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Bisphenol A (BPA), one of the widely known endocrine-disrupting chemicals, can be effectively degraded by advanced oxidation processes in water because of the powerful reactive oxygen species. In this study, Fenton, UV/Fenton, and metal ion/peroxymonosulfate (PMS) processes were compared to investigate BPA degradation efficiency and pathways initiated by hydroxyl radicals and sulfate radicals. In contrast to the Fenton system, which only degraded 60% of BPA within 15 min, the UV/Fenton system could degrade greater than 80% of BPA, because more hydroxyl radicals (•OH) were generated under the reduction of Fe

The transformation of iodide (I−) and hypoiodous acid (IO−) by Fe (II)-activated peroxydisulfate (PDS) in the presence of natural organic matter (NOM) was investigated. In the water of a reservoir in Shenzhen, four kinds of organic matter were detected: iodoform > diiodo-bromomethane > dibromo-iodomethane > dichloromethane. As pH increased from 3 to 10, I− conversion rate decreased from 31.0% to 11.0%. There is basically no iodic acid () generated under alkaline conditions, probably due to these organic matters. When PDS concentration is low, PDS can oxidize part of I− to IO−, and the oxidation of I− into reaction and continued oxidation reaction exist at the same time, so some is generated in the system. As the proportion of Fe (II) increases, the generation rate of gradually increases. When Fe2+/PDS is 1:5, 2:5, and 3:5, the conversion rates of are 4.7%, 6.5%, and 8.4%, respectively. There are two main reasons for this: (i) the reaction of IO− produced in the system with humic acid (HA) inhibits the further conversion of IO− to ; (ii) both HA and I- in the system can react with PDS, resulting in a reduction in the oxidation rate of I−. HIGHLIGHTS Formation of I-DBPs by Fe (II)/PDS process in real water was evaluated.; I-DBPs generation in various reaction conditions was examined.; Existence of HA showed apparent inhibition on IO3− generation.

The municipal solid waste (MSW) with high water content can be pre-treated by the mechanical dewatering technology to significantly decrease the leachate generation in sequential landfill treatment or to improve the efficiency for solid waste incineration, which has attracted great concerns recently. However, the generated mechanical dewatering wastewater (MDW) containing high organics and nitrogenous content has been one of the big challenges for the sustainable treatment of MSW. In this study, a pilot-scale integrated system composed of physiochemical pretreatment, anaerobic sequencing batch reactor (ASBR), partial nitrification SBR (PN-SBR), denitrification SBR (DN-SBR), and UV/O

Modifying PVDF membrane by blending hydrophilic nano TiO

Metal cations are present in domestic and industrial wastewater and have adverse effects on human and aqueous life. The present study describes the development of the molecular probe 9-anthracen-9-ylmethylene)hydrazineylidene)methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol (AMHMPQ) to detect Cr

Iodoform (CHI3) is one of the disinfection by-products (DBPs) that is formed in the pre-oxidation and disinfection processes of drinking water treatment. In this study, Fe(II)-activated persulfate oxidation (Fe2+/PS) was employed to degrade iodoform, the effects of initial reactants concentration, reaction parameters, kinetics model were investigated, and the underlying mechanisms of CHI3 degradation in Fe2+/PS oxidation process was unveiled. The results showed that the mole ratio Fe2+/PS of 1:5, initial PS concentration of 15 μmmol/L, and pH of 3.0 were identified as the optimum operating parameters. In addition, a relatively higher temperature could enhance CHI3 removal and deiodination. The kinetic model has two different reaction steps: a fast one during the first ten minutes of reaction; then followed by a much slower one. Suppression of the reaction by TBA and MeOH showed that the combined effects of SO4−· and ·OH contributed to the degradation of CHI3, but ·OH played a dominant role. The degradation pathways and the products of total liberated iodine species demonstrate that the applicability of the Fe2+/PS oxidation process for CHI3 degradation. These results indicated that the Fe2+/PS oxidation process is an effective advanced oxidation process for CHI3 removal in water treatment. Keywords: Fe2+/PS oxidation process, Iodoform degradation, Optimal operating conditions, Kinetics

Effluent organic matter (EfOM) is one of the major foulants responsible for the occurrence of membrane fouling during advanced wastewater treatment using nanofiltration (NF) technology. In this present study, we have reported a simple fouling indicator based on the properties of fractional fluorescence and molecular weight, termed as fluorescence-size-index (FSI), to predict the fouling propensity of NF when filtrating EfOM. Specifically, EfOM collected from twenty-one real sewage samples were first analyzed to quantify their fluorescent compositions and concentrations. The results showed that the EfOM consisted mainly of humic-like substances, soluble organism metabolites and fulvic-like substances, characterized by small-molecule organic matters (

The influence of ultrasonication on membrane performance was investigated by two ultrasonication modes, direct and indirect ultrasonication as pretreatment, and simply improved PVDF-TiO2 membranes' performance was systematically compared. Ultrasound intensity of 100% and ultrasonication time ranged from 1 to 2 h positively affect membrane permeability. Characterization results manifested that membrane structure was eventually optimized with an even nano-TiO2 dispersion by direct ultrasonication. Analysis of surface roughness reflected that PVDF-TiO2 (MS-U2) surface morphological pattern was peak-valley structure that resisted fouling greatly. A good fitting of experimental result and Tansel's simulation illustrated that anti-fouling ability was realized direct ultrasonication modified membrane. PVDF-TiO2 (MS-U2) membrane showing the lowest |τ| reflecting the time required to reach a certain level of the fouling degree was the lowest. Relying upon modified Hermia's model analysis, protein blockage within the membrane pore was one major fouling mechanism; surface blockage degree of PVDF-TiO2 (MS-U2) was relative slight. Fouling mechanism analyzed by two models reflected that PVDF-TiO2 (MS-U2) membrane exhibited a higher anti-protein fouling ability during cross-flow filtration process.

Moving bed biofilm reactor (MBBR) has attracted much interest because of its flexibility, compactness, and stable functioning. It is a powerful technology that can efficiently treat municipal, industrial, and other refractory wastewater and has advanced rapidly in recent years. This chapter presents recent advances in moving carriers’ modification, influential factors, and functional microorganisms in MBBR and its nutrients and micro-pollutants removal. Carriers constitute the core of MBBR processes, and modifying the carriers to further improve their film-forming performance is exhibited. The basic mechanisms of MBBR such as microbiology, stoichiometry, and growth kinetics are reported. The design and operation of MBBR process, treatment costs, and limitations are discussed. The chapter also highlights the effective removal in organics and nitrogen of MBBR with respect to the operating conditions (e.g., hydraulic retention time, temperature, dissolved oxygen concentration, and carrier filling rate), and the composition and concentration of pollutants in the influent. The application of MBBR for elimination of micro-pollutants and the corresponding changes in the microbial community are also reviewed. Finally, the future perspectives of MBBR are also recommended.

Completely loss of granular structural stability and reliable start-up of aerobic granular sludge (AGS) system are considered as the biggest challenges for its engineering application under seasonal temperature variation, especially extremely low temperatures. In this study, two identical sequencing batch reactors (SBR) were successfully start-up at 10 °C (R1) and 25 °C (R2), respectively, and then operated under a strategy of stepwise change of temperatures to investigate the stability of the granular sludge by examining its microbial characteristics, bis (3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), extracellular polymeric substance (EPS) and sludge physiochemical properties. The results showed that AGS formed under the low temperature preferentially secrete EPS and c-di-GMP for stable granulation and improvement of its resistance to temperature changes. Meanwhile, R1 successfully obtained aerobic granulation with high biomass concentration and superior settleability, as well as high pollutant removal performance. In comparison, R2 took a longer time for granulation and was subjected to serious disintegration of AGS. The matrix structure partially formed by filamentous bacteria during the start-up stage in R1 was one of major reasons for its own superiority beyond R2 in granulation. Slow-growing organisms such as autotrophic nitrifying and Anammox bacteria, phosphorus accumulation organisms, EPS-producing genera, and c-di-GMP pathway-dependent genera, were exclusively enriched in the R1 and resulted in higher pollutants removal efficiencies and stable structure, whereas Sphaerotilus dominated in R2 that related closely with its unstable performance. Therefore, the strategy based on the stepwise change of temperatures from extremely low temperatures may be one feasible way for the sustainable application of AGS system, which is of significance to address the challenging problems of AGS applications.

Solar evaporation has attracted considerable interest to alleviate the shortage of water resources in the past few years. Lots of works have been done focusing on evaporation materials, rate, and efficiency, however, little attempts have been made to remove the harmful volatile organic compounds (VOCs), a kind of contamination that inevitably evaporate and condense alongside with water, which seriously affect the distilled water quality. This perspective puts forward some technical ideas utilizing chemical or physicochemical methods, aiming at the development of multifunctional composite materials, and forming an integrated evaporation system, which manage to remove VOCs in situ at the interface of photothermal evaporation.

A novel Polyacrylonitrile (PAN) composite membrane involving ZIF-8 nanoparticles, named as ZIF-8/PAN membrane, was obtained via electrospinning to remove the Congo red (CR), Pb(II) and Cu(II) ions in industrial wastewaters, during which the adsorption mechanisms were examined in this study. The adsorption efficiency of the electrospun ZIF-8/PAN membrane was as high as 89%, 92% and 76% for CR, Pb(II) and Cu(II), respectively. Comparative analysis showed that ZIF-8 nanoparticles embedded in the ZIF-8/PAN membrane accounted for these enhanced adsorption capabilities. The adsorption behaviors of the ZIF-8 nanoparticles were investigated through experiments and theoretical analysis, and the results unraveled that the adsorption for CR by the ZIF-8 was mainly including electrostatic interaction, hydrogen bonding and π-π interaction, while those for Pb(II) and Cu(II) were mainly caused by ion-exchange and chemical adsorption. Parametric studies were conducted to optimize the conditions for removing CR, Pb(II), and Cu(II) by ZIF-8 nanoparticles, during which all of pollutants showed different reactions to the solution pH. This work not only develops a novel ZIF-8/PAN composite membrane for effective removals of pollutants, but also reveals the underlying mechanisms of pollutants adsorption in terms of molecular interactions, providing important understandings on fibrous materials design for efficient heavy metals and dyes removals in industrial wastewater treatment.

Biochar prepared from pineapple peel was facially combined with polyurethane sponges for the first time to form homogeneous biocompatible biocarriers, which can enhance denitrification performance in an anoxic MBBR. The experiments showed that a higher NO3–-N removal efficiency (96.24 ± 1.3%) and kinetic constant (0.26 h−1) were obtained in the MBBR employing these new biocarriers (B-MBBR), compared with a control MBBR with polyurethane sponges (C-MBBR). The attached and suspended biomass of the B-MBBR was increased by 47% and 26%, respectively. Biochar significantly enhanced the abundance of functional bacteria in terms of promoting biofilm (i.e., Leptonema), denitrifying bacteria (i.e., Thauera, Enterobacter and Pseudomonas) and electroactive bacteria (i.e., Geobacter) in the B-MBBR. Meanwhile, based on the content of coenzyme I (NADH) and denitrifying enzymes, biochar would also enhance electron transport activity for denitrification. Consequently, these facial prepared biocarriers are effective to enhance denitrification performance in MBBR with application significance.

Understanding the mechanism by which perfluorochemicals (PFCs) adsorbed on carbonaceous surface is eventually important to the design and process optimization of effective PFCs removal technologies. In this study, the possible binding mechanism of six different PFCs onto carbonaceous surface was investigated by means of first principles quantum mechanical methods based on density functional theory (DFT) calculation and wave function analysis. The adsorption process fitted well with pseudo-second-order kinetic indicated that chemical bonding could not be underestimated. The results indicate that there were monolayer adsorption, electrostatic and hydrophobic interactions existed in PFCs adsorption process. DFT results suggested that the adsorption of PFCs on carbonaceous surface was one chemisorption process that accompanied by Van der Waals interactions. As there was different head functional groups in PFOS and PFOA, their adsorption capacity mainly controlled by the availability of active sites that was occupied by PFCs. The variation of chain length of PFBS and PFOS also take a certain responsible for different adsorption paths, due mainly to their hydrophobic effect. The obtained results from wave function and DFT analysis give in-depth understanding of PFCs adsorption on carbonaceous surface and help to their effectively removal.

NaOH could promote volatile fatty acids (VFAs) with the deterioration of sludge dewaterability and high concentrations of ammonia nitrogen (NH4+-N) and soluble phosphorus (SP) in sludge fermentation system. Whether calcium peroxide (CaO2), as a solid base, could improve the status quo is unknown. Therefore it is necessary to study the effect of CaO2 on primary sludge (PS) fermentation. Five experimental groups were conducted with different gradient doses of CaO2 and high-throughput sequencing was conducted to reveal the mechanisms. The results showed that CaO2 contributed to enhancing the yield of organic matter, but also reduced SP and improved the sludge dewaterability. The optimal CaO2 dosage was 0.10g/g VSS, and the yields of VFAs elevated from 872 to 2794 mg COD L−1, respectively. The concentration of SP in fermentation liquor declined from 23.74 to 3.23 mg L−1. The sludge dewaterability was improved with decreasing capillary suction time (CST) from 365 to 227 s. NH4+-N in fermentation was also controlled and the concentration declined from 581 to 276 mg L−1. For revealing the mechanism, high-throughput sequencing results demonstrated that CaO2 enhanced the bacterial richness and diversity, and Alkaliphilus, Acinetobacter, Macellibacteroides, Arobacter and Zoogloea significant increased with CaO2 adding. Meanwhile, metabolic pathway abundance results demonstrated that CaO2 promoted the microbial metabolism, and amino acid and lipid metabolisms led to VFAs and SCOD concentration increasing. As a whole CaO2 changed the microbial composition and metabolisms, and then effected soluble substrate generation.

Alumina ceramic membranes were synthesized by pressing boehmite into disc form and sintering at different temperatures. Quantitative X-ray diffraction (QXRD) analysis was firstly used for determining the compositions of different types of alumina in membrane products. The result quantitative determined that alumina membranes experienced a series of phase transition from boehmite → γ-alumina → δ-alumina → θ-alumina → α-alumina from 450 to 1300 °C. Below 850 °C, no significant alumina transformation (i.e. γ-alumina was the dominate phase) was detected in fabricated membranes, which corresponded to stable membrane properties (i.e. porosity, BET surface area, pore size and chemical stability). At 950–1300 °C, substantial phase transformation was detected as follows, θ-alumina significantly increased from 1.21 to 61.6% (950–1125 °C), and α-alumina increased gradually from 3.98 to 100% (1100–1300 °C). Accordingly, the substantial phase transformation lead to the significant change in membrane properties at 950–1300 °C. Lower temperature (1150 °C) membrane containing 8.2% θ-alumina and 91.8% α-alumina showed comparable properties with 1300 °C consist of 100% α-alumina sintered products due to the similar alumina composition in the products. The overall results indicated that the properties of membrane were accordingly determined by the structure and content of alumina phases in membrane products. This strategy proposed a valuable method for production of lower temperature alumina-based ceramic membrane.

In-situ non-invasive observation of concentration polarization (CP) and fouling layer is of vital importance to understanding membrane filtration process and membrane permeability loss. This study developed a novel real-time technique, laser induced fluorescence (LIF) technique, to visualize CP development and fouling layer formation, and to measure solute concentration field on the membrane surface directly during cross-flow nanofiltration, which helped to quantitatively evaluate the effect of various operation conditions on membrane permeability. The solute concentration distribution on the membrane surface was successfully determined from the LIF images, and the fouling layer thickness was measured by series of processed images after binary subtraction. LIF results demonstrated that the fouling development experienced approximate two stages, i.e. rapid growth phase and consolidation phase, and visualized the transition from initial CP to the later fouling layer formation. Afterwards, the formed fouling layer tend to be steady with nearly unchanging concentration and thickness. Quantitative analysis proved that the operational hydraulic condition has a significant influence on the formation and stabilization of fouling layer. The developed method and obtained results were very useful to in-depth recognize the nanofiltration process and to understand the membrane fouling mechanism.

With the rapid development of printed circuit board (PCB) industry, the problem of the release of tetrabromobisphenol A (TBBPA) during PCB manufacturing processes was recognized and harmful to the receiving water body. In this study, TBBPA generation paths, fates in industrial wastewater in the PCB manufacturing processes were analyzed. Gas chromatograph-mass spectrometer (GC-MS) scanning results showed that the raw materials including solder mask ink, character ink and dry film mainly contained TBBPA. The PCB fabrication procedures, mainly including development, etching, stripping of inner layer manufacturing process, and pattern plating, tin-plating of outer layer manufacturing process, and development during the forming and surface treatment process would introduce TBBPA into wastewater. Flocculation and activated sludge process (ASP) that were commonly used for industrial wastewater treatment were selected to assess their removal capability for TBBPA in the wastewater, both which could remove more than 80% TBBPA. Low pH below 7, increased PAC and PAM dosages, and proper dosing during the slow-stirring stage could enhance the TBBPA removal of flocculation-sedimentation process. The ASP removes TBBPA mainly by the path of adsorption. High activated sludge concentration, low pH, medium-temperature and limited competitive adsorbates (NH4+, Cu2+) were beneficial to remove TBBPA by the ASP.

Three ceramic MBRs (CMBR) installed with varied electrodes, i.e. Cu, Ti and Fe, were operated in parallel under the minute electric field to evaluate their suppression effect on membrane fouling, by comparison with control CMBR. Fe-CMBR released Fe2+ continuously to induce a higher organic removal efficiency and a smooth fouling rate. There was significant electric-flocculation effect in the Fe-CMBR, reflected by the increased sludge particle size and zeta potential, and to improve sludge filterability. Application of minute electric field could also affect the CMBR supernatant organic content and components, which was another reason for fouling mitigation. The formed membrane fouling layer was more easily to be detached by simple backwashing in all electric CMBRs, since that there were significant electric repulsive force to prevent foulants deposition.

Four new triazole-decorated silver(I)-based cationic metal-organic frameworks (MOFs), {[Ag(L1)](BF4)}n (1), {[Ag(L1)](NO3)}n (2), {[Ag(L2)](BF4)}n (3), and {[Ag(L2)](NO3)}n (4), have been synthesized using two newly designed ligands, 3-fluoro-5-(4H-1,2,4-triazol-4-yl)pyridine (L1) and 3-(4H-1,2,4-triazol-4-yl)-5-(trifluoromethyl)pyridine (L2). When the fluorine atom was changed to a trifluoromethyl group at the same position, tremendous enhancement in the MOF dimensionality was achieved [two-dimensional to three-dimensional (3D)]. However, changing the metal salt (used for the synthesis) had no effect. The higher electron-withdrawing tendency of the trifluoromethyl group in L2 aided in the formation of higher-dimensional MOFs with different properties compared with those of the fluoro derivatives. The fluoride group was introduced in the ligand to make highly electron-deficient pores inside the MOFs that can accelerate the anion-exchange process. The concept was proved by density functional theory calculation of the MOFs. Both 3D cationic MOFs were used for dye adsorption, and a remarkable amount of dye was adsorbed in the MOFs. In addition, owing to their cationic nature, the MOFs selectively removed anionic dyes from a mixture of anionic, cationic, and neutral dyes in the aqueous phase. Interestingly, the present MOFs were also highly effective for the removal of oxoanions (MnO4- and Cr2O72-) from water.

The organics (C) and nitrogenous (N) pollutants removal paths by functional units in vegetation-activated sludge process (V-ASP) were investigated by using stable isotope probing and high-throughput sequencing for the first time. V-ASP system displayed superior treatment performance compared to conventional activated sludge system, as manifested by its greater C and N removal efficiencies, higher abundance of denitrifying and heterotrophic functional Genus, and better resistance to low temperature. Isotope δ13C and δ15N were continuously accumulated in plant roots allocated in the V-ASP, where suspended sludge demonstrated obviously higher C and N enrichment rates compared to the rhizosphere sludge. The mass balance estimation showed that bacterial dissimilation was the dominant removal paths for C (54.13%) and N (47.53%). The underlying pollutants removal paths evidenced the advantageous of V-ASP that is a high feasible and promising approach for decentralized wastewater treatment process.

Endevours on the enhancement of nitrate removal efficiency during methane oxidation coupled with denitrification (AME-D) has always overlooked the role of membrane employed. It would be highly beneficial to enrich the biomass content and to manage biofilm on the membrane, in the utilization of methane and denitrification. In this study, an innovative and scalable double-layer membrane (DLM) was designed and prepared for a membrane biofilm reactor (MBfR), to simultaneously enhance nitrate removal flux and methane utilization efficiency during aerobic methane oxidation coupled with the denitrification (AME-D) process. The DLM allowed quick bacterial attachment and biomass accumulation for biofilm growth, which would be then self-regulated for well distribution of functional microbes on/within the DLM. Upon a high biofilm density of over 70 g-VSS m−2 achieved on the DLM, the methane utilization efficiency of the MBfR was enhanced significantly to over 1.3 times than the control MBfR with conventional polypropylene membrane. The MBfR employed DLM also demonstrated the maximum nitrate removal flux of 740 mg-NO3−-N m−2 d−1 that was approximately 1.64 times of that in control MBfR at continuous-mode operation. This DLM indeed favored the enrichment of Type II aerobic methanotrophs of Methylocystaceae, and methanol-utilization denitrifiers of Rhodocyclaceae that preferentially utilize methanol as the cross-feeding intermediates to promote the methane utilization efficiency, and thus to enhance the nitrate removal flux. These results raised from new designed DLM confirmed the importance of membrane surface properties on the effectiveness of MBfR, and offered great potential to address challenging problems of MBfRs during engineering application.

Iodinated contrast media (ICM), which was widely used in medical imaging and was difficult to remove by conventional wastewater treatment methods, attained much attention due to its potential environmental impacts. Herein, iopamidol (IPM), one typical compound of ICM, was found to be rapidly degraded by ferrous activated persulfate oxidation (Fe(II)/PS) as compared with PS or Fe(II) alone. With a persulfate concentration of 1 mmol L−1, n(Fe(II))/n(PS) of 1:10, and a pH of 3.0, 78% IPM was degraded within 60 min, with a degradation rate of 0.1266 min−1. It was demonstrated that IPM degradation and deiodination were favored by a high temperature, while affected positively by acidic and neutral conditions. Radical quenching experiments and Electron Paramagnetic Resonace (EPR) spectra showed that the combined effects of SO4−· and ·OH contributed dominantly to degrade IPM, while the ·OH played an essential role during the degradation reaction. Through the Discrete Fourier Transform quantum chemical calculation, the possible reaction pathways for the oxidation of IPM by ·OH are as follows: IPM-TP651-TP667-TP541-TP557, IPM-TP651-TP525-TP557, IPM-TP705-TP631-TP661, and IPM-TP705-TP735. The obtained results showed that IPM could be degraded effectively by Fe(II)/PS system, giving a promising technique for IPM removal from water.

The soil−air partition coefficients (KSA) of polybrominated diphenyl ethers (PBDEs) and organophosphate flame retardants (OPFRs) is important for determining their fate in soil and air media. However, KSA values of OPFRs and PBDEs are not available from the current literature, and the effects of environmental factors such as temperature and relative humidity (RH) on KSA values are not clear. In this study, a solid-phase fugacity meter was used to measure the KSA values of PBDEs and OPFRs at different temperatures (25, 30, 35, 40, and 45 °C) and relative humidity (RH) conditions (