Terephthalic Acid Wastewater Research Articles

Development of an internal two-stage upflow anaerobic reactor integrating biostimulation strategies to enhance the degradation of aromatic compounds in wastewater from purified terephthalic acid and dimethyl terephthalate manufacturing processes

In this study, we aimed to establish high-rate biological treatment of purified terephthalic acid (PTA) and dimethyl terephthalate (DMT) wastewater that minimizes the inhibitory effects of high concentration benzoate and acetate. To achieve this, we developed a novel bioreactor system and biostimulation strategy. An internal two-stage upflow anaerobic (ITUA) reactor was operated with (i) a packed bed containing green tuff medium underlying (ii) a compartment seeded with anaerobic granular sludge. Ethylene glycol was amended to stimulate syntrophic interactions. Continuous operation of the system for 1,026 days achieve an organic removal rate of 11.0 ± 0.6 kg COD/m3/d. The abundance of aromatic degraders significantly increased during operation. Thus, we successfully developed a high-rate treatment system to treat wastewater from the PTA/DMT manufacturing processes by activating syntrophs in an ITUA reactor.

Dual-chamber up-flow fluidized hollow-fiber anaerobic membrane bioreactor (UF-HF-AnMBR) treating synthetic purified terephthalic acid wastewater: Granular sludge regranulation and methane production

Up-flow anaerobic sludge blanket is a representative way to treat high-strength industrial wastewater, but suffers from granule collapse and poor long-term performance. In this study, a dual-chamber up-flow fluidized hollow-fiber anaerobic membrane bioreactor (UF-HF-AnMBR) was constructed to enhance sludge regranulation and process stability for purified terephthalic acid (PTA) wastewater treatment. A stable and satisfactory aromatic compound removal (>99 %) was achieved at the organic loading rate of 7.15 ± 0.21 g-COD·Lreactor−1·d−1, with the methane yield of 0.345 ± 0.028 L·g-CODremoved−1. Although the granular sludge collapsed initially induced the pore blocking and membrane fouling, membrane separation promoted the agglomeration of small particles, sludge regranulation and biomass retention. Parallel factor analysis identified that the amino acid tryptophan in extracellular polymeric substances exerted a more critical effect on membrane fouling. The 16S rRNA and network analysis revealed the robust proliferation/enrichment of Methanosaeta, Pelotomaculum, etc., as well as the establishment of mutualistic symbiotic relationship among different species, ensured a stable microbial community and created a favorable circumstance for highly effective anaerobic treatment of PTA wastewater. This study proves that UF-HF-AnMBR can be an efficient and promising technique for sludge regranulation and microbe enrichment, advancing its application in PTA wastewater treatment and bioenergy recovery.

Semiconductor-assisted photofermentation system for terephthalic acid degradation and methane production

The fermentation degradation approach of purified terephthalic acid wastewater remains a grand challenge, due to the low degradation efficiency of the refractory terephthalic acid (TA) compound. Here, photocatalytic semiconductors (g-C3N4 and its-derived composites) are introduced to the anaerobic reactor to construct a semiconductor-assisted photofermentation system that enables to intensify the electron transfer process, in turn enhancing the overall TA degradation performances. Specifically, the g–C3N4–added group exhibits significantly improved methane production efficiency and TA degradation rate, increasing by 67.7 % and 36.1 %, respectively. Mechanisms reveal that such enhanced TA degradation is contributed from the key direct-interspecies-electron-transfer (DIET) process (that is intensified by the produced photogenic electrons) and the photocatalytic degradation process (that is amplified by the generated photogenic holes and hydroxyl radicals capable of efficiently oxidizing TA to simple organic matters). This study underscores the importance and high-efficiency of simply constructing semiconductor-assisted photofermentation systems for TA wastewater treatments, which can be implemented to harness other types of recalcitrant compounds-contained wastewaters.

Synthesis of bio-based materials from agricultural residues for treatment of petrochemical wastewater

4-Carboxybenzaldehyde (4-CBA), a major component of purified terephthalic acid wastewater, is toxic to living organisms and required to be removed before the discharge of treated wastewater in a natural water body. In this work, the adsorptive removal of 4-CBA was studied using bagasse fly ash (BFA), a waste product from the sugar industry. The adsorption capacity of BFA was compared with the commercially available adsorbent, granular activated carbon (GAC). A 4-factorial, 5-stage central composite design (CCD) was used to optimize 4-CBA removal and adsorption uptake by BFA using response surface methodology (RSM). The variables considered for the study were pH, adsorbent dose (m), initial concentration (Co) and time (t). At the optimum treatment conditions of pH = 4, m = 9 g/L, Co = 100 mg/L and t = 7.5 h, the removal efficiency and adsorption uptake of 4-CBA on BFA were found to be 79% and 9.9 mg/g, respectively. BET surface area of BFA was determined to be 284 m2/g. A kinetic study was performed using a first- and second pseudo-order model. The adsorption equilibrium data were fitted for various adsorption models. A positive value Delta H^{0} indicates that the adsorption process is endothermic. This study indicated that BFA is a cost-effective adsorbent for the removal of 4-CBA with high adsorption capacity and fast kinetics.Graphical

Deciphering the fate of osmotic stress priming on enhanced microorganism acclimation for purified terephthalic acid wastewater treatment with high salinity and organic load

Osmotic stress priming (OSP) was an effective management strategy for improving microbial acclimation to salt stress. In this study, the interaction between pollutants and microbiota, and microbial osmoregulation were investigated triggered by OSP (alternately increasing salinity and organic loading). Results showed that OSP significantly improved COD removal from 31.53 % to 67.99 % and mitigated the terephthalate inhibition produced by toluate, decreasing from 1908.08 mg/L to 837.16 mg/L compared with direct priming. Due to an increase in salinity, Pelotomaculum and Mesotoga were enriched to facilitate terephthalate degradation and syntrophic acetate oxidation (SAO). And organic load promoted acetate formation through syntrophic metabolism of Syntrophorhabdus/Pelotomaculum and SAO-dependent hydrogenotrophic methanogenesis. K+ absorbing, proline and trehalose synthesis participated in osmoregulation at 0.5 % salinity, while only ectoine alleviated intracellular osmolarity under 1.0 % salinity with OLR of 0.44 kg COD /m3. This study provided in-depth insight for microbial acclimation process of anaerobic priming of saline wastewater.

Waste carbon conversion and utilization in chemical wastewater treatment process: Experimental approaches from lab-to pilot-scale

Chemical wastewater often contains large amounts of waste organic carbon. The current chemical wastewater treatment plants are an open carbon emission system. Inspired by the topic of CO2 conversion and utilization, this study provided a redesigned flowchart of chemical wastewater treatment process via closed-loop carbon conversion and utilization system for the resource utilization of waste carbon from wastewater. Purified terephthalic acid (PTA) wastewater, a common chemical wastewater, was selected to test the feasibility of the proposed strategy. An integrated closed-loop system involving activated sludge-microalgae-pyrolysis process was employed. Initially, a laboratory-scale wastewater treatment system combining activated sludge with microalgae process was applied for the carbon conversion and utilization in PTA wastewater. The COD removal efficiency was obtained at 93.02%, and over 94% of CO2 was captured. Microbial DNA analysis of the activated sludge indicated that the functional microorganisms mainly included Proteobacteria, Bacteroidetes, and Chloroflexi. Metabolic analysis of the microalgae showed that the abundances of differential metabolites associated with carbon metabolism significantly increased after treatment. Furthermore, a pilot-scale integrated system was applied to test this strategy and in which obtained a good performance in COD removal and CO2 capture. The produced excess biomass during chemical wastewater treatment, which was usually viewed as hazardous solid waste, was converted to biochar and carbonaceous combustible gas via pyrolysis. The produced biochar could be used as photocatalysts to remove antibiotic. The findings provided a new design to simultaneously achieve water pollution control, carbon conversion & utilization, and resource & energy recovery in chemical wastewater treatment process.

Improved anaerobic degradation of purified terephthalic acid wastewater by adding nanoparticles or co-substrates to facilitate the electron transfer process

Improving the biodegradation efficiency of terephthalic acid (TA) wastewater processes is highly challenging, particularly in large-scale up-flow anaerobic sludge blanket (UASB) reactors.

Long-term performance, membrane fouling behaviors and microbial community in a hollow fiber anaerobic membrane bioreactor (HF-AnMBR) treating synthetic terephthalic acid-containing wastewater

Purified terephthalic acid (PTA) wastewater with properties of poor biodegradation and high toxicity is produced from refining and synthesis of petrochemical products. In this study, a lab-scale hollow fiber membrane bioreactor (HF-AnMBR) fed with synthetic PTA wastewater was operated over 200 days with stepwise decreased hydraulic retention time (HRT) to investigate the long-term performance, membrane fouling mechanism and microbial community evolution. Results showed that a stable chemical oxygen demand (COD) removal rate of 65.8 ± 4.1% was achieved at organic loading rate of 3.1 ± 0.3 g-COD/L-reactor/d and HRT 24 h, under which the methane production rate reached 0.33 ± 0.02 L/L-reactor/d. Further shortening HRT, however, led to the decreased COD removal efficiency and low methane bioconversion. A mild membrane fouling occurred due to the production of colloidal biopolymers and the interaction between increased colloidal substances secreted/cracked by microorganisms and membrane interface. Further 16S rRNA analysis indicated that microbial diversity and richness had changed with the variation of HRT while Methanosaeta, and Methanolinea species were always the dominant methanogens responsible for methane production. The results verify that HF-AnMBR is an alternative technology for PTA wastewater treatment along with energy harvesting, and provide a new avenue toward sustainable petrochemical wastewater management.

Treatment of Purified Terephthalic Acid Wastewater by Ozone Catalytic Oxidation Method

In this study, a Cu–Ce@Az ozone catalyst with multiple active components was prepared through the impregnation method to treat purified terephthalic acid (PTA) wastewater, and characterized by X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy, specific surface area analysis, X-ray energy spectroscopy, X-ray photoelectron spectroscopy, and other methods. The Cu–Ce@Az ozone catalyst had a developed pore structure with a large specific surface area and crystal structure. After calcination, the metallic elements Cu and Ce existed in the state of oxides CuO and CeO2. The effects of reaction time, solution pH, catalyst dosage, and ozone dosage on the catalytic oxidation performance of the Cu–Ce@Az ozone catalyst were studied. Adding tert-butanol reduced the removal rate of COD from the PTA wastewater through the catalytic oxidation system, which proves that a Cu–Ce@Az ozone catalyst treatment process of PTA wastewater follows the free-radical reaction mechanism. The results of 3D fluorescence spectroscopy analysis show that the organic matter in the PTA wastewater was converted into tryptophan organic matter and aromatic organic matter after the reaction of the catalytic oxidation system. Ultraviolet absorption spectroscopy analysis indicated that in unsaturated chemical bonds, some conjugated structures and benzene ring structures of organic matter in the PTA wastewater were destroyed.

Effect of mixed petrochemical wastewater with different effluent sources on anaerobic treatment: organic removal behaviors and microbial community.

Petrochemical industrial effluent contains industrial wastewater from various manufacturing processes. The mixed treatment of these different petrochemical wastewater effluents may influence the organic removal performance of the anaerobic processes. In this study, three typical petrochemical effluents, including polyester (PE), polyethylene terephthalate, and purified terephthalic acid wastewater, were collected. The effect of the mixed petrochemical wastewater on the organic removal and microbial community structure was investigated in the anaerobic batch assays via spectroscopy and high-throughput sequencing. The organic removal efficiencies were similar (71-85%) in all the batch assays for 90 h acclimation. The mixture of wastewater, especially the addition of PE wastewater, significantly prolonged organic removal process. It was related to the aromatic removal performance and microbial community structure during the mixed wastewater treatment. The microbial community structure in the mixed wastewater batch assay showed high similarity with that in the PE wastewater batch assay. Ignavibacterium, Syntrophus, and Pelotomaculum were crucial to the degradation of aromatic compounds together with Methanosaeta. The mixture of wastewater, especially the addition of PE wastewater, caused the decay of these functional microbes and resulted in the inefficient removal of the aromatic compounds.

The performance and bacterial community shifts in an anaerobic-aerobic process treating purified terephthalic acid wastewater under influent composition variations and ambient temperatures

Anaerobic-aerobic process is an efficient way to treat purified terephthalic acid (PTA) wastewater. In this study, the effect of changing feed composition on the performance of a combined upflow anaerobic fluidized bed (UAFB) and sequencing batch reactor (SBR) was investigated under ambient conditions (15–25 °C). The 187 days’ operation was divided into 4 stages by consecutively elevating the loading rate of terephthalic acid (TA), p-toluic acid, benzoic acid and acetic acid. Results revealed that almost all iso-phthalic acid, benzoic acid and acetic acid could be completely removed in the UAFB reactor, while only about 35% p-toluic acid was degraded in the UAFB reactor. Nevertheless, over 97.0% average COD removal efficiency could be achieved after the consecutive aerobic treatment. Furthermore, the load elevation of easily biodegradable organics might enhance the operational stability together with a less diverse bacterial community in anaerobic system. The microbial analysis elucidated a large amount of versatile aromatic degraders including Syntrophorhabdus, Syntrophus and Syntrophobacteraceae were observed in UAFB reactor, but they did not show clear correlation with any specific pollutant. Meanwhile, the growth of Thauera and Rhodobacteraceae in SBR reactor were stimulated by p-toluic acid load elevation, and both of them showed strong positive correlation with p-toluic acid degradation. Overall, this study provides a comprehensive insight into the organics degradation characteristics and bacterial profiles of UAFB-SBR process treating complex industrial wastewater at ambient temperatures.

Utilization of chemical wastewater for CO2 emission reduction: Purified terephthalic acid (PTA) wastewater-mediated culture of microalgae for CO2 bio-capture

The present study aimed to prove the potential of chemical wastewater utilization for CO2 emission reduction. Purified terephthalic acid (PTA) wastewater was applied as the culture medium of green microalgae (Chlorella pyrenoidosa) for CO2 bio-capture. Algal biomass and chlorophyll a content were determined as algal physiological response, and the CO2 capture efficiency and photosynthetic rate were also evaluated. Due to low pH value (pH = 4.40), the alga was unable to grow in the raw PTA wastewater, while it preferred tolerance and adaptation in the pH adjusted wastewater (pH = 7.40) and the treated PTA wastewater, respectively. Generally, 75.55–90.25 g/d of the algal biomass (dry weight) was yielded of the PTA wastewater per ton. While both chlorophyll a content of unit algal density and CO2 capture rate with the treated wastewater were higher than those with the untreated PTA wastewater. Additionally, the algal ability to fix CO2 was evaluated when the concentration of CO2 was set at 2%, 5%, 10% and 15%, respectively. Our results showed that the CO2 capture rate and the photosynthetic rate of the algae when cultured with the treated wastewater were higher than these with the untreated PTA wastewater. The highest algal CO2 capture rate was obtained as 82.15% (2% CO2, with untreated wastewater) and 91.59% (10% CO2, with treated wastewater), respectively. It is the first time to report algal CO2-capture with chemical wastewater-mediated culture, and our study provided a trinity model to achieve water saving, CO2 emission reduction and energy regeneration in an integrated strategy.

Efficient treatment of pure terephthalic acid wastewater with Na2S2O8 based on thermal activation

Abstract Terephthalic acid (TA) is an important industrial raw material. A large amount of wastewater, mainly containing TA, is generated in the pure terephthalic acid (PTA) producing process. In this study, an advanced oxidation process based on persulfate like Na2S8O8 was proposed to degrade TA. The result showed that higher temperature was conducive to degrade TA due to better thermal activation effect, causing more radicals to generate, and the removal ratio of TA reached to a high level of 95.2% at 80 °C. Meanwhile, the TA removal efficiency (maximum 97.4%) at alkaline conditions was better than that in both acidic conditions (about 94%) and neutral condition (85%) at 80 °C. It implied the removal of TA could be carried out effectively in thermal activation mode, and further intensified in the alkaline environment on the basis of thermal activation. The generation of free radicals with thermal activation could be used to explain the degradation mechanism of the organic. Overall, a max total organic carbon (TOC) removal of 97.7% could be achieved, and a probable reaction pathway was proposed with the identification of the intermediate products during TA oxidation. These results could provide a theoretical basis for lower energy consumption and effective treatment of PTA industrial wastewater, which is usually at 75–85 °C and suitable for thermal activation.

Preparation of a Fe-ZSM-5 Adsorbent and Its Selective Adsorption of p-Xylene Performance Exploration

In the purified terephthalic acid wastewater treatment process, a large amount of wastewater containing p-xylene (PX), Co2+, and Mn2+ would be by-produced and PX needs to be recycled to avoid affec...

Anaerobic bioconversion of petrochemical wastewater to biomethane in a semi-continuous bioreactor: Biodegradability, mineralization behaviors and methane productivity

Petrochemical wastewaters treatment represents a serious challenge due to the high toxicity and complex chemical components. In this study, the biodegradability, mineralization behaviors and methane productivity of eight different types of petrochemical wastewaters were evaluated in series of semi-continuous bioreactors. Methane production strongly depended on the characteristics of wastewaters and chemical constituents. The highest methane yield of 305.9 ± 2.7 mL/g-COD was achieved by purified terephthalic acid wastewater, followed by ethylene glycol, polyester, etc. Comparatively, one-step-SCN− wastewater produced the lowest methane yield (4.7 ± 0.7 mL/g-COD) owing to high toxicity and low biodegradability. Modified Gompertz model confirmed that purified terephthalic acid, ethylene glycol and polyester wastewaters had a short lag-phase of 1.2, 1.7 and 0.2 days, respectively. Nonetheless, the formation of by-products such as proteins, polysaccharides and ammonia nitrogen throughout anaerobic digestion reflected the high activity of anaerobic microorganisms, confirming the technical feasibility of anaerobic biotechnology in treating petrochemical wastewaters.

Purified Terephthalic Acid Wastewater Treatment Using Modified Two-Stage UASB Bioreactor Systems.

Microbial community dynamics and PTA wastewater degradation performance of sequentially connected two-stage upflow anaerobic sludge blanket (UASB) bioreactors have been studied for 225days. The working volume of acidogenic (R1) and methanogenic reactors (R2) have sixfold differences. Thus, the reactors operated under different hydraulic retention time (HRT) conditions, which are preferential for PTA wastewater content. Archeal and bacterial profiles of granules were analyzed with denaturing gradient gel electrophoresis (DGGE) and real-time quantitative PCR (Q-PCR) techniques. According to high-pressure liquid chromatography (HPLC) results, 4-Carboxybenzaldehyde (4-CBA) and acetic acid (AA) completely degraded in the first stage, whereas terephthalate (TA) and p-toluic acid (p-TA) degradation ratios were 90% and 47% in the second stage, respectively. The methane content of the UASB reactor was determined as 76% by gas chromatography (GC) analysis. Microbial community analysis indicated that the members of hydrogenotrophic methanogen groups Methanobacteriales and Methanomicrobiales were dominantly responsible for methane production throughout the process.

Study of degradation of p-toluic acid by photo-oxidation, peroxidation, photo-peroxidation and photo-fenton processes

p-Toluic acid is a major content of terephthalic acid wastewater and is a cause of secondary water pollution. p-Toluic acid in aqueous solution was degraded by using photo-fenton, photo-peroxidation, photo-oxidation and peroxidation processes. A low-pressure mercury vapour lamp was taken in combination with different oxidants to degrade p- toluic acid in this study. Substrate concentration was fixed by utilizing a UV–Visible spectrophotometer. The results indicated that photo-fenton process achieved degradation rate due to synergistic effect between UV and Fe2+/H2O2. The degradation rate follow the sequence: photofenton (UV/ Fe2+/H2O2) > photo-peroxidation (UV/H2O2) > photo-oxidation (UV) > peroxidation (H2O2). The photodegradation processes were adhered to first order dynamics.

Highly efficient treatment of terephthalic acid wastewater by Fenton-like combined biodegradation

Highly efficient treatment of terephthalic acid wastewater by Fenton-like combined biodegradation

Improved purified terephthalic acid wastewater treatment using combined UAFB-SBR system: At mesophilic and ambient temperature

In this study, a combined UAFB-SBR process was introduced to improve the treatment efficiency of PTA wastewater. The techno-economic feasibility of the process was evaluated in terms of organic removal efficiencies under mesophilic (37 °C) and ambient temperature (15–25 °C) during the long-term run. The lab-scale study revealed that all organic compounds present in the PTA wastewater could be efficiently removed under both mesophilic and ambient temperature, and p-toluic acid is probably the critical pollutant regulating the overall process performance in anaerobic stage, which should be seriously considered. The Miseq Sequencing results suggested that, along with the system temperature variation from mesophilic to ambient temperature, greater effects on bacterial community than archaeal community were detected in the UAFB reactor, while only slight variations were observed in the SBR reactor. Further taxonomy analysis demonstrated that within the UAFB reactor, the syntrophic partnership of Syntrophorhabdus, Syntrophus and Desulfovibrio with hydrogenotrophic methanogens were the main impetus for aromatic organics reduction. In the meanwhile, the intensively identified Thauera and Azoarcus groups were speculated of important roles in the aerobic degradation of aromatic compounds.

Selective adsorption of Co(II)/Mn(II) by zeolites from purified terephthalic acid wastewater containing dissolved aromatic organic compounds and metal ions

Selective separation and recovery of Co(II)/Mn(II) from purified terephthalic acid (PTA) production wastewater is very important to reduce the Co(II)/Mn(II) catalysts consumption and control the pollutant discharge. This work employed zeolites NaA, NaX, and HZSM-5 with different pore sizes and Na(I) contents to selectively separate and recover Co(II)/Mn(II) from PTA wastewater and to understand the adsorption mechanism. It is found that only NaA can exclusively adsorb Co(II)/Mn(II) through ion-exchange without adsorbing any aromatic organic compound (AOC); oppositely, HZSM-5 shows the highest adsorption capacity for AOCs but almost no adsorption for Co(II)/Mn(II); and NaX exhibits moderate adsorption capacities for both Co(II)/Mn(II) and AOCs. Moreover, pH can significantly impact the adsorption of both Co(II)/Mn(II) and AOCs due to the competitive adsorption between H(I) and Co(II)/Mn(II) and the electrostatic repulsion between AOCs and zeolites. The adsorption kinetics, isotherms, and thermodynamics were also investigated to lay a good basis for process development. Importantly, bench-scale experiments for simulating the industrial operation were carried out, and the results show that the adsorption capacity of the NaA particles for Co(II)/Mn(II) from the industrial PTA wastewater is 9.1/8.6 mg/g, respectively, without adsorbing any AOC. Therefore, an efficient strategy to selectively separate and recover Co(II)/Mn(II) from PTA wastewater was successfully developed.