Soluble Microbial Products Fractions Research Articles

Municipal wastewater treatment and fouling in microalgal-activated sludge membrane bioreactor: Cultivation in raw and treated wastewater

Since the advent of conventional activated sludge biological treatment plants, their low efficiency in nitrogen and phosphorus removal has become a significant concern. Therefore, in this study, the performance of microalgal-activated sludge membrane bioreactor (MAS-MBR) as a self-biological treatment or as a post-treatment for conventional biological treatments was investigated. A continuous MAS-MBR with two ratios of algae/sludge (only microalgae and 5:1) was used to treat raw and treated wastewater. The optimum case was achieved with the cultivation of mixed algae/sludge in raw wastewater (R2 case). In this case, the ammonium and phosphorus removal efficiencies were 94.36 ± 3.5 and 88.37 ± 3 %, respectively. Furthermore, the highest oxygen production rate (OPR) and oxygen uptake rate (OUR) values were obtained in this case (145.58 ± 3 and 68.43 ± 1.5 mgO2/lit.d, respectively). In addition, membrane fouling was adversely increased in R2 compared with other cases, indicating the necessity of membrane cleaning for high-performance bioreactors in nutrient removal. Transmembrane pressure (TMP) jump in R2 was captured after 14 days, while the results supported that the membrane fouling was influenced by raised production of carbohydrate fraction of soluble microbial products (SMPc) and protein fraction of extracellular polymeric substances (EPSp) at first and last stages, respectively. Therefore, although the MAS-MBR is a potential candidate as a self-biological treatment, the membrane fouling is high in this case.

Effects of temperature shocks on the formation and characteristics of soluble microbial products in an aerobic activated sludge system

The present study investigated the impacts of temperature shocks on the generation of soluble microbial products (SMPs) in an aerobic activated sludge system, focusing on biopolymers and low molecular weight (LMW) substances that significantly impact the effluent quality. The results indicated that raising the temperature increased SMP production. At 25 and 35 °C, all size fractions of SMPs increased linearly with the aeration time, and biopolymers comprised a large proportion of SMPs. At 5 and 15 °C, in contrast, only biopolymers increased linearly with the aeration time, and LMW substances were the predominant fraction of SMPs. The reduced bio-utilization of SMPs with an increase in temperature was associated with the decreased relative abundance of LMW substances, which is supported by the assimilable organic carbon bioassay measurements. The mass of the biopolymers for the SMPs and extracellular polymeric substances (EPS) was balanced at all temperatures, wherein a negative correlation was observed, indicating that increased SMPs in the water phase led to a decrease in EPS. The results of the reactive oxygen species (ROS) and toxicity assays confirmed that the immune defense reaction of the bacteria (induced by ROS) was the key factor for variations in LMW substances in the SMPs and EPS under temperature stresses.

Quantifying the Effect of COD to TN Ratio, DO Concentration and Temperature on Filamentous Microorganisms’ Population and Trans-Membrane Pressure (TMP) in Membrane Bio-Reactors (MBR)

Using moderate populations of filaments in the biomass of Membrane Bio-Reactors (MBRs) is a biological anti-fouling method which has been increasingly applied over the last few years. This study aims to quantify the effect of COD to TN ratio, Dissolved Oxygen (DO) concentration and temperature on filaments’ population and Trans-Membrane Pressure (TMP) in a pilot-scale MBR, with a view to reducing membrane fouling. The novelty of the present work concerns the development of a mathematical equation that correlates fouling rate (dTMP/dt) with the population of filamentous microorganisms, assessed by the Filament Index (FI), and with the concentration of the carbohydrate fraction of Soluble Microbial Products (SMPc). Apart from TMP and SMPc, other fouling-related biomass characteristics, such as sludge filterability and settleability, were also examined. It was shown that at high COD to TN ratio (10:1), low DO concentration in the filaments’ tank (0.5 ± 0.3 mg/L) and high temperature (24–30 °C), a moderate population of filaments is developed (FI = 1–2), which delays the TMP rise. Under these conditions, sludge filterability and settleability were also enhanced. Finally, TMP data analysis showed that the fouling rate is affected by FI and SMPc concentration mainly in the long-term fouling stage and increases exponentially with their increase.

The Use of Natural Minerals in a Pilot-Scale MBR for Membrane Fouling Mitigation

This study examines the effect of bentonite and zeolite concentration (0.25–5 g/L) on the membrane fouling of a fully automated, pilot-scale membrane bioreactor (MBR) treating high-strength synthetic municipal wastewater. Reversible fouling was estimated by sludge filterability measurements and irreversible fouling was estimated by the reduction of the carbohydrate fraction of soluble microbial products (SMPc), which are considered to be significant MBR foulants. Both minerals were added to biomass samples (during batch-mode experiments) which were obtained from the system’s aeration tank. Results showed that the optimal bentonite and zeolite concentrations were 3.5–4 g/L and 2.5–3.5 g/L, respectively. Interestingly, above these values, the addition of both minerals increased the examined fouling indices, i.e., the measured filterability times and the SMPc concentration, implying that they might act as foulants at high concentrations. Optical microscopy images of the biomass samples showed that the addition of minerals at the optimal concentrations did not affect significantly filamentous microorganisms, since filament index (FI) was practically unaffected (~2). Finally, regarding the system’s treating performance, it was found that the pilot-scale MBR can operate successfully with high-strength synthetic municipal wastewater, since remarkable behaviour was exhibited in terms of organics (BOD5, COD) and ammonium (NH4+-N) removal (>98%).

Feasibility Studies on the Effect of Natural Plant Compounds on Sludge Characteristics in a Batch-Type Aerobic Reactor and N-butyryl-L Homoserine Lactone

Quorum quenching using different kinds of inhibitors is a new subject of research that is used for biofilm prevention in wastewater treatment membrane systems. In this study, three natural compounds, namely tea, coffee and vanillin, were tested in order to evaluate their possible effects on wastewater sludge characteristics in a batch type aerobic reactor. The parameters evaluated included the soluble microbial products (total soluble microbial products, protein and carbohydrate fraction of soluble microbial products), extracellular polymeric substance concentrations (total extrapolymeric substances, protein and carbohydrate fraction of the extrapolymeric substances), floc size, zeta potential, sludge volume index and capillary suction time. The effects of these plant based compounds upon the quorum sensing N-butyryl-L-homoserine lactone signal were also investigated using gas chromatography – mass spectrometry (GC-MS) under optimized conditions. The results indicated different effects for each natural compound upon the sludge characteristics. The role of these natural compounds as quorum quenchers in the batch-type aerobic reactor was inconclusive due to their effects on extraction outputs. Understanding the effect of quorum quenchers on sludge characteristics is important and recent studies have been aimed at preventing biofilm formation in membrane bioreactors.

Viscosity dynamics and the production of extracellular polymeric substances and soluble microbial products during anaerobic digestion of pulp and paper mill wastewater sludges

The production processes of the pulp and paper industry often run in campaigns, leading to large variations in the composition of wastewaters and waste sludges. During anaerobic digestion (AD) of these wastes, the viscosity or the production of extracellular polymeric substances (EPS) and soluble microbial products (SMP) may be affected, with the risk of foam formation, inefficient digester mixing or poor sludge dewaterability. The aim of this study was to investigate how viscosity and production of EPS and SMP during long-term AD of pulp and paper mill sludge is affected by changes in organic loading rate (OLR) and hydraulic retention time (HRT). Two mesophilic lab-scale continuous stirred tank reactors (CSTRs) were operated for 800 days (R1 and R2), initially digesting only fibre sludge, then co-digesting fibre sludge and activated sludge. The HRT was lowered, followed by an increase in the OLR. Reactor fluids were sampled once a month for rheological characterization and analysis of EPS and SMP. The production of the protein fraction of SMP was positively correlated to the OLR, implicating reduced effluent qualities at high OLR. EPS formation correlated with the magnesium content, and during sulphate deficiency, the production of EPS and SMP increased. At high levels of EPS and SMP, there was an increase in viscosity of the anaerobic sludges, and dewatering efficiency was reduced. In addition, increased viscosity and/or the production of EPS and SMP were important factors in sludge bulking and foam formation in the CSTRs. Sludge bulking was avoided by more frequent stirring.

Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling.

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

Probing size characteristics of disinfection by-products precursors during the bioavailability study of soluble microbial products using ultrafiltration fractionation

Soluble microbial products (SMPs) discharged into surface water may increase the formation of disinfection by-products (DBPs) in downstream drinking water treatment plants. In this study, ultrafiltration (UF) fractionation was used to separate SMPs into homogenous components. An aerobic microbial experiment was conducted to evaluate the bioavailability of individual molecular weight (MW) fractions of SMPs in surface water and the impact on their DBP formation, facilitating the interpretation of SMPs characterization and DBPs reactivity. For SMPs, organics with MW < 1 kDa were the primary fraction, containing the most abundant humic substances. The 30 kDa < MW < 100 kDa fraction was the lowest in SMPs but had the highest SUVA values. After biodegradation, the bioavailability of physical fractions increased with the increasing MW size. However, the SUVA value, except for MW < 1 kDa, increased in individual fraction after biodegradation. Low molecular weight SMPs fractions (MW<10 kDa) were major precursors for DBP in which trichloromethane (TCM) was the most abundant. The 10 kDa <MW < 100 kDa fractions were found to be more active in formation of chloral hydrate (CH), and MW> 100KDa had relative abundant dichloroacetonitrile (DCAN) formation. After biodegradation, TCM precursors with MW < 1 kDa were removed by approximately 20%, whereas the increase of TCM formation was observed in 1 kDa < MW < 100 kDa fraction. CH formation from 1 kDa < MW < 10 kDa increased considerably, but those from 10 kDa < MW < 30 kDa decreased after biodegradation, as a result of the biotransformation of large organic acids to small organic acids. In terms of DBP reactivity, the TCM yield for the MW < 1 kDa fraction had no significant change while the 30 kDa < MW < 100 kDa fraction exhibited the greatest increase (approximately 8 times) in TCM yield.

Qualitative and quantitative spectrometric evaluation of soluble microbial products formation in aerobic granular sludge system treating nitrate wastewater.

In present study, the characteristics of soluble microbial products (SMP) were evaluated in aerobic granular sludge system during denitrification process under different chemical oxygen demand/nitrogen (C/N) ratios. Batch experiment showed that the effluent nitrate (NO3--N) concentration were 15.24 ± 1.83 and 1.72 ± 1.53mg/L at C/N ratio of 1 and 6, respectively. For the release of SMP, the protein (PN) and polysaccharide contents increased from 1.23 ± 0.38 and 7.46 ± 1.13mg/L to 1.80 ± 0.76 and 10.53 ± 1.24mg/L with increasing C/N ratios, respectively. Excitation-emission matrix identified four peaks in SMP, including aromatic PN-like, tryptophan PN-like, fulvic acid-like and humic acid-like substances. Fluorescence regional integration suggested that biodegradable PN-like substances occupied the percentage between 53.0 and 61.7% in SMP. Synchronous fluorescence spectra coupled with two-dimensional correlation spectroscopy indicated that the release of SMP fractions in the early stage (0-150min) changed in the following sequences: PN-like fraction > fulvic acid-like fraction.

Effect of acetate and propionate on the production and characterization of soluble microbial products (SMP) in aerobic granular sludge system

It is well known that soluble microbial products (SMP) derived from biological systems found in wastewater treatment plant effluent are responsible for chemical oxygen demand (COD). Aerobic granular sludge (AGS) is recognized as an efficient and innovative approach for wastewater treatment. Acetate and propionate as two dominant organic substances in wastewater need to be effectively removed before discharge. The aim of this study was to investigate the effectiveness of acetate and propionate to interfere with the accumulation, molecular weight (MW) distribution and composition of SMP in aerobic granular sludge (AGS) system using two identical sequencing batch reactors (SBR) named R1 and R2, respectively, thus reducing the COD. The results demonstrated that more SMP accumulated in R1 in presence of acetate compared to R2 treated with propionate. A positive correlation for SMP formation was detected as evidenced by aeration rates, but a negative correlation with hydraulic retention time (HRT). The MW distribution analysis suggested that small molecules (MW <3 kDa) were the dominant fraction of SMP in R1 and R2, accounting for 57–79% and 39–61%, respectively. In addition, gas chromatography-mass spectrometry (GC-MS) demonstrated that esters, alkanes, alkenes and alcohols were the predominant low-MW SMP in R1 and R2. More peaks were present in R2 (61) than R1 (46). Esters were the predominant SMP (39%) in R1, while alkanes were the predominant SMP (31%) in R2. Further, microbial community analysis indicated that more α- and γ-Proteobacteria groups which readily utilize low-MW SMP were found in R2 compared to R1-granules which may have contributed to less SMP accumulated in R2. The abundant genera in the granules were Zoogloea and Azoarcus, in particular, a greater quantity of Azoarcus was detected in R2 than R1-granules, which may be associated with higher degradation of aromatics in SMP.

Optimal biogas sparging strategy, and the correlation between sludge and fouling layer properties in a submerged anaerobic membrane bioreactor (SAnMBR)

Biogas sparging is considered to be an effective way to control membrane fouling in an anaerobic membrane bioreactor, but is primarily used with a constant gas flow. This paper examined whether different gassing strategies could lead to better fouling control, and tried to understand the correlation between sludge properties and the fouling layer by disaggregating them into supracolloidal (1–5µm), colloidal (0.45µm–1µm) and solute (<0.45µm) fractions. This study found that the “critical constant sparging rate” was 6L per minute (LPM) at a flux of 26L per square meter per hour (LMH). However, a sparging strategy of 3LPM for 30s alternating with 5LPM for 30s (Alter 3/5) reduced membrane fouling by 150% compared with a constant 4LPM strategy. The viscosity, colloid and floc sizes of the suspended sludge increased with decreasing sparging rate, while the concentration of supracolloidal particles, soluble microbial products (SMPs) proteins and carbohydrates, and extracellular polymeric substances (EPS) decreased with decreasing sparging rate. Colloids were the major foulants above 2LPM, while HPLC-SEC analysis showed that one main SMP fraction was above 1522kDa, and the other between 72 and 500kDa. The high MW compounds accumulated on the membrane, while the later permeated through into the effluent. With the Alt 3/5 strategy, SMPs were the primary foulants, and the particle sizes were a lot smaller than in the supernatant. The foulant SMPs not only originated from the reactor supernatant, but were also produced by biomass in the membrane fouling layer. Chemical analyses reflected the effect of different sparging rates on sludge properties, the production of colloids, SMPs and EPS, and the foulant components.

Quantification and kinetic characterization of soluble microbial products from municipal wastewater treatment plants

Soluble microbial products (SMP) formed by microorganisms in wastewater treatment plants (WWTPs) adversely affect final effluent quality and treatment efficiency. It is difficult to distinguish SMP from residual proteins, lipids and carbohydrates present in the influent that may persist during treatment. No method is currently available to determine quantitatively the extent to which SMP contribute to organic discharges from municipal WWTPs. In this work a modeling approach is presented which allows the SMP fraction of the effluent of a municipal WWTP to be quantified and described. The model is validated, in terms of utilization-associated products, biomass-associated products and extracellular polymeric substances, using influent from a municipal WWTP. SMP was found to account for, on average, 27 mg/L of chemical oxygen demand (COD), or 61% of the total COD in the WWTP effluent. Over 90% of the SMP was comprised of biomass-associated products. Five main factors influencing SMP formation in WWTP were evaluated. Neither wastewater composition nor mixed liquor suspended solids concentration was found to affect SMP production. On the other hand, a positive correlation was observed for SMP formation with both solids retention time and influent COD concentration, and a negative correlation with hydraulic retention time. Thus, operating or designing WWTPs with short solids retention and long hydraulic retention times could be considered as solutions for minimizing SMP production.

The effect of solids retention times on the characterization of extracellular polymeric substances and soluble microbial products in a submerged membrane bioreactor.

In this study, the effect of solids retention times (SRTs) on extracellular polymeric substances (EPS) and soluble microbial products (SMPs) were investigated in a membrane bioreactor (MBR) at SRTs of 10, 5 and 3 days. The results showed that more carbohydrates and proteins were accumulated at short SRT, which can due to the higher biomass activity in the reactor. The molecular weight (MW) distribution analysis suggested that macromolecules (MW>30 kDa) and small molecules (MW<1 kDa) were the dominant fraction of EPS and SMP, respectively. The reactor at shorter SRT had more small molecules and less macromolecules of carbohydrates. The MW distribution of total organic carbon (TOC) suggested that other organic moieties were exuded by microbes into the solution. The shorter SRT had more undefined microbial by-product-like substances and different O − H bonds in hydroxyl functional groups.

Kinetic characterization of acetate utilization and response of microbial population in super fast membrane bioreactor

The study investigated the functional relationships between changes in microbial community induced by different sludge ages (SRT) selected for super fast MBR operation on variable process kinetics, fate of soluble microbial products (SMPs) and system performance. Acetate, a simple and separately identifiable compound, was selected as the sole organic carbon source. MBR operation was monitored at steady-state at extremely low SRT levels of 2.0, 1.0 and 0.5d and a hydraulic retention time of 1.0h. Batch experiments were conducted for kinetic evaluation of MBR performance by model evaluation of oxygen uptake rate, polyhydroxybutyric acid and COD profiles. Bacterial DGGE profiles indicated that SRT exerted shifts in the composition of microbial community. Model evaluation of experimental data also confirmed molecular analyses, indicating variable growth kinetics for utilization of acetate and identified high and variable endogenous respiration as a function of SRT. Changes in the microbial community and process kinetics did not affect MBR performance, providing complete depletion of available acetate. Effluent COD remained below 17mg/L and entirely composed of SMPs. Particle size analysis revealed a bimodal distribution of the wide spectrum of SMPs above 13nm and below 2nm. Effective filtration size of the membrane was reduced to 8nm due to cake filtration effect. The retained fraction of SMPs was in the range of 1–2mg/L, but accumulated in the reactor volume, same way as biomass. Therefore, the real merit of super fast MBR was the very low levels of SMP generation (14–18mg COD/L), rather than the effective capture of accumulated COD due to cake filtration.

Characterization of soluble microbial products as precursors of disinfection byproducts in drinking water supply

Water pollution by wastewater discharge can cause the problem of disinfection byproducts (DBPs) in drinking water supply. In this study, DBP formation characteristics of soluble microbial products (SMPs) as the main products of wastewater organic biodegradation were investigated. The results show that SMPs can act as DBP precursors in simulated wastewater biodegradation process. Under the experimental conditions, stabilized SMPs had DBPFP (DBP formation potential) yield of around 5.6μmolmmol−1-DOC (dissolved organic carbon) and DBP speciation profile different from that of the conventional precursor, natural organic matter (NOM). SMPs contained polysaccharides, proteins, and humic-like substances, and the latter two groups can act as reactive DBP precursors. SMP fraction with molecular weight of <1kDa accounted for 85% of the organic carbon and 65% of the DBP formation. As small SMP molecules are more difficult to remove by conventional water treatment processes, more efforts are needed to control wastewater-derived DBP problem in water resource management.

The Effect of Media Fill Ratio on Membrane Fouling in Moving Bed Bioreactors-Membrane Bioreactor

This research investigated the effect of media fill ratio on membrane fouling in moving bed bioreactors-membrane bioreactor. The results shown the high removal of ammonia and COD, despite the membrane fouling conditions were really different in two bioreactors. The total modified fouling index (MFI) of IFAS 3000 was three times than MFI of IFAS 1500, and the soluble microbial products (SMP) present in the mixed liquor played an important role in the membrane fouling. No more correlation was found between the extracellular polymeric substances (EPS) concentration and fouling, and the average SMP of IFAS 3000 was higher than IFAS 1500. The carbohydrate of SMP occupied high fraction in all reactors. Large molecular weight (MW) components constituted the major fraction of EPS and SMP. The results indicated that higher media fill ratio can decrease membrane fouling effectively.

Implication of endogenous decay current and quantification of soluble microbial products (SMP) in microbial electrolysis cells

We designed a dual-chamber microbial electrolysis cell (MEC) which provided a large anode surface area against membrane surface area, but kept a short distance between the anode and the cathode. Current density ranged from 8.3 to 11 A m−2 of membrane surface area for chemical oxygen demand (COD) loading rate 0.3–6.3 kg COD/m3 d. Hydrogen recovery (from coulombs to H2) was as high as 93 ± 25% in the MEC, and hydrogen production rate ranged from 66.4 ± 18.0 to 137.2 ± 14.4 L H2/m2 d at an applied voltage of ∼1.2 V. As a result, H2 production costs were computed at $0.17–0.25/m3 H2 ($1.7–2.6/kg H2 at 25 °C and 1 atm) in the MEC using stainless steel mesh as the cathode. The MEC designed for maintaining high concentration of anode-respiring bacteria per membrane surface area generated 8.3 A m−2 of membrane area of which 57% was produced by endogenous decay of ARB under substrate deficient conditions. Soluble microbial products (SMP) were quantified for acetate-utilizing ARB in the MEC, and SMP fraction of influent COD was 23%. We separately measured biomass-associated products and utilization-associated products of SMP experimentally, which were 286 ± 100 mg L−1 and 59 ± 30 mg COD L−1, respectively.

Impact of methanogenic pre-treatment on the performance of an aerobic MBR system

The combination of anaerobic treatment with an aerobic MBR as a polishing step is an alternative to treat some industrial wastewater and/or urban wastewaters generated in warm climate countries. In this work a pilot-scale UASB reactor and an aerobic MBR as a polishing step was operated. The impact of the methanogenic stage on membrane fouling was studied. Operating fluxes of 11–18 L m−2 h−1 and permeabilities of 100–250 L m−2 h−1 bar−1 were reported. It was demonstrated that the recirculation of aerobic biomass to the anaerobic stage provoked a release of biopolymers due to the hydrolysis of aerobic biomass in these conditions. Depending on biomass concentration in membrane chamber, the presence of biopolymers worsened membrane performance. Fouling rate was three times higher when biomass concentration decreased from 8 to 2 g L−1, with similar concentrations of biopolymers present. Moreover, the presence of plastic support in the aerobic stage was shown to improve membrane performance, decreasing the concentrations of the studied fouling indicators.Carbohydrate fraction of soluble microbial products, biopolymer clusters (BPC) and transparent exopolymer particles (TEP) concentrations were studied as possible fouling indicators for this system. A strong correlation between both colloidal fraction of BPC (cBPC) and TEP with membrane fouling rate was observed.

P.1.e.032 Test/Retest reliability of an imaging task battery for pharmaco-fMRI

In this study, the effect of solids retention times (SRTs) on extracellular polymeric substances (EPS) and soluble microbial products (SMPs) were investigated in a membrane bioreactor (MBR) at SRTs of 10, 5 and 3 days. The results showed that more carbohydrates and proteins were accumulated at short SRT, which can due to the higher biomass activity in the reactor. The molecular weight (MW) distribution analysis suggested that macromolecules (MW > 30 kDa) and small molecules (MW < 1 kDa) were the dominant fraction of EPS and SMP, respectively. The reactor at shorter SRT had more small molecules and less macromolecules of carbohydrates. The MW distribution of total organic carbon (TOC) suggested that other organic moieties were exuded by microbes into the solution. The shorter SRT had more undefined microbial by-product-like substances and different OH bonds in hydroxyl functional groups.

Competitive effects and interactions during sorption of SMP fractions on activated carbon: Response surface approach for visualization of sorption profiles

The objectives of this study were to investigate the significance of the effects and interactions for during competitive sorption of soluble microbial products (SMP). Batch experiments were conducted to assess the competitive sorption characteristics and individual affinity of glucose (carbohydrate) and bovine serum albumin (BSA) (protein) as two representative fractions of SMP. The influence of surface availability was investigated by using carbon particles with different particle sizes (5−75 μm, 75−850 μm, and 850−1000 μm) and different carbon amounts. Competitive effects and interactions were evaluated for each adsorbate and surface availability. Competitive sorption mechanisms were quantified in relation to surface affinity of the SMP fractions. Sorption capacity profiles of the SMP fractions at equilibrium were developed using second-degree polynomial models for the experimental data and compared with the estimates obtained from the modified Langmuir-like model which uses single parameter sorption data to estimate competitive sorption profiles of systems with two adsorbates. Adequacy limitations of the modified Langmuir-like model for each SMP fraction were evaluated based on the significance of the synergistic and antagonistic effects between the two SMP fractions and the carbon surface availability.