Papermaking Wastewater Research Articles

Study on the Combination of Fixed Bed and Moving Bed Biofilm Reactor for Papermaking Terminal Wastewater Treatment

Papermaking wastewater mainly consists of black liquor, intermediate wastewater and white water. It suffers from its heavy amount, high level suspended solids and poor biodegradable property. In this paper, a combination of fixed bed and moving bed biofilm reactor was conducted to treat paper making wastewater in order to make full use of the advantages of both fixed bed and moving bed. As a result, the average values of COD, NH3-N and SS in effluent are 57.01 mg/L, 1.74 mg/L and 38 mg/L, respectively. The quality of the effluent could meet the demands of the Chinese standards for papermaking industrial water discharge pollutant.

Experimental Study on Papermaking Wastewater by Advanced Electrochemical Oxidation Method

Papermaking wastewater effluent from a biological processing unit was treated by an advanced treatment method-electrochemical oxidation process. The experiments were carried out in an electrochemical reactor using RuO2\SnO2 coated on titanium as anode and stainless steel as cathode. The changes of Chemical Oxygen Demand (COD) reduction and other relative parameters have been determined as a function of treatment time and applied current density. The optimum reaction time and current density was 60min and 5mA/cm2, respectively. Results indicate that as an advanced treatment method, electrochemical oxidation can treat papermaking wastewater to achieve the standard of effluents effectively.

Study on Treatment of Wastewater from Papermaking Using Fenton Oxidation

The performance of biochemical treatment effluent from paper making wastewater treated by Fenton process was evaluated. The experiment result shows that the importance of influencing factors for Fenton oxidation treatment was H2O2 concentrations > pH > FeSO4 concentrations > reaction time. With the optimal conditions of reaction, that is pH3 (initial pH5), FeSO4 3.6 mmol/L, H2O2 3.4 mmol/L, and reaction time 60 min, the removals of COD and color for papermaking wastewater reached over 85% and 90%, respectively. The result also showed that in the process of Fenton method in the treatment of papermaking wastewater, for removing COD, the function by oxidation account for 15.5%, and the function of flocculation accounted for 69.8%.

Advanced Oxidation Treatment of Papermaking Wastewater by Homogeneous Fenton Reaction

The quality of water from traditional two-stage biochemical treatment process of papermaking wastewater cannot meet the pollutants discharge standard of paper industry,therefore it is necessary to develop new advanced treatment processes to further treat the effluent. This paper adopts the homogeneous Fenton oxidation technology to treat the effluent from a secondary sedimentation tank of a papermaking factory by batch experiments. The optimum reaction conditions are H2O2dosage 6.54mmol/L, FeSO4.7H2O dosage 200mg/L, pH=3, t=1.5h and of all the experiments the dosage of polyacrylamide is 3ppm. The COD of the treated water is under 50mg/L and its removal rate can reach as high as 75.4%, the chroma almost falls to zero, the effluent meets the first grade of the national wastewater discharge standard. Therefore, the homogeneous Fenton is an effective alternative for papermaking wastewater advanced treatment, due to its high effect.

Fabrication of large-diameter tube-like mesoporous TiO2 via homogeneous precipitation and photocatalytic decomposition of papermaking wastewater

Large-diameter tube-like mesoporous TiO2 nanotubes were synthesized via homogeneous precipitation from aqueous solutions containing titanium oxysulfate (TiOSO4) using urea. The cationic surfactant cetyltrimethylammonium bromide was used as a structure-directing agent. Prepared samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and N2 adsorption–desorption isotherms. Experimental results indicated that the samples exhibit tube-like structures with lengths of approximately 6μm to 8μm, large tube diameters of approximately 500nm to 600nm, and a wall thickness of approximately 450nm. TEM images and N2 adsorption–desorption isotherms showed that the tube walls of the samples have a uniform mesoporous structure. A possible mechanism for the formation of tube-like mesoporous TiO2 was proposed. The photocatalytic activities of the large-diameter tube-like mesoporous TiO2 were assessed via the photocatalytic decomposition of papermaking wastewater under ultraviolet light irradiation. The effects of different parameters such as UV light irradiation, catalyst dosage and solution pH on photocatalytic activities of tube-like mesoporous TiO2 were studied. The as-synthesized tube-like TiO2 showed higher photocatalytic activities than Degussa P25. MTS3 exhibited the highest photocatalytic activity. The chemical oxygen demand and chroma percent degradations of papermaking wastewater were approximately 73.0% and 99.5%, respectively, at MTS3 dosage of 1.0g/L and pH value of 3.0 after 12h of photodegradation.

A control system based on field programmable gate array for papermaking sewage treatment

A sewage treatment control system is designed to improve the efficiency of papermaking wastewater treatment system. The automation control system is based on Field Programmable Gate Array (FPGA), coded with Very-High-Speed Integrate Circuit Hardware Description Language (VHDL), compiled and simulated with Quartus. In order to ensure the stability of the data used in FPGA, the data is collected through temperature sensors, water level sensor and online PH measurement system. The automatic control system is more sensitive, and both the treatment efficiency and processing power are increased. This work provides a new method for sewage treatment control.

Papermaking Waste Water Resource Recovery - A New Approach of Preparation of Coal Water Slurry

Papermaking waste liquid instead of water to prepare coal water slurry, which aim is turning waste into treasure. Not only can the waste fundamentally eliminate environment pollution, but also saving a lot of water resources. Because the waste contains large amounts of sodium, which is one of the main reasons of heating surface slagging of boiler. So it is necessary to improve and increase the soot blowing device of heating surface of boiler.

Synthesis and Photocatalytic Activity of Rod-Shaped Mesoporous TiO<sub>2</sub> Using Poly (ethylene glycol) as Templates

Rod-shaped TiO2 was synthesized via homogeneous precipitation by using PEG and urea as the structure directing agent and precipitation agent, respectively. The prepared samples were characterized by XRD, TEM, and FESEM. The XRD patterns of the samples indicated that the crystalline phase was anatase. TEM and FESEM images revealed the morphology of prepared TiO2 samples were rod-shaped, and densely packed with plenty of spherical-shaped units. RTS3 exhibited the highest photocatalytic activity for degradation of papermaking wastewater under UV light irradiation. CODCr percent degradation was about 75% under UV light irradiation in 12 h for RTS3.

The Study of Aluminum Sulfate Purifying Effects for Papermaking Wastewater

As a high concentration organic wastewater, papermaking wastewater is so strong stability that it is difficult to be decomposition by microorganisms [1, 2]. Through adding aluminum sulfate Al2（SO4）3, the stability of the wastewater will be changed and the value of the COD Cr will be lower. The effect of some important operation parameters, such as the dosage of the pharmaceuticals, pH value and stirring intensity were investigated and optimized. After the experimental, the results showed that, when the optimal dosage of Al2（SO4）3 was 1.5g/L, the solution pH controlled in 6~8, it could get the best treatment effect.

Chemical Cleaning of a Polyethersulfone Membrane Used for Concentrating the Effluent from Alkaline Peroxide Mechanical Pulping Plants

Fouling is one of the most common problems encountered when using membranes in treatment applications of papermaking wastewater. The alkaline peroxide mechanical pulping (APMP) process has been widely adopted all over the world. However, reports on the membrane treatment of APMP plant effluent are relatively rare. It is mainly attributed to the high operational cost of membrane recovery and replacement. So, we originally investigated the cleaning protocols for the polyethersulfone (PES) membranes fouled by APMP plant effluent. To maximize flux recovery, four chemical cleaning protocols were explored to clean the fouled membranes. Parameters evaluated included flux recovery percent, total solids, dichromate chemical oxygen demand (CODCr), five-day biochemical oxygen demand (BOD5), and color retentions of membranes. Scanning electron microscopy with an energy dispersive x-ray analyzer (SEM-EDX) and attenuated total reflection Fourier-transformed infrared spectroscopy (ATR-FTIR) were employed to give a more precise assessment of the cleaning processes. Results showed that the cleaning protocol of “0.2 wt% Triton X-100+absorbent cotton” presented the strongest cleaning effectiveness for the fouled PES membranes. Flux of the fouled membrane recovered to 98.5% that of the pristine membrane, and the retention of total solids, CODCr, BOD5, and color of the cleaned membrane were approximate to those of the pristine membrane. Examinations of SEM-EDX and ATR-FTIR revealed that the cleaned membranes had similar appearances with the pristine membrane, as well as elemental and chemical compositions.

PVA-SA Immobilized White-Rot Fungus to Treat Papermaking Wastewater

Effects of white-rot fungus BYBF treatment on properties of papermaking wastewater were investigated. The optimal immobilized conditions were the PVA 5%, SA 2.3%, active carbon 2%, 2% CaCl2 in saturated boric acid solution and pH = 7. Using these materials to form immobilized beads, which have great mechanical strength and big specific surfaces. Using these beads to immobilized BYBF to treating terminal wastewater. COD decreased from 411mg /l to 352mg/l in 4 days.

Removal Effect of Potassium Ferrate to COD in Different Wastewater

In order to research the removal effect of potassium ferrate to COD in the different wasterwater, the papermaking wastewater and the tanning wastewater were used as research objects. This paper was focused on evaluating the effectiveness of potassium ferrate preoxidation on COD removal by coagulation in different wastewater of papermaking and tanning. Potassium ferrate is a strong oxidant in the entire pH range: its redox potentials are 2.20 and 0.72 V in acidic and basic media, respectively ferrate (VI) ions will be reduced to Fe (III) ions or ferric hydroxide during the oxidation process, potassium ferrate has also the ability to act as coagulant. The removal efficiency was 78.21% to the papermaking wastewater and 85.51% to the tanning wastewater, respectively, when the dosage concentration of potassium ferrate was 20 mg/L. Altogether, potassium ferrate is a perfect sewage treatment agent to papermaking wastewater and tanning wastewater.

Application of Photocatalytic Oxidation Technology on Water Treatment

TiO2 catalyst is n-type semiconductor material. As long as the semiconductor absorbs photons of no less than the band gap width，it enters the excited state together with the formation of light-induced hole in the valence band simultaneously. It is perfectly capable of capturing electronic,and the photo-induced electron e- in the conduction band also has high activity to form a redox system in the semiconductor surface through which most of the organic pollutants and partial inorganic pollutants eventually degrade into innoxious substances. It describes the application of photocatalytic oxidation technology in the field such as treatment of industrial wastewater (inorganic polluted water; dye wastewater; papermaking wastewater; pesticide wastewater; oily wastewater) and drinking water. The research shows that various indexes (chromaticity; COD; mineralization rate; bacteria inactivation rate, etc.) of this technology in water treatment application have achieved the required standards.

Synthesis and photocatalytic activity of nanocrystalline TiO2 co-doped with nitrogen and cobalt(II)

Nitrogen-modified cobalt-doped TiO2 materials were successfully prepared via a modified sol–gel method. The structure and properties of the catalysts were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM, ultraviolet–visible light diffuse reflectance spectra (UV–Vis DRS), N2 adsorption–desorption isotherms, and energy-dispersive X-ray spectroscopy. The XRD patterns of the pure and co-doped TiO2 samples indicate that the predominant phase was anatase. The average grain size obtained from TEM was approximately 10 nm. The Brunauer–Emmett–Teller analysis results indicate that the specific surface area was 77.7 m2 g−1. The UV–Vis DRS results for the co-doped sample reveal an absorption edge that had been red-shifted to 500 nm. The photocatalytic activities of the samples were evaluated through photodegradation of papermaking wastewater under UV and visible light irradiation. Compared with the cobalt-doped TiO2 sample and Degussa P25, the 3 mol% N-doped mesoporous N/Co-TiO2 photocatalyst exhibited the highest photocatalytic activity, which can be ascribed to the synergistic effect of the N and Co co-doping.

Modeling a Paper-Making Wastewater Treatment Process by Means of an Adaptive Network-Based Fuzzy Inference System and Principal Component Analysis

In this paper, a predictive control system based on an adaptive network-based fuzzy inference system (ANFIS) was employed to develop models for predicting and controlling the performance of a paper-making wastewater treatment process. The system includes an ANFIS predictive model and an ANFIS controller. In order to improve the network performance, fuzzy subtractive clustering, euclidean distance clustering, and principal component analysis (PCA) were used to identify model architecture and extract and optimize the fuzzy rule of the model. For the developed predictive model, when predicting, mean absolute percentage error (MAPE) lay 6.06% adopting ANFIS, root mean square normalized error (RMSE) was 24.4485 and R was 0.9731. The control model, taking into account the difference between the predicted value of chemical oxygen demand (COD) and the set point, can effectively change the additive dosages. In order to verify the developed predictive control model, a paper-making wastewater treatment process was p...

Experimental study on chitosan composite flocculant for treating papermaking wastewater

k]In this study, the coagulating effect of a novel composite flocculant on treating papermaking wastewater was studied and discussed. Results indicated that it achieved the best coagulating effect when this composite flocculant consisting of 60 mg/l of polymerized ferrous sulfate, 2 mg/l of polyacrylamide and 0.4 mg/l of chitosan, and pH value of wastewater was adjusted to 7.5. It also observed that the removal rate of COD and SS with this novel composite flocculant reached 72.5% and 98.5% respectively. Compared with the conventional flocculant such as polyacrylamide/polyaluminium chloride, the percentage of removing COD and SS using this composite flocculant were increased by 15.2% and 6.4% respectively, moreover, its input cost was cut down by 18.4%. So this composite flocculant has significantly environmental and economic benefits.

Modeling of a paper-making wastewater treatment process using a fuzzy neural network

An intelligent system that includes a predictive model and a control was developed to predict and control the performance of a wastewater treatment plant. The predictive model was based on fuzzy C-means clustering, fuzzy inference and neural networks. Fuzzy C-means clustering was used to identify model’s architecture, extract and optimize fuzzy rule. When predicting, MAPE was 4.7582% and R was 0.8535. The simulative results indicate that the learning ability and generalization of the model was good, and it can achieve a good predication of effluent COD. The control model was based on a fuzzy neural network model, taking into account the difference between the predicted value of COD and the setpoint. When simulating, R was 0.9164, MAPE was 5.273%, and RMSE was 0.0808, which showed that the FNN control model can effectively change the additive dosages. The control of a paper-making wastewater treatment process in the laboratory using the developed predictive control model and MCGS (monitor and control generated system) software shows the dosage was computed accurately to make the effluent COD remained at the setpoint, when the influent COD value or inflow flowrate was changed. The results indicate that reasonable forecasting and control performances were achieved through the developed system; the maximum error was only 3.67%, and the average relative error was 2%.

Study on the Synthesis and Properties of Water-Soluble Chitosan Grafted Copolymer

Grafted chitosan(CTS) copolymer was synthesized by the aqueous solution polymerization method, using the ammonium persulfate as initiator graft, Acrylamide（AM）and methacrylamide trimethyl Ammonium Chloride (DMC) as the grafted monomer. The effects of reaction conditions on grafted copolymerization were studied. When the deacetylation degree of chitosan as raw material is 86%, the optimum reaction to produce CTS -AM-DMC ternary graft copolymers by first AM and then DMC sequence were obtained at [initiator] 0.08%, 50°Cand 3.5h.The structure of CTS-AM-DMC was characterized by FTIR and XRD. When the dosage of synthetic product is 0.3mg/L, the effect of flocculation on the papermaking wastewater is obvious better, which can make the light transmission up to 99%, and CODCr to 9mg/L.

Study on Cationic Starch Graft Copolymer in Papermaking Wastewater Treatment

Paper industry is one of the major environmental pollution industries in china, pulp and paper industry wastewater discharge amount is from 10% to 12% of the national total wastewater discharge amount. Cationic starch graft copolymer was prepared in laboratory and used to treat papermaking wastewater. The effects of its cationic degree, dosage, flocculation temperature, flocculation time and the combination with alum on papermaking wastewater treatment were investigated. It was found that the best flocculation in the treatment of papermaking wastewater is achieved when cationic degree of cationic starch graft copolymer is 27.38%, adding amount is 15mL, flocculation temperature is 50°C and the mass ratio of alum to cationic starch graft copolymer is 2: 1. The flocculation of composite flocculant made up with alum to cationic starch graft copolymer to papermaking wastewater is much better than only cationic starch graft copolymer is used.

Preparation of a New Adsorption Material and its Application in Wastewater Treatment

A kind of new adsorption material for wastewater treatment was made of fly ash as the main composition, with addition of sodium silicate, cement and pore forming material as the accessory materials, etc. Three kinds of practical wastewater were treated by using the new material, they were printing and dyeing wastewater, papermaking wastewater and coking wastewater, respectively. The results showed that removal COD efficiencies of the three kinds of wastewater were 57.89%, 71.43%, 80%, respectively, removal color efficiencies were 90%, 92%, 92%, respectively. The new developed material was mainly used for advanced treatment of the effluent water after biochemical process. It will be a substitute for activated carbon materials and have preferable application prospect.