Total Suspended Solids Research Articles

Polyethersulfone/fish-shrimp chitosan-based mixed matrix membrane for industrial wastewater treatment.

In this study, chitosan (CH) was synthesized by processing of fish-shrimp solid waste (shell). It was utilized in the preparation of polyethersulfone (PES)-based mixed matrix membrane (Mx/CHy) through the film casting method. The hydrophilicity of the membrane was modified by increasing the concentration of CH. The degree of deacetylation (DD%) of CH, analyzed using the acid-base titration method, was found to be 78%. The molecular weight cutoff (MWCO) of the membrane was analyzed using the polyethylene glycol rejection method. The surface properties such as mean pore size and hydrophilicity of the membrane were analyzed using a scanning electron microscope (SEM) micrograph and water contact angle meter. The membrane (M18/CH1.0) mean pore size and MWCO were 7.0nm and 1.8kDa, respectively, which is in the nanofiltration (NF) range. After cross-linking of CH with PES/PVP, hydrophilicity and porosity of the M18/CH1.0 increased. The feasibility of the membrane was tested for the treatment of industrial wastewater (iron and steel, distillery, and paper and pulp industry) by varying the feed pressure. The collected permeate through the M18/CH1.0 for all industrial wastewater was transparent. The M18/CH1.0 showed the removal efficiency as follows: turbidity, 65%; total dissolved solids (TDS), 86.6%; total suspended solids (TSS), 60.5%; chemical oxygen demand (COD), 99.5%; biochemical oxygen demand (BOD), 99.5%; and electrical conductivity (EC), 63.2% of distillery industry wastewater. In the case of steel and iron wastewater, it showed the removal efficiency for TDS, 48.3%; TSS, 65.3%; and EC, 42.2%. However, M18/CH1.0 removed the turbidity, 94.5%; TDS, 65.7%; TSS, 97.6%; and EC, 85.5% from the pulp and paper industry wastewater feed. The strong removal efficiency and resistance towards the fouling of the M18/CH1.0 make it a potential candidate for the application in the treatment of industrial wastewater.

Mixture density networks for re-constructing historical ocean-color products over inland and coastal waters: demonstration and validation

Ocean color remote sensing tracks water quality globally, but multispectral ocean color sensors often struggle with complex coastal and inland waters. Traditional models have difficulty capturing detailed relationships between remote sensing reflectance (Rrs), biogeochemical properties (BPs), and inherent optical properties (IOPs) in these complex water bodies. We developed a robust Mixture Density Network (MDN) model to retrieve 10 relevant biogeochemical and optical variables from heritage multispectral ocean color missions. These variables include chlorophyll-a (Chla) and total suspended solids (TSS), as well as the absorbing components of IOPs at their reference wavelengths. The heritage missions include the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua and Terra, the Environmental Satellite (Envisat) Medium Resolution Imaging Spectrometer (MERIS), and the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (Suomi NPP). Our model is trained and tested on all available in situ spectra from an augmented version of the GLObal Reflectance community dataset for Imaging and optical sensing of Aquatic environments (GLORIA) (N = 9,956) after having added globally distributed in situ IOP measurements. Our model is validated on satellite match-ups corresponding to the SeaWiFS Bio-optical Archive and Storage System (SeaBASS) database. For both training and validation, the hyperspectral in situ radiometric and absorption datasets were resampled via the relative spectral response functions of MODIS, MERIS, and VIIRS to simulate the response of each multispectral ocean color mission. Using hold-out (80–20 split) and leave-one-out testing methods, the retrieved parameters exhibited variable uncertainty represented by the Median Symmetric Residual (MdSR) for each parameter and sensor combination. The median MdSR over all 10 variables for the hold-out testing method was 25.9%, 24.5%, and 28.9% for MODIS, MERIS, and VIIRS, respectively. TSS was the parameter with the highest MdSR for all three sensors (MODIS, VIIRS, and MERIS). The developed MDN was applied to satellite-derived Rrs products to practically validate their quality via the SeaBASS dataset. The median MdSR from all estimated variables for each sensor from the matchup analysis is 63.21% for MODIS/A, 63.15% for MODIS/T, 60.45% for MERIS, and 75.19% for VIIRS. We found that the MDN model is sensitive to the instrument noise and uncertainties from atmospheric correction present in multispectral satellite-derived Rrs. The overall performance of the MDN model presented here was also analyzed qualitatively for near-simultaneous images of MODIS/A and VIIRS as well as MODIS/T and MERIS to understand and demonstrate the product resemblance and discrepancies in retrieved variables. The developed MDN is shown to be capable of robustly retrieving 10 water quality variables for monitoring coastal and inland waters from multiple multispectral satellite sensors (MODIS, MERIS, and VIIRS).

Transformation processes of total suspended solids and dissolved organic matter in rivers: Influences of different land use sources and degradation processes.

The riverine dissolved organic matter (DOM) pool constitutes the largest and most dynamic organic carbon reservoir within inland aquatic systems. Human activities significantly alter the distribution of organic matter (OM) in rivers, thereby affecting the availability of DOM. However, the impact of total suspended solids (TSS) on DOM under anthropogenic influence remains insufficiently elucidated. This study employed Fourier transform ion cyclotron resonance mass spectrometry, DOC characterization, and incubation experiments to investigate how land use and degradation processes influence TSS-DOM transformation in rivers. Our findings revealed that geographical patterns cause significant variations in both DOM composition and TSS content. Anthropogenic impacts led to an increase in autochthonous TSS content and an enhanced relative intensity (RI) of nitrogen (N)- and sulfur (S)-containing compounds in riverine DOM. The presence of TSS increased the bioavailability of DOM from 29.97% to 33.57%. However, during both photodegradation and combined degradation processes, the presence of TSS reduced the bioavailability of DOM. The degradation rate constant (k) of DOM decreased as degradation time increased. The k values were significantly correlated with the CHO components in natural rivers and with N- and S-containing components in human-influenced rivers. The degradation rates of DOC under different land uses were 0.05±0.04 d-1, 0.07±0.06 d-1, and 0.08±0.06 d-1 in forested, urban, and cropland-influenced rivers, respectively. The content of aliphatic compounds and the number of CHOS molecules in TSS-containing water were higher than in TSS-free water during the combined process of photochemical and microbial degradation, while the saturation and aromaticity of the compounds were lower. The characteristics of autochthonous DOM were more pronounced under the influence of TSS photorespiration. During drinking water disinfection, these small molecules derived from autochthonous TSS may contribute to an increase in disinfection by-products (DBPs) in drinking water. This study enhanced our understanding of how changes in autochthonous TSS content, driven by geographical heterogeneity and human activities, influence the biogeochemical processes of DOM in water, as well as the underlying molecular mechanisms and implications for water quality safety.

Seasonal Dynamics of Caligus clemensi Infestation in European Seabass and Flathead Grey Mullet Integrating Morphological, Molecular, Immunological, and Environmental Perspectives

This case study investigates the seasonal prevalence, morphological characteristics, molecular identity, host immune response, and environmental factors influencing Caligus clemensi infestations in farmed European seabass and flathead grey mullet at a single marine fish farm. A total of 600 fish (400 seabass, 200 mullet) were examined over one year, revealing seasonal fluctuations in parasite prevalence and intensity. C. clemensi infestation peaked in winter for seabass (75% prevalence) and spring for grey mullet (80% prevalence), with notable declines in summer and autumn for both species. Morphological analysis confirmed C. clemensi as the causative agent, exhibiting sexual dimorphism and characteristic features including a quadrilateral cephalothorax and disk-shaped lunules. Molecular characterization of the 18S rRNA gene corroborated the morphological identification, with phylogenetic analysis revealing a well-supported monophyletic clade for C. clemensi within the family Caligidae. Quantitative real-time PCR demonstrated significantly elevated interleukin-1β (IL-1β) expression in infected fish, indicating a robust inflammatory response. Grey mullet and seabass exhibited high IL-1β upregulation. Histopathological examination revealed severe gill tissue damage, vascular changes, and hepatic steatosis in infected fish. Water quality analysis identified several parameters exceeding permissible limits, including total suspended solids (4800-5100 mg/L), total dissolved solids (32000 mg/L), sulfates (2300 mg/L), and chlorides (18000 mg/L). These elevated levels, likely associated with nearby oil production and refining activities, created conditions conducive to parasite proliferation. The high total suspended solids might provide substrates for C. clemensi settlement and attachment, while increased dissolved ions could stress fish and reduce their parasite resistance. This multidisciplinary case study revealed complex host-parasite interactions between C. clemensi and farmed marine fish, highlighting the need for improved water quality and targeted parasite control to enhance aquaculture sustainability in the Suez Canal region.

Genera complying denitrifying phosphorus removal community contribute excellent SND-PR in a pilot cyclic SBR: Effect of DO, settling and recirculation rate on process performance.

This work investigated the role of operational conditions and typical functional microbes to maximize the nutrient removal efficiency of a pilot-scale sequencing batch reactor (SBR) system (100 m3/d) that treated municipal wastewater. The pilot system was operated in five phases, including start-up and four runs at variable cycle times (2.0, 1.5, 1.7, 2.0, and 3.0h) with an average readily biodegradable chemical oxygen demand (rbCOD) to chemical oxygen demand (COD) ratio of ∼15.3%. The best TN removal 'ηmax' of 75.6 ± 5.6% (TNinfluent= 27.5 ± 6.5 mg/L, TNeffluent ≤5.9 mg/L) and TP removal 'pmax' 77.9 ± 6.3% (TPinfluent= 3.8 ± 1.3 mg/L, TPeffluent ≤1.0 mg/L) along with the COD, biochemical oxygen demand (BOD), and total suspended solids (TSS) removal efficiencies of 87.3 ± 4.5%, 92.7 ± 2.8%, 92.0 ± 3.5%, respectively, were observed during run 3 (2h cycle) at settling/ total cycle times ratio (S/T) of 0.33 and recirculation/ total cycle times ratio (R/T) of 0.017 (6.4%), and operating DO of 0.5-2.5 mg/L. The denitrifying polyphosphate accumulating organisms 'DPAOs' of Burkholderia (17.0%), Rhodocyclales (6.1%), and Flavobacterium (8.7%) classes, and Nitrifiers of Nitrospira (5.4%) and Nitrosomonas (5.4%) classes were dominant in accomplishing simultaneous nitrification, denitrification, and phosphorus removal (SND-PR) in the pilot system.

Hybrid constructed wetlands for tertiary treatment of poultry slaughter wastewater to meet quality standards of discharge and reuse: a full-scale case study in Vietnam.

The construction and operation of a small-scale hybrid constructed wetland (HCW) system for tertiary wastewater treatment was presented. The HCW system includes a vertical sub-surface flow CW (VFCW), a horizontal sub-surface flow CW (HFCW), and a free water surface flow CW (FWSCW). Operated in series, it had a total area of 150 m2. It received 7.5 m3day of secondary effluent wastewater from the existing treatment system of a poultry slaughter enterprise at the production capacity of 500 ducks per day in an on-site experiment of 12months. The results showed that the removal efficiencies of biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total nitrogen (TN), orthophosphate (PO43--P), total phosphorus (TP), Escherichia coli (E. coli), and total coliforms (T. coli) reached average values of 76.2, 78.7, 77.1, 83.9, 86.3, 84.9, 72.3, 73.9, 98.9, and 96.4%, respectively, while the effluent concentrations of the study system complied with the most difficult limits not only for discharge into the receiving water source but also for reusing wastewater to water plants. The function made by various configurations such as a VFCW, a HFCW, and a FWSCW placed sequentially in the HCW system proved crucial to treat wastewater and make it reusable.

Wastewater quality evaluation in terms of wastewater quality index using hybrid constructed wetland for treatment of dairy and municipal wastewater.

The world's most pressing problem is water shortage, which is made worse by fast industrialization and urbanization, especially in places like India where untreated effluent presents serious threats to human health and the environment. In order to treat dairy and municipal wastewater, this study assesses the efficacy of a two-stage hybrid constructed wetland (CW) system. The WWQI is the primary focus of this evaluation over a range of mixing ratios. Before and after treatment, many physicochemical parameters were examined, including pH, total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphorus (TP), ammonia nitrogen ( ), and nitrate nitrogen ( ). The hybrid CWs system dramatically lowers pollutant concentrations, according to the results, with combinations containing higher amounts of MWW showing the best results. The WWQI values, which change from "unfit for any uses" in untreated DWW to "excellent" quality in treated MWW, show these advancements. The results highlight the potential of hybrid CWs as an effective and sustainable wastewater treatment method, especially when it comes to maximizing the proportion of dairy to municipal wastewater. This study adds to our knowledge of efficient wastewater treatment techniques and highlights the significance of incorporating eco-friendly technologies to tackle water scarcity issues. PRACTITIONER POINTS: Hybrid Constructed Wetlands (HCWs) are effective in removing TSS, BOD, COD, TP, ammonia nitrogen, and nitrate nitrogen from dairy and municipal wastewater. On the basis of HCWs performance determine the Wastewater Quality Index (WWQI) for four different ratio proportions of dairy and municipal wastewater. This index is more useful for water quality status determination and treated water reuse for various purposes. This also benefits sustainable treatment technology and contributes to achieving SDGs.

Application of Electronic Tongue for Detection and Classification of Lead Concentrations in Coal Mining Wastewater

This study evaluates the potential of an electronic tongue (E-tongue) as an innovative and alternative method for detecting and classifying lead concentrations in wastewater generated by coal mining activities in North Santander, Colombia. The E-tongue aims to complement traditional environmental monitoring techniques with a more efficient and accurate solution. A total of 110 wastewater samples were collected from two locations at a coal mine in the municipality of Toledo: one inside the mine (Point 2) and another outside the mine (Point 1). This research involved the physicochemical analysis of parameters such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), hardness, and alkalinity, conducted at the University of Pamplona’s laboratories. The integration of PCA with machine learning algorithms highlighted the E-tongue’s capability for the real-time, on-site detection and discrimination of lead concentrations in coal mining wastewater. Achieving a precision and accuracy above 90%, the SVM classifier outperformed alternative models such as the k-NN, Random Forest, Naïve Bayes, and Quadratic Discriminant Analysis. This demonstrates the system’s robustness and reliability in environmental monitoring, enabling the accurate classification of lead concentrations within the critical range of 0.05 to 1 ppm, essential for assessing contamination levels and ensuring water safety. These findings highlight the E-tongue system’s capability as a rapid, cost-effective tool for monitoring lead contamination in mining wastewater, presenting a viable alternative to conventional methods such as atomic absorption spectroscopy.

Optimization of Selected Parameters in Vertical, Horizontal, and Hybrid Surface Flow Constructed Wetland Systems for Improving the Treatment Efficiency of Textile and Sewage Effluents

Constructed wetland systems (CWSs) can offer cost-effective wastewater treatment in developing countries like Pakistan. This study focused on optimizing design and operational parameters of CWSs in horizontal surface flow (HSF), vertical surface flow (VSF), and hybrid mesocosms for treating sewage and textile effluents using local hydrophytes: Lemna minor, Typha latifolia, and Eichhornia crassipes. Pollutants and heavy metals (Cd, Cr, Cu, Pb, Ni, and Zn) were removed under different flow configurations, bedding materials, hydrophyte species, and hydraulic retention times (HRT) to optimize the overall contaminant removal efficiency (RE). Key findings indicated that the hybrid CWS achieved a maximum RE of 63.62% for total suspended solids (TSS) and 57.9% for biochemical oxygen demand (BOD) at an HRT of 3 days, with efficiencies declining at longer retention times. Additionally, the hybrid system showed maximum metal removal, with Cd and Cr RE reaching 75.2% and 70.5%, respectively. The study also highlighted the critical role of hydrophyte species and HRT in optimizing RE. Furthermore, the choice of hydrophyte species significantly influenced pollutant removal, with treatment cells containing mixed hydrophytes achieving the highest removal efficiencies (63.62%), followed by Eichhornia crassipes with high Cd (643.33 mgkg−1) and Cr (1103.72 mgkg−1) uptake. A lower HRT of 3 days resulted in the highest overall removal efficiency of 57.5%, which decreased with longer HRTs (from 6 to 9 days). Optimizing design and operational parameters is crucial for maximizing CWS treatment potential.

Designing climate-resilient sustainable drainage system (SuDS) for mass rapid transit (MRT) development: A hydrodynamic modelling approach

The progressive industrialisation and urbanisation of urban areas have significantly altered hydrological factors such as terrain, imperviousness, and surface flow. These developments, accompanied by increased traffic congestion and carbon emissions, contribute to climate change. Consequently, implementing Mass Rapid Transit (MRT) systems is crucial for alleviating traffic congestion and reducing carbon emissions globally. However, the changes in urban hydrology following development, combined with increased rainfall due to climate change, exacerbate risks of flooding, erosion, and sedimentation for the MRT development and surrounding low-lying areas. Therefore, researching urban drainage systems under climate change conditions for MRT development is essential. This study utilised 1D/2D hydrodynamic modelling and simulation to investigate the performance of an existing MRT drainage system designed with a control-at-source concept and a new sustainable drainage system incorporating infiltration engineering and flow-retarding techniques, including porous layers and a bioecological system to mitigate urban flooding erosion and sedimentation. The results show that the new sustainable drainage system, featuring permeable pavements and bioretention facilities, effectively integrates 30% of the MRT-developed land typology without requiring additional land acquisition, which is cost-effective and practical for mitigating major flooding and reducing total suspended solids, thereby controlling erosion and sedimentation.

Water quality within the greater Suva urban marine environment through spatial analysis of nutrients and water properties.

Coastal ecosystems in Pacific Island Countries and Territories are vital to local livelihoods, yet increasingly face pressures from urbanization. In Fiji, the Greater Suva Urban Area, where one-third of the nation's population live, exemplifies these challenges. This study examines spatial and temporal water quality variations in the coastal zone, focusing on physicochemical, nutrients, and clarity parameters. Using a Seabird Scientific SBE19 CTD and Thermo Scientific Orion™ AQUAfast™ colorimeter, coupled with hierarchical clustering and principal component analysis, six water quality clusters were identified, influenced by oceanic processes, river inputs, and anthropogenic activities. Key findings highlight nutrient enrichment near urban centers particularly at the Kinoya Sewage Treatment Plant outfall, where ammonia exceeded 17.8mg/L, and significant variation observed in nitrate (up to 0.24±0.06mg/L) and nitrite (up to 0.24±0.06mg/L) concentrations near river mouths. Seasonal runoff contributed to elevated turbidity (up to 3.5 NTU) and total suspended solids (up to 14.7mg/L) levels during wet months. Salinity, and temperature exhibited strong spatial and seasonal variability, reflecting land-ocean interactions and restricted water exchange. These findings emphasize the need for targeted action to mitigate nutrient pollution, urban runoff, and wastewater impacts. This study provides a cost-effective monitoring framework for water quality management, offering insights for sustainable coastal resource management in Fiji and other Pacific regions amidst urbanization and climate change.

Mercury patterns in lakes within a natural hotspot in the Southern Volcanic Zone of the Andes (Nahuel Huapi National Park, Patagonia, South America)

Environmental context The pristine oligotrophic lakes of Andean Patagonia are influenced by volcanic eruptions and atmospheric deposition. This study focuses on mercury (Hg) dynamics in two connected lakes in a natural Hg hotspot of the southern Andes. The lake waters have low dissolved organic carbon and moderate to high Hg concentrations, resulting in high Hg availability. These promote Hg binding to natural particulates, thereby favouring its incorporation into food webs. Rationale Mercury hotspots have been identified in pristine volcanic areas of the northern Patagonian Andes (South America). In this study, we investigated spatial and seasonal patterns of total mercury (THg) in two oligotrophic lakes in Nahuel Huapi National Park (Argentina), adjacent to the Puyehue Cordón Caulle volcanic complex (Chile). We hypothesise that THg levels in the lakes are linked to seasonal terrestrial inputs and that in-lake processes influence its distribution and availability. Methodology Water samples were collected seasonally in the connected lakes Pire (shallow) and Brazo Rincón branch of L. Nahuel Huapi (BR, deep). The concentration of THg was studied together with physicochemical variables, including the concentration and quality of dissolved organic matter (DOM). THg was measured by cold vapour atomic fluorescence spectrometry (CVAF) and DOM was characterised through absorbtion and fluorescence spectroscopy. Results Lakes showed moderate to high THg concentrations and remarkable Hg availability. THg increased downwards in the landscape and was associated with DOM terrestrial prints, indicating its co-transport from the catchment during high connectivity periods (from winter to early summer). In summer, THg levels were associated with higher mineralisation (higher dissolved inorganic carbon, DIC) and diffusion from sediments, especially in the shallow lake. THg availability and distribution were related to the quality of the DOM pool and the total suspended solids (TSS) year round. The high biotic contribution to TSS (higher chlorophyll-a:TSS) in BR indicated Hg binding to phytoplankton and incorporation into lake food webs. Discussion Pristine oligotrophic lakes influenced by natural Hg sources have a high potential for Hg accumulation in food webs because their typically high Hg and low DOC concentrations result in high Hg availability, promoting Hg binding to abiotic and biotic particles.

Spatio-temporal pollution assessment of Kulfo River using CCME-WQI and pollution tolerance index by benthic macroinvertebrates, Arba Minch, Ethiopia.

In developing nations, the biggest threat to public health is the quality of the water. The Kulfo River provides the majority demand of the domestic water and irrigation along its course; however, it is observed that wastes from anthropogenic and natural activities enter the river. Therefore, this study aimed to examine the pollution status by integrating conventional methods with benthic macroinvertebrates. One hundred twenty samples were collected for 15 water quality parameters from five sampling sites during dry and rainy events. The mean concentration of DO, TSS, BOD5, COD, ortho-phosphate, and turbidity did not meet the standard limits in five sampling sites during the rainy season. Benthic macroinvertebrates were collected from the left, middle, and right sides of the river for each sampling site and examined using the Benthos Biomonitoring Protocol Network Manual. CCME index and PTI index of benthic macroinvertebrates were used to examine the pollution status of the river. According to CCME index result, S2 (39.79), S3 (38.90), and S4 (37.71) are classified under poor pollution status during the rainy season and S1 (92.13) and S5 (95.70) are categorized as good and excellent pollution status in the dry season, respectively. On the contrary, based on the PTI index result, S2 (7.0), S3 (9.0), S4 (9.0), and S5 (9.0) are classified under poor pollution status during the rainy season, whereas S2 (14.0), S3 (10.0), and S4 (15.0) are categorized under fair, and sampling sites S1 (21.0) and S5 (20.0) have good pollution status in the dry season. Based on study findings, the Kulfo River is contaminated by pollutant intrusion, resulting in a decrease in its quality. Therefore, management of solid, liquid, runoff, and domestic activities is critical in upstream tributaries and Arba Minch town to prevent river water quality deterioration.

Dissolved phosphorous through dry-wet-dry transitions in a small-dammed river basin: integrated understanding on transport patterns, export controls, and fate.

An integrated understanding of dissolved phosphorous (DP) export mechanism and controls on export over dry and wet periods is crucial for riverine ecological restorations in dammed river basins considering its high bioavailability and retention rates at dams. Riverine DP transport patterns (composition, sources, and transport pathways), export controls, and fate were investigated over the 2020 wet season (5 events) and dry seasons before and after it (2 events: dry(before) and dry(after)) in a semi-arid, small-dammed watershed to comprehend the links between terrestrial DP sources and aquatic DP sinks. Close spatiotemporal monitoring of the full range of phosphorous and total suspended solids (TSSs) and subsequent analyses (hysteresis, hierarchical partitioning, and coefficient of variation) provided the basis for the study. Total-DP (TDP) shared 13-39% (25%) of total-P (TP) through storms, dissolved organic-P (DOP) shared 6-21% (12%), and phosphate-P shared (PO4-P) 7-22% (13%). DP forms displayed strong connections with discharge trends across the wet season, and marked changes in the shares were reported over dry-wet and wet-dry transitions. The DOP fraction of TDP increased from 4% in dry(before) baseflow to 64% at the end of the wet season. The DOP flux increment in stormflow was 20 folds compared to dry(before) baseflow, while that of PO4-P was 2 folds. DOP displayed the least spatial source heterogeneity with minimum anthropogenic pressure on inherent fluxes. DOP originated from overland and near-stream soil sources and was transported via surface runoff and soil water runoff, respectively. Across the wet season, the attrition of overland DOP sources and activation of near-stream soil DOP sources through strengthened hydrological connectivity governed the seasonal DOP trends. Surface and groundwater runoff pathways were important for PO4-P delivery during stormflow; nonetheless, wastewater treatment plant (WWTP) effluent was the main PO4-P source under both baseflow and stormflow regimes, followed by near-stream traditional agriculture lands. The interaction patterns of small dam systems with DP inputs through dry-wet periods were explained. The riverine PO4-P fluxes were profoundly impacted by in-stream biogeochemical and physical processes and small dam systems, while riverine DOP fluxes were relatively less influenced.

Integration of Machine Learning and Remote Sensing for Water Quality Monitoring and Prediction: A Review

Aquatic ecosystems play a crucial role in sustaining life and supporting key green and blue economic sectors globally. However, the growing population and increasing anthropogenic pressures are significantly degrading terrestrial water resources, threatening their ability to provide essential socioeconomic services. To safeguard these ecosystems and their benefits, it is critical to continuously monitor changes in water quality. Remote sensing technologies, which offer high-resolution spatial and temporal data over large geographic areas, including surface water bodies, have become indispensable for these monitoring efforts. They enable the observation of various physical, chemical, and biological water quality indicators, which are essential for assessing ecosystem health. Machine learning algorithms are well suited to handle the complex and often non-linear relationships between remote sensing data and water quality parameters. By integrating remote sensing with machine learning techniques, it is possible to develop predictive models that enhance the accuracy and efficiency of water quality assessments. These models can identify and predict trends in water quality, supporting timely interventions to protect aquatic ecosystems. This paper provides a thorough review of the major remote sensing techniques for estimating water quality indicators (e.g., chlorophyll-a, turbidity, temperature, total nitrogen and total phosphorous, dissolved organic, total suspended solids, dissolved oxygen, and hydrogen power). It examines how machine learning can improve water quality assessments. Additionally, it identifies key research gaps in current methodologies and suggests future directions to address challenges in water quality monitoring, aiming to improve the precision and scope of these critical efforts.

NaOH-Enhanced Wet Air Oxidation of Municipal Sludge for High-Quality Carbon Source Production

Many volatile fatty acids (VFAs) are produced after wet air oxidation, which could be a potential carbon source. In this study, we investigated the impact of NaOH on the removal of hazardous organics and the changes in the produced carbon source. The total and soluble chemical oxygen demand (SCOD) removal rates decreased to 47.9% and 55.3% with 51.6% NaOH addition. The removal rates of total suspended solids (82–85%) and volatile suspended solids (97–99%) remained stable under all conditions. Additionally, the concentrations of acetic acid and isovaleric acid increased with a high pH value. Fluorescent substances closely related to aromatic protein and fulvic acid-like substances were identified and degraded significantly with the addition of NaOH. Moreover, 41.3% NaOH addition (initial pH 13.0) could yield a VFAs/SCOD ratio of 30.5%, demonstrating the good biocompatibility of the carbon source. The effect of the nitrogen element was also considered, with the ratio of the 5-day biological oxygen demand to the total nitrogen being 7.2, indicating that the oxidation solution could provide an abundant carbon source. Thus, the sludge-derived carbon source is suitable to supply biological treatment units for municipal wastewater.

Efficiency of Electrocoagulation for Laboratory Wastewater Treatment Using Aluminum Electrodes

Environmental analysis of waste generated from residual samples in a testing laboratory is necessary to mitigate its impact. This study aims to assess the performance of electrocoagulation (EC) using aluminum (Al) electrodes in reducing Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), and pH level in laboratory wastewater. This investigation successfully employed an EC process utilizing Al electrodes in both anode and cathode configurations. The experimental conditions include Voltage (10, and 20 V), contact time (15, 30, 45, and 60 minutes), and the electrode configuration (monopolar and bipolar). The results indicated that a bipolar configuration of Al electrode relatively outperformed a monopolar configuration. Optimal condition was achieved at 20 V, and contact time of 60 minutes. Results showed COD removal efficiency up to 96.15% reducing COD from 627.45 to 24.183 mg/L, TSS removal efficiency up to 92.45%, lowering TSS from 53 to 4 mg/L. While pH increased during the process, it remained within acceptable limits. This substantial reduction in pollutants significantly improved water quality, surpassing regulatory standards. The results suggest that EC is a promising approach for achieving sustainable treatment for laboratory wastewater.

Combined application of metagenomics and FEAST to trace sources of microbial eukaryotic contamination in the Pasig-Marikina-San Juan (PAMARISAN) river system in Metro Manila, Philippines.

Microbial eukaryotes are vital to global microbial diversity, but there is limited information about their composition and sources in contaminated surface waters. This study examined the pathogens and potential sources of microbial eukaryotic communities in polluted sink environments using the 18S rDNA amplicon sequencing combined with the fast expectation-maximization for microbial source tracking (FEAST) program. Six sampling sites were selected along the Pasig-Marikina-San Juan (PAMARISAN) River System, representing different locations within the waterway and classified as sinks (n = 12), whereas animal fecal samples collected from various farms were classified as sources (n = 29). Taxonomic composition revealed Stramenopila, Alveolata, Rhizaria (SAR), Archaeplastida, and Excavata in the rivers, accounting for 85.1%, 13.2%, and 0.36% mean abundance of microbial sink communities, respectively. Clinically relevant human pathogens were also observed in sink environments. The correlation test demonstrated that dissolved oxygen, total suspended solids, pH, temperature, fecal coliform count, and phosphates were important environmental factors driving community variations. Moreover, FEAST results indicated that sewage (19.6%) was the primary source of microbial eukaryotes, followed by duck (0.644%) and cow (0.566%) feces. Spatio-seasonal variations showed higher contributions at downstream stations and during the wet season, highlighting the role of rainfall in enhancing microbial dispersal. Results from community-based microbial source tracking can be used to explore factors shaping microbial eukaryotes in freshwater environments, assess potential pathogen-related hazards, and inform river conservation and management strategies. Furthermore, this also serves as preliminary data for microbial eukaryotic source tracking in the Philippines, laying groundwork for future research.

Comparative Study of Modified and Conventional Bioballs for Organics Removal from Sewage Treatment

One of the challenges researchers have to deal with is achieving a high surface area for the biofilm plastic media used in wastewater treatment. This study evaluates bioball biofilm reactors using two different bioball configurations (modified and conventional bioballs). It evaluates the performance of each configuration based on the biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solid (TSS) while monitoring the pH, temperature, and DO during a 36-day operation time. The lab-scale rector consists of a 1m3 feeding tank, a 100 L aeration tank, and a settling tank with a two-hour retention time and operated using real domestic wastewater. The removal efficiency for all parameters shows that the modified bioball reactor shows better organic matter removal efficiency (7% better BOD removal, 6% better COD, and 4% better TSS removal). In summary, the modified bioball reactor has promising potential to facilitate the construction of compact treatment plants or modernize poor-performing treatment plants.

Machine learning analysis for the Hilla River water quality index- Iraq

<p>Since industrial and human activities have been developed in different ways in Iraq, water quality has been declining along ‎the Hilla River, the only water resource for drinking water in the Hilla City, Iraq. In this research, The Weighted Arithmetic Water Quality Index (WQI) along the river was analysis using linear regression machine learning algorithm. Water quality parameters including Turbidity ‎‎(Turb), Electric Conductivity (EC), Hydrogen Ions (pH), Total ‎Suspended Solid (TSS), Chloride ‎Ions (Cl), Sulfate Ions (SO4), Alkaline (ALK), Total ‎Hardness (TH), Calcium Ions (Ca), ‎Potassium Ions (k), Sodium Ions (Na), Magnesium ‎Ions (Mg), and Total Dissolved Solid (TDS) were utilized to determine WQI from January 2016 to June 2021 depending on datasets from five sampling stations located along the river at the main city. It was noticed that the river WQI ‎has a significant relationship with ‎Turb only (positive proportion). ‎ This relationship between WQI and Turbidity in ‎the river is limited to ‎a WQI value of 220, Thus, two ‎linear regression models were developed and validated: One for WQI values greater than ‎‎220 and another for the values less than 220.‎ In addition, ‎the results of this study showed that the Hilla River is severely polluted since WQI values are high. The ‎best WQI and turbidity value were in 2018. However, ‎in 2020 and 2021, ‎there were some improvement in WQI and turbidity compared to 2019.      </p>