Flocculation Time Research Articles

Dispersion polymerization of AM-AMPS-DAM-DOH and its sand control property

Sand production in oil wells is a common challenge during the oil extraction process. Water-soluble polymers have attracted attention due to their low toxicity, cost-effectiveness, ease of direct injection, and excellent thermal stability. However, the dry polymer injection process commonly used in offshore oil fields is complex. Therefore, this paper employs acrylamide (AM), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), a dihydroxy monomer (DOH), and a functional monomer (DAM) containing ketone groups and self-crosslinking properties as monomers. A polymer latex type sand control agent was prepared through dispersion polymerization for direct application on offshore platforms. This paper utilizes flocculation time and maximum sand free flow rate as inspection indicators and utilizes both the one-factor-at-a-time method and the surface response method to optimize the synthesis conditions of the sand control agent. The optimal synthesis conditions are obtained: total monomer concentration of 9.15 wt%, DOH concentration at 10 wt% of the total monomer concentration, ammonium sulfate (AS) concentration of 27.02 wt%, dispersant concentration of 2.13 wt%, initiator concentration at 0.25 wt% of the total monomer concentration, reaction time of 12 h, and reaction temperature of 40 °C. Under the conditions of concentration ≥2000 mg/L and curing time ≥4 h, the sand control agent is suitable for sand stabilization under formation conditions of temperatures between 50 and 80 °C, pH levels ranging from 3 to 9, salinity <30000 mg/L, and sand particle size of ≥100 μm. The research results of this paper can serve as a valuable reference for the control of oilfield sand production.

Effects of a new synthetic Fe-PAM flocculants on filtration and consolidation of bentonite slurry

To improve the dewatering performances of the waste slurry, a new Fe-Polyacrylamide (Fe-PAM) flocculant was synthesized. Comparative analysis with various ionic forms of polyacrylamide (PAM) reveals that the Fe-PAM flocculant has the shortest flocculation time, the lowest optimal shear gradient for flocculation, and the best filtration performance. The capillary suction time (CST) of Fe-PAM treated slurry was improved from 262.3 s (raw sample) to 6.0 s. Moreover, sludge treated with Fe-PAM exhibits the lowest porosity under the same consolidation pressure and the highest permeability at the same void ratio. In addition, mercury intrusion porosimetry (MIP) results indicated that the Fe-PAM-treated sample features the highest number of largesized inter-aggregate pores (average value of 184.2 nm and median value of 23.2 nm) and the greatest pore connectivity (60.55 %), contributing to its superior permeability. The effectiveness of Fe-PAM is further elaborated through a synergistic flocculation mechanism, encompassing the electrical neutralization effect of the inorganic metal Fe3+ and the adsorption bridging effect of PAM's long-chains. This study demonstrates the potential of the synthesized Fe-PAM flocculant to enhance the dewatering efficiency of high-water content slurry and offers valuable insights for synthesizing advanced flocculants in slurry treatment engineering.

Clay Tailings Flocculated in Seawater and Industrial Water: Analysis of Aggregates, Sedimentation, and Supernatant Quality.

High-molecular-weight anionic polyacrylamide was used to analyze the effect of kaolin on the structure of particle aggregates formed in freshwater and seawater. Batch flocculation experiments were performed to determine the size of the flocculated aggregates over time by using focused beam reflectance measurements. Sedimentation tests were performed to analyze the settling rate of the solid-liquid interface and the turbidity of the supernatant. Subsequently, a model that relates the hindered settling rate to the aggregate size was used to determine the mass fractal dimension (Df). Flocculation kinetics revealed that greater amounts of kaolin generated larger aggregates because of its lamellar morphology. The maximum size was between 10 and 20 s of flocculation under all conditions. However, the presence of kaolin reduced the settling rate. The fractal dimension decreased with the increase in the kaolin content, resulting in the formation of irregular and porous aggregates. By contrast, factors such as the flocculation time, water quality, and quartz size had limited influences on the fractal dimension. Seawater produced a clearer supernatant because of its higher ionic strength and precoagulation of particles. Notably, the harmful effect of clays in seawater was reduced.

Effects of different flocculants and environment on the flocculation effect of potato starch-processing wastewater

ABSTRACT Potato starch-processing wastewater belongs to high-concentration organic wastewater, as direct discharge is more polluting to the environment. Flocculation treatment, as the initial process of wastewater purification, can remove large debris in wastewater, reduce energy consumption for subsequent treatment and reduce production costs. In this study, the effects of traditional flocculants and biological flocculants on the treatment of potato starch-processing wastewater under different pH, dosage, stirring rate and settling time were studied. It was found that traditional flocculants and biological flocculants have their own advantages in the purification ability of organic matter, and the removal rates of suspended solids (SS) and total phosphorus (TP) of traditional flocculants are better than biological flocculants for sweet potato starch-processing wastewater, but the flocculation time and settling time are long. Biological flocculants are environmentally friendly, safe and non-polluting, and do not produce secondary pollution when the flocculation treatment of wastewater is conducive to the secondary reuse of wastewater and flocculation sediment resource treatment. According to the flocculation effect and cost, chitosan is the best flocculant for treating sweet potato starch-processing wastewater.

A Novel Process for the On-Site Preparation and Application of Polyferric Chloride (PFC) for Surface Water Treatment

This is the first study to describe a novel, patented process for the on-site synthesis and subsequent direct utilisation of Polyferric Chloride (PFC) at low Fe concentration dosing, which aims to facilitate the potential replacement of Polyaluminium Chloride (PAC) during surface water treatment (e.g., from reservoirs) for drinking water production. For this purpose, the PFC was synthesised and subsequently used as a coagulant in simulated surface water samples under different synthesis and coagulation/flocculation conditions, namely for different pre-hydrolysed Fe concentrations, pre-hydrolysis pH, coagulation pH, and flocculation times. The effectiveness of PFC was examined mainly in terms of total organic carbon (TOC) removal and the residual Fe concentration. The obtained results showed that the pre-hydrolysed Fe concentration at 0.5 ± 0.25%, pre-hydrolysis at pH 2.5 ± 0.25, coagulation at pH 5.5–7.0 and a flocculation time of 5 min could result in the highest TOC removal (i.e., residual values &lt; 0.60 mg/L) and the lowest residual Fe concentration (&lt;5 μg Fe/L), which is acceptable for a water quality assessment. These values are also substantially lower when compared to the respective TOC and residual metal concentrations using PAC (usually, the relevant obtained values are around TOC &gt; 1 mg/L and Al &gt; 50 μg/L).

Machine learning framework for modeling flocculation kinetics using non-intrusive dynamic image analysis

The implementation of a machine learning (ML) model to improve both the effectiveness and sustainability of the water treatment system is a significant challenge in the water sector, with the optimization of flocculation processes being a major setback. The objective of this study was to develop a ML model for predicting flocs evolution of the flocculation process in water treatment. Furthermore, we have devised a framework for its potential adoption in large-scale water treatment. Therefore, the paper can be split into two parts. In the first one, flocculation evolution has been studied from an experimental setup, using a non-intrusive image acquisition method. Subsequently, the ML framework has been implemented. Batch assay data of two velocity gradients (Gf 20 and 60 s−1) and flocculation time of three hours were partitioned into five groups for flocs length range 0.27–3.5 mm and upscaled using linear method. Multilayer Perceptron (MLP) and Long-Short Term Memory (LSTM) models, and traditional time series model, Auto Regressive Integrated Moving Average (ARIMA) were explored to predict floc length evolution data. The experiments illustrate the kinetics of flocculation, where the initial stage is characterized by a rapid floc growth followed by a plateau during which floc length fluctuates within a narrow range. Results demonstrate that ML is sensitive to flocculation; however, the model should be selected with care. ARIMA model is not suitable for predicting number of flocs with negative test accuracy (R2). In contrast, MLP recorded R2 of 0.86–1.0 for training and 0.92–1.0 for testing, across Gf 20 s−1 and Gf 60 s−1. LSTM model has the best prediction R2 of 0.92–1.00 for Gf 20 s−1 and accurately predicts the number of flocs across all groups and Gfs. Our study has proven that the developed framework could be replicated for water treatment modeling and promotes the application of smart technology in water treatment.

Microalgae Biomass Harvesting Using Chitosan Flocculant: Optimization of Operating Parameters by Response Surface Methodology

Bioflocculants can be used for cost-effective harvesting of microalgae biomass on an industrial scale. This study investigates the flocculation-based harvesting approach to recovering Chlorella vulgaris microalgae biomass using chitosan biopolymer. Response surface methodology (RSM) was used to design the experiments and optimize the critical operating parameters. Box-Behnken Design (BBD) was employed at three levels, and 17 experimental runs were conducted to determine the optimal conditions and the relationship between operating parameters. The highest biomass recovery of 99.10% was achieved at the following optimized conditions: pH of 5, flocculation time of 45 min, and chitosan concentration of 10 mg/L. Both experimental results and model outputs indicated that pH significantly impacts microalgae harvesting and that process performance is less dependent on chitosan concentration and flocculation time. The quadratic model has shown the best fit with the experimental results. The results could be applied to large-scale microalgae harvesting applications to promote microalgae biomass recovery and reduce operating costs.

Quartz Fine Particle Processing: Hydrophobic Aggregation by Shear Flocculation

This study investigates the hydrophobic aggregation of fine quartz particles through shear flocculation induced by dodecylamine in aqueous solutions. The effect of stirring speed, collector concentration, flocculation time, and pH were investigated. The results showed that the impact of stirring speed on particle aggregation in the absence of a collector is very limited. Quantitative analyses demonstrated that the variation of collector concentration intensified the flocculation process more than the stirring rate. Numerical optimization showed that the large volume occupied by the flocs was 12.3 mL, achieved with a stirring speed of 2135 rpm and dodecylamine concentration of 1.39 × 10−2 mol·L−1. The highest quartz particle aggregation was observed at pH 10.5, corroborating the importance of the non-dissociated amine molecules for particle hydrophobization. High zeta potential values did not result in reducing aggregation, indicating that hydrophobicity was the governing factor in the shear flocculation process.

Removal of Turbidity from Raw water by Novel Coagulant Based on PVC Pipe Waste and Sodium Alginate

In the current study, waste polyvinyl chloride pipes were used as a primary material in the reactions, which are widely used for water supply and drainage systems where the waste pipes were prepared by cleaning them from suspended materials and grinding them into small particles, then reacting natural polymers from a plant; Alginic acid. We have obtained modified polymer (PVC/Alginate) or AL-PVC which have been grinded to obtain a powder. Four methods were used to characterize the properties of natural and prepared polymers: Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM) X-ray diffraction (XRD), and thermogravimetry (TGA-TG). The effectiveness of AL-PVC polymer as a coagulant flocculant in the treatment of surface water has been studied. Tests were carried out in the laboratory on two kinds of water (50 NTU and 100 NTU). The first one is the synthesis of water mixed with high and low concentrations of bentonite, simulating thus turbid water. The second one is raw water from the treatment station of the Shatt Al-Arab River. The performance of the coagulation-flocculation process has been assessed by measuring the supernatant turbidity for different pH, doses, and flocculation times of the AL-PVC polymer. The obtained results show that AL-PVC polymer effectiveness was strongly dependent on pH and the doses of AL-PVC polymer, the initial turbidity, and the water quality. The physical and chemical methods used in the present study of water treatments are mainly due to their simplicity, ease of use, low cost as well as excellent removal efficiency.

Advanced Treatment of Coking Wastewater by Polyaluminum Silicate Sulfate for Organic Compounds Removal.

Coking wastewater is a typical high-strength organic wastewater, for which it is difficult to meet discharging standards with a single biological treatment. In this study, effective advanced treatment of coking wastewater was achieved by coagulation with freshly prepared polyaluminum silicate sulfate (PASS). The performance advantage was determined through comparison with commercial coagulants including ferric chloride, polyferric sulfate, aluminum sulfate and polyaluminum chloride. Both single-factor and Taguchi experiments were conducted to determine the optimal conditions for coagulation with CODCr and UV254 as indicators. A dosage of 7 mmol/L PASS, flocculation velocity of 75 r/min, flocculation time of 30 min, pH of 7, and temperature of 20 °C could decrease the CODCr concentration from 196.67 mg/L to 59.94 mg/L. Enhanced coagulation could further help to remove the organic compounds, including pre-oxidation with ozonation, adsorption with activated carbon, assistant coagulation with polyacrylamide and secondary coagulation. UV spectrum scanning and gas chromatography-mass spectrometry revealed that the coagulation process effectively removed the majority of organic compounds, especially the high molecular weight alkanes and heterocyclic compounds. Coagulation with PASS provides an effective alternative for the advanced treatment of coking wastewater.

Study on the flocculation mechanism of a bioflocculant from Acinetobacter sp. TH40 combined with graphene oxide for the removal of metal ions from water.

In order to realize the simultaneous removal of nine metal ions from water, in this study, an excellent flocculant suitable for the simultaneous removal of multiple metal ions in water was developed by using the excellent flocculation properties of graphene oxide (GO) combined with biological flocculants. First, this study investigated the concentrations and pollution levels of nine metal pollutants in surface water and groundwater of a typical city in central China. The maximum concentrations of these nine metal ions were Al 0.29, Ni 0.0325, Ba 0.948, Fe 1.12, As 0.05, Cd 0.01, Zn 1.45, Mn 1.24, and Hg 0.16 (in mg/L). Second, the three-dimensional structure diagram of GO was established. Gaussian16W software and the pm6D3 semi-empirical method were used to analysis the structure and the vibration of GO. The B3LYP function and basis set DEF2SVP was used to calculate the single point energy. Third, with varying the flocculation time, it was found that the maximum flocculation efficiency could reach more than 80.00% under the optimal conditions, that is, with a metal ion mixture of 20mg/L. The optimal dosage of GO was 15mg/L. The optimal time for bioflocculation efficiency was 2.5h, and the optimal concentration of bioflocculant was 3mg/L. The optimal flocculation efficiency was 82.01% under the optimal conditions.

Study of low cost of microalgae chlorella sp. harvesting using cationic starch flocculation technique for biodiesel production

The crisis of energy has become the main concern for human civilization. Microalgae is an attractive source of biomass for energy production because it has high productivity, does not compete with food, do not require a large area and its ability to absorb CO2. Chlorella sp. has the potential to be used as raw material for biodiesel due an oil content of 28-32% and easily developed in Indonesia. Harvesting is a very cost-determining step in converting algal biomass into biodiesel. Cationic starch has a strong potential as a flocculant agent because of its abundance and low price. This research aims to identify the potential of cation starch as a flocculant agent and obtain optimum the condition for harvesting Chlorella sp. Based on this study, cationic starch can be used as an alternative organic flocculant for Chlorella sp. The optimum dose and flocculation are 1 g/L dosage, 400 rpm flocculation speed and 15 minute flocculation time. With the optimum condition, harvesting efficiency on the laboratory scale is 98.23% and the pilot scale is 96.05%. This difference in harvesting efficiency values indicates that the efficiency tends to decrease with a larger volume of Chlorella sp.

Removal of colloidal impurities by thermal softening-coagulation-flocculation-sedimentation in steam assisted gravity drainage (SAGD) produced water: Performance, interaction effects and mechanism study

Effective removal of colloidal impurities from steam-assisted gravity drainage (SAGD) produced water is essential for enhancing water recycling in industry. Response surface methodology (RSM) was employed to optimize the thermal softening-coagulation-flocculation-sedimentation process with softeners (Ca(OH)2, MgO and Na2CO3), poly-DADMAC as coagulant, and cationic polyacrylamide (PAM) as flocculant, and assess the interaction effects of operational variables for sludge volume index (SVI) and the removal efficiency of turbidity (TSS), particulate hardness, silica, total organic carbon (TOC) and total inorganic carbon (TIC) in synthetic SAGD produced water. The optimal conditions at 0.93 desirability were 67 mg/L poly-DADMAC dose, 14 min mixing time with softeners only, 200 rpm coagulation speed, and 16 min flocculation time. At this condition, the predicted maximum removal of turbidity, TSS, particulate hardness, silica, TOC and TIC were 99.2 %, 99.1 %, 99.4 %, 27.0 %, 69.0 %, and 30.3 %, respectively, and the value of SVI was 38.1 mL/g. Our results indicated that poly-DADMAC dose and mixing time with softeners only were the most influential factors for the treatment process. Furthermore, the temperature effect on removal mechanisms was investigated at optimal conditions under room temperature and high temperature (80 °C). The results of floc characterization and surface force measurement indicated that temperature could facilitate the removal of colloidal impurities via forming larger and denser flocs and changing their surface composition. The results also provided confirmation that adsorption and subsequent bridging are the main removal mechanisms in the coagulation-flocculation process. This study illuminates the importance of the interactions among operational variables and provides in-depth insights into the mechanism for the removal of colloidal impurities under high temperature.

Characteristics of waste mud treated by construction waste-slag based flocculation-solidification combined method

Nowadays, the flocculation-solidification combined method (FSCM) is considered suitable for mud treatment and recycling. However, the traditional FSCM uses ordinary Portland cement (OPC) as the main solidifying material, which pollutes the ecological environment. Currently, the evaluation mechanism of solidification efficiency is not accurate, the treatment of mud with different water content is not detailed enough, and the assessment of carbon emission is unclear. Accordingly, this paper introduces solid waste such as construction waste powder (concrete and brick mix recycled fine aggregate) and slag powder for solidification based on the traditional FSCM. Within the study context, the alkali activation effects of quicklime, NaOH, and NaSiO3 are compared to develop a new solidification agent. Besides, the flocculation time and peak settling rate are measured experimentally, and anionic polyacrylamide(APAM) is added separately to compare low-water-content mud (LW-MS) (ω < 70 %) and high-water-content mud (HW-MS) (70 %≤ω ≤ 300 %). The intrinsic flocculation-solidification mechanism is analyzed and demonstrated through microscopic testing.Finally, the feasibility of construction waste-slag based flocculation-solidification combined method (CWS-FSCM) is verified through field test. In terms of solidification effectiveness, carbon emissions and economy, CWS-FSCM performs better than the traditional FSCM.

Effective Chlorella vulgaris Biomass Harvesting through Sulfate and Chloride Flocculants

Efficient microalgae harvesting is a great challenge hindering diverse industrial applications of microalgae. Flocculation is regarded as an effective and promising technology for microalgae harvesting. In this study, sulfate (Al2(SO4)3 and Fe2(SO4)3) and chloride flocculants (AlCl3 and FeCl3) were used to harvest Chlorella vulgaris. Flocculation conditions, including flocculant dose, flocculation time, stirring speed, stirring time, and flocculation pH, were optimized, and flocculant effects on microalgal cell status, floc characteristics, biomass composition, algal cell re-culture, and media recycling were investigated. All flocculants exhibited efficient flocculation efficiency (93.5–98.8%) with lower doses of sulfate salts (60 mg/L algal culture) and higher doses of chloride salts (100 mg/L algal culture). The tested flocculants had no obvious influence on biomass composition (including lipids, carbohydrates, proteins, and carotenoids), and microalgal cells in flocs could efficiently regrow. The spent medium of all treatments was successfully recycled for subsequent cell growth, thus reducing dependency on fresh medium.

Synthesis of a chitosan-based flocculant CS-g-P(AM-IA-AATPAC) and evaluation of its performance on Ni2+ removal: Role of chelating-coordination and flocculation

Ni2+ rich wastewater has caused critical water contamination, a growing issue of environmental pollution as well as serious threat to aquatic organisms and human health. It is of great significance and urgent to develop a novel and efficient wastewater treatment technology for Ni2+ removal. The efficient removal of Ni2+ by flocculation has always become a hot and focus topic. In this study, a novel chitosan (CS) graft modified flocculants CS-g-P(AM-IA-AATPAC), namely CS-g-PAAI, is prepared by microwave initiation and polymerization, and is applied in the removal of Ni2+. The effects of microwave power, microwave irradiation time, initiator concentration and pH on the CS graft polymerization efficiency and flocculant molecular weight were investigated and optimized, so as to further understand the rules of microwave initiation and CS-g-PAAI graft and polymerization. Various characterization methods indicated the successful grafting and synthesis of CS-g-PAAI. Meanwhile, the structural characteristic results manifested that CS-g-PAAI possessed a good thermal stability, a coarse and porous apparent morphology, and its chemistry and crystal structure was evidently changed and affected after graft polymerization. Compared with CS, PAA and CS-g-PAA, the removal efficiency of Ni2+ by CS-g-PAAI is more exceedingly favorable and desirable. The flocculation effect of Ni2+ by CS-g-PAAI is as high as 86.3% at the optimal condition of pH = 9, flocculant dosage = 4 mg/L, the stirring speed = 400 rpm, and flocculation time = 30 min. Meanwhile, the generated Ni2+ floc size (d50) and fractal dimension (Df) can reach a high value (d50 = 339.3 µm, Df = 1.98), which accelerates the sedimentation and separation of the formed Ni2+ flocs. CS-g-PAAI shows excellent flocculation and coordination ability by its powerful coordination groups to strengthen the adsorption and chelating of Ni2+ ions and generate colloidal particles for subsequent flocculation. Then, efficient flocculation was carried out and proceeded through the bridging effect, the concomitant sweeping and netting action.

Dendrimer modified composite magnetic nano-flocculant for efficient removal of graphene oxide

Graphene oxide (GO) as an emergingnanomaterial has been widely used in water purification. However, practical removal of GO from water environment and industrial waste liquid remains a critical challenge.Here, a poly (amideamine)dendrimer (PAMAM) modified composite magnetic nano-flocculant (Fe3O4@SiO2@PAMAM) was fabricated and a new strategy for removal of GO was proposed combining the advantages of flocculation with magnetic separation. Results showed that high removal efficiency of more than 82.41 % could be attained under the conditions of an initial GO concentration of 100 mg/L, flocculation time of 60 s, Fe3O4@SiO2@PAMAM dose of 100 mg/L, and pH of 6.0. The maximum removal capacity of Fe3O4@SiO2@PAMAM for GO was approximately 238.10 mg g−1. Based on the charge neutralization and sweep flocculation, the prepared Fe3O4@SiO2@PAMAM demonstrated excellent application performance for removing GO in surface water, domestic sewage, and industrial waste liquid. A new magnetic nano-flocculant and an alternative technology strategy for treatment of GO was presented.

Ultrafine quartz flocculation: Part I. System characterization and variables selection

A characterization study was performed to verify the more relevant physicochemical properties for quartz flocculation with polyacrylamide, as well as to define which variables should be further investigated regarding this flocculation system. Polyacrylamide was evaluated through molecular weight, radius of gyration, and infrared spectrometry. A natural quartz sample was investigated regarding its particle size distribution, specific surface area, mineralogical and chemical composition. The zeta potential of quartz with flocculant and surfactant was also analyzed. The results indicated that the quartz had high purity and particle sizes between 38 and 10 µm, which was within the intended particle size range; the flocculant presented a suitable molecular weight for the proposed flocculation system. Based on literature, nine variables were chosen to be investigated in Part II of this study: flocculant and surfactant concentration, flocculant and surfactant conditioning time, flocculation addition time, agitation intensity, pH of the suspension, flocculation time, and solid concentration.

Implementation of FeSO4·H2O as an Eco-Friendly Coagulant for the Elimination of Organic Pollutants from Tertiary Palm Oil Mill Effluent: Process Optimization, Kinetics, and Thermodynamics Studies

The biologically treated palm oil mill effluent (POME) urges further treatment to minimize the residual pollutant concentration for safe discharge in the nearest watercourse. In the present study, the post-treatment of biologically treated POME was conducted using ferrous sulfate monohydrate (FeSO4·H2O) as a coagulant. The influence of the FeSO4·H2O coagulation of POME was determined on the elimination of biochemical oxygen demand (BOD), suspended solids (SS), and chemical oxygen demand (COD) with varying flocculation time (min), slow mixing speed (rpm), coagulant doses (g/L) and pH. The FeSO4·H2O coagulation–flocculation experimental conditions were designed following the central composite design (CCD) of experiments and optimized by employing response surface methodology (RSM) based on the optimal SS, COD, and BOD elimination from POME. The maximum BOD, SS, and COD elimination achieved were about 96%, 97%, and 98%, respectively, at the optimized experimental condition. The surface morphology and elemental composition analyses of raw FeSO4·H2O and sludge generated after coagulation revealed that the FeSO4·H2O effectively removed the colloidal and suspended particles from POME. The well-fitted kinetic model equation was the pseudo-second-order kinetic equation to describe the FeSO4·H2O coagulation–flocculation behavior. The thermodynamics properties analyses revealed that the FeSO4·H2O coagulation of POME was non-spontaneous and endothermic. The residual SS, COD, and BOD in treated POME were determined to be 28.27 ± 5 mg/L, 147 ± 3 mg/L, and 6.36 ± 0.5 mg/L, respectively, lower the recommended discharged limits as reported by the Department of Environment (DoE), Malaysia.

A comparative analysis of degradation efficiencies using alum and orange peel waste for the treatment of tannery wastewater

The tannery wastewater effluent consists of complex compounds requiring a series of treatment processes to meet the desirable effluent discharge standards. The current study deals with the comparison of degradation efficiencies obtained in terms of turbidity, total suspended solids (TSS) and chemical oxygen demand (COD) removal by using alum as a chemical coagulant, orange peel powder (OPP) and activated orange peel powder (AOPP) as naturally obtained adsorbents respectively. The experimental analysis showed that the maximum COD reduction of 49 % approx. was obtained using AOPP at optimum coagulant dosage of 2 g/L, at pH 4 and flocculation time of 30 min. Scanning Electron Microscope (SEM) showed that the AOPP consists of porous structure that leads to adsorption of pollutants over the surface. Brunauer–Emmett–Teller (BET) analysis resulted in surface area reduction of AOPP from 11.663 m2/g to 1.289 m2/g before and after adsorption correlating the experimental results of the study. Moreover, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Total organic carbon (TOC) proved that the chemical properties also play an important role in degrading the pollutants present in TWE. It can be concluded that the AOPP can be used as a cost-efficient alternative for pre-treatment of TWE.