Development and modeling of an integrated fixed-film activated sludge (IFAS) system for simultaneous nitrogen and carbon removal from an industrial estate wastewater.

The potential of an integrated fixed film activated sludge (IFAS) bioreactor for developing simultaneous aerobic and anoxic micro-zones under continuous aeration regime to promote carbon and nitrogen removal from Faraman industrial estate wastewater was evaluated in the present research. The effects of three independent variables on carbon and nitrogen removal were assessed. Overall, the optimum condition with 94 %, 77 %, and 2 NTU of COD (chemical oxygen demand) removal, Total nitrogen (TN) removal, and effluent turbidity has been specified with hydraulic retention time (HRT) of 11 h, air flow rate (AFR) of 3.5 L/min, and filling ratio (FR) of 50 %. To assess the stability of treating processes in the system, the IFAS system was operated in this optimal condition. Moreover, the simulation of the bioreactor was accomplished via calibration and verification of GPS-X model. GPSX simulation results and experimental data were compared using an independent sample T-test, which the T-test result confirmed that there was no significant difference between them.

Arsenic and total dissolved solids removal using antibacterial/antifouling nanofiltration membranes modified by functionalized graphene oxide and copper ferrodioxide.

The intrinsic hydrophilicity of metal compounds, such as copper ferrite (CuFe2 O4 ), and organic compounds, including graphene oxide (GO) and triethylenetetramine (TETA), make them promising adsorbents for heavy metals removal. The presence of lone pairs in these compounds is observed in modified polyethersulfone membranes used for the separation of arsenic (As) and total dissolved solids (TDS), including mono and divalent salts from aqueous solutions. The objective of this study was to investigate the performance of GO-TETA-CuFe2 O4 membranes for wastewater treatment applications. The membranes were characterized for their optimal mechanical strength (tensile strength) and high negative charge (zeta potential) on the surface. Separation tests were conducted at different pressures and pH levels to evaluate the membrane's effectiveness in removing contaminants. In addition, the membranes were examined for their antibacterial properties. The modified membrane exhibited superior performance compared with the control membrane, with TDS removal rates of 93.8%, As3+ removal rates of 81.2%, and As5+ removal rates of 87.9%. The contact angle of the modified membrane was reduced, resulting in an increase in pure water flux from 13.11 to 27.87 L/m2 .h. The modified membrane also demonstrated significantly higher resistance to fouling than the control membrane, with a resistance increase from 6.78 × 10+12 to 2.07 × 10+12  m-1 . This contributed to the improved separation performance of As and TDS in a cross-flow setup. The results suggest that the GO-TETA-CuFe2 O4 modified membrane has great potential for use in water treatment applications. PRACTITIONER POINTS: GO-TETA-CuFe2 O4 was successfully used for modification of PES NF membrane structure. The efficiency of blended NF membranes with GO-TETA-CuFe2 O4 significantly increased. The modified membranes exhibited significant water flux and antifouling properties. The GO-TETA-CuFe2 O4 /PES membranes showed high rejection of heavy metal ions and TDS than PES. The GO-TETA-CuFe2 O4 /PES membranes exhibited desirable antibacterial activity.

Design of a new polyethersulfone nanofiltration membrane with anti-fouling properties using supported protic ionic liquid modification for dye/salt removal.

Facile techniques to fabricate the nanofiltration membranes with ideal molecular sieving is one of the most interesting subjects in membrane separation technology. In this study, the application of modified graphene oxide (GO) with triethylenetetramine (TETA), CuFe2 O4 , and acetic acid (AC) (supported GO-TETA-CuFe2 O4 @AC) as a supported protic ionic liquid (PIL) modifier for polyethersulfone (PES) membrane was evaluated to approve the improvement of anti-fouling properties and wastewater rejection of the fabricated membranes. To enhance the key properties of graphene oxide, it was modified by hydrophilic nanomaterials (TETA-CuFe2 O4 ). High flux and promising flux recovery ratio (up to 95% compared to the unmodified membrane) can be observed in the modified membranes. The modified membranes by GO-TETA-CuFe2 O4 @AC were studied at optimum concentrations (0.5 wt.%) for salt rejection and different dyes. The obtained data indicated that the modified membranes by GO-TETA-CuFe2 O4 @AC indicated higher salt removal (up to 97% for BaCl2 than the unmodified membrane), which was related to the efficient modification. The obtained pure water flux (PWF) for bare and optimal modified membrane from 13.11 to 27.87 kg/m2 ·h, respectively. To exact evaluate the effect of membrane modification on performance examination, the modified membranes were evaluated for chlorine resistance testing. This study aimed to develop cost-effective nanofiltration (NF) membranes with high anti-fouling properties and to determine the maximum filtration capacity of in-time dyes and salts in effluents. PRACTITIONER POINTS: A GO-TETA-CuFe2O4 mixed matrix membrane was prepared for removal of salts and dyes. The effect of GO-TETA-CuFe2O4 enhanced the hydrophilicity and porosity. The membrane exhibited superior antifouling properties and ions rejection.

Enhanced oil removal from a real polymer production plant by cellulose nanocrystals-serine incorporated polyethersulfone ultrafiltration membrane.

As discharging oily wastewater from industries to the environment is a potential threat for the aquatic ecosystem, in this research, oil removal from a real case of Kermanshah polymer production plant wastewater was investigated. The focus of this study was on improving the oil rejection performance of polyethersulfone (PES) ultrafiltration membrane due to adding cellulose nanocrystals (CNC) and modified CNC with serine amino acid (CNC-Ser) in PES mix matrix. From the results, the membranes embedded with CNC-Ser showed better performance in terms of water flux, flux recovery ratio, and oil rejection (higher than 97%) compared to the modified membranes with CNC. The lowest water contact angle (41.37°), smoother surface, and higher negative surface potential (- 24 mV) were achieved for the optimum loading of CNC-Ser. Besides, long-term performance of the membranes with optimum loading of CNC and CNC-Ser were compared in both dead-end and cross-flow setups.

Color removal from wastewater using a synthetic high-performance antifouling GO-CPTMS@Pd-TKHPP/polyether sulfone nanofiltration membrane.

Modified graphene oxide with 5,10,15,20-tetrakis-(4-hexyloxyphenyl)-porphyrin and palladium (II) (signified by GO-CPTMS@Pd-TKHPP) prepared as a novel antifouling polyether sulfone (PES) blended nanofiller membrane. The membrane efficiency has been analyzed such as pure water flux (PWF), hydrophilicity, and antifouling features. By increasing of modified graphene oxide percentage from 0 to 0.1 wt.% in the polymer matrix, the PWF was incremented from 14.35 to 37.33 kg/m2·h at 4 bar. The membrane flux recovery ratio (FRR) has been investigated by applying powdered milk solution; the FRR results indicated that the 0.1 wt.%-modified graphene oxide membrane showed a positive effect on fouling behavior with Rir and FRR value 8.24% and 91.76%, respectively. The nanofiltration membrane performance was assessed applying the Direct Red 16 dye rejection. It was demonstrated that the optimal membranes (0.1 wt.%-modified graphene oxide) had notable dye removal (99.58% rejection). The results are also verified by measuring the scanning electron microscopy (SEM), water contact angle (WCA), and atomic microscopy analysis (AFM).

Optimization of the electrochemical reduction process and ORP effects in nitrate removal.

Nitrate contaminated water resources, a huge environmental problem for countries, including our own. This research aims to evaluate the efficiency of the electrochemical process for the removal of nitrate from the aqueous solution by direct and alternating current. Experiments were done by the Taguchi method, including electrode array, time exposure, voltage, pH, and the initial concentration of nitrate. Minitab 17 and SPSS 18 software were utilized to design and data analysis. In detail, the connection of the electrodes was monopolar, and the direct current (DC) has a greater efficiency as alternating current (AC) in the nitrate removal (p > 0.001). In AC, the nitrate initial concentration, voltage, electrodes material, contact time, and pH have the most effect on the nitrate removal. The optimized conditions for nitrate removal include Al-Al electrode, pH of 7, a voltage of 30 V, and nitrate initial concentration of 100 mg/L with the contact of time 150 min. Selection of appropriate materials for electrodes construction, adequate voltage, and removal of intervention agents from aqueous solution led to greater removal efficiencies. The optimized conditions that can reduce the aqueous solution ORP with high speed and the electrochemical reactor efficiency for nitrate removal were increased. PRACTITIONER POINTS: Electrochemichal (EC) process is evaluated for treatment of nitrate wastewater for the first time. High removal efficiency (over 95%) from nitrate wastewater was obtained. Minimizing energy consumption and maximizing nitrate removal were simultaneously achieved in the integrated single EC process.