Optimization of Coagulation-Flocculation Process for Mature Landfill Leachate Treatment Using Response Surface Methodology (RSM) (original) (raw)
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DESALINATION AND WATER TREATMENT
The aim of this study is to assess the performance of an industrial effluent steel industrial wastewater (SIWW) highly loaded with ferric salts from Maghreb Steel Company as coagulant for stabilized landfill leachate treatment. Response surface methodology and central composite design were applied to optimize the coagulation-flocculation process and to model the relationships between independent variables (coagulant dose and effluent pH) and responses (chemical oxygen demand (COD) and turbidity removal, and sludge production). Quadratic polynomial models developed for these responses indicated that the optimum conditions were 8 mL/L of SIWW at pH 2.75. These results showed good agreement between experimental and model predictions. 55.43% and 87.55% of COD and turbidity removal, respectively and with 19 mL/L of sludge production from treatment of this leachate by coagulation-flocculation using a SIWW-based coagulant were demonstrated. Accordingly, it is concluded that SIWW can be used as an effective and alternative coagulant for the pre-treatment of stabilized landfill leachate by a coagulation-flocculation process.
Avicenna Journal of Environmental Health Engineering, 2019
Landfill leachate is highly polluted and generated as a result of water infiltration through solid waste produced domestically and industrially. This study investigated the applicability of the response surface methodology (RSM) to optimize the removal performances of chemical oxygen demand (COD), color, and suspended solids (SS) from landfill leachate by coagulation process using Tin tetrachloride pentahydrate. The leachate samples were collected from Alor Pongsu Landfill (APLS) in Perak, Malaysia. Before starting the experiments, general characterization was carried out for raw leachate samples to investigate their physical and chemical properties. The effects of the dosage and pH of SnCl 4 on the removal performances were evaluated as well. An ideal experimental design was performed based on the central composite design (CCD) by RSM. In addition, this RSM was used to evaluate the effects of process variables and their interaction toward the attainment of their optimum conditions. The statistical design of the experiments and data analysis was resolved using the Design-Expert software. Further, the range of coagulant dosage and pH was selected based on a batch study which was conducted at 13 000 mg/L to 17 000 mg/L of SnCl 4 and pH ranged from 6 to 10. The results showed that the optimum pH and dosage of SnCl 4 were 7.17 and 15 g/L, respectively, where the maximum removal efficiency was 67.7% for COD and 100% for color and SS. The results were in agreement with the experimental data with a maximum removal efficiency of 67.84 %, 98.6 %, and 99.3%, for COD, color, and SS, respectively. Overall, this study verified that the RSM method was viable for optimizing the operational condition of the coagulation-flocculation process.
Dosage and pH optimization on stabilized landfill leachate via coagulation-flocculation process
MATEC Web of Conferences, 2018
Treatment on the generated landfill leachate is crucial as it can cause serious toxicological effects and environmental hazards, particularly when the unfavorable contaminants are left accumulated for a long period of time. The purpose of this study was to determine the optimum coagulant dosage of polyaluminium chloride (PAC) in selected dosage ranges (2250-4500 mg/L) and to analyse the ideal pH of leachate sample (pH 3-10). PAC was tested on stabilized leachate taken from Simpang Renggam Landfill Site (SRLS), by investigating the percentage removals of five significant parameters, which were suspended solids, chemical oxygen demand (COD), ammonia, and heavy metals (iron (Fe) and chromium (Cr)). The removal efficiency was determined by a series of experiments using jar test. From the obtained results, it was found that 3750 mg/L and pH 7 were the optimum conditions for PAC dosage and sample pH, respectively. The conventional optimization test showed satisfactory results for suspende...
Journal of Sustainable Development, 2009
The effect of a coagulation process with ferrous sulfate as a coagulant on COD, apparent color and turbidity was evaluated using response surface methodology (RSM). A jar test method was used for the pre-treatment of mature landfill leachate of the Pulau Burung Sanitary Landfill, Malaysia. The results of response surface methodology (RSM) showed that ferrous sulfate was most efficient under alkaline conditions and with a coagulant dosage 10 g/l. At the optimum setting for coagulant dosage was 10 g/l and pH 11.7, resulted in maximum of (22%) in COD, (42%) in apparent color, and (31%) in turbidity. It was observed that the COD, apparent color and turbidity reductions decreased with pH and FeSO 4 levels beyond the optimum conditions. This paper illustrates the usefulness of experimental design in running experiments and optimization.
DESALINATION AND WATER TREATMENT, 2021
Landfill leachate contains persistent organic pollutants, and therefore, it must be treated before it is released into natural water courses. The present study, reports on investigations about the removal efficiencies of turbidity, chemical oxygen demand (COD) and phenols from leachate using a biocoagulant/bioflocculent (cactus cladode) as well as the volume of generated sludge. The experimental variables (pH and coagulant dosage) were optimized by applying response surface methodology (RSM) equipped with the central composite faced design. An empirical quadratic polynomial model can accurately model the surface response with R2 values greater than 92% for all the responses. The results of confirmatory experiments correspond to the model predictions, which demonstrate that RSM can achieve good predictions with the least number of required experiments. Results showed that the reduction efficiencies for turbidity, COD and phenols at pH 2 and cactus dosage of 1.48 g L–1 were, respectiv...
Coagulation-flocculation was studied as pretreatment option for stabilized landfill leachate from a dumpsite in Ranchi, India. Alum, ferric chloride and a novel Polyacrylamide grafted Gum Ghatti (GGI-g-PAM) were used for coagulation-flocculation. Experiments at different coagulant doses and pH were conducted in Jar test apparatus, process evaluation was based on removal of chemical oxygen demand (COD), total suspended solids (TSS), turbidity, ammonia and color. Alum at 9500 mg/L and at pH 6 led to 63% COD removal, 71% TSS removal and 59% turbidity removal. Ferric chloride at 2500 mg/L and at pH 4 led to 80% COD removal, 53% TSS removal and 65% turbidity removal. GGI-g-PAM at 100 mg/L and at pH 7 led to 38% COD removal, 90% TSS removal and 22% turbidity removal. Ferric chloride at 2000 mg/L dose and at pH 4 led to 54% ammonia removal but color removal was insignificant. Alum at 9500 mg/L and at pH 6 removed 79% color but ammonia removal was insignificant. GGI-g-PAM was ineffective fo...
Abstract— In this work we examined the application of coagulation–flocculation for the treatment of stabilized leachates. Jar-test experiments were employed in order to determine the optimum concentration conditions for the removal of organic matter. Coagulant–flocculant combination, effective dosage Ferric chloride, Aluminum sulphate and Alginate were tested as conventional coagulants, whereas five commercial polyelectrolyte were co-examined: tree anionic and two cationic. The results indicate a coagulant FeCl3 remove of 67, 3% and 87% of COD and turbidity respectively from the stabilized landfill leach ate For optimal concentration of 3000 mg / l and a variable concentration of flocculant Astral, removal efficiencies of COD and turbidity varies respectively by 64% and 100%. We obtained for variable concentrations of FeCl3 and an optimal concentration of 198 mg/l of flocculant Astral yields disposal respectively 70.5 and 84% for COD and turbidity. These results are comparable to th...
Assessment of coagulation pretreatment of leachate by response surface methodology
Coagulation-flocculation is a relatively simple technique that can be used successfully for the treatment of old leachate by poly-aluminum chloride (PAC). The main objectives of this study are to design the experiments, build models and optimize the operating parameters, dosage m and pH, using the central composite design and response surface method. Developed for chemical organic matter (COD) and turbidity responses, the quadratic polynomial model is suitable for prediction within the range of simulated variables as it showed that the optimum conditions were m of 5.55 g/L at pH 7.05, with a determination coefficient R² at 99.33%, 99.92% and adjusted R² at 98.85% and 99.86% for both COD and turbidity. We confirm that the initial pH and PAC dosage have significant effects on COD and turbidity removal. The experimental data and model predictions agreed well and the removal efficiency of COD, turbidity, Fe, Pb and Cu reached respectively 61%, 96.4%, 97.1%, 99% and 100%.
Treatment of Landfill Leachate through Coagulation Process
Landfill leachate can be defined as a liquid that passes through the municipal solid waste (MSW) landfill and has extracted dissolved and suspended matter from it. The generation of leachate is a major problem for MSW landfills and causes significant threat to surface water and groundwater. Special care is required for efficient treatment and disposal. In addition, landfill leachate is complex waste water with considerable variation in both quality and quantity. The composition and concentration of pollutants are influenced by the types of waste deposited, hydro geological factors and more significant by the age of the landfill site. In general, leachate is highly contaminated with organic contaminants measured as chemical oxygen demand (COD), biochemical oxygen demand (BOD) and also with high ammonium nitrogen concentration. The main focused of this research is to investigate the performance of chemical treatment by coagulation process and to compare the efficiency of coagulants on removal of COD and TSS with standard tools in leachate samples which was collected from Rajbondh landfill in Khulna. The collected leachate samples were tested in the laboratory through the standard methods to measure the relevant parameters. The characteristics of leachate were: pH=8.6; BOD5=142.1 mg/L; COD=5760 mg/L; Temperature=28.7ºC; Electric Conductivity=5.67µs/cm; TS=17000 mg/L; TDS=16600 mg/L; TSS=400 mg/L; Turbidity=336 NTU; Color=17800 pt-co; Alkalinity=1700 mg/L; Salinity=2800 mg/L; T.C.=740; F.C.=300. The coagulation of leachate was accomplished by a technique consisted of Poly-Aluminum Chloride (PAC), Aluminum Sulphate (Al 2 (SO 4) 3 .18H 2 O) as Alum and Ferrous Sulphate (FeSO 4) in various dosages and different pH values (2, 5, 7 and 9). Results showed that the efficiency for COD removal by PAC at pH=9 and 2500 mg/L of coagulant dose, by Alum at pH=9 and 2500 mg/L of coagulant dose, by Ferrous Sulphate at pH=7 and 2000 mg/L of coagulant dose. The COD removal efficiency for PAC, Alum and Ferrous Sulphate were 81.82, 75 and 85.71% respectively. Results also showed that efficiency for TSS removal by PAC that was obtained at pH=5 and 2500 mg/L concentration of coagulant dose, by alum at pH=7 and 2500 mg/L concentration of coagulant dose and by ferrous sulphate at pH=9 and 2000 mg/L of coagulant dose. The TSS removal efficiency for PAC, Alum and ferrous sulphate are 46.15, 60 and 72.73% respectively. In this study carried out the COD and TSS removal efficiency both were better for ferrous sulphate. To depict the performance of used chemical coagulations then compared to the standards leachate discharge which are available in the literature.