Sewage Treatment Research Articles

Recycling of Reclaimed Water in China: Current Situation, Development Trend, and Countermeasures

Recycling of reclaimed water is an important way to develop water resources and reduce pollution discharge. At present, the utilization rate of reclaimed water is low in China and the recycling system is inadequate. Therefore, from the perspective of "carbon peaking and carbon neutrality" dual carbon propulsion and "water resources protection, water environment governance, and water ecological restoration" three water co-governance, this study first systematically combined the water resources situation, water supply structure, urban domestic sewage collection and treatment, and recycling of reclaimed water in all provinces （municipalities and autonomous regions）. Data collected in 2022 showed that the capacity of municipal sewage treatment was approximately 62.689 billion cubic meters annually, the capacity of reclaimed water production was approximately 28.98 billion cubic meters annually, and the utilization rate of reclaimed water was approximately 28.76%. There were 20 provinces with the utilization rate of reclaimed water less than 25%, among which the utilization rate of reclaimed water was less than 5% in Shanghai, Chongqing, Xizang, and Jiangxi. The situation of water resources did not match the development of the utilization rate of reclaimed water. Therefore the utilization paths of reclaimed water must be broadened and the utilization rate of reclaimed water must be improved crucially. Moreover, the related policies, laws, and regulations and standards of reclaimed water in China were listed. The technical and benefit feasibility analysis of reclaimed water utilization was carried out, and the development trends and existing problems of reclaimed water utilization in China were investigated. Finally, the countermeasures and suggestions of the recycling of reclaimed water from the aspects of technology development, management policy, fund guarantee, and publicity incentive are proposed, to promote the resource treatment of sewage, realize the synergistic reduction of pollution and carbon emissions in sewage treatment, help achieve the goal of carbon peak carbon neutrality, and accelerate the construction of a beautiful China. This study can provide reference and guidance for regional recycling of reclaimed water.

Biodegradation of various edible oils and fat by Staphylococcus petrasii sub sp. jettensis VSJK R1 for application in bioremediation of lipid rich restaurant wastewater.

The disposal of fat, oil, and grease (FOG) pollutants from various sources, including restaurants, food processing facilities, and domestic kitchens, poses significant challenges to wastewater treatment systems. In this study, we isolated and characterized a novel bacterial strain. The result of 16S rRNA gene and phylogenetic analysis showed that the isolate was Staphylococcus petrasii sub sp. jettensis and named as VSJK R1 (Fig. S1). It was tested for its biodegradation potential of FOG contaminants. Our investigation revealed that Staphylococcus petrasii sub sp. jettensis VSJK R1 effectively degraded a variety of edible oils, including soybean, sunflower, cottonseed, palm, groundnut, and butter, with notable efficiency. Optimization studies were conducted to determine the optimal conditions for biodegradation, including the effects of nitrogen, carbon, phosphorus, pH, temperature, and salt concentration. Results indicated that organic nitrogen sources and glucose as carbon source significantly enhanced biodegradation rates, while the addition of phosphorus further improved degradation efficiency within specific concentration ranges. Moreover, the optimal pH for biodegradation was found to be neutral, with temperature ranging between 22°C and 45°C favoring microbial activity. Remarkably, Staphylococcus petrasii sub sp. jettensis VSJK R1 exhibited resilience to high salt concentrations, making it suitable for treatment of wastewater with elevated salt content. Additionally, comparative studies with other microbial strains underscored the unique biodegradation capabilities of Staphylococcus petrasii sub sp. jettensis VSJK R1, particularly in degrading various edible oils. The results suggest promising applications of this novel isolate in bioremediation efforts targeting FOG pollutants in wastewater treatment plants and grease traps. Future research may focus on scaling up the bioremediation process and field testing the efficacy of Staphylococcus petrasii sub sp. jettensis VSJK R1 in real-world wastewater treatment scenarios.

Inferring failure risk of on-site wastewater systems from physical and social factors

Aging infrastructure and climate change present emerging challenges for clean water supply and reliable wastewater services for communities in the United States (US). In Georgia, for example, the failure rates of on-site wastewater systems (OWTS) have increased from 10% to 35% in the last two decades as the systems age. In this work, we develop a hierarchical Bayesian model to understand the different contributions of physical and social factors driving OWTS failures using a long-term collection of 201,000 Georgia’s OWTS inspection records. The out-of-sample validation accuracy of our hierarchical Bayesian model is 70% within Georgia, outperforming other machine learning models that do not consider the multiscale nature of the problem. Overall, we find counties that experience more extreme precipitation and are situated in steeper-sloped regions are significantly associated with increased failure risks. Uncertainties, meanwhile, are largely associated with counties experiencing more precipitation and have lower median housing value.

Full-scale simultaneous partial nitrification, anammox, and denitrification for the efficient treatment of carbon and nitrogen in low-C/N wastewater

A full-scale simultaneous partial nitrification, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) reactor was initiated to address the problem of high energy consumption for the treatment of low C/N wastewater. The SNAD system achieved a nitrogen removal rate of 0.9 kg/(m3·d) at an influent NH₄+–N concentration of 500 mg/L after 450 days of stable operation. Partial nitrification was achieved by maintaining free ammonia levels at 0.8 ± 0.3 mg/L and dissolved oxygen concentrations between 0.3 mg/L and 1.2 mg/L, which resulted in synergistic nitrogen removal, with anammox contributing 61 % and denitrification contributing 39 %. Microbiological analyses indicated that the dominant microorganisms were Candidatus Brocadia, Thauera, Denitratisoma, and Nitrosomonas. In conclusion, study provides a solid foundation for the broader implementation of the SNAD process in wastewater treatment systems.

Wastewater Quality Assessment at Amarah Sewage Treatment Plant: Implications for Agricultural Use and Environmental Safety

This study examines the quality of treated wastewater from the Amarah Sewage Treatment Plant (ASTP) in Iraq for potential agricultural use and compares it to the water quality standards of Iraq, Egypt, and the USA. The effluent was analyzed over a five-month period for various parameters, including pH, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), and concentrations of ions, such as chloride (Cl-), sulfate (SO4-2), phosphate (PO43-), nitrate (NO3-), and ammonia (NH3). The findings showed that the pH and TDS measurements of the treated wastewater fell within the acceptable range, according to the regulations set by all three countries. The concentrations of Cl-, SO4-2, PO43-, NO3-, and NH3 in the treated wastewater were also within the acceptable limits set by the Iraqi standards. However, chloride and sulfate levels occasionally exceed permissible thresholds. The treated wastewater from ASTP is generally suitable for the irrigation of certain crops, but it is important to implement a monitoring and control system to ensure consistent water quality. Finally, investments are needed to improve treatment processes and establish educational programs for farmers to enhance their understanding of proper wastewater usage. These measures are crucial for protecting public health and conserving water resources, particularly in regions facing water scarcity.

Hazard Study of Sludge from Mining Wastewater Treatment Systems (Tailings), Accumulation of Contaminants and Potential Utilization Proposals

The increase in gold mining activities has led to a substantial rise in tailings generation, which carry distinct physicochemical and microbiological properties. This study aimed to evaluate the hazardous characteristics of mining tailings using the CRETIB (corrosivity, reactivity, explosiveness, toxicity, ignitability, biological-infectious) methodology. The research analyzed concentrations of heavy metals including arsenic, cadmium, copper, chromium, lead, mercury, nickel, and zinc, alongside parameters such as pH, cyanide, hydrogen sulfide, and coliform bacteria. Tailings samples were collected from a mine in Ponce Enriquez, Ecuador, at the surface and at a depth of 2 m across three monitoring campaigns. The results indicate that the tailings do not exhibit hazardous characteristics according to CRETIB criteria. While arsenic, chromium, copper, nickel, zinc, and mercury concentrations showed significant differences between the surface and 2 m depth, accumulating at the bottom of the tailings dam by 30–72%, parameters such as pH, cyanide, and hydrogen sulfide were higher at the surface, likely due to volatilization and precipitation effects. Lead did not show significant differences, but also tended to accumulate at depth. These findings suggest that the tailings could be safely utilized in the production of construction materials such as bricks, geopolymer concrete, and fiber cement, promoting circular economy practices and sustainable development in mining.

Removal of pharmaceutical compounds from sewage effluent by the nanofiltration membrane

Membrane is a promising technology for water treatment, and its commercial production has emerged globally. However, commercial membranes' effectiveness is still uncertain due to the new types of contaminants, such as pharmaceutical compounds (PC). Thus, in the current work, the performance of two commercial membranes (NFX and GC) has been evaluated using feed water from the effluent of sewage treatment plants (STP) and hospital wastewater (HWW). The spiked feed water contains PC classes of analgesics/anti-inflammatory, anti-hypertensives, beta-blockers, and psychiatric/antidepressants. The percentage difference between feed and permeate was measured. While the fouling properties of the membranes are also evaluated using STP and HWW as feed, along with the pure water flux in a variable-pressure setting, the results showed that NFX exhibits excellent, consistent rejection for the targeted PCs (>80 %). GC showed a broader range of rejection (10 % to 90 %) and presented a better flux flow than NFX. The main rejection factor is due to the membrane's pore size variation and the layer construction, which refer to the absorption, size exclusion, and diffusion of the PCs instead of the type of feed water and the flux. Current work provides scientific data on the diverse fabrication and market-available types of membranes, which would pose various efficiencies towards the type of targeted pollution.

Porous polymers embedded with iron carbon enhanced densified activated sludge formation and wastewater treatment

Municipal wastewater treatment plants in China face significant challenges in effectively removing pollutants from low-strength wastewater with a low carbon-to-nitrogen (COD/N) ratio. This study proposes a novel approach incorporating porous polymers embedded with iron-carbon (PP-IC) into an activated sludge system to enhance treatment. The PP-IC accelerated the formation of densified activated sludge (DAS), characterized by small particle sizes (<200 μm), excellent settleability (sludge volume index: 61 mL/g), and improved pollutant removal efficiency, with total nitrogen and total phosphorus removal rates increasing by 14.4 % and 57.4 %, respectively. DAS formation was achieved within 7 days and stabilized after 42 days. The enrichment of microorganisms, including unclassified_f_Caldilineaceae, Dechloromonas, and Candidatus Accumulibacter, further enhanced pollutant removal. Additionally, Fe2+, Fe3+ and hydroxyl radical (·OH) produced by iron-carbon micro-electrolysis supported DAS formation. Microbial interactions with the iron shavings sustained the long-term stability of the micro-electrolysis process. This synergistic mechanism significantly improved pollutant removal in wastewater treatment.

Solar Sonophotocatalytic Hydrogen Recovery from Sulphide Wastewater

Sonolysis-assisted photocatalytic hydrogen recovery from sulphide wastewater was conducted using Carbon nanotube (CNT) deposited ZnS/Fe2O3 core-shell particles. The synthesized photocatalyst was characterized for XRD, UV-DRS, SEM, EDX, HRTEM, FTIR, PL and XPS. Effect of catalyst dosage, photolytic volume and sacrificial agent (SO32-) concentrations were conducted for maximum hydrogen production. After optimization studies, it is observed that the maximum amount of hydrogen yield was obtained with 0.2M concentrations of sacrificial agent, 0.05g/L of catalyst dosage and 150mL of liquid depth. The prepared photocatalyst is found to be stable up to 6 cycles. Sonophotocatalysis shows better performance than sonolysis and photocatalysis. 6250 μmol/h is the highest H2 yield recovered from the sulphide containing wastewater collected from the sewage treatment plant.

Carbon Emissions from Sludge Treatment in a Sewage Treatment Plant: Field Study Investigation in Guangzhou, China

Carbon Emissions from Sludge Treatment in a Sewage Treatment Plant: Field Study Investigation in Guangzhou, China

Environmental behavior and risk of the emerging organic contaminants halogenated carbazoles in chemical industrial park clusters

Polyhalogenated carbazoles (PHCZs) are emerging organic contaminants and have attracted extensive concern because of their widespread occurrence and dioxin-like toxicity. However, the distribution characteristics, environmental behavior, and fate of PHCZs are still poorly understood. In this study, 74 composite environmental samples from 21 Chinese cities were collected around industrial parks in the Yangtze River Delta. The PHCZ concentration ranges in sediment and soil samples were 12.7–5.21 × 103 and 34.6–1.81 × 103 ng/g, respectively, which is equivalent to or higher than those of well-known persistent organic pollutants in the similar areas. The dominant congeners of PHCZs in sediment and soil were 3-chlorocarbazole and 3,6-dichlorocarbazole. Industrial emissions, especially from printing and dyeing textiles, were the main contributors to the high PHCZ environmental concentrations. Potential toxic effects of the PHCZs were evaluated using the toxic equivalent (TEQ) method. The TEQs of PHCZs in sediment and soil were up to 550 and 554 pg TEQ/g dry weight, respectively. The estimated TEQ value of sediment and soil exceeded the corresponding safety guideline, which indicated that PHCZs in the Yangtze River Delta posed high health risks. This study provides an important theoretical basis for controlling and reducing the ecological risks of PHCZs in the chemical industry. At the same time, it also provides reference for the priority control and revision of discharge standards for PHCZs in sewage treatment plants in future.

Enhanced Phthalate Degradation in Sewage Plant by Heterogeneous Electro-Fenton modifiedd bimetallic Single-Atom Catalyst

Enhanced Phthalate Degradation in Sewage Plant by Heterogeneous Electro-Fenton modifiedd bimetallic Single-Atom Catalyst

Uncovering the causal relationships in plant-microbe ecosystems: A time series analysis of the duckweed cultivation system for biomass production and wastewater treatment

The complex interplay among plants, microbes, and the environment strongly affects productivity of vegetation ecosystems; however, determining causal relationships among various factors in these systems remains challenging. To address this issue, this study aimed to evaluate the potential of a data analytical framework called empirical dynamic modeling, which identifies causal links and directions solely from time series data. By cultivating duckweed, a promising aquatic plant for biomass production and wastewater treatment, we obtained a 63-day time series data of plant productivity, microbial community structure, wastewater treatment performance, and environmental factors. We confirmed that empirical dynamic modeling can identify the correct causal directions among temperature, light intensity and plant growth, solely from time series data. Extending the analysis to microbial community data suggested that the bacterial family Comamonadaceae positively affects host duckweed growth and nitrogen removal. Additionally, the predicted abundance of bacterial genes relevant to xenobiotics biodegradation was shown to have a positive effect on organic pollutant removal, supporting the significant role of bacterial metabolism in phytoremediation performance. These results demonstrate the effectiveness of empirical dynamic modeling in uncovering causal relationships within vegetation ecosystems, which are difficult to examine comprehensively through conventional experiment-based approaches.

Visible light-assisted S-doped red mud-based Fe-Co PBA derivatives activated PMS for efficient degradation of oxytetracycline from acidic to alkaline conditions: Degradation mechanism, degradation pathways and toxicity evaluation

Building an economically efficient, adaptable, and environmentally friendly advanced oxidation system is crucial for the treatment of antibiotic wastewater. In this study, we prepared a sulfur-doped red mud (RM) based Fe-Co Prussian blue analog derivative material (SRPD) using solid waste RM. Due to the doping of sulfur, SRPD possessed more abundant active sites (Co2+/Fe2+) and superior photocatalytic performance compared to other materials. Therefore, the SRPD/peroxymonosulfate (PMS)/Vis system exhibited the best degradation performance for oxytetracycline (OTC), with good reusability, resistance to impurity anions, adaptability to different water qualities, no secondary pollution, and maintained excellent performance under acidic, neutral, and alkaline conditions. Analysis has shown that the participation of surface S2- species in active sites regeneration was an important reason for achieving satisfactory degradation efficiency under neutral and alkaline conditions. In addition, there were significant differences in the charge transfer ability, surface morphology, and surface composition of SRPD in different pH systems, which affected the amount and types of main reactive oxygen species generated by PMS activation. As a result, the degradation pathways of OTC in SRPD/PMS/Vis systems with different pH values were somewhat different, but the detoxification ability towards OTC was excellent. This study exhibits certain reference significance for improving the degradation performance under neutral and alkaline conditions, and is an excellent candidate system for practical wastewater treatment.

Predicting organic matter and nutrient removal efficiency in a constructed wetland using data mining

Vertical and horizontal flow constructed wetlands (VF and HF CWs) are most widely used in the treatment of domestic sewage, storm runoff and selected industrial wastewaters. Current research focuses on the search for new applications, alternative substrates and developing mathematical and statistical methods to model the process of removing pollutants in CWs. This is important from a scientific and practical point of view. The performance of VF CWs with two types of substrate (gravel and Certyd - a waste material) was investigated over a two-year period. The following parameters were analyzed: biological oxygen demand (BOD5), chemical oxygen demand (COD), ammonia nitrogen (N-NH4), total nitrogen (N-Total), total phosphorus (P-Total) and dissolved oxygen (DO). At the same time, both the temperature of the inlet sewage and the air temperature were monitored. A support vector machine with a Gaussian kernel function was used to model the treatment efficiency. To select the model parameters, a 10-fold cross-validation was applied. The models applied were characterized by a very good fit. The expected average efficiency of organic removal was 88.3% (BOD5) and 80.8% (COD) in the bed filled with Certyd, and 83.8% (BOD5) and 76.9% (COD) in the bed with a classic filling. The predicted average efficiency of N-NH4 and N-Total removal in CWs filled with Certyd and gravel were 80.4 and 74.2%, and 59.6% and 57.0% respectively.

What rural ecological governance goals do local residents prefer? Evidence from Hainan, China

Rural ecosystems restoration requires the joint participation of rural residents and government in governance. This study aims to analyze whether rural ecological governance goals are consistent with rural residents' preferences and how they affect rural residents' utility levels, which are key to rural residents' ecological governance participation behavior. Using survey data from 653 rural residents in Hainan Island, China, this paper applies a choice experiment method and a random parameter logit model to identify differences in rural residents' preferences for different rural ecological governance policy goals and their governance participation behaviors. The results show that increasing the coverage rate of sewage treatment facilities, reducing fertilizer and pesticide application, and increasing rural biodiversity can significantly enhance rural residents' ecological governance participation utility, thereby promoting their choice of ecological governance options. Rural residents' participation behavior in rural ecological governance is also influenced by individual and household characteristics such as ethnicity, labor size, net farm income, ICT usage, and ecological knowledge level. Based on these findings, policymakers should strengthen communication of governance policies and objectives, respect rural residents' policy goal preferences, prioritize the implementation of rural ecological governance models that increase the coverage of wastewater treatment facilities, reduce fertilizer and pesticide application, and increase rural biodiversity, and rely on ICT devices to popularize ecological knowledge among rural residents.

Environmental and economic assessment of urban wastewater reclamation from ultrafiltration membrane-based tertiary treatment: Effect of seasonal dynamic

This study aimed to assess the environmental and economic performance of an ultrafiltration (UF) tertiary treatment of effluent from an urban wastewater treatment facility. Data from a UF demonstration plant composed of commercially available equipment, including industrial hollow-fiber membranes was used to project a full-scale facility. The results from the demonstration plant recommended different ranges of transmembrane fluxes and sparging air demands under summer and winter conditions to prevent excessive fouling. The energy balance of the full-scale facility would be 0.308 ± 0.112 kWh·m−3 in summer and 0.140 ± 0.040 kWh·m−3 in winter, with blowers' being the main consumers (86–93 %). CAPEX accounted for €0.030 ± 0.002·m−3 in summer and €0.027 ± 0.002·m−3 in winter and membrane acquisition represented 66–69 % of the investment cost. Energy expenditure was the major OPEX cost (66–79 %), with a total operating cost of €0.077 ± 0.023·m−3 and €0.042 ± 0.008·m−3 in summer and winter, respectively. The final average value obtained for the TAC was €0.107 m−3 in summer and €0.068 m−3 in winter. The environmental assessment confirmed optimizing energy consumption and membrane requirements as the main factors influencing environmental sustainability. Specifically, summer and winter emissions of 0.079–0.175 and 0.043–0.079 kgCO2eq·m−3 (Global warming potential); 8.1 · 10−4–1.7 · 10−3 and 4.8 · 10−3–8.1 · 10−3 m3·m−3 (water consumption); 0.019–0.041 and 0.010–0.019 kg oileq·m−3 (fossil fuel scarcity); and 1.4 · 10−4–2.9 · 10−4 and 7.7 · 10−4–1.4 · 10−4 kg Cueq·m−3 (mineral resource scarcity) were calculated, respectively. The obtained permeate quality complied with the most stringent Spanish and EU regulations.

Salmonella sp. Tied to Multistate Outbreak Isolated from Wastewater, United States, 2022.

We isolated Salmonella enterica serovar Senftenberg in raw wastewater from 2 Pennsylvania wastewater treatment facilities during June 2022. Whole genome sequencing revealed 4 isolates separated by <4 single nucleotide polymorphisms from S. enterica Senftenberg in a cluster from the 2022 nationwide outbreak linked to contaminated peanut butter.

The impacts of socioeconomic development and climate change on long-term nutrient dynamics: A case study in Poyang Lake

The anthropogenic activities associated with rapid socioeconomic development affect global climate change and the water quality of lake ecosystems. However, the impacts of socioeconomic and climate changes on lake nutrient dynamics require additional study. In this study, we used a long-term dataset (1987–2021) of Poyang Lake to identify the nutrient dynamics and assess the impacts of social and climatic factors on nutrient concentrations. The filtering trajectory method (FTM) suggested that in Poyang Lake, nutrients first increased and then decreased, with TP reaching its highest value of 157 μg/L in 2015. The study employs a combination of structural equation modeling (SEM) and FTM to identify the complex interactions between socio-economic and climatic factors affecting nutrient concentrations in Poyang Lake. The SEM results revealed that socioeconomic factors rather than climate change determined the long-term changes in TN and TP. Additionally, FTM results verified that GDP, urbanization (Ur) and P-fertilizer (Pfer) were the key drivers of TN; Ur, population (P), and sewerage treatment rate (STR) were the primary factors of TP. Through generalized additive models (GAMs), we observed that GDP accounted for 86 % of the temporal variability in TN and 45.7 % of that in TP, exhibiting inverted U-shaped relationships with both TN and TP. Air temperature (AT), a climatic factor accounted for only 44.6 % and 14.8 % of the variation in TN and TP, respectively. In addition, Pfer explained 66.0 % of the variation in TN, and STR explained 50.4 % of the variation in TP with a peak TP at the STR threshold of approximately 80 %. Our findings highlight the importance of Pfer and STR as critical indicators for watershed nutrient management. The identification of key temporal drivers and nutrient trajectories provides a scientific basis for developing management strategies. The results highlight coordinated control strategies for water pollution and carbon reduction as essential measures for mitigating climate change.

The Long-Term Variations of Phytoplankton Biomass in the Lower Nakdong River: 2000~2021

Objectives : Globally, the mass proliferation of phytoplankton driven by climate change has emerged as a significant societal issue. This study analyzes over two decades of long-term hydraulic, hydrological, and water quality data collected from the lower Nakdong River, along with changes in phytoplankton community biomass. The aim is to evaluate long-term trends in water quality and the ecological changes occurring in this region.Methods : The monitoring site in the lower Nakdong River is Mulgeum, where samples were collected weekly from January 2000 to December 2021 for the analysis of physicochemical water quality characteristics, as well as phytoplankton abundance and species composition. The hydrological status was assessed using flow rate data from the Jin-dong (Haman) station of the Nakdong River, along with rainfall data from the Korea Meteorological Administration for eight regions influencing the lower Nakdong River.Results and Discussion : Analysis of the annual average concentration changes of water quality parameters at the Mulgeum intake site in the lower Nakdong River found that water quality has generally improved since the construction period (2009-2012) of the weir. This improvement is attributed to the strengthening of T-P water quality standards for sewage treatment plant discharges in 2012, which resulted in enhanced phosphorus treatment at wastewater facilities in the river's middle and upper regions. Consequently, significant reductions were observed in the annual average concentrations of BOD, NO&lt;sub&gt;3&lt;/sub&gt;-N, T-N, and T-P. Evaluating long-term changes in flow rate and rainfall, it was found that both annual average rainfall and flow rate decreased after the weir was installed, particularly from May to September when temperatures rise. Rainfall decreased by approximately 8% to 38%, while flow rate decreased by 46% to 62%. Long-term temperature changes indicated that summer temperatures increased by 0.9&lt;sup&gt;o&lt;/sup&gt;C to 1.4&lt;sup&gt;o&lt;/sup&gt;C, and winter temperatures rose by 1.6&lt;sup&gt;o&lt;/sup&gt;C to 2.0&lt;sup&gt;o&lt;/sup&gt;C, resulting in an overall annual average increase of about 1.3&lt;sup&gt;o&lt;/sup&gt;C. An analysis of long-term changes in phytoplankton biomass and community composition revealed an increase in average biomass from 3,639 cells/mL before the weir was installed to 4,034 cells/mL afterward, representing an increase of about 11%. In winter, the dominance period and biomass of diatoms decreased, while in summer, the biomass and dominance period of cyanobacteria increased. Notably, in August, biomass increased approximately 7.5 times, rising from 2,009 cells/mL before the dam to 15,059 cells/mL afterward. This significant increase was identified as a key factor in the overall rise in phytoplankton biomass following the weir's installation.Conclusion : Recent climate change impacts, such as rising average temperatures and shifting rainfall patterns, have become increasingly evident in South Korea. This study utilizes over 20 years of long-term data to demonstrate that, in the lower Nakdong River, there has been a gradual decline in both rainfall and flow rates, accompanied by an increase in average temperatures. Consequently, the dominance period and biomass of diatoms have decreased. In contrast, cyanobacteria, which thrive in warmer conditions, have experienced an extended dominance period into early spring and late autumn as a result of rising temperatures, leading to an overall increase in cyanobacterial biomass.