Hybrid Treatment Systems for Dye Wastewater

In the paper

“Studies generally show that AOPs and membrane processes are more costly than biological processes.”

In the paper

“Conversely, enhancement of COD removal (e.g., after ozonation) 127 or improvement of settleability of sludge (e.g., after electrofloatation) 43,130 may require physico-chemical treatment subsequent to AOPs.”

What the sources say

• ?Not checked — no full text of the sourcecites [127] source
• ?Not checked — no full text of the sourcecites [43] source
• ?Not checked — no full text of the sourcecites [130] source

In the paper

“The main step in dye removal for activated carbon amended biological process is microbial degradation, which is higher than adsorption on both activated carbon as well as on biomass.49”

What the sources say

• ?Not checked — no full text of the sourcecites [49] Costa C., 1997, Water Res. source

In the paper

“A novel approach entailing partial bioregeneration (physical adsorption on fluidized biological GAC followed by biodegradation and desorption), coupled with complementary periodic physical regeneration of 50% of total GAC, has been reported by Vuoriranta et al. 217 The system was observed to achieve an improved COD and color removal apart from reduction in regeneration cost and weight loss of GAC.”

What the sources say

• ?Not checked — no full text of the sourcecites [217] Vuoriranta P., 1994, Water Sci. Technol. source

In the paper

“In the coagulation process, it is difficult to remove highly water-soluble dyes, and even more important, the process produces a large quantity of sludge.179”

What the sources say

• ?Not checked — no full text of the sourcecites [179] source

In the paper

“These processes are cost prohibitive and complex at the present level of their development.163”

What the sources say

• ?Not checked — no full text of the sourcecites [163] source

In the paper

“A typical example of such processes is combination of advanced oxidation with an activated sludge treatment where the chemical oxidation is specifically aimed to partially degrade the recalcitrant contaminants to more easily biodegradable intermediates, thereby, enhancing subsequent biological unit and simultaneously avoiding the high costs of total mineralization by AOP.”

In the paper

“On the other hand, the dose of coagulants and consequently the quantity of the chemical sludge after biological treatment are smaller compared to those in coagulation followed by biological treatment.57,75,100”

What the sources say

• ?Not checked — no full text of the sourcecites [57] Dulkadiroglu H., 2002, Water Sci. Technol. source
• ?Not checked — no full text of the sourcecites [75] Grau P., 1991, Water Sci. Technol. source
• ?Not checked — no full text of the sourcecites [100] source

In the paper

“Further oxidation may not lead to any significant changes in the molecular weight distribution, but results in an increasing mineralization of low molecular weight biodegradable substances.92”

What the sources say

• ?Not checked — no full text of the sourcecites [92] source

In the paper

“Their stand alone application in treating textile/dye waste is, however, relatively ineffective 79,101,163 , for example, only 50% removal was achieved using either alum or ferrous sulfate for an azo reactive yellow dye.79”

What the sources say

• ?Not checked — no full text of the sourcecites [79] source
• ?Not checked — no full text of the sourcecites [101] source
• ?Not checked — no full text of the sourcecites [163] source

In the paper

“Nonetheless, the extent of combined COD removal achievable with this strategy may be limited in some cases, making utilization of a longer oxidation period necessary and the following biological process redundant.170”

What the sources say

• ?Not checked — no full text of the sourcecites [170] Poole A. J., 2004, Water Res. source

In the paper

“Biological treatment is a cost-competitive and eco-friendly alternative.”

In the paper

“Virtually all the known physico-chemical and biological techniques have been explored for treatment of extremely recalcitrant dye wastewater; none, however, has emerged as a panacea.”

• Also stated in: § I. INTRODUCTION · plain

  “despite the fact that virtually all the known physico-chemical and biological techniques have been explored for decolorization, 79 none has emerged as a panacea.”

What the sources say

• ?Not checked — no full text of the sourcecites [79] source

In the paper

“Coagulation followed by adsorption was reported to produce effluent of reuse standard, apart from cutting down the coagulant consumption by 50%, hence, lowering the volume of sludge formed, in comparison to coagulation only.163”

What the sources say

• ?Not checked — no full text of the sourcecites [163] source

In the paper

“combination of appropriate techniques is deemed imperative to devise technically and economically feasible options.”

• Also stated in: § I. INTRODUCTION · plain

  “combination of different techniques is required to devise a technically and economically feasible option.”

In the paper

“If considerable amount of biodegradable compounds originally exist in the wastewater, pre-oxidation step obviously will not lead to a significant improvement of biodegradability, rather will cause unnecessary consumption of chemicals.”

In the paper

“Although simultaneous adsorption and biodegradation treatment occasionally has been demonstrated as a mere combination of adsorption and biodegradation without any mutual enhancement 159 and has controversies in bioregeneration hypothesis 225 , application of this process to the treatment of textile wastewaters is an important economic improvement.”

What the sources say

• ?Not checked — no full text of the sourcecites [159] source
• ?Not checked — no full text of the sourcecites [225] source

In the paper

“Cost-competitive biological options are rather ineffective while physico-chemical processes are restricted in scale of operation and pollution profile of the effluent.”

In the paper

“For instance, Fenton-like treatment using Nafion-Fe +3 membrane, rather than direct addition of iron salt 17 , or immobilized TiO 2 photocatalysis rather than photo-Fenton process 164 would facilitate further biological treatment under biocompatible pH making neutralization redundant.”

What the sources say

• ?Not checked — no full text of the sourcecites [17] Balanosky E., 1999, Water Sci. Technol. source
• ?Not checked — no full text of the sourcecites [164] source

In the paper

“Accordingly although the dye removal in that process has frequently been reported to be better than in the conventional activated sludge process 161,197 , mode of COD removal may be the same.49”

What the sources say

• ?Not checked — no full text of the sourcecites [161] source
• ?Not checked — no full text of the sourcecites [197] source
• ?Not checked — no full text of the sourcecites [49] Costa C., 1997, Water Res. source

In the paper

“As mentioned earlier, adsorption is a non-destructive method involving only phase change of pollutants, and hence imposes further problem in the form of sludge disposal.”

In the paper

“Hybrid processes based on membrane and photocatalysis have been reported to eradicate the problem of ultrafine catalyst to be separated from the treated liquid in case of slurry reactors, with the added advantage of membrane acting as selective barrier for the species to be degraded.”

In the paper

“Hence it is strongly believed that their combination will result in more free radicals, thereby increasing the rates of reactions.72,73”

What the sources say

• ?Not checked — no full text of the sourcecites [72] source
• ?Not checked — no full text of the sourcecites [73] source

In the paper

“Carbonbiocatalyst amalgamation in adsorption cartridges for decoloration has been commercialized ('BIOCOL') in UK.48”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [48]

In the paper

“To sustain an uninterrupted supply of non-specific extra cellular enzyme by fungi, the reactor requires to be operated under a quasi-controlled environment (acidic pH) with simultaneous supply of an easily biodegradable carbon source (e.g., starch used in textile sizing).”

In the paper

“It is worth mentioning here that recovery/ reuse of both chemicals and water is different from that of only water, in that, the former entails handling of the point sources separately, while the latter may be achieved by following usual end-of-pipe strategy (mixing different streams).”

In the paper

“Under natural pH (10.66) 5 min pre-ozonation (293 mg/l), removing high UV-absorbing components (60% reduction in UV 254 ), accelerated subsequent 55 min.H 2 O 2 (50 mmol/l)-UV(25W) treatment, enhancing its COD & TOC removal efficiency by a factor of 13 & 4, respectively; the combined treatment yielding 25% COD, 50% TOC & complete color removal (Initial COD=1476 mg/l; TOC= 336mg/l).”

What the sources say

• ?Not matched

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  cites 8 (2001)

In the paper

“H 2 O 2 , yielding .OH by reacting with hydrated electron formed in radiolysis of water, achieved enhanced decoloration (100%, 50 ppm dye) and COD removal (76-80%) with 1 and 15 kGy doses for RB5 and RB15, respectively, decoloration (%) being the highest at the lowest dose rate (0.14 kGy/h).”

What the sources say

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  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 194 (2002)

In the paper

“Development of such a system offering stable 99% decoloration and 97% TOC removal from synthetic textile wastewater along with avoidance of membrane fouling has been recently documented.78”

What the sources say

• ?Not checked — no full text of the sourcecites [78] source

In the paper

“TOC removal [180 min.]:30%; Decoloration [30 min.]:75-85% for 60-100 mg/L concentration; Low efficiency due to radical scavenging by the graphite cathode.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 116 (2004)

In the paper

“Combined sonolysis (520 kHz) and ozonation (irradiation intensity, O 3 input and volume were 1.63 W cm -2 ; 50 l h/1; and 600 ml) showed synergistic effect, doubling the decolorization (100%, 15 min.)and mineralization (76%, 1hr) rate.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 90 (2001)

In the paper

“Chemical synergism of photochemical & electrochemical processes yielded enhanced decoloration (95%), COD removal (87%) & TOC removal (81%) in 30 min [Dye=1 mmol/l; 500W lamp, 6.64 mWcm -2 ; 1gTiO 2 /200 ml; 30 V DC; Natural pH(6.6)].”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 6 (2002)

In the paper

“Membrane filtration of biologically pretreated dye wastewater 109 has been occasionally reported to require less cost than that for direct membrane filtration 108 of dye bath, presumably as the former involves less membrane fouling.”

What the sources say

• ?Not checked — no full text of the sourcecites [109] Koyuncu I., 2001, Water Sci. Technol. source
• ?Not checked — no full text of the sourcecites [108] Koyuncu I., 2001, Water Sci. Technol. source

In the paper

“Moreover, use of the AOP for post treatment will minimize its light penetration limitation, which would be significant if it were used for pre-treatment.”

In the paper

“85% color removal (Dye=100 mg/l) & 90% COD removal within 10 mins.with 24.5 mmol H 2 O 2 /l and 1.225 mmol FeSO 4 /l at pH=3, resulting effluent having only 7.29% inhibition in bioluminescence test.Presence of dispersing agent reduces removal efficiency.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 153 (2003)

In the paper

“UV (125 W)-H 2 O 2 (565.8mg/l, 16.6 mM): Complete decoloration (35 min.)& 82% TOC removal (60 min.)for 40 mg/l dye at natural pH (7.5), although subsequent toxicity test recommended.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 46 (2002)

In the paper

“Sonication (50 kHz, 150 W) enhanced oxidation property of MnO 2 (1 g/l) by improving mass transfer, removal of passivating outer oxide layer & production of H 2 O 2 , eventually realizing 94.93% decolorization (argon atmosphere) and 48.12 % TOC removal (oxygen atmosphere) [initial pH=3, 240 min.].”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 68 (2003)

In the paper

“Removals (60 min.)-Photocatalysis(0.1 g/l anatase TiO 2 , 125 W, fluency rate 31.1 J m 2 s -1 , pH=11): Color= 90%, TOC= 50%; Ozonation (pH=11, 14 mg/l): Color= 60%, TOC= negligible; Combined: Color=100%, TOC> 60%, Toxicity=50%”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 146 (2000)

In the paper

“This example may be further extended to filtration of segregated dye bath effluent utilizing membrane of appropriate molecular cut off size which allows passage of salt but retains dye.Consequently dye bath water containing salt may be reused for dye bath reconstruction, while the membrane-concentrate may be degraded in anaerobic digester.”

In the paper

“Due to declining membrane costs 34 , recovery and reuse of chemicals and water using membrane is expected to gain rapid acceptability in near future.”

What the sources say

• ?Not checked — no full text of the sourcecites [34] source

In the paper

“However, because of the numerous site-specific factors and assumptions inevitably made in such estimates, a direct comparison is difficult.”

In the paper

“Decoloration (20 mg/l dye): 100% in 10 min.by O 3 (6 l/min.O 2 ) with/without UV; 80% in 25 min.by H 2 O 2 -UV.Negligible enhancement of ozonation by UV (low power) due to absorption of most UV by dye.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 192 (1995)

In the paper

“Rinsing water may be reused after reclamation by membrane while the concentrated waste may be degraded in anaerobic digester.219”

What the sources say

• ?Not checked — no full text of the sourcecites [219] Wenzel H., 1996, Desalination source

In the paper

“The MBR system has been envisaged to be capable of coping with the impedances in implementation of white-rot fungi in large scale industrial waste treatment, such as, rather slow fungal degradation 147 , loss of the extracellular enzymes and mediators with discharged water 235 , and excessive growth of fungi 236 .”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Moreira M. T., 1998, J. Biotechnol. source
• ?Not checked — no full text of the sourcecites [235] Zhang F., 2000, Bioprocess Eng. source
• ?Not checked — no full text of the sourcecites [236] Zhang F. M., 1999, Enzyme Microb. Technol. source

In the paper

“Dye removal (0.5 mmol/l), 150 min., pH 3: UV (64W, 365nm)-H 2 O 2 (10 mmol)= 88.68% decolourisation , 59.85% degradation.Sunlight-H 2 O 2 = 80.15% decolourisation, 50.91% degradation.Dye auxiliaries like Na 2 CO 3 , NaOH seriously retard decoloration rate while NaCl does not.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 149 (2004)

In the paper

“In contrast to negligible removal by MW (300W), or less removal by photocatalysis (75W, 0.3mW cm -2 ; 30 mg TiO 2 /30 ml) alone, combined process achieved 97% decoloration (Dye= 0.05 mM) and 73% TOC removal within 3 hrs at pH=5.5.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 84 (2002)

In the paper

“Besides, post treatment of the MBR-permeate by an AOP will ensure complete decoloration.”

In the paper

“95% color (Dyes= 0.5 g/l), 48% COD (initially= 3784 mg/l) removal and 10 times improvement in BOD 5 /COD ratio at natural acidic pH of dye bath ( 3.6 mM Fe +2 ; [Fe +2 ]: [O 3 ]= 1:14; FeSO 4 .7H 2 O= 1000 mg/l).Negligible TOC removal is due to low O 3 dose of 14 g/l.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 9 (2001)

In the paper

“However, both the processes furnish potential of water reuse, thereby, achieving further cost savings.”

In the paper

“A treatment scheme comprising activated carbon amended anaerobic reactor preceding aerobic MBR realizes stable decoloration along with high TOC removal, with concurrent improvement in activated sludge dewaterability and reduction in filtration resistance.157”

What the sources say

• ?Not checked — no full text of the sourcecites [157] source

In the paper

“This eventually leads to a poor color and COD removal performance.”

In the paper

“Treatment trains composed of conventional physico-chemical and biological systems involve sustainable cost 155 , however, their removal performance may not satisfy contemporary stricter regulations.”

What the sources say

• ?Not checked — no full text of the sourcecites [155] Nicolaou M., 1992, Water Sci. Technol. source

In the paper

“Enhanced decoloration (100% for 50 mg/l dye) & mineralization (95%) in 1 hr (19W lamp, 1g/l TiO 2 , 100 mg/l H 2 O 2 , pH=5.4) along with 85% reduction in toxicity.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 173 (2003)

In the paper

“Such practice may, however, give rise to concern about salinity increase in biological plant.”

In the paper

“Decoloration and TOC removal of dye (0.5 mM) in 0.5 mmol l -1 NaCl solution within 60 min.(Natural pH) : i) Adsorption on packed material: 9%, --; ii)Photocatalysis [TiO 2 (antase= 70%)-coated quartz sand, 500 W high-pressure mercury lamp]: 70%, 20%; iii) Electro-oxidation [30.0 V DC cell voltage, reaction flow rate=190 ml min -1 , 0.05 MPa airflow]: 77%, 7%; iv) Photoelectrocatalysis: 96%, 38%.Ob”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 238 (2003)

In the paper

“UV (15 W)/ H 2 O 2 (optimum dose 24.5 mmol/l): 15 min.: [Decolorization>65%, COD removal= 40-70%], 60 min.: [Decolorization> 99%]; Degradation by products unobjectionable.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 152 (2002)

In the paper

“Sonication (320 kHz) dramatically enhanced oxidation efficiency of UV(6@11W)+H 2 O 2 ( 0.1 ml/l) system (pH=11) by improving oxygen uptake & transfer, the combined process achieving 94% dye (0.1 g/l) removal in 60 min.following pseudo 1 st order kinetics.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 63 (1999)

In the paper

“Over 90% decolorization of 100 ppm dye within 24 hr.(70-80% within first 6 hr.) with 10 mM CuSO 4 , 200 mM ange N=N , Reactive N=N black 5; Poly AQ B-411, Reactive AQ blue 2, RBBR AQ , Acridin (Basic) AQ orange; Azure blue TH , Crystal violet TPM H 2 O 2 and low dose of glucaric acid (15 mM).Insensitive to pH, unlike fenton reaction.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [2004]

In the paper

“These concerns have led to new and/or stricter regulations concerning colored wastewater discharges, rendering the decolorization process further difficult and costly.”

In the paper

“This assumption was prompted by the fact that such practice realizes cost-savings through reduction in production of waste and consumption of fresh chemicals/water, and consequently the usual payback period of the high capital investment associated with it is 2-3 years or less.151,180”

What the sources say

• ?Not checked — no full text of the sourcecites [151] source
• ?Not checked — no full text of the sourcecites [180] source

In the paper

“Sunlight, supplying higher number of photons (3-4x10 -3 W cm -2 ) than the low power artificial source (350 nm, 6W, 1.3x10 -4 W cm -2 ), resulted in faster complete decoloration (15-30 min.)and complete (or near) TOC removal (20-60 min.)for dye concentration of 100 mg/l with 10 mg/l Fe +2 and 100-250 mg/l H 2 O 2 [pH=3].”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 207 (2004)

In the paper

“The concentrates generated there from and discarded streams (including dye), however, entail further effective economical treatment.”

In the paper

“Wu et al. 224 reported a cost-competitive dye wastewater reclamation system involving deep aeration activated sludge prior to bioactivated carbon and nanofiltration, which, in addition to yielding prolonged membrane life and recovery/reuse potential, allowed direct discharge of concentrated membrane-retentate.”

What the sources say

• ?Not checked — no full text of the sourcecites [224] Wu H.-Z., 2005, Desalination source

In the paper

“compounds too large to be adsorbed onto ACC are successfully retained by the membrane (>98% turbidity & 15-40% dye removal)”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 168 (2000)

In the paper

“Annualized total installation cost is US$ 243,000 while saving generated from water reuse is US$ 98,000.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 120 (2001)

In the paper

“With expected decline in membrane cost to US$ 50 m -2 in 2004, the unit cost would reduce to US$ 0.181 m -3 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 228 (2004)

In the paper

“49% turbidity & 71% color removal by clariflocculation & ozonation, respectively”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 139 (2002)

In the paper

“Membrane bioreactor US$ 0.273 m -3 Municipal wastewater”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 228 (2004)

In the paper

“Reuse after Membrane filtration (i), followed by UV/H 2 O 2 (ii), concurrent with reuse after membrane concentrate treatment by Wet air oxidation (iii) and Biological (iv) US$ m -3 (i) 0.53 (ii)2.6 (iii)4.4(iv)0.13”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 120 (2001)

In the paper

“contributed to achievement of final 66% COD and 93% color removal”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 139 (2002)

In the paper

“Required fresh water supply (50% of total) incurs a further cost of 0.92 US$ m -3 .”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 42 (2001)

In the paper

“Sonification (320 kHz) significantly enhanced the decoloration (Dye= 0.1 g/L) efficiency of UV/ H 2 O 2 .Higher flow rate (insufficient irradiation) necessitated higher dosing rate of H 2 O 2 .”

What the sources say

• ?Not matched

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  cites 64 (2001)

In the paper

“A payback of investment cost may be expected in 3 yrs with the saving of water supply cost.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 139 (2002)

In the paper

“Reuse after Membrane filtration (i), followed by UV/H 2 O 2 (ii), concurrent with reuse after membrane concentrate treatment by Wet air oxidation (iii) and Biological (iv) US$ m -3 (i) 0.53 (ii)2.6 (iii)4.4(iv)0.13”

What the sources say

• ?Not matched

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  cites 120 (2001)

In the paper

“high turbidity (27%) & TSS (30%) removal by the subsequent UF membrane”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 139 (2002)