Chemical Coagulation Research Articles

Dissolved organic material changes during combined treatment of a mixture of landfill leachate and anaerobic digestate using deammonification and chemical coagulation.

The current study investigates the combined treatment of wastewater of anaerobic digestate and landfill leachate, using deammonification and coagulation/flocculation processes. The deammonification section studies the performance of a full-scale deammonification plant in nitrogen and chemical oxygen demand (COD) removal, monitored over 2 years. For further COD reduction from the deammonification effluent (DE) to meet the environmental regulatory standards, coagulation/flocculation using three different Al-based coagulants was used to treat the DE. Results revealed that the deammonification plant showed 80% average ammonium removal from the mixed feed over the study period. Additionally, 30% of the feed COD was removed in the deammonification plant. COD analysis after treatment using coagulants revealed that the polyaluminum chloride modified with Fe had the best performance in reducing COD to meet the environmental standards. Excitation-emission matrix-parallel factor analysis (EEM-PARAFAC) of the dissolved organic material (DOM) samples indicated that fluorescents were the compounds mostly affected by the coagulant types. DOM analysis using 2D correlation Fourier-transform infrared spectroscopy revealed that the applied coagulants showed minor differences in removing different functional groups, despite having different COD reduction performance. Wastewater elemental analysis indicated elevated metal concentrations in low pH conditions (<6) due to re-stabilization of the flocs using coagulants.

TREATMENT OF LEACHATE FROM ERBIL LANDFILL SITE BY ELECTRO- AND CHEM-ICAL COAGULATION METHODS

Landfill leachate is commonly heavily contaminated wastewater. and consists of a high number of organic compounds, inorganic salts, toxic gases and heavy metals that exert a serious threat to the environment and public health. Thus, it requires treatments before direct release into receiving waters. This paper presents the results of electrocoagulation (EC) and chemical coagulation (CC) treatment of leachate from the Erbil landfill site. The removal efficiency of chemical oxygen demand (COD), phosphate (PO43-), total suspended solids (TSS), total organic compound (TOC), and color of leachate was studied using iron and aluminum electrodes. The removal percentages were also compared to those produced by electrochemically generated Fe2+ and Al3+ dosages. The effect of different pH values on the removal efficiency of these parameters was evaluated at optimal conditions. The removal percentages for chemically added coagulants were lower than those for electrochemically generated Fe2+ and Al3+. In EC, the highest COD removal efficiency of 92% and 87% was achieved at the original concentration (C1) for iron and aluminum electrodes, respectively. The iron and aluminum electrodes also showed a maximum color removal of 90% and 95%, respectively, for the original undiluted leachate solution. Both Fe and Al electrocoagulation methods were not effective in removing TOC from the leachate of municipal solid waste. The highest removal efficiency of 78% was achieved at a 1:4 diluted solution (C2) using the Al-electrocoagulation method. The maximum removal percentage for PO43- was 94% at C1 using the Fe-electrocoagulation system. However, both systems were not very effective in removing TSS.

Investigating the efficiency of oak powder as a new natural coagulant for eliminating polystyrene microplastics from aqueous solutions

Polystyrene (PS) is a commonly used plastic material in disposable containers. However, it readily breaks down into microplastic particles when exposed to water environments. In this research, oak powder was used as a natural, inexpensive, and eco-friendly coagulant. The present study aims to determine the effectiveness of oak powder in removing PS from aquatic environments. The Box-Behnken model (BBD) was used to determine the optimal conditions for removal. The removal efficiency was evaluated for various parameters including PS concentration (100–900 mg/L), pH (4–10), contact time (10–40 min), and oak dosage (100–400 mg/L). The maximum removal of PS microplastics (89.1%) was achieved by using an oak dose of 250 mg/L, a PS concentration of 900 mg/L, a contact time of 40 min, and a pH of 7. These results suggest that oak powder can effectively remove PS microplastics through surface adsorption and charge neutralization mechanisms, likely due to the presence of tannin compounds. Based on the results obtained, it has been found that the natural coagulant derived from oak has the potential to effectively compete with harmful chemical coagulants in removing microplastics from aqueous solutions.

Characterization and treatment of tunneling wastewater using natural and chemical coagulants.

Particles are a concern regarding tunneling wastewater, but gaps remain in understanding metal(loid)s content and coagulation efficiency. In this research, characterization of the wastewaters before and after treatment was investigated by chemical analysis and various techniques for particle characterization. Then, laboratory work was conducted to evaluate effectiveness of sedimentation and use of coagulants to remove particles and particle-associated contaminants. Both natural (chitosan) and chemical coagulants (ferric chloride sulfates and polyaluminium chloride solution), were applied in a jar test system. The results indicated that short-time sedimentation alone substantially reduced the particle content and particle-associated pollutants, including metal(loid)s, while subsequent chemical coagulation was required to comply with discharge limits. The optimum dosages of chitosan, PIX, and PAX for water 1 after pre-treatment (15 min sedimentation) were 1 mg/L, 3 mg Fe/L, and 3 mg Al/L, respectively, while a dosage of 2 mg Al/L gave the best results in water 3. Furthermore, chemical coagulation significantly decreased the volume density of particles in the diameter range of 1-100 μm, showing that coagulants are efficient for the removal of smaller particles not removed by conventional sedimentation.

Effective turbid water treatment using natural eco-friendly coagulants derived from oat and onion seeds

Conventional chemical coagulants are used for potable water treatment, which requires unsustainable mining and transformation of raw materials for their production with costly sludge disposal. Natural coagulants are potential alternatives to chemical coagulants. This study emphasized the use of natural eco-friendly coagulants (oat and onion seed) for turbid water treatment. Coagulant seeds were characterized by different techniques such as SEM, EDX, FTIR, and zeta potential analyzer. Response surface method (RSM) was used to optimize the coagulation process. The effect of initial water turbidity, pH, coagulant seed extract dose, slow mix time, and settling time on the efficiency of turbidity removal was studied. The relation between removal efficiency and the main three significant operational parameters (initial water turbidity, pH, and coagulant extract dose) was fitted to a quadratic model. The optimal removal was achieved at alkaline and neutral media (pH = 7–11 for oat extract and pH = 7–9 for onion extract). The turbidity removal efficiency was 99% using 6 ml/L oat extract dose and 98.9% using 4 ml/L onion extract dose at pH equal to 8 and initial turbidity of 190 NTU. The effect of using oat extract or onion extract with alum was studied, and the results indicated that the optimum dose was found to be 1 ml/L of a natural extract with 10 mg/L alum. Furthermore, oat and onion extract aids were able to decrease the organic load in the treated water. Oat and onion seed extracts were proven to be efficient and eco-friendly natural coagulants or coagulant aids for surface water treatment.

A Comprehensive Review of Water Treatment Methods for Heavy Metal Ion Removal from Wastewater

Wastewater pollution with heavy metals presents serious problems with not only environmental integrity but also human health safety. This review is a complete review that includes different removal methods and technologies for heavy metals from wastewater and proceeds to include the traditional techniques as well as the advanced ones. The traditional techniques such as chemical precipitation, ion exchange, adsorption, membrane filtration, coagulation, and flocculation along with their effectiveness and some of the pitfalls are provided in this discussion. Moreover, the developments of the past years such as nanotechnology, electrochemical methods, hybrid systems, and biological treatments are further outlined as ways to improve treatment outcomes and lower the environmental impact. Efficiency of treatments factors including the pH, temperature, metal concentration, the reactor design, operation parameters, and costs considerations are critically examined to provide ideas into how to improve the performance of the treatments. By means of the combination of state-of-the-art technologies and treated-liquid effectiveness components, this review seeks to supply information for the betterment of heavy metals removal in wastewater treatment, and as such give a cleaner and healthier surrounding to the future generations.

Machine learning-based performance evaluation and sludge characterization studies of oxidized starch-aluminum electrode assisted by direct current treatment of dye laden wastewater

The performance evaluation, sludge characterization and bi-optimization of treating dye-laden wastewater using oxidized starch-aluminum electrode assisted by direct current was investigated. Variables considered are current density (CD), wastewater pH, oxidized starch (OS) dosage and electrode inter-distance. Electrocoagulation batch reactor incorporated with jar test module was used for the experiment. FTIR, XRD and SEM were conducted to investigate structure, composition and morphology of starch and generated sludge. Sludge settling characteristics and filterability were studied. Response surface methodology (RSM) and artificial neural network (ANN) approach were used to optimize the process. The FTIR peaks revealed alcohol and carboxylic OH groups, while atomic structure indicated partly crystalline pattern. The results showed 96.22 % color removal using 6.6 mA/cm2 CD, 1.0 g/L OS, 4 cm inter-distance, and wastewater pH 4; 100 % COD removal using 4.4 mA/cm2 CD, 1.0 g/L OS, and 3 cm inter-distance at pH 7; and 99.99 % phosphate removal applying 2.2 mA/cm2 CD, 1.0 g/L OS, and 4 cm between electrode at pH 7. The sludge settling indicated lag, hindered, transition and compression zones, while sludge volume indices were less than 80 mg/g. The ANOVA revealed significant models with Prob > F < 0.0001 for color, COD and phosphate with R2 of 0.9741, 0.9819, and 0.9311, respectively. The ANN with superior R2 > 0.99 for all the response variables, indicated better optimization approach. From the forgoing, the use of combined technology; electro and chemical coagulation is beneficial toward achieving better result in the treatment of dye laden wastewater.

Biodegradability enhancement and sequential treatment of real chemical industry wastewater by chemical coagulation and Electro-Fenton processes

A sequential treatment with chemical coagulation in the first step and Electro-Fenton (EF) in the second step was applied to chemical industry wastewater. By coagulation using Poly Aluminum Chloride (PAC) as a coagulant, 57.5% chemical oxygen demand (COD), 96.8% total suspended solids (TSS), and 90.5% color index (CI) removal were obtained. In the EF process applied after chemical coagulation, the design parameters were optimized by the central composite design. Two quadratic models of the four factors were established with the COD and CI as two responses. Optimized conditions of the EF were pH 2.5, Fe2+ dose 5 mM, applied current 1 A, and reaction time 60 min. Under these conditions, the COD removal from the validation experiments was 63.5%. In total, 84.5% COD removal was achieved with the two-step treatment. By extending the reaction time in EF to ensure the discharge limits, 89.5% COD removal was reached, and the COD concentration decreased to 193 mg/L after 240 min. At the same time, the 5-day biochemical oxygen demand (BOD5)/COD ratio increased from 0.1 to 0.57 after 240 min. Consequently, the discharge limit was provided and the biodegradability was improved.

Evaluation of Using Sequential Electrocoagulation and Chemical Coagulation for Urea Removal from Synthetic and Domestic Wastewater

The presence of urea in wastewater can give rise to many issues, including the proliferation of algae as a consequence of eutrophication as well as the discharge of ammonia, which exerts a detrimental impact on aquatic organisms. To assess the efficacy of several treatment strategies for lowering urea concentrations, this study compared the removing performances of electrocoagulation (EC) with those of conducting electrocoagulation and chemical coagulation in sequence (EC-CC) or vice versa (CC-EC). Many effective parameters of electrocoagulation have been studied, such as current density, spacing between electrodes, electrolyte type, and electrolysis time. A scanning electron microscope was used to investigate the electrode morphology, and a Fourier transform infrared was conducted to analyze the formed sludge. The electrocoagulation was carried out at its optimum conditions at 30 A/m2, and the chemical coagulation was conducted using three types of iron coagulants: FeSO4, Fe2(SO4)3, and FeCl3. The results showed insufficient improvement in urea removal for synthetic and domestic wastewater via EC-CC, regardless of the coagulant type. The urea removal efficiency via EC-CC improved by less than 0.5% and 5.5% for synthetic and domestic wastewater, respectively. In contrast, CC-EC proved a better improvement for urea removal for both synthetic and domestic wastewater, but only for FeCl3. Treatment by CC-EC at 30 A/m2 for 60 min using iron electrodes and 0.5 g/L of FeCl3 resulted in an improvement in the removal efficiency of urea by about 3.4% and 10.40% for synthetic and domestic wastewater, respectively. CC-EC achieved better removal of COD from domestic wastewater than that achieved by EC-CC by 6%. The results obtained from the study indicate that the CC-EC process is a cost-effective method for removing urea from both synthetic and domestic wastewater.

Chemical Coagulation Applied for the Removal of Polyethylene and Expanded Polystyrene Microplastics

Chemical Coagulation Applied for the Removal of Polyethylene and Expanded Polystyrene Microplastics

Extraction and Characterization of Natural Coagulant Made from Banana Plant Stems (Musa acuminate) for the Removal of Turbidity from Wastewater

Wastewater treatment with chemical coagulants has a variety of drawbacks, including sludge management, cost, concerns for human health, and environmental pollution. In light of this, a study was conducted to determine whether banana plant stem (Musa acuminate) made coagulant can effectively reduce turbidity (NTU) of wastewater. In this study, conventional extraction method was used to extract the coagulant from the banana plant stem by using NaCl (0.1, 0.5, 1 M) solvent. After extraction, the coagulation efficiency of each produced coagulant was computed in terms of their turbidity removal efficiency (%) from sampled wastewater. The sampled wastewater had an average turbidity value of 893 NTU. Response surface methodology (RSM) and central composite design (CCD) were used to study the effects of NaCl solvent concentration (M), extraction time (min), and particle size (mm) on the coagulation efficiency (%) of the extracted coagulant. In addition, the coagulant was characterized such as FTIR analysis, point of zero charge value determination, and inulin compound presence analysis. From all prepared coagulants, the maximum coagulation efficiency obtained was 86.3% at the optimum conditions, such as 0.55 M (NaCl) of solvent concentration, 1.25 mm particle size, and 20 min of extraction time. The characterized coagulant had 6.2 points of zero charge value and also had various types of functional groups. Based on the findings of this study, it can be said that the coagulant prepared from banana stems (Musa acuminate) was an efficient natural coagulant that could be applied to treat wastewater.

Glass Fiber Manufacturing Wastewater Treatment Using Chemical Coagulation and Combined Electrooxidation Processes

This study investigated the oxidation of wastewater generated during the production of glass fiber manufacturing material, which contains high organic carbon (18.32 g/L) and has a pH of 8.8, by chemical coagulation and electro-advanced oxidation techniques. It was determined that the organic content of the wastewater decreased by 53% with chemical coagulation. After electrocoagulation with Al/Al electrode pair for 300 minutes at 500 mA, 73% TOC removal was achieved at pH 8.8. While 50% mineralization was completed in 2 h at 400 mA in electrocoagulation with Fe/Fe electrode pair, 71% TOC removal was obtained in the combined EC/EF process by adding hydrogen peroxide to the medium under the same conditions. It was observed that the success of the anodic oxidation methods alone was lower. The electro-Fenton application after electrocoagulation was effective (78% TOC removal) but required work at pH 3 and a longer treatment time.

Turbidity reduction efficacies of seed kernels of Mango (Mangifera indica) genotypes in Uganda

Alum and ferric salts as traditional chemical coagulants for turbidity removal in water and wastewater are expensive, and have known harmful effects. Thus, attempts to replace the chemical coagulants with safe and effective natural solutions are increasingly being made in terms of research studies to investigate the coagulation efficacies of various plants one of which is Mango (Mangifera indica). It is worth noting that M. indica has various genotypes of different origins across the world. In this study, eight (8) common M. indica genotypes in Uganda were identified, protein contents of their seed kernels determined, and coagulating efficacies investigated. Coagulation solution of each selected genotype was obtained by dissolving 5 g powder of the selected Mango seed kernel sample in 100 mL of distilled water. Next, 5 mL of this coagulant (or stock) solution was used to treat 200 mL of turbid water with turbidity ranging from 15 to 120 NTU. Using 0.01 M hydrochloric acid as an extraction solvent, protein contents of selected genotypes including Apple mango, Kate, Kent, Bire, Doodo red, Takataka, Kagoogwa, and Tommy Atkins were 38.02 %, 30.66 %, 15.94 %, 22.11 %, 21.50 %, 16.98 %, 16.36 %, and 17.87 %, respectively. Efficacies of coagulant from Apple mango, Kate, Kent, Bire, Doodo red, Takataka, Kagoogwa, and Tommy Atkins seed kernel samples were 92.2, 89.3, 66.0, 78.7, 76.9, 71.1, 68.9, and 73.1 %, respectively. Apple mango was the best performing genotype as a coagulant and this was followed by Kate. Coagulation efficacy was generally found to increase with increasing turbidity and/or coagulant's concentration. For instance, Apple Mango coagulant removed 16.7 %, 50.3 %, and 92.2 % of initial turbidity 15, 65 and 120 NTU, respectively. Kent removed 57.5, 66, and 69 % of initial turbidity 120 NTU using 5, 20, and 30 mL of stock solution, respectively. This study demonstrated the influence of the choice of a plant genotype on coagulation efficacy.

Rice mill wastewater management in the era of circular economy

Several nations around the world use rice as their primary food staple because of its tremendous nutritional value. India's expanding population has sparked a proliferation of rice mills as a result of the country's growing rice demand. However, small and medium-scale industries lack adequate facilities for processing effluents and other waste generated. Paddy is typically processed by parboiling, which involves soaking it in water, boiling it with steam, and then drying and milling. Around 1–1.5 L of water is necessary to partially cook 1 kg of unhusked rice, with approximately half of this water being discharged as effluent. Disposal of rice mill effluent (RME) in water bodies or on the land causes severe damage to soil and water. An inclusive examination of diverse approaches for the treatment and stabilization of partially cooked rice milling effluents is provided. Moreover, the document provides a concise overview of contemporary and environmentally friendly technologies for treating RME. Adsorption, electrocoagulation, chemical coagulation, and bioremediation using microbes, plants, and microalgae are all included in these methods. This manuscript discusses the concept of a circular economy, which is focused on enhancing environmental sustainability through the recycling and repurposing of generated waste into raw materials for the creation of new products. In addition, this review aims to focus on the impact of RME on soils and water species and the status of sustainable management at the point of circular economy with RME bioenergy production (bioelectricity, biomethane, and bio-hydrogen).

Bacterial nanocellulose and its application in heavy metals and dyes removal: a review.

This review discusses the application of bacterial nanocellulose (BNC) and modified BNC in treating wastewater containing heavy metals and dye contaminants. It also highlights the challenges and future perspectives of BNC and its composites. Untreated industrial effluents containing toxic heavy metals are systematically discharged into public waters. In particular, lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), zinc (Zn), and arsenic (As) are very harmful to human health and, in some cases, may lead to death. Several methods such as chemical precipitation, ion exchange, membrane filtration, coagulation, and Fenton oxidation are used to remove these heavy metals from the environment. However, these methods involve the use of numerous chemicals whilst producing high amount of toxic sludge. Meanwhile, the development of the adsorption-based technique has provided an alternative way of treating wastewater using BNC. Bacterial nanocellulose requires less energy for purification and has higher purity than plant cellulose. In general, the optimum growth parameters are crucial in BNC production. Even though native BNC can be used for the removal of heavy metals and dyes, the incorporation of other materials, such as polyethyleneimine, graphene oxide, calcium carbonate and polydopamine can improve sorption efficiencies.

Comparing the effectiveness of ferric chloride chemical coagulant and natural coagulant of plane tree leaves in turbidity removal from industrial wastewater

Comparing the effectiveness of ferric chloride chemical coagulant and natural coagulant of plane tree leaves in turbidity removal from industrial wastewater

The potential and constraints of replacing conventional chemical coagulants with natural plant extracts in water and wastewater treatment

The potential and constraints of replacing conventional chemical coagulants with natural plant extracts in water and wastewater treatment

Performance of Plant-Based Coagulants in Removing Turbidity and Chemical Oxygen Demand (COD) in Industrial Wastewater: A Systematic Review and Meta-Analysis

Industrial effluent contains high concentrations of pollutants, such as heavy metals, which can cause risks to human health and the ecosystem. Chemical coagulants such as aluminum and iron salts are typically used as a coagulant in the wastewater treatment plant. The effectiveness of chemical coagulants is good in the clarification of wastewater, but excessive use is not sustainable and toxic. This study focuses on the removal of turbidity and chemical oxygen demand (COD) of various industrial effluents, including dairy wastewater, textile wastewater, paper, and paper mill industry, by comparing the removal between plant-based and chemical coagulants. The study aims to quantify the ability of plant-based coagulants to remove turbidity and COD in industrial effluents. A systematic review was used to conduct this study by using a systematic search strategy (PRISMA) in the relevant databases, which are Scopus, Web of Science, and Google Scholar. Only experimental studies that test both plant-based and chemical coagulants were chosen to proceed with metaanalysis to validate the efficiency of the plant-based coagulant to remove turbidity and COD in different industrial effluents by using Cochrane RevMan 5.4 software. Twenty-five articles were evaluated, and high heterogeneity was found among those studies. The mean difference (MD) and 95% confidence interval (CI) showed a significantly increasing percentage of turbidity and COD removal by plant-based coagulant by -1.64 % (-3.49, 0.21) and -5.39% (-8.85, -1.93) respectively for all wastewaters. The result supports the application of plant-based coagulant to sustain wastewater treatment due to its eco-friendly, non-toxic, biodegradable, and capability to sustain the pH of water after treatment.

Wastewater Treatment Using Wood Ash and Cement as Chemical Coagulant.

Water is essential for daily activities and maintaining human well-being. However, in many less-developed countries, including Ethiopia, the lack of a well-developed wastewater treatment system leads to contaminated surface water. This poses significant risks to human health. To address this problem, wastewater can be treated using locally available materials such as wood ash and cement as chemical coagulants. The objective of this study was to treat wastewater using these materials. The study involved analyzing a 20-liter sample of wastewater from the Awetu River in Jimma City, Ethiopia. The materials used for the treatment included wood ash, cement, and lemon. Various doses of cement and wood ash were prepared and added to the wastewater. The results showed that 5 g was the optimum dosage for effectively treating the wastewater. The treated water at the optimum dosage exhibited significant improvements in turbidity, total dissolved solids, conductivity, and color, meeting drinking water criteria. Overall, the study concludes that locally available materials such as wood ash and cement can be successfully utilized as chemical coagulants for wastewater treatment. This approach offers a viable solution for improving water quality and reducing the risk of waterborne diseases.

A comparative investigation of chemical coagulation and electrocoagulation for the post-treatment of confectionery wastewater

A comparative investigation of chemical coagulation and electrocoagulation for the post-treatment of confectionery wastewater