Adsorption of lead, zinc and cadmium ions from contaminated water onto Peganum harmala seeds as biosorbent

Peganum harmala seeds were assessed as biosorbent for removing Pb²⁺, Zn²⁺and Cd²⁺ ions from aqueous solutions. The effects of various parameters such as the aqueous solution pH, the contact time, the initial metal concentration and the amount of adsorbent in the process were investigated. The adsorption efficiencies increased with pH. It was found that about 95 % of lead, 75 % of zinc and 90 % of cadmium ions could be removed from 45 ml of aqueous solution containing 20 mg l^?1 of each cation with 2 g of adsorbent at pH 4.5 after 15 min. The quantitative desorption of cadmium from adsorbent surface was achieved using 10 ml of a 0.5 M nitric acid solution. This condition was attained for lead and zinc ions with 10 ml of 1 M hydrochloric acid solution. Kinetic investigation of the process was performed by considering a pseudo-second-order model. This model predicts the chemisorption mechanism of the process. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models were tested for describing the equilibrium data. It was found that the Freundlich model describes the experimental data resulting from the adsorption of lead ions. However for cadmium and zinc ions, the adsorption equilibria were interpreted with the Langmuir model.     

Capacity of quartz fibers with high filtration efficiency for capturing soot aerosol particles

Two proposed quartz fibrous filters with dissimilar solid volume fractions and thicknesses are investigated for their efficiency in removing soot aerosol particles from air. Soot particles are sourced from a candle burning in a chamber, and the tests involve 1.5 h of continuous loading of particles at three different flow rates: 4.5, 8.15 and 9.55 l/min. The fractional efficiency, morphology and pressure drop of both clean and loaded filters are studied using a scanning mobility particle sizer, scanning electron microscope and differential pressure gauge. Both filters have relatively similar levels of efficiency 93% for particle size (100–400 nm) at the lowest flow rate. At higher flow rates, the re-entrainment process effects the filtration efficiency of both filters. At the higher flow rate of 8.15 l/min, the filter with a higher solid volume fraction and thickness shows a higher pressure drop and an efficiency level of 95%. Increasing the flow rate to 9.55 l/min helps to pass the particles with diameters larger than 100 nm through two filters. This phenomenon decreases the fractional efficiency of both filters during the loading time.     

Desorption of tetracycline from montmorillonite by aluminum,calcium, and sodium: an indication of intercalation stability

As the uptake of cationic drugs, such as tetracycline (TC), was attributed to cation exchange, the stability of adsorbed TC on a Ca-montmorillonite SAz-2 was studied using cationic solutions of different valence charges under different pH conditions. At the initial loading of 356 mg g^?1, the amounts of TC desorbed by 0.05 M AlCl₃, CaCl₂, and NaCl were 133 ± 4, 83 ± 6, and 50 ± 4 mg g^?1, respectively, or 37, 23, and 14 %. However, when the amount or percentage of TC desorbed was normalized to the equivalence of each cation, the values were in the range of 44–50 mg g^?1 or 11–14 % per 10 mmol of charge. The kinetics of TC desorption were moderately fast and almost reached equilibrium in 6 h. The results followed the pseudo-second-order kinetic model with reaction rate in the order of AlCl₃ > CaCl₂ > NaCl at a higher initial TC loading level. The total amount of TC desorbed after five desorption cycles followed the order of AlCl₃ > CaCl₂ > NaCl, too, suggesting that cations with higher positive charges, thus, less hydrated, are preferred to remove adsorbed cationic drugs. The FTIR analyses showed larger band shift when Al³⁺ was used as the desorbing reagent. The XRD patterns before and after TC desorption revealed no changes in basal spacing, even after five desorption cycles, suggesting that the removal of TC from SAz-2 was largely from the external surfaces.     

Empirical and mechanistic evaluation of sodium exchange isotherms on natural mineral and organic adsorbents and organically functionalized nanoparticles

This study was conducted to evaluate the efficiency of low-cost adsorbents including bentonite, kaolinite and zeolite saturated with calcium and potassium, potato and wheat residues, and three metal oxide nanoparticles functionalized with an acidic extract of potato residues in improving the quality of sodic waters. The optimization of factors such as pH, contact time, and adsorbent dosage was investigated using a solution containing sodium, calcium, magnesium, and potassium. The optimal pH and contact time were 7.0 and 24 h, respectively. The optimal dosage for using functionalized nanoparticles was 0.1 g and for using other adsorbents was 1.0 g. The sodium exchange isotherms were conducted in binary sodium–calcium and sodium–potassium and quaternary sodium–calcium–magnesium–potassium systems. Zeolite saturated with potassium was the most effective adsorbent in removing sodium from aqueous solutions with an average removal efficiency of 69.2 and 66.5 % in binary and quaternary systems, respectively. Freundlich and Langmuir equations fitted well to experimental data in both binary and quaternary systems. Cation selectivity coefficients calculated based on the Gaines–Thomas convention varied with changing pH and adsorbent dosage. Graphical and statistical evaluations confirmed that the mechanistic cation exchange model using average Gaines–Thomas selectivity coefficients in geochemical PHREEQC program was able to successfully simulate the sodium exchange on different adsorbents in both systems. The Gaines–Thomas selectivity coefficient values greater than unity and as a consequence, the negative values of the Gibbs free energy change of adsorption indicated that sodium exchange reactions in the presence of different adsorbents used is this study were exergonic and spontaneous.     

Column experiments to investigate transport of colloidal humic acid through porous media during managed aquifer recharge

Colloids act as vectors for pollutants in groundwater, thereby creating a series of environmental problems. While managed aquifer recharge plays an important role in protecting groundwater resources and controlling land subsidence, it has a significant effect on the transport of colloids. In this study, particle size and zeta potential of colloidal humic acid (HA) have been measured to determine the effects of different hydrochemistry conditions. Column experiments were conducted to examine the effects on the transport of colloidal HA under varying conditions of pH (5, 7, 9), ionic strength (<0.0005, 0.02, 0.05 M), cation valence (Na⁺, Ca²⁺) and flow rate (0.1, 0.2, 0.4 ml/min) through collectors (glass beads) to model the properties and quality of artificial recharge water and changes in the hydrodynamic field. Breakthrough curves showed that the behavior of colloidal HA being transported varied depending on the conditions. Colloid transport was strongly influenced by hydrochemical and hydrodynamic conditions. With decreasing pH or increasing ionic strength, a decrease in the peak effluent concentration of colloidal HA and increase in deposition could be clearly seen. Comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca²⁺ than with monovalent Na⁺. Changes in hydrodynamic field (flow rate) also had an impact on transportation of colloidal HA. The results of this study highlight the need for further research in this area.     

Selective nickel and cobalt uptake from pressure sulfuric acid leach solutions using column resin sorption

Selective removal of Ni and Co, from a high pressure acid leach (HPAL) solution of a Brazilian laterite nickel ore that contains relatively high concentration of impurities, was carried out with an ion exchange chelating resin possessing iminodiacetic acid group (Amberlite IRC 748®). The resin was tested in column experiments. The experimental results showed that higher pH values improved the ion exchanger performance and higher nickel load capacities were achieved. Besides, increasing nickel concentration in solution, nickel uptake and selectivity were substantially improved. The breakthrough experimental curves also showed that many metals were immediately brokenthrough just after the initiation of the feed, while the breakthrough of Ni began later. These results suggested that it is feasible to purify HPAL solution recovering nickel selectively using the chelating resin Amberlite IRC748® if some specific conditions related to pH, flow rate and nickel concentration are applied. Removal of metals from the resin was successfully performed with HCl and H₂SO₄ solutions. Nickel was eluted concentrated more than 20 times its initial concentration in the feed solution, while only a trace amount of impurities was eluted.     

Determination of Free Nickel Ion Concentrations Using the Ion Exchange Technique: Application to Aqueous Mining and Municipal Effluents

Free metal ion concentration is generally considered a useful indicator of a metal’s bioavailability and ecotoxicity to aquatic biota. This article reports the speciation of nickel in mining and municipal effluents from Sudbury (Ontario, Canada), and also in model solutions containing a fully characterized laurentian fulvic acid (LFA) at environmentally relevant concentrations. A column ion exchange technique (IET) using a cation exchange resin (Dowex 50W-X8) was applied to determine free nickel ion concentrations. In model solutions, reasonable correlation was found between the predictions of an equilibrium-based computer speciation code, Windermere Humic Aqueous Model (WHAM) VI, and the results obtained by IET at low nickel-to-fulvic acid ratios. However at higher mole ratios, the WHAM VI predicted higher free nickel ion concentrations than IET. Only three out of six effluent samples showed reasonable agreement between the IET and the WHAM VI results, indicating the need for further development of IET for application to effluent waters.     

Sorption of Cd<Superscript>2+</Superscript> ions onto zeolite synthesized from perlite waste

In this work, the studies on the formation of zeolites from expanded perlite waste and their use in the sorption process of Cd²⁺ ions will be reported. Such approach is innovative and has not been investigated elsewhere. The results of the synthesis of zeolites from aluminosilicate waste using hydrothermal method were presented. By-product from the process production of expanded perlite was used as the starting material. Theoretical and practical aspects of Cd²⁺ ions sorption process onto material synthesized in selected conditions (a material with good sorption capacity can be obtained by 24 h reaction of 1 g of perlite waste in 10 mL of 4.0 M NaOH solution with at 70 °C) will be presented. The atomic absorption spectroscopy has been used as the main method, from which the effective cation exchange capacity as well as the proportion of ion exchange to chemisorption in the sorption process have been determined. Structural analyses of the sample before and after sorption process have been also carried out by the mid-infrared spectra measurement, especially pseudolattice range of the spectra was analyzed in detail in which changes caused by ion exchange of non-tetrahedral ions have been observed.     

Studies on the solid acidity of heated and cation-exchanged montmorillonite using n-butylamine titration in non-aqueous system and diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy

The effects of heating and cation exchange on the solid acidity of montmorillonite were investigated using n-butylamine titration in non-aqueous system and diffuse reflectance Fourier transform infrared spectroscopy. The number of total, Brønsted, and Lewis acid sites showed the same modulation tendency with increasing heating temperature, reaching a maximum at 120 °C and subsequently decreasing until it reaches a minimum at 600 °C. The Lewis acid sites result from unsaturated Al³⁺ cations, and their number increased with the heating temperature due to the dehydration and dehydroxylation of montmorillonite. The generation and evolution of Brønsted acidity were mainly related to interlayer-polarized water molecules. Water adsorbed on the unsaturated Al³⁺ ions also acted as a Brønsted acid. The acid strength of the Brønsted acid sites was dependent on the polarization ability of the exchangeable cation, the amount of interlayer water, and the degree of dissociation of the interlayer water coordinated to exchangeable cations. All cation-exchanged montmorillonites exhibited different numbers of acid sites and various distributions of acid strength. Brønsted acidity was predominant in Al³⁺-exchanged montmorillonite, whereas the Na⁺- and K⁺-exchanged montmorillonites showed predominantly Lewis acidity. Moreover, Mg²⁺- and Li⁺-exchanged montmorillonites exhibited approximately equal numbers of Brønsted and Lewis acid sites. The Brønsted acidity of cation-exchanged montmorillonite was positively correlated with the charge-to-radius ratios of the cations, whereas the Lewis acidity was highly dependent on the electronegativity of the cations. The acid strengths of Al³⁺- and Mg²⁺-exchanged montmorillonites were remarkably higher than those of monovalent cation-exchanged montmorillonites, showing the highest acid strength (H ₀ ≤ ?3.0). Li⁺- and Na⁺-exchanged montmorillonites exhibited an acid strength distribution of ?3.0 < H ₀ ≤ 4.8, with the acid strength ranging primarily from 1.5 to 3.3 in Li⁺-exchanged montmorillonite, whereas only weaker-strength acid sites (1.5 < H ₀ ≤ 4.8) were present in K⁺-exchanged montmorillonite. The results of the catalysis experiments indicated that montmorillonite promoted the thermal decomposition of the model organic. The catalytic activity showed a positive correlation with the solid acidity of montmorillonite and was affected by cation exchange, which occurs naturally in geological processes.     

Bioelectricity generation from brewery wastewater in a microbial fuel cell using chitosan/biodegradable copolymer membrane

Wastewater treatment with bioelectrical generation is an attractive feature with microbial fuel cells. The chitosan/biodegradable copolymer proton exchange membrane was used to assess its performance with brewery wastewater in a dual chambered microbial fuel cell. The biodegradable copolymer was made by thermal condensation of malic acid and citric acid in 3:1 ratio and then blended with chitosan to form a membrane via solution casting and solvent evaporation techniques. The performance of the chitosan/biodegradable copolymer membrane was evaluated in bioelectricity production with brewery effluent as an anolyte in a carbon electrode microbial fuel cell. Additionally, the competence of the prepared blend proton exchange membrane is compared with the commercial Nafion 117 membrane and Agar salt bridge in separate microbial fuel cell units with the same effluent and electrodes. At neutral pH, the effect of adding metabolites such as glucose and acetate to the anolyte was also investigated. The maximum current density and power density generated with chitosan/biodegradable copolymer membrane was 111.94 mA m^?2 and 3022.39 mW m^?2, respectively, whereas the Nafion 117 membrane had a maximum current density of 120.23 mA m^?2 and power density of 3486.73 mW m^?2.     

偶氮氯磷mA—溴化十六烷基吡啶光度法测定化探样品中钍

铀试剂Ⅲ光度法测定钍一般能满足岩石矿物分析要求,但对ppm级钍的化探样品的分析,由于试剂质量问题难以达到要求。偶氨氯膦Ⅲ虽然灵敏度较高,但需用有机溶剂萃取,且稀土和铀的干扰严     

Extraction of extracellular polymeric substances from activated sludge using sodium oxalate

In this study, sodium oxalate was employed to extract extracellular polymeric substances (EPS) from activated sludge samples. The optimum dose of sodium oxalate was 1.34 g/g VSS (volatile suspended solids), and the extraction time was 60 min at pH 7. The total EPS contents obtained under the optimized conditions were approximately 191 mg/g VSS, and they predominantly consisted of proteins, polysaccharides and humic substances. The extraction efficiencies of the chosen method for the major biopolymers were 39, 43 and 410 % higher compared with the ethylenediaminetetraacetic acid (EDTA), cation exchange resin and control methods. Cell lysis measured in terms of deoxyribonucleic acid, and unidentified EPS were approximately 50 % lower in the sodium oxalate method than in the NaOH and EDTA methods. The EPS composition and the ratio of proteins/polysaccharides (1.38–2.21) were extremely dependent on the operating conditions maintained during the extraction. The inductively coupled plasma spectroscopic results demonstrated that the release of divalent metals, such as Ca²⁺ and Mg²⁺, from the sludge matrix was directly correlated with higher EPS extraction efficiencies in the sodium oxalate protocol. Moreover, the precipitation of Ca²⁺ and Mg²⁺ as metallic oxalates disrupted the floc structure and subsequently enhanced the EPS recovery. Fourier transform infrared studies revealed the presence of functional groups due to EPS molecules in all extracted samples.     

Chemically induced fracturing in alkali feldspar

Fracturing in alkali feldspar during Na⁺–K⁺ cation exchange with a NaCl–KCl salt melt was studied experimentally. Due to a marked composition dependence of the lattice parameters of alkali feldspar, any composition gradient arising from cation exchange causes coherency stress. If this stress exceeds a critical level fracturing occurs. Experiments were performed on potassium-rich gem-quality alkali feldspars with polished (010) and (001) surfaces. When the feldspar was shifted toward more sodium-rich compositions over more than about 10 mole %, a system of parallel cracks with regular crack spacing formed. The cracks have a general (h0l) orientation and do not correspond to any of the feldspar cleavages. The cracks are rather oriented (sub)-perpendicular to the direction of maximum tensile stress. The critical stress needed to initiate fracturing is about 325 MPa. The critical stress intensity factor for the propagation of mode I cracks, K _Ic, is estimated as 2.30–2.72 MPa m^1/2 (73–86 MPa mm^1/2) from a systematic relation between characteristic crack spacing and coherency stress. An orientation mismatch of 18° between the crack normal and the direction of maximum tensile stress is ascribed to the anisotropy of the longitudinal elastic stiffness which has pronounced maxima in the crack plane and a minimum in the direction of the crack normal.     

Impact of Channel Deepening on Tidal and Gravitational Circulation in a Highly Engineered Estuarine Basin

Deepening of estuarine channels is a common practice to ensure navigation. Here, we investigate whether such deepening impacts physical processes such as the strength of the estuarine exchange flow, the horizontal salinity gradient, and tidal dynamics. We analyze recent and historical hydrodynamic observations in Newark Bay, New Jersey, to assess the effect of channel deepening on tides, circulation, and salinity. The Bay’s navigational channel has undergone significant deepening, from 3 to 10 m in the nineteenth century to ~16 m today. Observations presented here include sea-level data from the nineteenth, twentieth, and twenty-first century, and moored Doppler current data and bottom salinity measurements made over the past 20 years. Results show a doubling of the estuarine exchange flow, a slight increase in salinity and in the horizontal salinity gradient, a decrease in tidal current amplitude, and a spatially variable change in the tidal range. The doubling of the exchange flow is consistent with the Hansen and Rattray scaling provided that the horizontal salinity gradient is unable to fully adjust landward because the dredging is limited to a short reach of the estuary. However, uncertainty in channel depth leaves open the possibility that the exchange flow is also augmented by an increase in the horizontal salinity gradient and/or a reduction in vertical mixing. Nevertheless, results demonstrate that a relatively small (15%) increase in depth appears to have doubled the exchange flow. We believe that this result is relevant to other systems where dredging is limited to a short reach of an estuary.     

An easy and fast IC-CL procedure for the monitoring of Cu(II) and Co(II) in environmental samples

A luminol chemiluminescence (CL) detection/flow injection analysis technique coupled with ion chromatography (IC) has been employed for the determination of low levels of Cu(II) and Co(II) in drinking water samples. The detection system was the CL of luminol/perborate or luminol/percarbonate in alkaline medium catalyzed by these transition metals. Oxalic acid in a solution of KOH and N(CH₃)₄OH was used as an eluent in the IC to improve the column selectivity (Dionex CS5A). Concentration and pH of the eluent affected simultaneously the CL intensity and the retention times (t _R). Under the elution conditions used here, the retention times of both metal ions were much greater when the concentration of oxalic acid was decreased. Thus, R _t(_Cu) = 2.15 min and t _R(_Co) = 4.50 min were measured at 80 mM oxalic acid concentration, while t _R raised to 4.12 and 18 min for Cu(II) and Co(II), respectively, using a 10-mM concentration, but on the other hand, the CL signals showed substantially higher values when the concentration of oxalic acid was lesser in the eluent. An optimum oxalic acid concentration of 20 mM and an eluent pH = 4.7 were selected in order to have reproducible signals with a total analysis time of 10 min. The optimum flow rate for the mobile phase was 1.5 mL min^?1. The concentration and pH of the postcolumn reagents also affected the CL signal, obtaining optimum concentrations of 5 mM for both oxidants (perborate or percarbonate) and luminol, this last dissolved in a 0.1-M borate buffer at pH 12. The optimum flow rate for the postcolumn reagents was 1 mL min^?1. Linear calibrations for both transition metal ions were established, with calculated detection limits of 0.15 ng mL^?1 for Co(II) and 0.20 μg mL^?1 for Cu(II). Others ions commonly present in natural waters showed little or no interference. The method was successfully applied to water samples spiked with Cu(II) and Co(II), obtaining recoveries in the range of 85–128%, depending on the metal concentrations.     

Effects of sheet flow rate and slope gradient on sediment load

Sheet erosion is known as one of the most important forms of erosion, particularly in agricultural land. The purpose of this study was to investigate the effect of flow rate and slope gradient on runoff and sediment discharges in two different soils. Experiments were conducted using a tilting flume facility with the test area of 0.2?×?1.0 m. Overall, 24 experiments on two soils (clay loam and sandy clay loam textures) including six flow rates (75, 100, 125, 150, 175, and 200 ml/s) and two slope gradients (1.5 and 2 %) were performed. The selected flow rates and flume slopes were generated to simulate sheet erosion. The results showed that for both soils and slopes, unit flow discharge (q) and sediment concentration increased with increasing flow rate; however, the effect of slope gradient on flow discharge depends on soil type. In addition, sandy clay loam exhibited higher values of q and sediment concentration and consequently, it showed greater amounts of sediment load. At the start of event, sediment concentration was high but it decreased to approach a steady state. In addition, the time needed to reach a steady state condition was shorter for sandy clay loam than that for clay loam soil and in lower flow rates than higher flow rates. For each soil and slope, there was a direct relationship between sediment load and flow rate. The result implied that the effect of slope gradient on sediment load was almost greater in sandy clay loam soil than clay loam soil. Moreover, the differences between sediment loads of two soils are enlarged at slope 2 %.     

Effect of grain growth on cation exchange between dunite and fluid: implications for chemical homogenization in the upper mantle

The effect of grain growth on the cation exchange between synthesized forsterite aggregates (i.e., dunite) and nickel-rich aqueous fluid was evaluated experimentally at 1.2 GPa and 1,200°C. The grain boundary (GB) migration caused nickel enrichment in the area swept by the GBs in a fashion similar to that reported for stable isotope exchange in the quartz aggregates. The progress of the grain growth resulted in an increase in the average nickel concentration in the dunites of up to ~80 times that was calculated for a system having stationary GBs. The overall diffusivity of the nickel along the wet GBs and interconnected fluid networks was found to be 6.5 × 10⁻¹⁹–6.7 × 10⁻¹⁸ m³/s, which is 4–5 orders of magnitude higher than the grain boundary diffusivity in the dry dunite. These results show that the grain growth rate is a fundamental factor in the evaluation of the time scale of chemical homogenization in the upper mantle.     

Assessment of chemical properties and hydro-geochemical coefficients at the Qareh Sou Basin,Golestan Province,Iran

This paper focuses on the Qareh Sou Basin in Golestan Province, Iran. Golestan Province is the third largest cereal producer in Iran and water scarcity and salinity are major problems in this area. This study attempts to facilitate the comprehension of system behavior with respect to water quality issues and hydro-geochemical coefficients within the Qareh Sou Basin. This study was carried out during the year 2010. Various parameters, such as pH, EC, chloride, sulfate, bicarbonate, sodium, potassium, calcium and magnesium have been determined for evaluation purposes. Then, Ca/Mg, Na/Cl, Mg/(Ca + Mg), Ca/HCO₃, (Ca + Mg)–(HCO₃ + SO₄), (Na + K)–Cl, (Ca + Mg + Na + K)–Cl, HCO₃ + SO₄, Ca + Mg and chloro-alkaline indices (CAI) were calculated. Results show that cation exchange probably is an important factor in the hydrochemistry and silicate mineral weathering. Also, CAI-1 plot against CAI-2 demonstrates that most of samples have positive values which suggest normal ion exchange in the system. The carbonic acid is the main agent of calcite, limestone and dolomite weathering which occurs in some stations. According to Chadha’s diagram, the type of water is determined as Ca–Mg–HCO₃.     

Treatment of vinasse by electrochemical oxidation: evaluating the performance of boron-doped diamond (BDD)-based and dimensionally stable anodes (DSAs)

The removal of colour and organic compounds from vinasses derived from the wine distillery industry was studied using boron-doped diamond-based electrodes and dimensionally stable anodes. The maximum reduction of organic compounds and colour was attained with the use of boron-doped diamond-based electrode after 10 h of operation at a current density of 6.6 mA cm^?2. The current efficiency obtained was about 90% with a specific energy consumption (measured in terms of removal of chemical oxygen demand) of 17 kWh kg^?1 COD removed. The dimensionally stable anodes were capable of removing 6–47% of the organic material and reached 60% decolourisation but with a lower current efficiency (between 85 and 10%) and much higher specific energy consumption values. The anaerobic digestion of vinasse after 1 h of treatment using boron-doped diamond-based electrode showed an effective mineralisation of the organic matter contained in the sample leading to an increase in methane production during anaerobic digestion.     

Utilization of palm oil mill effluent for polyhydroxyalkanoate production and nutrient removal using statistical design

The optimization for poly-β-hydroxyalkanoate production was carried out with nutrient removal efficiency for total organic carbon (TOC), phosphate, and nitrate from palm oil mill effluent waste. The experiment was conducted in a fabricated fed-batch reactor and the data obtained was analyzed using central composite rotatable design and factorial design for response surface methodology as a systematic approach for designing the experiment statistically to obtain valid results with minimum effort, time, and resources. The analysis of numerical optimization with propagation of error showed that 66 % of poly-β-hydroxyalkanoate production can be obtained with nutrient removal of TOC and nitrate by 19 and 3 %, respectively. However, phosphate removal efficiency was not found to be much effective. More over, the chemical oxygen demand: nitrogen phosphate (509 g/g N), chemical oxygen demand: phosphate (200 g/g P), air flow rate (0.59 L/min), substrate feeding rate (20 mL/min), and cycle length (20 h) were the optimized variables for maximum poly-β-hydroxyalkanoate production and nutrient removal.