll density gradient method, the dextran blue method, and the settling velocity method. In this study, a comparison was made between these four methods to measure granule density for granules from a full-scale granular sludge plant treating domestic sewage. The effect of salinity on granule density was assessed as well. Three out of the four evaluated methods yielded comparable results, with granule buoyant densities between 1025.7 and 1028.1 kg/m3 and granule biomass densities between 71.1 and 71.5 g/L (based on volatile suspended solids (VSS)). The settling velocity method clearly underestimated the granule density, due to the complex relation between granule properties and settling velocity. The pycnometer method was the most precise method, but it was also quite susceptible to bias. The granule buoyant density increased proportionally with salinity, to 1049.2 kg/m3 at 36 g/L salinity. However, the granule biomass density, based on VSS, remained constant. This showed that the granule volume was not affected by salinity and that the buoyant density increase was the result of diffusion of salts into the granule pores. Overall, the granule density can be measured reliably with most methods, as long as the effect of salinity is considered. The results are discussed in light of operational aspects for full-scale granular sludge plants. [ABSTRACT FROM AUTHOR]

The knowledge of acoustic wave propagation in a borehole embedded in gas hydrate-bearing sediments is of great significance for the exploitation of gas hydrate. A gas hydrate-bearing sediment is a typical three-phase porous medium containing two solids and one fluid. However, until now, the borehole acoustic wavefield and its component waves within such a porous medium have never been calculated. In this work, a real-axis integration method is proposed to calculate the borehole acoustic field embedded in a three-phase porous medium based on the Biot-type three-phase theory. Meanwhile, a component wave approach, combined with the branch-cut integral method and the residue theorem, including residues at leaky poles is proposed to study the borehole wave propagation of a three-phase porous medium. The branch points and poles of the potential acoustic wave function are obtained, which correspond to the normal and leaky modes on various Riemann sheets. On this basis, the excitation intensity and waveforms of each component are obtained. The result shows that the waveform summed up from all individual waves agrees well with the full waveform calculated by real-axis integration, which provides a theoretical basis for the subsequent inversion of reservoir parameters by using the information of various mode waves. [ABSTRACT FROM AUTHOR]

Assessment of the seawater quality is based on the calculation of the integrated index water pollution (IWP). The average concentration of the most significant pollutants in a local area of the sea during a certain period expressed in units of the maximum allowable concentration (MAC) is at the core of the index. The long-term practice of using the IWP has allowed for significant additions and corrections in the calculation methodology and in scientific interpretation of results, which improves the accuracy of assessing the state of marine environment based on standard hydrochemical studies. To assess the seawater quality by one parameter, a six-rank scheme is proposed, the scale of which was developed on the basis of the MAC for an analyzed substance. Additional criteria of seawater pollution related to eutrophication, amount of marine litter, pollution of bottom sediments and suspended solids and tissues of marine biota are proposed. [ABSTRACT FROM AUTHOR]

La2O3 and CeO2, as main rare earth oxides, with unique physical and chemical properties have been widely used in catalyst and grinding industry. In this study, the effects of La2O3 and CeO2 on the anaerobic process were investigated. The biological methane production tests showed that 0–0.05 g/L La2O3 and 0–0.05 g/L CeO2 enhanced anaerobic methanogenesis process. The result showed maximum specific methanogenic rates of La2O3 and CeO2 were 56.26 mL/(h·gVSS) and 49.43 mL/(h·gVSS) and, compared with the control, increased 4% and 3%, respectively. La2O3 significantly reduced the accumulation of volatile fatty acids (VFAs), whereas CeO2 had no similar effect. Dissolution experiments demonstrated that the content of extracellular La in the anaerobic granular sludge reached 404 μg-La/g volatile suspended solid (VSS), which was 134 times higher than that of extracellular Ce (3 μg-Ce/gVSS). The content of intracellular La reached 206 μg-La/gVSS, which was 19 times higher than that of intracellular Ce (11 μg-Ce/gVSS). The different stimulation between La3+ and Ce3+ could be attributed to the different dissolution of La2O3 and CeO2. The result of this work is helpful to optimize anaerobic processes and to develop novel additives. Practitioner Points • Novel anaerobic additives were developed. • La2O3 and CeO2 in 0–0.05 g/L enhanced organics degradation and methane production. • The addition of La2O3 significantly reduced the accumulation of volatile fatty acids. • The solubilization of La2O3 was stronger than CeO2. • The promoting effects of low concentrations of La2O3 and CeO2 were derived from dissolved La and Ce. [ABSTRACT FROM AUTHOR]

In recirculating aquaculture systems (RASs), the effective treatment of aquaculture tailwater is essential to maintain the health of the RAS. This study investigated the optimal time and method for tailwater treatment during three periods of the aquaculture of the Litopenaeus vannamei: nursery (0–26 d), middle (27–57 d), and later (57–104 d). The variation of several water parameters during the dissolution of total suspended solid (TSS) in tailwater, applied with the effects of ozone on the microorganism and water quality parameters were investigated. Results showed that the TSS concentrations in tailwater decreased with time, although not significantly (P>0.05), whereas total ammonia nitrogen (TAN), nitrite (NO2−-N), and nitrate (NO3−-N) increased significantly (P<0.05). Therefore, TSS should be removed from the tailwater as early as possible, being most optimal within 4 h. Ozone removed 38.24%–48.95% of TSS, 17.78%–90.14% of TAN, and 87.50%–98.90% of NO2−-N after 4 h of treatment. However, it resulted in the significant accumulation of NO3−-N. Moreover, the total number of Vibrio and bacterial counts in aquaculture tailwater was reduced completely by ozone within 4 h. Thus, these results provided technical details and data support for the effective treatment of tailwater from shrimp RAS. [ABSTRACT FROM AUTHOR]

In the present study, investigation of the applicability and efficiency of electrochemical oxidation (EO) processes for slaughterhouse wastewater (SWW) was targeted by evaluating the treatment efficiency and energy consumption values. The effects of operating parameters, such as the type of supporting electrolyte (SE) (Na2SO4, NaNO3, NaCl, and KCI), supporting electrolyte concentration (SE concentration) (0.1–0.4 M), initial wastewater pH (3–11), and current density (CD) (4.06–12.18 mA/cm2) on the removal of chemical oxygen demand (COD), suspended solids (SS), turbidity, and color were investigated. The most effective electrolyte type was observed to be NaCl. The experiment with 0.2 M SE type and 4.06 mA/cm2 current density, at a stirring speed of 400 rpm was accepted as optimum. For these conditions, it was observed that the COD, color, turbidity, and suspended solids (SS) removals were 80.05, 98.64, 99.18, and 98.47%, and energy consumption of 210.7 kWh/m3, respectively. It has been observed that the electro-oxidation process provides substantial efficiency in undesirable parameters in wastewater after 3 h of operation. Additional processes can be added to this process so that the SWW can be reused after treatment, and the recovery and further treatment of the wastewater can be achieved. [ABSTRACT FROM AUTHOR]

Activated sludge processes contain various groups of microorganisms with different metabolic properties, which are responsible for contaminants removal. Therefore, it is important to elucidate the general structure and functional properties of biomass in activated sludge processes. For this purpose, a full-scale domestic biological wastewater treatment plant in Tunceli (Turkey), Tunceli WWTP (wastewater treatment plant), was monitored to observe seasonal variations in process performance and biomass properties for a year. It was observed that nitrifying bacteria developed abundantly in the rainy and cool spring season as they were suppressed in summer because their large losses took place due to an environment containing high alkalinity values. In September, aerobic heterotrophic, nitrify, denitrify, and anaerobic activities increased. It can be said that the biomass contained young and mature microorganism in this environment in which the sludge volume index (SVI) value increased to 196 mL/g. As a result of the improvement in the structural and functional properties of biomass, the nitrogen removal efficiency reached 99%. Throughout the whole study, the structural improvement observed in biomass was reflected in its removal activity. The amount of biomass and removal activity decreased with the abundance of organic matter in the influent at the period in which biomass was closer to being categorized in the aged sludge class. The results showed that as the lowest mixed liquid suspended solids (MLSS) and mixed liquid volatile suspended solids (MLVSS) values of the year were 530 and 400 mg/L, respectively, in November 2017, MLSS and MLVSS values reached the highest amount (1700 and 1400 mg/L, respectively) in December 2017 when aerobic heterotrophic activity accelerated with a decrease in organic matter level. [ABSTRACT FROM AUTHOR]