Textile dyeing wastewater negatively influences the hematological profile and reproductive health of male Swiss albino mice

Objective:To determine the effects of textile dyeing industrial wastewater on the hematological parameters and reproductive health including histoarchitecture of male gonad(testes)of mice.Methods:Twenty-four Swiss albino mice at 4-weeks old were divided into four groups(n=6 per group).Mice of group 1 supplied with normal drinking water were served as the control group.Mice of group 2,3 and 4 were supplied normal drinking water mixed with textile dyeing wastewater at 5%,10% and 20% concentration,respectively.After completing 24 weeks of treatment,different hematological profile,weight of testes,gonadosomatic index(GSI),sperm concentration and morphology were measured.Moreover,histopathological changes in testes were examined.Results:Hematocrit value and hemoglobin concentrations were decreased in all groups of wastewater-treated mice compared to the control group.Likewise,weight of testes,GSI and sperm concentration were decreased significantly in wastewater-treated mice in comparison to the control group.The percentage of morphologically healthy epididymal sperm was significantly reduced in wastewater-treated mice.Histopathological examination revealed degenerative changes in seminiferous tubules,a smaller number of spermatogenic cells,elongation of seminiferous tubules and degenerative changes of seminiferous tubules in wastewater-treated mice.Conclusions:Textile dyeing wastewater has harmful effects on hematological profile and reproductive health of male mice.

A pilot scale anoxic/oxic membrane bioreactor(A/O MBR) for woolen mill dyeing wastewater treatment

A pilot scale(10 m 3/d) anoxic/oxic membrane bioreactor(A/O MBR) was tested for dyeing wastewater treatment of woolen mill without wasting sludge in 125 days operation. Results showed that the effluent quality was excellent, i.e. effluent COD less than 25 mg/L, BOD 5 under 5 mg/L, turbidity lower than 0 65 NTU, and colour less than 30 DT, and met with the reuse water standard of China. The removal rates of COD, BOD 5, colour, and turbidity were 92 4%, 98 4%, 74% and 98 9%, respectively. Constant flux operation mode was carried out in this study, and backwash was effective for reducing membrane fouling and maintaining constant flux. Membrane fouling had heavy impact on energy consumption. More attention should be paid on pipe selection and design for the sidestream MBR system, too.

Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%—78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

Photocatalytic degradation of textile dyeing wastewater through microwave synthesized Zr-AC,Ni-AC and Zn-AC

The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons（Zr-AC, Ni-AC, Zn-AC） were successfully fabricated through microwave irradiation method. The synthesized nanoparticles were characterized using XRD, HR-SEM, XPS and BET. The optical properties of Zr-AC, Ni-AC and Zn-AC composites were investigated using UV–Vis diffuse reflectance spectroscopy. The photocatalytic efficiency was verified in the degradation of textile dyeing wastewater（TDW） in UV light irradiation. The chemical oxygen demand（COD） of TDW was observed at regular intervals to calculate the removal rate of COD. Zn-AC composites showed impressive photocatalytic enrichment, which can be ascribed to the enhanced absorbance in the UV light region, the effective adsorptive capacity to dye molecules, the assisted charge transfer and the inhibited recombination of electron-hole pairs. The maximum TDW degradation（82% COD removal） was achieved with Zn-AC. A possible synergy mechanism on the surface of Zn-AC was also designed. Zn-AC could be reused five times without exceptional loss of its activity.

Decolorization on Indigo Dyeing Wastewater by Laccase from Coriolus versicolor

[ Object] The study aimed to discuss the decolorization on indigo dyeing wastewater by laccase from Coriolus versicolor. [ Method ] Firstly, the effects of temperature, pH, indigo concentration, HBT concentration, laccase dosage on the decolorization of indigo dyeing wastewater by laccase/HBT, and then the synergism of laccase and acid cellulase was analyzed. [Result] Using ABTS as the substrate, the kinetic parame- ters, K,, and Vmax, were 0.318 mmol/L and 0.035 5 mmol/（ L . min） respectively. The decolorization rate of indigo reached 96.5% when the lacca- se acted on indigo for 40 min with HBT as an introducer at temperature 50 ℃, pH =4.5, indigo concentration 100 mg/L, HBT concentration 0.1% and laccase dosage 100 lU/L. Due to the synergism of laccase and acid cellulase during the bio-finishing of blue jeans, the backstaining degree of blue jeans reduced by 85% when the amount of laccase added was 15 000 IU/kg. Menawhile, the synergism of the laccase and acid cellulase de- creased indigo concentration in wastewater by 83.8%. [ Conclusion ] The laccase from Coriolus versicolor had a good prospect in the bio-finishing of blue jeans and the decolorization of indigo dyeing wastewater.

Synergistic coagulation of bauxite residue-based polyaluminum ferric chloride for dyeing wastewater treatment

Considering that Fe,Al elements in bauxite residue are active components for water purification,an effective polyaluminum ferric chloride(PAFC)coagulant derived from bauxite residue,with Fe2O3 content>5.1%,Al2O3%>6.5%,basicity>65%,was successfully prepared.The effect of as-prepared PAFC on the zeta potential for printing and dyeing wastewater was investigated.Comparing with polyferric chloride(PFC)and polyferric sulfate(PFS)for printing and dyeing wastewater treatment,prepared bauxite residue-based PAFC exhibited the optimal performance in the aspects of chromaticity and chemical oxygen demand(COD)removal rate.Furthermore,the combination of bauxite residue-based PAFC and PFS for synergy coagulation of such wastewater demonstrated an obvious positive effect.With the proportion between as-prepared PAFC and PFS to be 2.5:1,the COD of treated wastewater could be further reduced to meet the national level A standard of China,providing a promising route to solve the problem of substandard printing and dyeing sewage outfall by a simple coagulation strategy.

Degradation of Synthetic Dyeing Wastewater by Underwater Electrical Discharge Processes

Electrical discharge treatments of synthetic dyeing wastewater were carried out with two different systems： underwater pulsed electrical discharge （UPED） and underwater dielectric barrier discharge （UDBD）. Reactive Blue 4 （RB4） and Acid Red 4 （AR4） were used as model contaminants for the synthetic wastewater. The performance of the aforementioned systems was compared with respect to the chromaticity removal and the energy requirement. The results showed that the present electrical discharge systems were very effective for degradation of the dyes. The dependences of the dye degradation rate on treatment time, initial dye concentration, electrical energy, and the type of working gas including air, 02, and N2 were examined. The change in the initial dye concentration did not largely affect the degradation of either RB4 or AR4. The energy delivered to the UPED system was only partially utilized for generating reactive species capable of degrading the dyes, leading to higher energy requirement than the UDBD system. Among the working gases, the best performance was observed with O2. As the degradation proceeded, the concentration of total dissolved solids and the solution conductivity kept increasing while pH showed a decreasing trend, revealing that the dyes were effectively mineralized.

Kinetics of aerobically activated sludge on terylene artificial silk printing and dyeing wastewater treatment

Aerobically activated sludge processing was carried out to treat terylene artificial silk printing and dyeing wastewater (TPD wastewater) in a lab-scale experiment, focusing on the kinetics of the COD removal. The kinetics pa-rameters determined from experiment were applied to evaluate the biological treatability of wastewater. Experiments showed that COD removal could be divided into two stages, in which the ratio BOD/COD (B/C) was the key factor for stage division. At the rapid-removal stage with B/C>0.1, COD removal could be described by a zero order reaction. At the mod-erate-removal stage with B/C<0.1, COD removal could be described by a first order reaction. Then Monod equation was introduced to indicate COD removal. The reaction rate constant (K) and half saturation constant (KS) were 0.0208-0.0642 L/(gMLSS)h and 0.44-0.59 (gCOD)/L respectively at 20 C-35 C. Activation energy (Ea) was 6.05104 J/mol. By comparison of kinetic parameters, the biological treatability of TPD wastewater was superior to that of traditional textile wastewater. But COD removal from TPD-wastewater was much more difficult than that from domestic and industrial wastewater, such as papermaking, beer, phenol wastewater, etc. The expected effluent quality strongly related to un-biodegradable COD and kinetics rather than total COD. The results provide useful basis for further scaling up and efficient operation of TPD wastewater treatment.

Treatment of a dyeing wastewater from a woolen mill using an A/O membrane bio-reactor

An anaerobic/oxic membrane bioreactor (A/O MBR) was used for treatment of dyeing wastewater from a woolen mill. COD and color of the wastewater were 54—473 mg/L and 40—400 dilution time (DT) respectively. The ratio of BOD 5/COD was less than 0.13. By the A/O MBR process, the average removal of COD, BOD 5, color and turbidity was 82%, 96%, 71% and 99%, respectively. The average COD, BOD 5, color and turbidity of effluent was 37 mg/L, 0.8 mg/L, 40 DT and 0.44 NUT respectively. The effluent COD met the local standard of reuse water in Beijing, China. The average COD volume load of the anaerobic biological tank was 0.0483 kgCOD/(m 3·d) and that of the aeration tank of the MBR was 0.3589 kgCOD/(m 3·d). The sludge load of the MBR was 0.19 kgCOD/(kg·MLSS·d) on average and the maximum of that was 0.4 kgCOD/(kg·MLSS·d). The flux of the A/O membrane bioreactor could be remained at larger than 50 L/(h·m 2·0.1MPa). The results indicated that A/O membrane bioreactor has technical feasibility for treatment of woolen mill wastewater.

Dyeing wastewater treatment with a complex adsorption-coagulation agent

To remove effectively the pollutants from printing and dyeing wastewater, a new complex adsorption-coagulation agent was developed and employed in dyeing wastewater treatment. The experimental results showed that better removals of COD, turbidity and color could be efficiently realized under the operating conditions of mixing at 150 r/min, reacting within 5 min and dosing at 15 g/L and 20 g/L, respectively. Combined with the settled sludge, the agent could be recycled for further adsorption and coagulation within 10 times. Compared to the conventional coagulants, the newly-developed agent had such merits as suitability for wide pH range of wastewater, less sludge production, reutilization of the condensed sludge and low operation cost.

Stability of expanded granular sludge bed process for terylene artificial silk printing and dyeing wastewater treatment

Terylene artificial silk printing and dyeing wastewater(TPD wastewater), containing averaged 710 mg/L terephthalic acid(TA) as the main carbon source and the character pollutant, was subjected to expanded granular sludge bed(EGSB) process. The stability of the EGSB process was firstly conducted by laboratory experiment. TA ionization was the predominated factor influencing the acid-base balance of the system. High concentration of TA in wastewater resulted in sufficient buffering capacity to neutralize the volatile fatty acids(VFA) generated from substrate degradation and provided strong base for anaerobic system to resist the pH decrease below 6.5. VFA and UFA caused almost no inhibition on the anaerobic process and biogas production except that pH was below 6.35 and VFA was at its maximum value. Along with the granulating of the activated sludge, the efficiency of organic removal and production rate of biogas increased gradually and became more stable. After start-up, the efficiency of COD removal increased to 57%—64%, pH stabilized in a range of 7.99—8.04, and production rate of biogas was relatively high and stable. Sludge granulating, suitable influent of pH and loading were responsible for the EGSB stability. The variation of VFA concentration only resulted in neglectable rebound of pH, and the inhibition from VFA could be ignored in EGSB. The EGSB reactor was stable for TPD wastewater treatment.

Preparation of Ce-TiO_(2)-RGO catalyst and its application in the treatment of printing and dyeing wastewater

Ce-TiO_(2)-RGO composite photocatalyst was prepared by sol-gel method and ultrasonic treatment.The effect of Ce doping mass fraction on the degradation of textile printing and dyeing wastewater was studied.The catalysts were characterized by XRD,SEM,TEM,UV-vis and PL.The results showed that,Ce-TiO_(2)particles uniformly adsorbed on the GO surface,and the particle diameter of Ce-TiO_(2)was approximately 25-110 nm.After Ce doping,the absorption band edge of TiO_(2)-RGO composite photocatalyst was redshifted and the band gap was reduced.With the increase of Ce doping mass fraction,the PL intensity of Ce-TiO_(2)-RGO composite photocatalyst first decreased and then slightly increased,and the emission peak intensity of 6%Ce-TiO_(2)-RGO composite photocatalyst was the lowest at 410 nm and 470 nm.Taking textile printing and dyeing wastewater as the research object of degradation,the COD removal rate of 6%Ce-TiO_(2)-RGO reached the maximum of 82.21%at 180 min,and the COD value after degradation was 88.95 mg/L which was in line with the wastewater discharge standard.On the other hand,at 180 min,the degradation rate for textile printing and dyeing wastewater by 6%Ce-TiO_(2)-RGO also reached the maximum(99.21%).Therefore,the Ce-TiO_(2)-RGO composite photocatalyst showed great application potential in the treatment of textile dyeing wastewater.

Advanced treatment of dyeing wastewater towards reuse by the combined Fenton oxidation and membrane bioreactor process

The performance of combined Fenton oxidation and membrane bioreactor （MBR） process for the advanced treatment of an effluent from an integrated dyeing wastewater treatment plant was evaluated. The experimental results revealed that under the optimum Fenton oxidation conditions （initial pH 5, H 2 O 2 dosage 17 mmol/L, and Fe^ 2＋ 1.7 mmol/L） the average total organic carbon （TOC） and color removal ratios were 39.3% and 69.5% after 35 min of reaction, respectively. Results from Zahn-Wallens Test also represented that Fenton process was effective to enhance the biodegradability of the test wastewater. As for the further purification of MBR process, TOC removal capacity was examined at different hydraulic retention times （HRT） of 10, 18 and 25 hr. Under the optimum HRT of 18 hr, the average TOC concentration and color of the final MBR effluent were 16.8 mg/L and 2 dilution time, respectively. The sludge yield coefficient was 0.13 g MLSS/g TOC and TOC degradation rate was 0.078 kg TOC/（m ^3 ·day）. The final effluent of MBR can meet the reuse criteria of urban recycling water – water quality standard for miscellaneous water consumption GBT18920-2002.

Dyeing and printing wastewater treatment using fly-ash coated with chitosan

Printing and dyeing industry is a considerable source of environmental contamination. In this study treatment of printing and dyeing wastewater with a new type of sewage treatment agent, fly-ash coated with chitosan particles （FCCP）, was examined. The effects ofpH, stirring time, sedimentation time and temperature on color, COD, turbidity and NH3-N removal were determined. The optimum dosage of FCCP and the influence of individual factors on removal efficiency were tested. The optimum parameters determined using the L16 （45） orthogonal experiment were as follows： FCCP （weight ratio of chitosan to fly-ash 1：6） dosage, 4 g.L^-1; temperature, 35℃; pH, 4. The stirring time and sedimentation time were 20 min and 5 h, respectively. Under these optimum conditions, the color, COD and NH3-N removal ratios were 97%, 80% and 75%, respectively.

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

Adding iron salt or iron hydroxide to sludge-mixed liquor in an aeration tank of a conventional activated sludge processes(bioferric process)can simultaneously improve the sludge’s filterability and enhance the system’s treatment capacity.In view of this,Fe(OH)3 was added to a submerged membrane bioreactor(SMBR)to enhance the removal efficiency and to mitigate membrane fouling.Bio-ferric process and SMBR were combined to create a novel process called Bioferric-SMBR.A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out.Bioferric-SMBR showed potential superiority,which could enhance removal efficien-cy,reduce membrane fouling and improve sludge character-istic.When volumetric loading rate was 25% higher than that of common SMBR,the removal efficiencies of Bioferric-SMBR on COD,dye,and NH_(4)^(+)-N were 1.0%,9.5%,and 5.2%higher than that of common SMBR,respectively.The trans-membrane pressure of Bioferric-SMBR was only 36%of that in common SMBR while its membrane flux was 25% higher than that of common SMBR.The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged.The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans.The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR,respectively.

Poultry keratin based decolorants for dyeing wastewater treatment

One of the challenges in wastewater treatment is the low efficiency in decoloring dyeing wastewater.Chicken feather,as a waste material,has a great potential in decoloring the dyeing wastewater.In this study,a lab synthesized dyeing wastewater prepared with acid blue-A dye was treated with a chicken feather keratin-based composite decolorant KA(keratin agent)using batch decoloration techniques.A modified KA(MKA)was also developed to improve the decoloration efficiency.The decoloration performance of the two decolorants was then evaluated in terms of decoloring rate,at various decolorant dosages,pH,reaction temperature and time.Under optimal conditions,the decoloration rates of the KA and MKA in treating the dyeing wastewater were 91.8%and 94.3%,respectively.IR and TEM results indicated that the KA and MKA decolorants removed the dye stuff from the dyeing wastewater by physical adsorption as well as chemical reactions.

Production and application of a novel bioflocculant by multiple-microorganism consortia using brewery wastewater as carbon source

The flocculating activity of a novel bioflocculant MMF1 produced by multiple-microorganism consortia MM1 was investigated. MM1 was composed of strain BAFRT4 identified as Staphylococcus sp. and strain CYGS1 identified as Pseudomonas sp. The flocculating activity of MMF1 isolated from the screening medium was 82.9%, which is remarkably higher than that of the bioflocculant produced by either of the strains under the same condition. Brewery wastewater was also used as the carbon source for MM1, and the cost-effective production medium for MM1 mainly comprised 1.0 L brewery water （chemical oxygen demand （COD） 5000 mg/L）, 0.5 g/L urea, 0.5 g/L yeast extract, and 0.2 g/L （NH4）2SO4. The optimal conditions for the production of MMF1 was inoculum size 2%, initial pH 6.0, cultivating temperature 30℃, and shaking speed 160 r/min, under which the flocculating activity of the MMF1 reached 96.8%. Fifteen grams of purified bioflocculant could be recovered from 1.0 L of fermentation broth. MMF1 was identified as a macromolecular substance containing both protein and polysaccharide. It showed good flocculating performance in treating indigotin printing and dyeing wastewater, and the maximal removal efficiencies of COD and chroma were 79.2% and 86.5%, respectively.

Preparation of Chitosan-TiO_2 Composite and Application in the De-coloration of Reactive Dyes Wastewater

Chitosan-TiO2 composite has been prepared by the sol-gel process. Tetrabutyl titanate( TTB) was used as a precursor to obtain nano TiO2 sol,which was then added into acid solution of chitosan to form titania network in the matrix. SEM,TG,and Fourier transform infrared spectroscopy( FTIR) were employed to characterize morphology and structure of the Chitosan-TiO2 composite. The resulting hybrid has potential applications for the adsorption and sonolytic-degradation of organic dyes in wastewater.The result shows that the de-coloring ratio reaches 97. 2% at the optimum conditions with the help of ultrasound.

Construction of direct-Z-scheme heterojunction photocatalyst of g-C_(3)N_(4)/Ti_(3)C_(2)/TiO_(2)composite and its degradation behavior for dyes of Rhodamine B

Direct-Z-scheme g-C_(3)N_(4)/Ti_(3)C_(2)/TiO_(2)photocatalyst with giant internal electric field was prepared by onestep aqueous sonication self-assembly method using g-C_(3)N_(4)and MXene of Ti_(3)C_(2)as the source materials.The chemical composition and structure of the catalysts was characterized by FT-IR,XRD,SEM,TEM,and XPS.The XPS characterization indicated that Ti_(3)C_(2)was partially oxidized to TiO_(2)during the composite process.As a result,an efficient direct-Z-scheme heterojunction structure consisting of the g-C_(3)N_(4)and TiO_(2)with Ti_(3)C_(2)as an electron bridge was constructed.The photocatalytic performance of the prepared catalysts was evaluated by degrading the Rhodamine B(RhB)wastewater.Compared with the single g-C_(3)N_(4),the g-C_(3)N_(4)/Ti_(3)C_(2)/TiO_(2)composite photocatalyst exhibited efficient and stable photocatalytic degradation ability,with a degradation efficiency as high as 99.2%for RhB under optimal conditions(2%Ti_(3)C_(2),pH=3).The high degradation performance of g-C_(3)N_(4)/Ti_(3)C_(2)/TiO_(2)for RhB was attributed to the combination of Ti_(3)C_(2),TiO_(2),and g-C_(3)N_(4)components,forming a direct-Z-scheme heterojunction with a high-speed electron transport channel structure.The role of Z-scheme heterojunctions in electron transport is verified by photoelectrochemical characterization,along with photoluminescence(PL).Our research provides a simple method to design photocatalysts by constructing direct-Z-scheme electron transport channels for highly efficient treatment of dye wastewater.

An innovative integrated oxidation ditch with vertical circle(IODVC) for wastewater treatment

The oxidation ditch process is economic and efficient for wastewater treatment, but its application is limited in case where land is costly due to its large land area required. An innovative integrated oxidation ditch with vertical circle(IODVC) system was developed to treat domestic and industrial wastewater aiming to save land area. The new system consists of a single channel divided into two ditches(the top one and the bottom one by a plate), a brush, and an innovative integral clarifier. Different from the horizontal circle of the conventional oxidation ditch, the flow of IODVC system recycles from the top zone to the bottom zone in the vertical circle as the brush is running, and then the IODVC saved land area required by about 50% compared with a conventional oxidation ditch with an intrachannel clarifier. The innovative integral clarifier is effective for separation of liquid and solids, and is preferably positioned at the opposite end of the brush in the ditch. It does not affect the hydrodynamic characteristics of the mixed liquor in the ditch, and the sludge can automatically return to the down ditch without any pump. In this study, experiments of domestic and dye wastewater treatment were carried out in bench scale and in full scale, respectively. Results clearly showed that the IODVC efficiently removed pollutants in the wastewaters, i.e., the average of COD removals for domestic and dye wastewater treatment were 95% and 90%, respectively, and that the IODVC process may provide a cost effective way for full scale dye wastewater treatment.