Biomass In Reactor Research Articles

Simulation of Reaction Kinetics and Heat Transfer Effects on Product Yields from Fast Pyrolysis of Oil Palm Empty Fruit Bunch Biomass in Fluidized Bed Reactor

The present work aims to optimize the operating conditions for biofuel production from fast pyrolysis of oil palm empty fruit bunch (OPEFB) biomass in a fluidized bed reactor. The coupled model of global reaction kinetics and heat transfer was applied to investigate the effects of operating conditions (reaction temperature in the range of 748–798 K, vapor residence time in the range of 0.5–2 s, and particle size in the range of 150–500 μm) on the yields of products (liquid (bio-oil), gas, and char) and particle heat transfer of the OPEFB biomass fast pyrolysis. The simulation results of the present model validated the reported experimental data of the product yields of OPEFB biomass fast pyrolysis. The results showed that the maximum yield of high-quality liquid product was obtained at a vapor residence time of 1 s and a reaction temperature of 773 K. Moreover, the OPEFB particle size in the range of 300–350 μm gave the highest yield of liquid product and the good heat transfer of particles. The optimum operating conditions from the simulation of the coupled model can be utilized for the experimental work of fast pyrolysis for different kinds of biomass in a fluidized bed reactor.

Thermal loss analysis and improvements for biomass conversion reactors

The published torrefaction design analysis either ignore thermal loss or assume a generic value in their characterization of biomass thermochemical reactors. This study, using a small-scale biomass reactor prototype for torrefaction as an example, demonstrates a low-cost but scientifically rigorous way to measure thermal losses, and proposes a mathematical description to fit with the measurements. Losses from reactor side walls and losses from char-cooling segment were characterized and analyzed separately using total solid energy flux as a basis. The thermal dissipation for both reactor side walls and char-cooling segment depended primarily on solid residence time, and hence minimizing the solid residence time was proposed as a process improvement. The other improvement tested was using heat from the char-cooling segment to preheat the air fed to the reactor. For the considered torrefaction reactor, the char-cooling segment length of 0.5 m combined with an outer jacket width of 0.01 m, ensured faster cooling of char product and lower temperature gradient in the bed, therefore, resulting in 75% savings in energy loss compared to the default design case without air pre-heating in place. The presented mathematical analysis with some experimental measurements not only quantified the thermal losses but also helped to identify improvements to the torrefaction reactor design to optimize their key parameters for scaling.

Experimental study on fluidization, mixing and separation characteristics of binary mixtures of particles in a cold fluidized bed for biomass fast pyrolysis

To guarantee the uniform mixing of biomass and inert particles in the fluidized bed reactor for the full and complete reaction during the biomass fast pyrolysis process, a visualized cold fluidized bed experimental apparatus was set up to investigate the effects of static bed height, moisture content and particle diameter on the fluidization quality of single component particles, and the mixed volume ratio on the fluidization characteristics of binary mixtures. The results showed that the appropriate static bed height was significant for the stability of the fluidized bed. As the moisture content increased, the minimum fluidization velocity increased rapidly while the fluidization index continued to decrease. In addition, the fluidization performed on binary mixtures of larch/quartz sand-2 indicated that the same minimum fluidization velocity was the key parameter for the two kinds of particles to be fully fluidized simultaneously, avoiding the semi-fluidization phenomenon. The mixed volume ratio of larch (M = 10.3%)/quartz sand-2 and superficial gas velocity range were also the important factors affecting fluidization and mixing quality, and the optimal value were 1: 3 and 3–5 umf, respectively.

Microbial Community Redundancy and Resilience Underpins High-Rate Anaerobic Treatment of Dairy-Processing Wastewater at Ambient Temperatures.

High-rate anaerobic digestion (AD) is a reliable, efficient process to treat wastewaters and is often operated at temperatures exceeding 30°C, involving energy consumption of biogas in temperate regions, where wastewaters are often discharged at variable temperatures generally below 20°C. High-rate ambient temperature AD, without temperature control, is an economically attractive alternative that has been proven to be feasible at laboratory-scale. In this study, an ambient temperature pilot scale anaerobic reactor (2 m3) was employed to treat real dairy wastewater in situ at a milk processing plant, at organic loading rates of 1.3 ± 0.6 to 10.6 ± 3.7 kg COD/m3/day and hydraulic retention times (HRT) ranging from 36 to 6 h. Consistent high levels of COD removal efficiencies, ranging from 50 to 70% for total COD removal and 70 to 84% for soluble COD removal, were achieved during the trial. Within the reactor biomass, stable active archaeal populations were observed, consisting mainly of Methanothrix (previously Methanosaeta) species, which represented up to 47% of the relative abundant active species in the reactor. The decrease in HRT, combined with increases in the loading rate had a clear effect on shaping the structure and composition of the bacterial fraction of the microbial community, however, without affecting reactor performance. On the other hand, perturbances in influent pH had a strong impact, especially when pH went higher than 8.5, inducing shifts in the microbial community composition and, in some cases, affecting negatively the performance of the reactor in terms of COD removal and biogas methane content. For example, the main pH shock led to a drop in the methane content to 15%, COD removals decreased to 0%, while the archaeal population decreased to ~11% both at DNA and cDNA levels. Functional redundancy in the microbial community underpinned stable reactor performance and rapid reactor recovery after perturbations.

Thermal Degradation Kinetics and FT-IR Analysis on the Pyrolysis of Pinus pseudostrobus, Pinus leiophylla and Pinus montezumae as Forest Waste in Western Mexico

For the first time, a study has been carried out on the pyrolysis of wood residues from Pinus pseudostrobus, Pinus leiophylla and Pinus montezumae, from an area in Western México using TGA analysis to determine the main kinetic parameters (Ea and Z) at different heating rates in a N2 atmosphere. The samples were heated from 25 °C to 800 °C with six different heating rates 5–30 °C min−1. The Ea, was calculated using different widely known mathematical models such as Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose. The Ea value of 126.58, 123.22 and 112.72 kJ/mol (P. pseudostrobus), 146.15, 143.24 and 132.76 kJ/mol (P. leiophylla) and 148.12, 151.8 and 141.25 kJ/mol (P. montezumae) respectively, was found for each method. A variation in Ea with respect to conversion was observed with the three models used, revealing that pyrolysis of pines progresses through more complex, multi-stage kinetics. FT-IR spectroscopy was conducted to determine the functional groups present in the three species of conifers. This research will allow future decisions to be made, and possibly, to carry out this process in a biomass reactor and therefore the production of H2 for the generation of energy through a fuel cell.

Using sequentially coupled UV/H2O2-biologic systems to treat industrial wastewater with high carbon and nitrogen contents

This study evaluated the performance of a sequentially coupled UV/H2O2-anoxic system to treat industrial wastewater (IWW). Initial IWW characterization showed a high chemical oxygen demand (COD) load (13,261 mg L−1, 6,880 mg L−1 of total organic carbon (TOC), 569 mg L−1 of total nitrogen (TN), and an alkaline pH (9.1 ± 1.51). Using advanced oxidation processes (AOPs), removal efficiencies of 49.4 % of COD and 85 % of total organic carbon (TOC) were achieved after 60 min of UV-C irradiation (82 W m−2) using a H2O2/COD ratio of 0.78:1. Under these conditions, a 50 % transformation of TN into nitrites and nitrates (NO2+NO3)-N was also observed. After the AOP, the partially treated IWW was mixed with municipal wastewater (MWW) at ratio of 1:10, based on toxicity test results, and then used as the influent of the biological process. The biological process consisted of anoxic suspended and attached biomass coupled sequentially after the UV/H2O2 system. Both biological systems (attached and suspended biomass reactors) efficiently removed (NO2+NO3)-N, achieving 85 % removal of TN, 41.8 % removal of TOC, and 49.2 % removal of COD and denitrification process was found to occur after the AOP through the biological systems. In addition, pH values ranging from 6 to 7.6 were observed after the biological treatment, which suggests that the resulting effluent could be treated using conventional water treatment.

Ex Situ Catalytic Pyrolysis of Algal Biomass in a Double Microfixed-Bed Reactor: Catalyst Deactivation and Its Coking Behavior

The catalytic fast pyrolysis (CFP) of algal biomass was conducted in a newly developed double microfixed-bed reactor. Real-time measurements of catalytic vapors as a function of the cumulative biom...

Enzyme response of activated sludge to a mixture of emerging contaminants in continuous exposure.

The relevant information about the impacts caused by presence of emerging pollutants in mixtures on the ecological environment, especially on the more vulnerable compartments such as activated sludge (AS) is relatively limited. This study investigated the effect of ibuprofen (IBU) and triclosan (TCS), alone and in combination to the performance and enzymatic activity of AS bacterial community. The assays were carried out in a pilot AS reactor operating for two-weeks under continuous dosage of pollutants. The microbial activity was tracked by measuring oxygen uptake rate, esterase activity, oxidative stress and antioxidant enzyme activities. It was found that IBU and TCS had no acute toxic effects on reactor biomass concentration. TCS led to significant decrease of COD removal efficiency, which dropped from 90% to 35%. Continuous exposure to IBU, TCS and their mixtures increased the activities of glutathione s-transferase (GST) and esterase as a response to oxidative damage. A high increase in GST activity was associated with non-reversible toxic damage while peaks of esterase activity combined with moderate GST increase were attributed to an adaptive response.

Performance and microbial community analysis of two sludge type reactors in achieving mainstream deammonification with hydrazine addition

The deammonification process is a promising and energy efficient nitrogen removal technology. Since deammonification process has succeeded in high-strength ammonia nitrogen wastewater treatment (sidestream deammonification) but its application in treating low-strength ammonium nitrogen wastewater (mainstream deammonification) remains a great challenge. In this study, mainstream deammonification process in two reactors maintained stability with hydrazine (N2H4) addition. The two reactors consisted of a deammonification granular reactor and a mixed ammonia oxidizing bacteria (AOB) flocculent with anaerobic ammonia oxidizing bacteria (AnAOB) granular reactor. Deammonification granular reactor had a more efficient total nitrogen removal efficiency (TNRE, 80.5 ± 5.8%) and nitrogen removal rate (NRR, 0.33 ± 0.04 g/(L·day)). The advantage of retain biomass in granular sludge reactor lead to a more balanced ex-situ activity between AOB (0.37 mg N/(g VSS·h)) and AnAOB (0.43 mg N/(g VSS·h)). Candidatus Brocadia and Nitraspira were detected the dominant genus responsible for the observed AnAOB and nitrite oxidizing bacteria (NOB), respectively. The more obvious effect of N2H4 on enhancing AnAOB and suppressing NOB both in ex-situ activity and genus abundances in mixed sludge reactor were also founded may due to loose spatial distribution among species.

Development of Biomass Gasification Technology with Fluidized-Bed Reactors for Enhancing Hydrogen Generation: Part I, Hydrodynamic Characterization of Dual Fluidized-Bed Gasifiers

Various means for enhancing hydrogen content in the syngas from gasification of solid biomass in fluidized-bed reactors were investigated in this study. Steam or oxygen-rich gas can be supplied as gasification medium, to improve the syngas characteristics. Alternatively, a so-called “indirect gasification technology” realizes the thermo-chemical conversion processes in dual reactors, respectively, for combustion and gasification, where gaseous streams in between are separated while solid materials are circulated through. Hence, with air as oxidant for combustion this system features the advantage of producing nearly nitrogen-free syngas. Baseline experiments were firstly carried out to identify performance features; then, parametric studies were conducted and positive trends for enhancing hydrogen generation via biomass gasification were revealed. Moreover, hydrodynamic characteristics in dual reactors were comprehensively envisaged in the cold-flow models to facilitate subsequent investigation into thermo-chemical processes. The experimental results indicated that the circulation mass of the bed material driven by the operating air exceeded the design value, which gave a comfortable safety factor of the engineering design. In addition, the average pressure distribution measured by the cyclic operation of the system was similar to that of the published literature. Based on the experimental results of the cold model, the suggestions of the operating tests in the hot model were addressed. Further efforts will be pursued to establish databases for clean energy and carbon abatement technologies.

Temperature Effects on Methanogenesis and Sulfidogenesis during Anaerobic Digestion of Sulfur-Rich Macroalgal Biomass in Sequencing Batch Reactors.

Methanogenesis and sulfidogenesis, the major microbial reduction reactions occurring in the anaerobic digestion (AD) process, compete for common substrates. Therefore, the balance between methanogenic and sulfidogenic activities is important for efficient biogas production. In this study, changes in methanogenic and sulfidogenic performances in response to changes in organic loading rate (OLR) were examined in two digesters treating sulfur-rich macroalgal waste under mesophilic and thermophilic conditions, respectively. Both methanogenesis and sulfidogenesis were largely suppressed under thermophilic relative to mesophilic conditions, regardless of OLR. However, the suppressive effect was even more significant for sulfidogenesis, which may suggest an option for H2S control. The reactor microbial communities developed totally differently according to reactor temperature, with the abundance of both methanogens and sulfate-reducing bacteria being significantly higher under mesophilic conditions. In both reactors, sulfidogenic activity increased with increasing OLR. The findings of this study help to understand how temperature affects sulfidogenesis and methanogenesis during AD.

Comparison of suspended and granular cell anaerobic bioreactors for hydrogen production from acid agave bagasse hydrolyzates

Acid agave bagasse hydrolyzates have been used as a substrate for hydrogen production, however, bioreactors are unstable and with poor performance. Granular biomass could be more successful in producing hydrogen from acid agave bagasse hydrolyzates in comparison with suspended biomass. Thus, this study aimed to evaluate the effect of increasing concentrations of acid agave hydrolyzates on hydrogen production, to compare the hydrogen productivity and stability of granular biomass in an expanded granular sludge bed (EGSB) reactor and suspended biomass in an anaerobic sequencing batch reactor (AnSBR) fed with acid hydrolyzates, and finally to determine the variation of microbial communities established in both bioreactor configurations. In batch tests, the heat-treated inoculum produced hydrogen from acid agave hydrolyzates without observing inhibition at 6.3 g/L of carbohydrates (CHO). This hydrolyzate concentration was used to start up the AnBSR, which reached a productivity of 226 ± 53 mL H2/L⋅d at organic loading rates (OLR) from 3.2 to 4.5 gCHO/L⋅d. The hydrogen production stability index decreased from 0.8 to 0.6 at increasing OLR, and the AnSBR failed at the highest OLR of 5.7 g/L⋅d. The EGSB reactor reached the highest productivity of 361 ± 130 mL H2/L⋅d at an OLR of 7.4 gCHO/L⋅d, but with a low stability index of 0.6. Independently of the bioreactor configuration, microbial communities associated with the production of acetate/lactate were successfully established in both configurations with the prevalence of Lactobacillus spp. A low abundance of typical H2 producers like Clostridium was always observed over the whole period of operation (<10% of the total abundance). In sum, the hydrogen productivity from acid agave hydrolyzates was higher for the EGSB reactor than for the AnSBR, but with much lower stability. The evidence provided by this study suggests the establishment of metabolic pathways for hydrogen production from organic acids.

Effect of the temperature on the spent coffee grounds torrefaction process in a continuous pilot-scale reactor

Several studies in Literature have analyzed the torrefaction treatment process of biomass in batch reactors. Nevertheless, in order to check the industrial applicability of a process, it is more interesting to carry out torrefaction tests in continuous pilot plant reactors. Thus, the present study reports the results of continuous semi-industrial scale (500 kg/h) torrefaction experiments employing spent coffee grounds (SCG) as a feedstock in a horizontal rotary reactor. Torrefaction tests were carried out at three different temperatures (210 °C, 235 °C, and 260 °C) for 90 min, in order to evaluate the yields of solid, liquid (water and tar) and gaseous products and their composition. In particular, the effectiveness of the decarbonization and deoxygenation processes was investigated, analyzing the carbon and oxygen distribution. Within the temperature range, torrefaction yielded solid of 55.2–85.8 wt% with an increase of the higher heating value (HHV) of 5.1–15.4% compared to the raw material. Liquid fraction yield was in the range of 11.3–34.3 wt%, with a moisture content of 73.7–91.9% and HHV between 18.8 and 23.4 MJ/kg on dry basis. Gas fraction represented 2.9–10.5 wt% of the raw biomass withHHVbetween 1.95 and 3.55 MJ/Nm3. Acids (mainly acetic acid) were the major compounds in the tar fraction, accounted up to 68 wt%, while CO2 was the main product of the deoxygenation reactions in the gaseous fraction (76.6–86.9 vol%). From the perspective of mass yield and energy density enhancement, 260 °C was considered to be the optimal temperature for torrefaction of SCG.

Numerical investigation of in situ gasification chemical looping combustion of biomass in a fluidized bed reactor

In-situ gasification chemical looping combustion (iG-CLC) depends on the solid fuel gasification rate and the contact between gasification products and oxygen carriers. In this work, a three-dimensional simulation is carried out to investigate the iG-CLC performance of biomass in a fluidized bed reactor by means of the multi-fluid model with the bubble-based bi-disperse drag model to consider the bubble effect on the interphase drag force. The model can give a reasonable prediction on the experimental results. The result reveals that an increase of operating pressure of 0.2 MPa can promote the CO2 yield by 5%, whereas the change of the feed port height from the reactor bottom also greatly influences the outlet gas compositions.

Reactor Performance and Morphology of Aerobic Sludge Biomass in the Presence and Absence of Ni(II) Ion in Feed

Heavy metals are frequently encountered in domestic wastewaters (sources being the usage of paints, batteries, electronic goods, etc.). It can get carried away by storm water through municipal sewer systems to the domestic wastewater treatment plants and affecting the biomass. The present work aims to study the impact of nickel [Ni(II)] ion on settling characteristics, metabolic activity and morphology of aerobic sludge biomass in sequential batch reactors (SBRs) in addition to reactor performance. Four SBRs, namely RNi0 (control), RNi5, RNi25 and RNi75, with different concentrations of Ni(II) (0, 5, 25 and 75 mg/L, respectively) in the feed are studied to investigate its impact on aerobic sludge biomass. Reactors are operated in a sequential batch mode with a cycle time of 12 h. At the start of the stressed phase of operation, i.e., the presence of Ni(II) in feed, the COD removal of reactors RNi25 and RNi75 is deteriorated to as low as 50 and 30%, respectively. Settling velocity and compactness of aerobic biomass in the reactors with Ni(II) in feed improved as compared to control. In the recovery phase of operations, when Ni(II) is absent in feed, the reactors show stable performance with nearly 80% COD removal for all the reactors. Notable changes are observed in aerobic biomass morphology and in biomass activity for all the reactors in stressed as well as recovery phases of operations. This study presents results of extensive investigation of aerobic sludge biomass subjected to stressed phase of operation with Ni(II) in the feed and subsequent recovery phase operation with feed without Ni(II).

Mild hydrothermal treatment on microalgal biomass in batch reactors for lipids hydrolysis and solvent-free extraction to produce biodiesel

Mild hydrothermal treatment (245 °C) was used to break microalgal cell walls for lipids hydrolysis and solvent-free extraction in batch reactors to obtain biocrude for biodiesel production. Microalgal biocrude obtained through hydrothermal treatment for 10 min had the highest heating value (33.83 MJ/kg), the highest carbon and hydrogen contents (69.63% and 9.39%), and the lowest nitrogen content (3.56%). Fourier transform infrared spectroscopy showed that microalgal biocrude had increased long-chain alkane peaks and disappeared carbohydrate peaks compared to the original microalgal biomass. Thermogravimetric analysis implied that triglycerides in microalgal biomass were hydrolyzed into fatty acids through hydrothermal treatment, while fatty acids and protein hydrolysates reacted to produce amides with higher boiling points. After 10 min subcritical hydrothermal treatment with microalgal solid concentration of 5% at 245 °C and esterification reactions (100 °C)with methanol and H2SO4 catalysts, the solvent-free lipids extraction efficiency was improved from 69.9% (260 °C) to 95.0 wt% without losing the valuable unsaturated fatty acids in microalgae cells. The resulted main compositions of C16:0, C16:1 and C20:5 in microalgal biodiesel reached the highest of 22.7%, 24.1% and 16.2% (based on total lipids in microalgae), much higher than those lipids obtained from 260 °C treatment (C20:5 = 6.1%).

Experimental investigation on sorption enhanced gasification (SEG) of biomass in a fluidized bed reactor for producing a tailored syngas

Synthetic fuel production from renewable energy sources like biomass is gaining importance driven by the ambitious targets for reducing greenhouse gas emissions worldwide. Sorption enhanced gasification (SEG) proposes carrying out the gasification of biomass in the presence of a CO2 sorbent, which allows producing a syngas with a suitable composition for a subsequent synthetic fuel production step. This study aims at analysing the effect of different operating parameters (e.g. steam-to-carbon (S/C) ratio, CO2 sorption capacity and sorbent-to-biomass ratio) in the syngas composition and char conversion obtained in a 30 kWth bubbling fluidized bed gasifier, using grape seeds as feedstock. The importance of reducing the formation of higher hydrocarbons through a high steam-to-carbon ratio and using a CO2 sorbent with high sorption capacity is assessed. C3-C4 and unsaturated C2 hydrocarbons contents below 1%vol. (in dry and N2 free basis) can be achieved when working with S/C ratios of 1.5 at gasification temperatures from 700 to 740 °C. Varying the amount of the CO2 separated in the gasifier (by modifying the temperature or the CO2 sorption capacity of the sorbent) the content of H2, CO and CO2 in the syngas produced can be greatly modified, resulting in a module M = (H2-CO2)/(CO + CO2) that ranges from 1.2 to almost 3.

Augmentation of Granular Anaerobic Sludge with Algalytic Bacteria Enhances Methane Production from Microalgal Biomass

The efficiency of anaerobic digestion relies upon activity of the inoculum converting organic substrate into biogas. Often, metabolic capacity of the inoculum needs to be augmented with new capabilities to accommodate changes in the substrate feed composition. However, bioaugmentation is not a widely used strategy possibly due to the lack of studies demonstrating successful applications. This study describes the bioaugmentation of granular anaerobic sludge digesting mixed algal biomass in batch-scale reactors. The addition of an algalytic bacterial mixture to the granular consortium increased methane yield by 11%. This study also investigated changes in the microbial 16SrRNA composition of the augmented and non-augmented granular inoculum, which demonstrates a significant change in the hydrolytic microbial community. Overall, the studies’ results aim to provide a feasible checklist to assess the success rates of bioaugmentation of anaerobic digestion applications.

Experimental and numerical study of a directly irradiated hybrid solar/combustion spouted bed reactor for continuous steam gasification of biomass

The concept of hybrid solar gasifiers is proposed to couple autothermal gasification with solar gasification so as to meet the requirement for stable and continuous operation under intermittent or fluctuating solar irradiation. Solar process hybridization through partial oxy-combustion of the feedstock appears to be crucial because thermochemical processes are very sensitive to small solar energy input variations, and require permanent control of thermodynamic conditions to ensure fuel production quality. This work aims to study solar-hybridized steam gasification of biomass in a novel directly-irradiated lab-scale reactor based on the principle of conical jet spouted beds. This concept was first numerically simulated to thoroughly analyze the reactor operation and to provide insights into the temperature distribution, fluid flow dynamics, reactive particle trajectories/conversion, gas species distribution and flame location inside the reactor. A two-phase flow model was developed including discrete phase model for the reactive biomass particles undergoing both combustion and pyro-gasification, and coupled heat and mass transfer. Thereafter, solar-only and mixed solar-combustion experiments were carried out under real concentrated solar flux and the effects of process hybridization on syngas yield and reactor performance were investigated. The results confirmed that O2 feeding rate is a relevant variable to control the process temperature. Accordingly, a continuous operation of the solar reactor can be ensured with variable solar energy input.

Pentachlorophenol biodegradation in two-phase bioreactors operated with absorptive polymers: Box-Behnken experimental design and optimization by response surface methodology

The biodegradation of pentachlorophenol (PCP), the most toxic among chlorophenols, was extensively investigated in solid-liquid two-phase bioreactors (according to Box-Behnken experimental design) to demonstrate the feasibility of this technological platform. Process performance optimization for the subsequent scale up was also performed. The process was catalysed by an acclimated microbial consortium and the partitioning phase consisted of Hytrel 8206 polymer. The virtuous combination of polymer uptake/release and microbial biodegradation allowed achieving practically complete biodegradation efficiencies and rates in the range of 4.0–7.8mg/(L h) for PCP concentrations up to 100mg/L far above those previously tested. Detected biodegradation rates are one order of magnitude higher than the ones reported for suspended biomass reactors. A regression model based on 3 independent variables (initial PCP and biomass concentration and polymer-to-water ratio) was formulated to predict the volumetric biodegradation rate. The significance of independent variables and their interactions was tested by the analysis of variance (ANOVA) with 95% confidence limit. The model resulted adequate and the polymer-to-water ratio was identified as the most significant factor affecting the system response. Maximization of the biodegradation rate has been achieved for PCP concentration of 100mg/L, biomass concentration of 1 gVSS/L and polymer-to-water ratio of 9%.