Removal of cyanide from acrylonitrile wastewater using gas membrane

2011 ◽  
Vol 64 (11) ◽  
pp. 2274-2281 ◽  
Author(s):  
Jinling Wu ◽  
Jianlong Wang ◽  
Haiyang Liu ◽  
Shijun He ◽  
Xia Huang
Keyword(s):  
Membrane Fouling ◽  
Removal Rate ◽  
Treatment Strategies ◽  
Pilot Scale ◽  
Inorganic Salts ◽  
Operational Parameters ◽  
High Concentration ◽  
Operational Conditions ◽  
Industrial Wastewaters ◽  
Pre Treatment

Acrylonitrile wastewater is one of the most refractory industrial wastewaters as it contains cyanide at a high concentration. This study introduced a safe, effective and economic strategy, that is, use of the gas membrane to acrylonitrile wastewater treatment. Due to the complicated constituents of acrylonitrile wastewater, cyanide removal rate by gas membrane is very low. In order to enhance HCN removal, the operational conditions were optimized; pre-treatment strategies for fouling mitigation were also proposed and tested for acrylonitrile wastewater. The optimal operational parameters were achieved at an acidified pH of 5.0, wastewater velocity of 0.14 m s−1, NaOH concentration of 10% and a temperature of 40 °C. The major factor affecting HCN removal was the pH of the acidified wastewater. The reason for the low removal rate was further explored and found to be the decrease of HCN transfer coefficient, which was caused by membrane fouling. Furthermore, the predominant foulants have been identified as colloidal organic materials and inorganic salts. Alkalization, which is effective in reducing these materials, has been proven to be most effective in mitigating membrane fouling and improving HCN removal, which was also confirmed by a pilot-scale study. The overall removal rate was therefore significantly enhanced to 87.1%.

scholarly journals Heterogeneous Photo-Fenton Catalytic Degradation of Practical Pharmaceutical Wastewater by Modified Attapulgite Supported Multi-Metal Oxides

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 156
Author(s):  
Manjing Lu ◽  
Jiaqi Wang ◽  
Yuzhong Wang ◽  
Zhengguang He
Keyword(s):  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Catalytic Degradation ◽  
Gas Chromatography Mass Spectrometry ◽  
Pharmaceutical Wastewater ◽  
High Concentration ◽  
Modified Attapulgite ◽  
Cod Removal Rate ◽  
Pre Treatment ◽  
Almost All

Chemical synthetic pharmaceutical wastewater has characteristics of high concentration, high toxicity and poor biodegradability, so it is difficult to directly biodegrade. We used acid modified attapulgite (ATP) supported Fe-Mn-Cu polymetallic oxide as catalyst for multi-phase Fenton-like ultraviolet photocatalytic oxidation (photo-Fenton) treatment with actual chemical synthetic pharmaceutical wastewater as the treatment object. The results showed that at the initial pH of 2.0, light distance of 20 cm, and catalyst dosage and hydrogen peroxide concentration of 10.0 g/L and 0.5 mol/L respectively, the COD removal rate of wastewater reached 65% and BOD5/COD increased to 0.387 when the reaction lasted for 180 min. The results of gas chromatography-mass spectrometry (GC-MS) indicated that Fenton-like reaction with Fe-Mn-Cu@ATP had good catalytic potential and significant synergistic effect, and could remove almost all heterocycle compounds well. 3D-EEM (3D electron microscope) fluorescence spectra showed that the fluorescence intensity decreased significantly during catalytic degradation, and the UV humus-like and fulvic acid were effectively removed. The degradation efficiency of the nanocomposite only decreased by 5.8% after repeated use for 6 cycles. It seems appropriate to use this process as a pre-treatment for actual pharmaceutical wastewater to facilitate further biological treatment.

scholarly journals Determination of optimum operational conditions for the removal of 2-MIB from drinking water by peroxone process: a pilot-scale study

2020 ◽  
Vol 20 (6) ◽  
pp. 2339-2347
Author(s):  
M. Fakioglu ◽  
H. Gulhan ◽  
H. Ozgun ◽  
M. E. Ersahin ◽  
I. Ozturk
Keyword(s):  
Drinking Water ◽  
Contact Time ◽  
Advanced Oxidation Process ◽  
Removal Rate ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Operational Conditions ◽  
Taste And Odor ◽  
Water Supply And Treatment

Abstract Taste and odor in drinking water are one of the main problems of the water supply and treatment sector. Peroxone is an effective advanced oxidation process, which combines ozone with hydrogen peroxide to create hydroxyl radicals that decompose organic compounds. 2-Methylisoborneol (2-MIB) is one of the significant taste and odor causing compounds, which can be removed with the peroxone process. In this study, removal of a 2-MIB compound by peroxone process was investigated in a pilot-scale treatment plant and optimum operational conditions were determined. For safety reasons, it is important that residual O3 and H2O2 concentrations in the water leaving the reactor should not exceed 0.1 and 0.5 mg/L, respectively. Results indicate that while dissolved ozone concentration was below the indicated limit for all experiments, concentrations over 0.5 mg/L residual H2O2 were observed during the experiments with an H2O2:O3 ratio of 0.5. This limit exceedance affected the decision on the ideal peroxone ratio along with the 2-MIB removal results. Therefore; optimum H2O2:O3 ratio was determined as 0.3. 2-MIB removal efficiency of 81% was achieved at the optimum H2O2:O3 ratio with a contact time of 15 min. According to the results, 2-MIB removal rate had a linear correlation with the contact time.

Treatment of septage in constructed wetlands in tropical climate: lessons learnt from seven years of operation

2005 ◽  
Vol 51 (9) ◽  
pp. 119-126 ◽  
Author(s):  
T. Koottatep ◽  
N. Surinkul ◽  
C. Polprasert ◽  
A.S.M. Kamal ◽  
D. Koné ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Treatment Options ◽  
Pilot Scale ◽  
Flow Mode ◽  
Critical Limit ◽  
Local Conditions ◽  
Tropical Regions ◽  
Operational Conditions ◽  
Pre Treatment ◽  
Sanitation Systems

In tropical regions, where most of the developing countries are located, septic tanks and other onsite sanitation systems are the predominant form of storage and pre-treatment of excreta and wastewater, generating septage and other types of sludges. The septage is disposed of untreated, mainly due to lack of affordable treatment options. This study presents lessons that have been learned from the operation of pilot-scale constructed wetlands (CWs) for septage treatment since 1997. The experiments have been conducted by using three CW units planted with narrow-leave cattails (Typha augustifolia) and operating in a vertical-flow mode. Based on the experimental results, it can be suggested that the optimum solids loading rate be 250 kg TS/m2 yr and 6-day percolate impoundment. At these operational conditions, the removal efficiencies of CW units treating septage at the range of 80–96% for COD, TS and TKN were achieved. The biosolid accumulated on the CW units to a depth of 80 cm has never been removed during 7 years of operation, but bed permeability remained unimpaired. The biosolid contains viable helminth eggs below critical limit of sludge quality standards for agricultural use. Subject to local conditions, the suggested operational criteria should be reassessed at the full-scale implementation.

Comparative investigation on the impact of polymeric substances on membrane fouling during sub-critical and critical flux operation of a municipal membrane bioreactor

2008 ◽  
Vol 58 (9) ◽  
pp. 1849-1855 ◽  
Author(s):  
S. Lyko ◽  
T. Wintgens ◽  
T. Melin
Keyword(s):  
Membrane Fouling ◽  
Pilot Scale ◽  
Comparative Investigation ◽  
Hollow Fibre ◽  
Size Exclusion ◽  
Dominant Factor ◽  
Permeate Flux ◽  
Critical Flux ◽  
Operational Conditions ◽  
The Impact

Soluble organic macromolecules are ubiquitous in activated sludge supernatant. For the operation of membrane bioreactors (MBR) this group of substances is considered as the dominant factor causing severe membrane fouling due to the concentration polarisation phenomenon. The well established critical flux concept for the characterisation of membrane bioreactor's operation limits is based on filtration data only. As there is an cause-and-effect relation between the partial retention of organic compounds and the limited flux according the critical flux concept the aim of this study was to draw a comparison between different permeate fluxes on the retention of organic macromolecules. Thus, a municipal pilot-scale MBR with three capillary hollow fibre membrane modules was operated in sub critical, critical and supercritical flux mode, respectively and the retention of macromolecules was quantified by size exclusion chromatography. Three permeate extraction pumps allow a simultaneous operation with different operational conditions for each membrane module and proved the crucial impact of permeate flux on the fouling rate. The interchange of these conditions gave evidence of an optimised start-up procedure for MBRs characterised by higher permeate fluxes. An increased flux causes both a higher retention of soluble macromolecules and subsequent a higher fouling rate.

Performance and membrane foulant in the pilot operation of a novel biofilm-membrane reactor

2002 ◽  
Vol 2 (2) ◽  
pp. 177-183
Author(s):  
K. Kimura ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Reactor ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
Manganese Concentration ◽  
Membrane Cleaning ◽  
Chemical Washing ◽  
Pre Treatment ◽  
Solid Liquid ◽  
Solid Liquid Separation

We have developed a novel biofilm-membrane reactor (BMR) in which a nitrifying biofilm is fixed on the surface of a rotating membrane disk. With this reactor, both strict solid-liquid separation and oxidation of ammonia nitrogen can be simultaneously performed. Based on the results obtained in previous bench-scale experiments, a pilot-scale study was conducted using river water at a water purification plant. The results obtained in the pilot study can be summarized as follows. (1) By implementation of pre-treatment (coagulation and sedimentation) and simple membrane cleaning (sponge cleaning), the filter run could be continued for 17 months without any chemical washing. (2) Sufficient nitrification was observed when water temperature was high. Deterioration in nitrification efficiency during winter was reduced by the addition of phosphorus. (3) In addition to nitrification, biological oxidation of AOC and manganese can be expected with the BMR. In this study, both AOC and manganese concentration in the permeate decreased to a level less than 10 μg/L. (4) Irreversible membrane fouling, which was thought to be mainly caused by manganese, became significant as the operation period became longer.

scholarly journals The Treatment of High Concentration Dyeing Wastewater with Pulsed Current Electrocoagulation

2016 ◽  
Vol 10 (5) ◽  
pp. 87 ◽  
Author(s):  
Jun Wang ◽  
Hong Cheng Tan ◽  
Yong Liang Zhang ◽  
Yong Zhang Pan
Keyword(s):  
Electrode Materials ◽  
Ph Value ◽  
Anaerobic Treatment ◽  
Ammonia Nitrogen ◽  
Pulsed Current ◽  
Dyeing Wastewater ◽  
High Concentration ◽  
Operational Conditions ◽  
Effluent Quality ◽  
Pre Treatment

<p>In this study, a small pulsed current electrocoagulation device was used to treat high concentration dyeing wastewater from a specific dyeing mill, and the effects of the electrode materials, reaction time, voltage, pH value, and aeration on the results of the treatment were examined. The results showed that under the following operational conditions: electrode materials were iron electrodes, time period was 15 min, voltage was 120 V, and initial pH was approximately 6, the removal rates of the COD, ammonia nitrogen, and color were 79.45%, 23.89%, and 87.50%, respectively. On this basis, a pulsed current electrocoagulation device, with a handling capacity of 0.5 m<sup>3</sup>/h, was used to conduct a pilot plant test for a period of one month. The results showed that the effluent quality (COD 1217.4 mg/L and NH<sub>4</sub><sup>+</sup>-N 358.2 mg/L on average) of the high-concentration dyeing wastewater, whose COD and NH<sub>4</sub><sup>+</sup>-N concentrations were 5328 mg/L, 595 mg/L, respectively after the treatment of a pulsed current electrocoagulation reactor, was superior to the effluent quality (COD 1400 mg/L and NH<sub>4</sub><sup>+</sup>-N 450 mg/L) of the mill’s actual pre-treatment system (flocculation-anaerobic treatment-acidification), and fully reached the influent requirements of the subsequent aerobic treatment. The results of this study showed that pulsed current electrocoagulation reactors may be effectively used for the pre-treatment of high concentration dyeing wastewater due to the observed advantages, such as good treatment effects, small investment, and economical space occupation.</p>

The fouling characterization and control in the high concentration PAC membrane bioreactor HCPAC-MBR

2005 ◽  
Vol 51 (6-7) ◽  
pp. 77-84 ◽  
Author(s):  
G.T. Seo ◽  
S.W. Jang ◽  
S.H. Lee ◽  
C.H. Yoon
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Pilot Scale ◽  
High Concentration ◽  
Nakdong River Basin ◽  
Cake Layer ◽  
Experimental Apparatus ◽  
Operation Period

This study focuses on the experimental investigation to identify the effect of PAC at high concentrations on the fouling of membranes. A pilot-scale experimental apparatus was installed at a water treatment plant located downstream of Nakdong river basin, Korea. Effluent of rapid sand filter was used as influent of the system, which consists of PAC bio-reactor, submerged membrane module (hollow fiber with pore size 0.1 μm) and air supply facility. PAC was dosed at 40 g/L initially and it was not replaced during the operation period. Suction type filtration was carried out at intervals of 12 min. suction and 3 min. idling. At the initial flux 0.36 m/d, the system could be operated stably for around 90 days at target trans-membrane pressure (TMP) of 40 kPa. Among total resistance of membrane filtration, cake and gel layer resistance, Rc+Rg, was the dominant fraction (more than 90% of the total) to increase the filtration pressure, which means that the filtration resistance could be controlled by the PAC cake layer and then irreversible membrane fouling could be prevented. Three minutes air backwashing every 3 days could extend the operation period to 127 days. Organics were analyzed in terms of molecular weight structure. The influent of the system consists of 15.0% and 74.4% of hydrophobic and hydrophilic natural organic matter (NOM), respectively. Hydrophobic and hydrophilic (electrostatic) interaction was the main factor on fouling of the membrane in the reactor. Hydrophobic fraction decreased slightly in the effluent, which means hydrophobic NOM removal in the reactor by adsorption. Organics accumulated in the membrane were extracted for analysis after a certain period of operation. The fraction of hydrophobic and hydrophilic organics was 41.4% and 38.9%, respectively. On the basis of the experimental results, the hydrophobic organics were the major materials causing the fouling of the membrane, which should be changed to other types of material.

scholarly journals Capillary Nanofiltration under Anoxic Conditions as Post-Treatment after Bank Filtration

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1599 ◽  
Author(s):  
Jeannette Jährig ◽  
Leo Vredenbregt ◽  
Daniel Wicke ◽  
Ulf Miehe ◽  
Alexander Sperlich
Keyword(s):  
Organic Carbon ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Bank Filtration ◽  
Organic Micropollutants ◽  
Current Water ◽  
Pre Treatment ◽  
Iron And Manganese ◽  
Good Retention

Bank filtration schemes for the production of drinking water are increasingly affected by constituents such as sulphate and organic micropollutants (OMP) in the source water. Within the European project AquaNES, the combination of bank filtration followed by capillary nanofiltration (capNF) is being demonstrated as a potential solution for these challenges at pilot scale. As the bank filtration process reliably reduces total organic carbon and dissolved organic carbon (DOC), biopolymers, algae and particles, membrane fouling is reduced resulting in long term operational stability of capNF systems. Iron and manganese fouling could be reduced with the possibility of anoxic operation of capNF. With the newly developed membrane module HF-TNF a good retention of sulphate (67–71%), selected micropollutants (e.g., EDTA: 84–92%) and hardness (41–55%) was achieved together with further removal of DOC (82–87%). Fouling and scaling could be handled with a good cleaning concept with acid and caustic. With the combination of bank filtration and capNF a possibility for treatment of anoxic well water without further pre-treatment was demonstrated and retention of selected current water pollutants was shown.

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