Waste Input Research Articles

Modeling atmospheric microplastic cycle by GEOS-Chem: An optimized estimation by a global dataset suggests likely 50 times lower ocean emissions

Modeling atmospheric microplastic cycle by GEOS-Chem: An optimized estimation by a global dataset suggests likely 50 times lower ocean emissions

Carbon reduction of plastic’s circular strategies: tracking the effects along supply chains with waste input–output modeling

Plastic is a material associated with various Greenhouse Gas (GHG) emissions along the life cycles of different products. Many economies have adopted or planned for strategies to reduce, reuse, and recycle plastic goods and materials. The benefits of reductions in waste generation and GHG emissions need to be evaluated for setting the priority to select policy instruments for managing various plastic materials, products, and wastes. Several studies have made evaluations for the circulation of plastic using different models. However, many models for the circular economy focused on the effect on the macroeconomy rather than the detailed supply chain effects of an individual policy proposal. The reason could be the lack of an environmental assessment model with sufficient clear resolutions in the sectors, waste types, and waste treatments. In addition, the structure of the models limits many studies in modeling the scenarios diverting end-of-life products from waste treatments to recycling and reuse as secondary materials. To bridge this gap, this study adopted the waste input–output analysis methodology and compiled the models of baseline and four scenarios using the material flow and waste stream data of Taiwan with reference to a classification of four kinds of circular intervention from a review paper. We provide the details about the modeling results and settings for diverting plastic to the solid recovered fuel for power generation, closing the loops of plastic bags, extending the life of plastic cabinets and other plastic products, and improving the plastic products supply chain’s resource efficiencies. In the illustration of the results of GHG reductions in the supply chains and waste treatment activities, we present Sankey diagrams, which make the analysis of supply chains more straightforward. The developed method to render the Sankey diagram from the modeling result of an input–output-based model is presented in this article.

Alternative Fuels Substitution in Cement Industries for Improved Energy Efficiency and Sustainability

The conventional energy source in cement industries is fossil fuels, mainly coal, which has a high environmental footprint. On average, energy expenditures account for 40% of the overall production costs per ton of cement. Reducing both the environmental impact and economic expenditure involves incorporating alternative energy sources (fuels) such as biomass, solid-derived fuel (SDF), refuse-derived fuel (RDF) etc. However, within cement plants, the substitution of conventional fossil fuels with alternative fuels poses several challenges due to the difficulty in incorporating additional fuel-saving techniques. Typically, an additional 3000 MJ of electricity per ton of clinker is required. One of the most effective solutions to this is thermal optimization through co-processing and pre-processing, which makes it possible to implement additional fossil-fuel-saving techniques. In developing nations such as Togo, waste-management systems rely on co-processing in cement factories through a waste-to-energy relationship. Also, there are some old cement plants with low-efficiency, multi-stage preheaters without pre-calciners, reciprocating huge coolers, low-efficiency motors etc., which still operate and need to be made environmentally sustainable. However, compared to modern kilns which can have up to 95% of energy recovery from waste, an old suspension preheater kiln can recover only up to 60% of its heat energy depending on the cooler type, and due to the lack of a bypass and combustion chamber (pre-calciner). This research paper evaluated the performance of a cement plant incorporating AF and presents the procedures and recommendations to optimize AF substitution in cement plants. To achieve this, a comparative performance study was carried out by assessing the alternative fuel characteristics and the equipment performance before and after the incorporation of the alternative fuel. Data were collected on the optimum substitution ratio, pre-processing and co-processing performance, raw-meal design and economic analysis. Results indicated that the cost to be covered per ton of waste input is €10.9 for solid-derived fuel (SDF), €15 for refuse-derived fuel (RDF), and that the co-processing cost optimization for the cement plant could have a cost saving of up to 7.81€/GJ. In conclusion, it is recommended that appropriate kiln and alternative-fuel models be created for forecasting production based on various AF.

Fate and effects of fish farm organic waste in marine systems: Advances in understanding using biochemical approaches with implications for environmental management

AbstractParticulate waste from open‐cage fish farms in marine systems can cause organic enrichment of seabed habitats and enter the food web through consumption by wild organisms, with potential for broader ecosystem changes. Effects on biogeochemistry and benthic ecology are reasonably well understood in inshore, sheltered and soft sediment systems. However, food web effects and interactions with epifauna and larger consumers is less well understood, as is the fate of these discharges in more dynamic coastal areas with complex hydrodynamic regimes. Expected expansion of the aquaculture industry globally includes farming new areas that are more environmentally dynamic and biodiverse, with potentially sensitive habitats. Therefore, the aim of this review was to examine how biochemical tools can assist in identifying and managing impacts. Biochemical tools such as bulk stable isotopes and fatty acids can reliably trace the fate of fish waste in the environment and the food web, and have advanced our understanding of waste dispersal, as well as providing greater insights into biological interactions with fish wastes. This includes elucidating trophic subsidies to wild organisms, candidate species for co‐culture and waste assimilation mechanisms in native communities. Ultimately, biochemical tools can support improved environmental management, by helping to identify the zone of influence for spatial planning, providing additional ‘forensic’ evidence for farm‐related change, and by identifying potential risks to high‐value species and habitats. In this way, they can inform targeted research to link fish waste inputs meaningfully to potential ecosystem changes to better understand the consequences to support sustainable industry expansion.

Techno-Economic Analysis of Waste-to-Suburban Cooking Energy Critical Infrastructure Development in Southwestern Nigeria

This study examined the techno-economic specifications for a Waste-to-Suburban Cooking Energy<strong> </strong>critical infrastructure project in Southwestern Nigeria. Technological and project economic data for the W2E project were obtained from strategic sources and energy project foresight/analysis framework used. The results showed residential upgraded biogas-for-cooking demand of approximately 10,243 m<sup>3</sup>/month, and municipal solid waste (MSW) input of approximately 80 tonnes/month. The planned biogas plant had estimated costs of US $120,000, a throughput of almost 15,364 m<sup>3</sup>/month and required 5 acres of land for construction. Project economic viability indicator estimates were: Initial Investment – US $256,500, annual profits – US $40,000, Net Present Value (NPV) – US $142,000, maximum payback period – 7 years, and annual Return-on-Investment (ROI) – 16%. Socio-economic benefits per month included the constant supply of cheap cooking fuel, comparative cooking energy cost savings (biogas-to-LPG usage) of US $3,810, and the elimination of almost 80 tonnes of MSW from the environment. The study concluded that the Waste-2-Biogas critical infrastructure project was technically, environmentally, and socio-economically viable, and was suitable for deployment across suburban Southwestern Nigeria.

Illegal pollution loading accelerate the oxygen deficiency along the coastal lagoons of eastern Red Sea

The current study attempts to show how the two coastal lagoons near the eastern Red Sea lose oxygen when there is a significant input of organic waste. The strain caused by this problem is being increased by the expanding internal population migration trend toward the coastline region. The two main environmental factors that control when the marine environment changes from oxic to suboxic and eventually to anoxic conditions are the quantity of organic matter and the mixing of the water column. The samples were taken between the years of 2017 and 2018 in both the summer and the winter from the lagoons of Al-Shabab and Al-Arbaeen. Both places were situated on the Red Sea’s eastern shore. The quantity of DO along both lagoons was extremely important since it frequently indicates hypoxic to anoxic conditions. In the current study, the Al-Arbaeen lagoon’s peak anoxia was noted in both the summers of 2017 and 2018. In the Al-Arbaeen lagoon, the maximum concentration of H2S was recorded at 48.21 μM in 2017 and 45.67 μM in 2018, respectively. The current work unequivocally demonstrates how NO3 and NO2 are lost as ammonia builds up. As is obvious, the Al-Arbaeen lagoon recorded the highest level of TOC during the 2017 summer, with a concentration of 329 μM. The distribution of DO and TOC at both lagoons shows a clear correlation between the high level of TOC and oxygen consumption.

The impact of combined sewer outflows on urban water quality: Spatio-temporal patterns of fecal coliform in indianapolis

Many urban waterways with older stormwater drainage systems receive a significant amount of untreated or poorly treated waste from Combined Sewer Outflow (CSO) systems during precipitation events. The input of effluent waste from CSO to urban water streams during storm events often leads to elevated fecal coliform, specifically Escherichia Coli (E. Coli) in these waterways. The aim of the study is to examine fecal coliform concentration, water chemistry, and water quality parameters to better understand spatio-temporal patterns of fecal coliform associated with CSO events in three waterways from Indianapolis, Indiana (USA). The waterways are Pleasant Run Creek (PRW), Fall Creek (FC) and White River (WR). The sampling occurred biweekly over one year for PRW, nine months for FC, and an intense (∼every three days) sub-analysis of the presumed peak period of fecal coliform growth (July) for WR. All PRW and FC sampling sites significantly exceeded the EPA contact standard limit of 200 CFU/100 mL for fecal coliform concentrations during the sampling period. We found no relationship between fecal coliform levels and the number or density of CSO outfalls above a given site. The most significant predictors of increased fecal coliform concentrations were precipitation on the sampling day and cumulative degree days. The most significant predictors of decreased fecal coliform were maximum precipitation during the ten-day window prior to sampling and median discharge during a three-day window prior to sampling. These findings suggest a push-pull balance within the system where CSO activation and seasonal gradients replenish and promote fecal coliform growth. At the same time, large hydrologic events act to flush and dilute fecal coliform concentrations. The results from this study help us to better understand how different drivers influence fecal coliform growth and how this information can be potentially used to predict and remediate the conditions of urban water streams.

Digitizing the Construction Waste Management Process – Studying the Attitudes of the Participants in the Sector

Although the concept of “sustainability” has been known since the last century, it has acquired an increasingly key role and importance in almost all sectors of modern economy and development in the last decade, becoming a “good practice” for both the private and public sectors. Examples of sustainable practices and solutions in construction are also gaining speed and influence, although for the time being, sustainable construction has entered as a strategy more deeply in the USA and the countries of Western Europe than in our country. This includes the sustainable management of construction waste, i.e. planned and sustainable disposal, recycling and input of construction waste in future projects. The main goal of the article is to reveal the opinion and attitudes of the main participants in the construction waste management process in support of the hypothesis that there is a need to digitize this process in our country.

Fuzzy Automatic Control of the Pyrolysis Process for the Municipal Solid Waste of Variable Composition

control of the pyrolysis process of municipal solid waste (MSW) of variable composition and moisture content. The fuzzy control method is developed and studied that makes it possible to carry out the proper automatic control of the pyrolysis plant with the determination of the optimal ratio of air/MSW for various types of waste and with different moisture content values to ensure high efficiency of the MSW disposal process. The effectiveness study of the proposed fuzzy control method is performed in this paper on a specific example, in particular, when automating the pyrolysis plant for the MSW disposal with the reactor volume of 250 liters. The obtained simulation results confirm the high efficiency of the developed method, as well as the feasibility of its use for designing automatic control systems of various pyrolysis plants that operate under conditions of changes in the composition and moisture content of input waste.

Assessing Plastic Waste Discharges into the Sea in Indonesia: An Integrated High-Resolution Modeling Approach That Accounts for Hydrology and Local Waste Handling Practices

Plastic litter is increasingly accumulating in the marine environment, with rivers considered key pathways for entry. Current estimations of plastic input into the sea from land-based sources are limited in accounting for the mobilization and transport of plastic generated in the whole catchment area or in considering local variations in waste handling practices. Here, we show that, with an integrated discharge modeling approach (based on actual rainfall and local estimates for exposed mismanaged plastic waste), more realistic temporal estimates of plastic discharges into the sea can be constructed. Applying this approach to Indonesia enabled us to estimate the total national inputs of plastic waste into the sea from rivers and coasts and how these vary with rainfall, while providing insight into those catchments, local communities, and waste handling practices that most contribute to plastic waste leakages. We found that the plastic fluxes vary significantly in both the short and long term and that the total amount of plastic waste discharged during wet years may be twice as much as during dry years. Furthermore, river size, catchment population density, local waste management, and proximity of point sources influence river plastic waste loads. Such an integrated assessment can be very effective in helping to prioritize where interventions are most needed and, in combination with frequent monitoring, can provide evidence of the impact that upstream measures have on preventing plastic inputs into the sea.

Composition of Chinook salmon faecal wastes with implications for environmental management

Intensive salmon aquaculture is now a major industry globally, with Chinook salmon (Oncorhynchus tshawytscha) the dominant culture species in New Zealand. Understanding the composition of Chinook salmon wastes is important for assessing environmental risks of coastal open-cage aquaculture, both in terms of nutrient inputs, and for evaluating potential characteristics that could be used as fish waste markers in the environment. The aim of our study was to describe the biochemical composition of faecal waste from Chinook salmon with a view to describing the characteristics most important for assessing waste inputs in the environment. A broad suite of biochemical characteristics, including nutrient, mineral and trace element concentrations, bulk carbon and nitrogen stable isotope and compound specific Ᵹ13C fatty acid and amino acid values, were measured during an experiment on fish kept in a recirculating aquaculture system (RAS) and fed a standard commercial pellet diet. We found that all biochemical characteristics of feed were conserved in faecal material, but some were conserved better than others. Fatty acid composition was similar in feed and faeces, but element profiles differed and showed high variability in faeces. Carbon and nitrogen bulk stable isotope values of faecal samples were generally lower than mean feed signatures, particularly for Ᵹ15N. For compound specific stable isotopes, the Ᵹ13C values in most fatty acids were similar to that of feed, however, Ᵹ13C values in amino acids were lower (with the exception of phenylalanine and glutamic acid). Based on our findings, we suggest that it may be possible to predict biochemical composition of faeces for well-conserved, or predictably-altered indicators using composition of feed samples alone. The differences between feed and faeces for some markers (e.g., elements, nutrient ratios, Ᵹ15N and Ᵹ13C in amino acids) may be useful for distinguishing between the presence of these two farm-derived wastes in the environment. Our results also suggest that the elemental composition of Chinook salmon waste is generally similar to that of other salmonid species, and supports the transfer of element composition data from other salmonids when setting mass balance model parameters for Chinook salmon.

Assessing the Sorting Efficiency of Plastic Packaging Waste in an Italian Material Recovery Facility: Current and Upgraded Configuration

The first step in reintroducing plastic waste into the recycling cycle is to use material recovery facilities (MRFs). However, while the composition and types of plastic waste are changing over time, the layout of MRFs does not always adapt to this change. In this paper, an existing MRF in Southern Italy was chosen as a reference to evaluate its current performance and to estimate possible improvements in sorting through a specific upgrade. First, an analysis of the amount, composition, and sources (in terms of type of waste and distance from the MRF) of the input waste was conducted. The composition of the input waste was then compared with the amount of selected output waste streams in order to calculate the current sorting efficiency of each stream and compare it with the values obtained from the upgrade. Lastly, the current performance of the plant was compared with a previous assessment of the same MRF in order to highlight possible variation. Results showed how the incoming waste was mainly composed of packaging plastic waste, and that some plastic waste not yet selected by the plant ended up in specific output streams. Therefore, the current performance of the MRF resulted high for PET and PE bottles (80.2% and 92.8%, respectively), in contrast to mixed or flexible packaging, where the efficiency achieved lower values (55–50%). These values were caused by a weakness in the 2D flow sorting line, which the upgrade mostly addressed. The upgraded configuration increased the production of recyclable waste from 34.32% to 50.39%, especially due to the recovery of small flexible packaging films in PE and biopolymers.

A mathematical investigation for the simulation and forecasting of a biodigester operations

In this paper we formulate various mathematical models to describe the processes of anaerobic digestion of an organic waste treatment plant, based on its chemical kinetics, stoichiometry and on the biological aspects that influence the chemical reactions of anaerobic digestion. The latter is a process of degradation of the organic substance by microorganisms in the absence of oxygen, used in plants that have the purpose of producing biomethane and compost. This type of process is very complex and for its realization different chemical phases are involved as well as the presence of different bacterial families. The chemical reaction reagent represents the digester substrate; the products are biogas (methane and carbon dioxide) and digestate (degraded organic substances, from which compost is obtained). The populations modeled here are the reactants of chemical reactions and their products, as well as microorganisms. The latter play an important role as they carry the reactions inside the anaerobic reactor in which they live.Each mathematical model formulated consists of a system of ordinary differential equations, numerically integrated with the use of MATLAB software. The models are formulated both in non-operational and operational conditions. In the first case, in which neither new daily organic waste inputs nor product releases are expected, the system variables are studied at steady state as functions of the parameters. The operating models, on the other hand, also consider the daily input and output of the plant.

Difference in Energy Input and Output in Agricultural Production under Surface Irrigation and Water-Saving Irrigation: A Case Study of Kiwi Fruit in Shaanxi

China’s kiwi industry has seen rising production costs and shrinking planting areas in recent years; at the same time, the lack of professional production standards leads to the input redundancy and waste of production factors in the production process of kiwifruit, which intensifies the dilemma of unsustainable agricultural production. This has brought more and more serious challenges to the sustainable development of the industry. In order to solve this problem and clarify the composition and utilization efficiency of energy in the production process of kiwifruit, this study took Chinese kiwifruit production as the research object and analyzed the energy input and output under surface irrigation and water-saving irrigation from the perspective of energy. The results show that the energy input of kiwifruit production under traditional surface irrigation was 85.4 GJ/ha, and the energy output was 59.7 GJ/ha. Among all energy input elements, mineral fertilizers accounted for the highest proportion of energy input, accounting for 48.31%. Under water-saving irrigation, the energy input and output of kiwifruit production are 72.3 GJ/ha and 62.3 GJ/ha; the highest energy input is also mineral fertilizer. The data envelopment analysis results also confirmed that there is a large redundancy in the amount of mineral fertilizer. Compared with surface irrigation, water-saving irrigation technology has effectively improved the energy ratio (from 0.70 to 0.86), energy productivity (from 0.37 kg/MJ to 0.45 kg/MJ) as well as net energy (from −25.8 GJ/ha to −9.93 GJ/ha). Thus, promoting the application of water-saving irrigation technology and increasing the proportion of fertigation during the kiwi production process are necessary measures to promote the sustainable development of China’s kiwi industry.

Do Not Be Anticlimactic: Farmers’ Behavior in the Sustainable Application of Green Agricultural Technology—A Perceived Value and Government Support Perspective

The production mode of “high input, high yield and high waste” in the agricultural system poses a serious threat to the environment and the quality of agricultural products. Accelerating the adoption of green agricultural technology (GAT) by farmers is an emergency measure. However, according to microsurvey data, many farmers give up GAT within a year after adopting it. The implementation of this measure has been anticlimactic. Based on a survey of 1138 kiwi growers in Shaanxi Province, China, this paper builds a theoretical model and conducts empirical exercises to gain insight into the effects of perceived value, government support and their interaction with kiwi growers’ sustainable application of GAT. We find that perceived value and government support have a significant impact on the sustainable application of GAT. Government support plays a moderating role in the influence of perceived value on the sustainable application of GAT. Furthermore, in order to overcome the potential endogeneity problem caused by the two-way causal relationship between subjective variables, “owning a smartphone” was selected as the instrumental variable. The 2SLS model was used for endogeneity analysis, and the OLS model was used for the robustness test. This paper discusses the relevant theories and policy implications of environmental management.

A review of methods to trace material flows into final products in dynamic material flow analysis: From industry shipments in physical units to monetary input–output tables, Part 1

AbstractDynamic material flow analysis (dMFA) is widely used to model stock‐flow dynamics. To appropriately represent material lifetimes, recycling potentials, and service provision, dMFA requires data about the allocation of economy‐wide material consumption to different end‐use products or sectors, that is, the different product stocks, in which material consumption accumulates. Previous estimates of this allocation only cover few years, countries, and product groups. Recently, several new methods for estimating end‐use product allocation in dMFA were proposed, which so far lack systematic comparison. We review and systematize five methods for tracing material consumption into end‐use products in inflow‐driven dMFA and discuss their strengths and limitations. Widely used data on industry shipments in physical units have low spatio‐temporal coverage, which limits their applicability across countries and years. Monetary input–output tables (MIOTs) are widely available and their economy‐wide coverage makes them a valuable source to approximate material end‐uses. We find four distinct MIOT‐based methods: consumption‐based, waste input–output MFA (WIO‐MFA), Ghosh absorbing Markov chain, and partial Ghosh. We show that when applied to a given MIOT, the methods’ underlying input–output models yield the same results, with the exception of the partial Ghosh method, which involves simplifications. For practical applications, the MIOT system boundary must be aligned to those of dMFA, which involves the removal of service flows, sector (dis)aggregation, and re‐defining specific intermediate outputs as final demand. Theoretically, WIO‐MFA, applied to a modified MIOT, produces the most accurate results as it excludes massless and waste transactions. In part 2 of this work, we compare methods empirically and suggest improvements for aligning MIOT‐dMFA system boundaries.

Thermal Twin 4.0: Digital Support Tool for Optimizing Hazardous Waste Rotary Kiln Incineration Plants

The present paper focuses on developing a novel virtual representation framework for optimizing standalone hazardous waste rotary kiln incineration plants. A digital support tool can be provided to optimize the plant's waste management, operation, and maintenance by combining thermochemical-based simulation models with a fuel classification system. First of all, the virtual representation can be used to determine the waste composition of not entirely analyzed waste streams. Furthermore, the determined waste compositions of historically fed waste streams can be used to enable further advanced applications. The determined waste compositions are linked with the appropriate waste code and supplier, which first enables the monitoring of the delivered waste streams. In the case of recurring fractions, the virtual representation can be used to optimize the barrel sequence to reach homogenous waste inputs. Additionally, the plant operation can be optimized regarding stable operation conditions due to the knowledge about waste compositions of recurring fractions. The parametrization results fit very well with the comparable sensor values. Therefore, the novel virtual representation of the hazardous waste incineration plant could definitely make a reasonable contribution to optimize the efficiency of thermal waste treatment within the hazardous waste sector in Austria and Europe.Graphical

Consideration on Proper Management and Final Disposal of Residues from SRF Manufacturing Facilities in South Korea

Solid Refuse Fuel (SRF) manufacturing facilities process 4.72 million tons of waste annually. The residues generated after manufacturing SRF products account for 35–40% of the input waste, and most of them are finally disposed of in landfills. The process flow and management status of SRF manufacturing facilities were investigated, and the residues generated from SRF manufacturing facilities using municipaland industrial waste, respectively, were separated by particle size. The appropriate separation conditions for the residues according to the characteristics of the input raw materials were presented through the analysis of loss on ignition (LOI), organic foreign substance content, heating value, and carbon content. Based on this, the appropriate management criteria (draft) for the subsequent treatment of final residues were derived to improve recyclability. Residues generated in the SRF manufacturing process need to be additionally separated into combustibles and incombustibles through cylindrical rotary separating devices before subsequent the final disposal process.

Accounting for Heterogeneity in Performance Evaluation of Norwegian Dairy and Crop-Producing Farms

It is critical to analyze the performance of enterprises to achieve sustainable agricultural development. Several studies have been conducted to assess farm performance. However, the studies have been criticized for failing to account for farm heterogeneity (which is frequently unobserved) in their evaluation of Norwegian agricultural performance. Technically, a farm is efficient if it can produce a certain amount of output with the fewest possible inputs and no input waste. In this paper, efficiency scores are calculated using a production function with both a random intercept and a random slope parameter, addressing the issue of unobserved heterogeneity in stochastic frontier analysis. Using Norwegian dairy and crop farms as a case study, we demonstrate the viability of improving the agriculture industry and reducing resource waste. The case study was established on data collected from 5884 dairy farms and 1880 crop farms from the years 2000 to 2019. According to the empirical findings of the case study, dairy and crop producers used inefficient technologies and squandered production resources. If all farmers follow a sustainable and efficient path to produce agricultural output, they could increase output by 15–18%. Farmers must follow sustainable paths, and politicians must encourage farm experience exchange so that less efficient dairy and crop-producing farms can learn from the most efficient farms to achieve sustainable development.

Environmental Impact Assessment Using Diatoms in Thamirabarani River, Tirunelveli District, Tamil Nadu, India

The present study provides a detailed report on the occurrence and record of diatom taxa from the Thamirabarani River. A total number of 55 diatom taxa belonging to 25 genera were identified. The result shows the abundance of diatom genera viz. Amphora, Aulacoseira, Cyclotella, Cymbella, Eunotia, Gomphonema, Melosira and Ulnaria in the study area indicated varying pollution levels and pristine conditions. The diversity of diatom taxa in Site 1 and Site 3-7 indicate that the river water is not polluted in these locations. Domestic waste input in the river at Site 2 area may responsible for the dominant occurrence of moderate pollution tolerant diatoms taxa. The abundance of pollution tolerant diatom taxa in Site 8, Site 9 and Site 10 areas of the river indicates high pollution. The Canonical Correspondence Analysis (CCA) results also show that the concentration of diatom taxa and physico-chemical parameters suggest the release of industrial effluents and anthropogenic activity. The proper waste water treatment methods need to be implemented along the catchment areas of the river to ratify pollution levels. Keywords: Diatoms, Thamirabarani River, Pollution, Water Quality, Anthropogenic Impact