Treatment Of Black Liquor Research Articles

Electrocoagulation treatment of black liquor from soda-AQ pulping of wheat straw.

The effect of electrocoagulation treatment was investigated on black liquor from soda-anthraquinone (AQ) pulping of wheat straw. Removal of phenol, chemical oxygen demand (COD), color, total suspended solids (TSS), total dissolved solids (TDS), and total solids (TS) from black liquor was investigated at different current densities by using aluminum electrodes at various electrolysis times (10, 25, 40, 55, and 70 min) and pH levels (3, 5, 7, 9, and 10.5). It was observed that at 16 V, electrolysis time of 55 min and current density of 61.8 mA/cm(2) were sufficient for the removal of the pollutants. Energy consumption was evaluated as an important cost-relation parameter. Results showed that the electrocoagulation treatment reduced color intensity from the high initial value of 18,750 to 220 PCU. This was strongly influenced by the pH level of the wastewater. In addition, it was found that the removal efficiency increased with increasing of current density. The maximum efficiencies for removal were 98.8, 81, 80, 92, 61, and 68 % for color, phenol, COD, TSS, TDS, and TS, respectively. The lowest energy consumption values were obtained at neutral pH after 55 min. Electrocoagulation was found to be an effective, simple, and low-cost technique to treat black liquor.

Biodegradation of Black Liquor

Bacterial strains and yeast strains were screened for treatment of black liquor. 17 bacterial cultures of genus – arthrobacter, cellulomonas, chainia, pseudomonas and glucanobacter were used. 19 yeast cultures having genus-kluyveromyces, pachysolen, pichia, rhodotorula, saccharomyces, candida and yerrowia were used for study. At pH 8.0, 58.33% sugar utilization, 16.14% phenol degradation, 37.81% decolorization was obtained by using Candida catanula NCIM 3337, C. brumptii 3402, Pseudomonas fluorescens 2653 respectively. 45.63% sugar utilization, 29.48% phenol degradation, 20.97% decolorization was observed by using Yerrowia lipolytica NCIM 3472, Pseudomonas fluorescens 2173, Yerrowia lipolytica 3589 respectively at pH 6.5. 63.49% sugar utilization was observed by Pseudomonas fluorescens 2141 at pH 4.5. 28.85% phenol degradation was done by Pachysolen tannophilus 3445 at pH 4.5. 63.26% decolorization was observed for Candida lambica 3532 at pH 4.5. Use of biomass for decolorization was attempted in this study. Fermentation of fruits was carried out. Sapota, fig, papaya, pineapple, banana, guava and tamarind were used for fermentation. Fermentation was done by using baker's yeast. Residue from ethanol fermentation was used for decolorization of black liquor. Decolorization was obtained by residue from banana and tamarind fermentation residue was higher. It was 63.79 and 65.62% decolorization for banana and tamarind fermentation residue respectively.

Microbial Treatment to Black Liquor

Black liquor is released from pulp and paper industry. It is hazardous in nature and harmful to environment. We have screened bacterial cultures for treatment of black liquor. 18 bacterial cultures were used for screening of biodegradation of black liquor (1:5 diluted). We have used two different pH i.e. 9.0 and 5.5 for study. Among bacterial cultures we attempted to use Pseudomonas sp., Arthrobacter, Pseudomonas fluroscence and Pseudomonas pudita for screening. Baker's yeast was also used for study at pH 9.0 and 5.5. Study of sugar utilization, phenol degradation and decolorization was carried out. Pseudomonas fluorescens NCIM 2174 utilized 47.5% sugar at pH 9. In case phenol degradation, 30.35% degradation was observed by Arthrobacter simplex NCIM 2449 at pH 9. 27.85% decolorization by done by Pseudomonas putida NCIM 2872 at pH 5.5. Pseudomonas fluorescens NCIM 2174 has shown 10.36% phenol degradation and 2.76% decolorization at pH 9. Arthrobacter simplex NCIM 2449 utilized 37.7% sugar and 8.23% decolorization observed at pH 9. 4.34% sugar utilization and 17.71% phenol degradation was observed with Pseudomonas putida NCIM 2872 at pH 5.5. Baker's yeast has shown 10.94% sugar utilization and 15.59% decolorization at pH 5.5. 14.27% phenol degradaton was obseved with Baker's yeast at pH 9.

Preparing, Characterizing, and Evaluating Ammoniated Lignin Diesel from Papermaking Black Liquor

Managing papermaking black liquor has always been a problem in the papermaking industry. Alkali lignin is biologically difficult to treat and is the main factor that affects the treatment of papermaking black liquor. In this study, we used ammonization to process lignin from papermaking black liquor into ammoniated lignin and then added the ammoniated lignin into diesel oil by applying microemulsion technology. We investigated the influences of several process parameters on the diesel separation rate using an orthogonal array design. The ranges of hydrophilic–lipophilic balance (HLB), emulsifier, and co-emulsifier were from 8.3 to 9.3%, from 4 to 6%, and from 0.8 to 1.6%, respectively. When range analysis and analysis of variation (ANOVA) were conducted, the order of affecting ammoniated lignin diesel production was determined as follows: HLB > emulsifier > co-emulsifier. Meanwhile, optimum microemulsion process conditions were found as follows: HLB (9.3%), emulsifier (6%), and co-emulsifier (1.6%). The physicochemical characterizations of ammoniated lignin diesel were determined to evaluate its feasibility as an engine oil. Engine capacity load velocity characteristic trial was conducted, and the engine emission of ammoniated lignin diesel was determined. Results show that ammoniated lignin diesel can save pure diesel by nearly 10% compared to traditional diesel; consequently, ammoniated lignin diesel can be used directly as a suitable fuel.

Environmentally safe treatment of black liquor with Comamonas sp. B‐9 under high‐alkaline conditions

The strain Comamonas sp. B-9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three-Kingdoms Dynasty of ancient China (A.D. 220-280). It could be used to treat black liquor (BL) with high-alkaline pH and with an initial chemical oxygen demand (COD) of 18,000-25,000 mg L(-1) , without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B-9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC-MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B-9 were diminished, while 4-methyl benzaldehyde, 3,4,5-trihydroxybenzoic acid ethyl ester, and 4-hydroxy-3,5-dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B-9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high-alkaline conditions.

Properties of Heat Treatment Alkaline Pulping Black Liquor

For a large-scale industrial separations and purifications of the lignin in the alkaline pulping, we use aluminum chloride as a catalyst to heat the alkaline pulping black liquor, in order to discuss effects in the nature of high temperature heat treatment process in the alkaline pulping black liquor and aluminum chloride on the nature of alkaline pulping black liquor. The results show that temperature increased and the lignin and carbohydrate content increased and the solids content and pH decreased in the high temperature heat treatment process. When joining the catalyst aluminum chloride, lignin, carbohydrates, solids content and pH value were increased, and increased with increasing amount of aluminum chloride. It proves that the Aluminum chloride plays a big role in the process of the alkaline pulping black liquor heat treatment. It will provide some theoretical basis of the heat treatment of alkaline pulping black liquor.

Influence of Influent Concentration on Papermaking Black Liquor Treatment with Wet Air Oxidation Method

Black liquor was processed with wet air oxidation technology in these experiments. Influence of its influent concentration was researched. COD, absorbance, turbidity and pH of the water samples were measured and analyzed. The results showed that: the treatment effect of each index in black liquor treatment with wet air oxidation method gradually weakened with the increase of influent concentration from the overall point of view; when papermaking black liquor was processed by wet oxidation, the water samples was weak alkaline basically, with pH in between 7.83 to 8.70. COD removal, decolorization removal and turbidity removal basically improved with the extension of time, the COD removal and decolorization removal can reach 50 % or more basically. When influent concentration was greater than 5500 mg/L, turbidity removal was less than 40 %. So the influent concentration of the black liquor in wet oxidation treatment should not be too large, the influent concentration of 2500 mg/L to 4000 mg/L is appropriate.

Effects of Influent pH on Papermaking Black Liquor Treatment with WAO Method

Papermaking black liquor was processed with WAO method，Chroma of papermaking black liquor water was 1,250,000 times and COD concentration was7028 mg/L. Effects of influent pH on its treatment were researched. The CODCr, absorbance, turbidity and pH of effluent water were determined. COD removal, decolorization removal, turbidity removal were analyzed. The results showed that: treatment effects gradually weakened with the increase of influent pH in the treatment of papermaking black liquor with WAO method. Influent pH was in between 3.0 to 7.0 appropriate. When papermaking black liquor was processed by wet air oxidation after, COD removal, decolorization and turbidity removal basically improved with the extension of time, reaction time set at 60 min was appropriate.

Influence of Reaction Pressure on Papermaking Black Liquor Treatment with Wet Oxidation Method

The papermaking black liquor of one Paper Mill in ChaoZhou, GuangDong Province was treated with the wet oxidation method and the influence on treatment effect with the reaction pressure was researched. Experimental results showed that the papermaking black liquor was treated by the wet oxidation method; the treatment effect was showed upward trend with the increase of the reaction pressure, and the reaction pressure of 3.5 MPa is appropriate. The papermaking black liquor was treated by the wet oxidation method, the influent pH about 8.00 showing weakly alkaline basically. The decolorization removal and turbidity removal first increases and then slightly decreases basically with the increase of reaction time.When the reaction time is 60 min, the treatment effect is overall best. The decolorization removal can reach 61.1 % and the turbidity removal can reach 73.8 %.

Enhanced remediation of black liquor by activated sludge bioaugmented with a novel exogenous microorganism culture

Black liquor (BL) is a notoriously difficult wastewater to treat due to the economic and efficiency limitations of physiochemical methods and intrinsic difficulties with bioremediation strategies caused by the high pH (10-13) and lignin content. This study investigated the feasibility of a novel bioaugmentation strategy for BL treatment, which uses a mixed microorganism culture of lignocellulose-degrading microorganisms isolated from degraded bamboo slips. Black liquor treatment was assessed in terms of chemical oxygen demand (COD) and color removal with a sequencing batch reactor organic loading rate of 9kg COD/L·day under highly alkaline conditions (pH 10). Results revealed that bioaugmented activated sludge treatment of BL with special mixed microorganisms significantly enhanced the removal efficiency of COD, color, and lignin from the wastewater up to 64.8, 50.5, and 53.2%, respectively. Gel permeation chromatography profiles showed that the bioaugmentation system could successfully degrade high molecular lignin fragments in black liquor. This work confirms bioaugmentation as a feasible alternative strategy for enhanced biological treatment of wastewater with high lignin content and high organic load rate under strongly alkaline conditions.

Isolation and purification of lignin and silica from the black liquor generated during the production of bioethanol from rice straw

Bioethanol production from lignocellulosic agricultural residues is an attractive future biofuel option from the standpoints of food security and environment friendliness. The safe disposal of the black liquor produced during the process of lignocellulosic ethanol production however remains a challenge. In this study, a method has been developed for the efficient recovery of lignin and silica from black liquor. Rice straw was pre-treated in two different steps, with dilute acid hydrolysis followed by alkaline peroxide delignification. Lignin and silica were isolated from the black liquor by precipitation method using dilute sulphuric acid for reducing the pH of the black liquor. The pH values required for the recovery of lignin and silica were optimised separately. Two different precipitation and separation methods were followed for product recovery from black liquor. Chemical characterisation of isolated lignin was done by FTIR and compared with commercial lignin to evaluate its potential industrial applications. The quality of the filtrate after precipitate separation was also monitored in each step by COD and TDS analyses. Two-stage treatment of black liquor, which involves isolation of silica and lignin separately, was found to provide superior quality products and cleaner effluent than the direct precipitation of lignin without the separation of silica from black liquor.

Treatment of Cotton Pulp Black Liquor Using Micro-Electrolysis in Sequencing Batch Reactor

Micro-electrolysis process was conducted to treat the anaerobic digestion effluent of cotton pulp black liquor in sequencing batch reactor (SBR). Three key factors including reaction time, pH, and iron-carbon volume ratio were investigated for their impacts on the treatment efficiency. The effluent of micro-electrolysis polished by coagulation process was performed with Al2(SO4)3and PAC as coagulators. The results show that the optimum conditions of the micro-electrolysis treatment were pH 5.5, iron-carbon volume ratio 1:1, and reaction time 8h. Al2(SO4)3was selected as the coagulator with the addition of 400mg/L. The removal efficiency of COD reaches 93.2% with Micro-electrolysis combined with coagulation process. In addition, the B/C ratio has risen from 0.016 to 0.68(>0.3), which creates favorable conditions for the subsequent aerobic process. Consequently, the micro-electrolysis and coagulation process are highly efficient to dispose the anaerobic digestion effluent of cotton linters pulp black liquor. What’s more, this technology has the advantages of low operating cost, small land occupation and high efficiency.

Treatment of Cotton Pulp Black Liquor Using Micro-Electrolysis in Sequencing Batch Reactor

Treatment of Cotton Pulp Black Liquor Using Micro-Electrolysis in Sequencing Batch Reactor

Ligninolytic Enzymes of Lentinus polychrous Grown on Solid Substrates and its Application in Black Liquor Treatment

Ligninolytic Enzymes of Lentinus polychrous Grown on Solid Substrates and its Application in Black Liquor Treatment

Research on Super Critical Water Oxidation Based on Papermaking Black Liquor Treatment

Super Critical Water Oxidation is an innovative and high technology. This article discussed properties of Super Critical Water (SCW), the reaction mechanism, technological process, strength and weakness of Super Critical Water Oxidation (SCWO).The future of SCWO is also prospected.

Black Liquor Decolorization by Selected White-Rot Fungi

Five different strains of white-rot fungi have been tested for their ability to decolorize black liquor on plates and on solid-state fermentation using vermiculite as the solid inert support. Since the high salt concentration inhibited the growth of all fungi, the black liquor was dialyzed against distilled water prior to use. A preliminary step on plates was carried out to qualitatively determine the capacity of the fungal strains for black liquor decolorization. Out of the five fungi studied, Phanerochaete sordida, Pycnoporus sanguineus, and Trametes elegans exhibited the more conspicuous decolorization halos in malt extract medium, while the decolorization by all the strains was not evident when a defined culture medium was used. Cultures on solid-state fermentation using vermiculite as solid support were also tested, the liquid phase was malt extract or glucose-based medium and supplemented with different black liquor concentrations. Decolorization of black liquor was largely affected by the fungal strain, the concentration of black liquor, and the carbon source. The percentage of color removal ranged from 6.14% to 91.86% depending on the fungal strain and culture conditions. Maximal decolorization was observed in malt extract cultures after 60 cultivation days. Interestingly, decolorization in malt extract medium increased with increasing black liquor concentration. The highest decolorization value was achieved by Steccherinum sp. which reduced up to 91.86% the color of the black liquor in malt extract medium; this percentage is equivalent to 5.2 g L(-1) of decolorized black liquor, the highest value reported to date. Traditional technologies used for the treatment of black liquor are not always effective and may not to be an environmentally friendly process. Vermiculite-white-rot fungi systems are presented in this work as a promising efficient alternative for the treatment of black liquor.

Activated sludge and chemical treatment process for Chemi-Thermo-Mechanical Pulping black liquors

Characterisation and treatment of the black liquor coming from Chemi-thermo-mechanical pulping (CTMP) of wheat straw was evaluated in this research. Toxicity of the liquor was evaluated and it was found high in Biological Oxygen Demand (BOD) 0.45%, Chemical Oxygen Demand (COD) 1.85%, dissolved solids 1.04%, suspended solids 0.33%, total sulphur contents 2.42% and silica contents 0.45%. Activated sludge and chemical treatments were employed to make it environment-friendly. Activated sludge removed 63% total solids, suspended solids 90%, BOD 67% and COD up to 60%. Chemical treatment of this liquor involved use of anionic and cationic polymers together with alum to remove soluble COD and suspended solids from the liquor. Effluent thrown out after combined treatment was below 200 ppm in total solids, 300 FAU in turbidity, 700 ppm in BOD and 800 ppm in COD.

Bacterial decolorization of black liquor in axenic and mixed condition and characterization of metabolites

The pulping byproducts (black liquor) cause serious environmental problem due to its high pollution load. In order to search the degradability of black liquor, the potential bacterial strains Citrobacter freundii (FJ581026) and Citrobacter sp. (FJ581023) were applied in axenic and mixed condition. Results revealed that the mixed bacterial culture are more effective than axenic condition and can reduce 82% COD, 79% AOX, 79% color and 60% lignin after 144 h of incubation period. Additionally, the optimum activity of lignin degrading enzyme was noted at 96 h and characterized as manganese peroxidase (MnP) by SDS–PAGE analysis. Further, the HPLC analysis of control and bacterial degraded sample has shown the reduction as well as shifting of peaks compared to control indicating the degradation as well as transformation of compounds of black liquor. The comparative GC-MS analysis of control and degraded black liquor revealed that along with lignin fragment some chlorophenolic compounds 2,4,6-trichlorophenol, 2,3,4,5-tetrachlorophenol and pentachlorophenol were detected in black liquor degraded by axenic culture whereas these chlorophenolic compounds were completely absent in black liquor degraded by mixed bacterial culture. These chlorophenol inhibit the oxidative degradation which seems a major reason behind the low degradability of axenic degradation compared to mixed culture. The innovation of this aerobic treatment of alkaline black liquor opens additional possibilities for the better treatment of black liquor along with its metabolic product.

Changes in protein content of Culex pipiens mosquito treated with two agriculture waste extracts

Third larval instars of Culex pipiens were exposed to sub-lethal concentration LC25 of Black and White liquors (waste extract from rice straw) for 24 hours to study its effect on protein content quantitative and qualitative. The total protein contents in larval treated either with black liquor or with white liquor were high in all developmental stages except in pupal stage Black liquor treatment was low but not significantly as compared to the control insect. The protein profile of the treated larvae and other developmental stages (pupa, adult female and adult male) was evaluated to explain their mode of action. Electrophoretic analysis of total proteins revealed inhibitory action of the tested compounds on the protein contents. The appearance and disappearance of certain protein fractions by application of these compounds may be explain their larvicidal activity and disorders occurred during different developmental stages.

Biological treatment of high-pH and high-concentration black liquor of cotton pulp by an immediate aerobic-anaerobic-aerobic process

In this study, an immediate aerobic-anaerobic-aerobic (O/A/O) biological process was established for the treatment of black liquor of cotton pulp and was tested by both laboratory-scale batch experiment and pilot-scale continuous experiment. The effects of the hydraulic retention time (HRT) were studied, as were the alkaliphilic bacteria number, the culturing temperature and the concentration of black liquor on COD (chemical oxygen demand) removal. The total COD (COD(tot)) removal rate of the novel O/A/O process, for a black liquor with influent COD(tot) over 8,000 mg/L and pH above 12.8, was 68.7+/-4% which is similar with that of the traditional acidic-anaerobic-aerobic process (64.9+/-3%). The first aerobic stage based on alkaliphilic bacteria was the crucial part of the process, which was responsible for decreasing the influent pH from above 12 to an acceptable level for the following treatment unit. The average generation time of the alkaliphilic bacteria in the black liquor was about 36 minutes at 40 degrees C in a batch aerobic activated sludge system. The efficiency of the first aerobic stage was affected greatly by the temperature. The COD(tot) removal at 55 degrees C was much lower in comparison with the COD(tot) removal at 45 degrees C or 50 degrees C. Both the laboratory-scale batch experiments and the pilot-scale continuous experiment showed that the COD(tot) removal rate could reach about 65% for original black liquor with a pH of about 13.0 and a COD of 18,000-22,000 mg/L by the immediate O/A/O process. The first aerobic stage gave an average COD(tot) removal of 45.5% at 35 degrees C (HRT = 72 h) at a volume loading rate of 3.4 kg COD m(-3) d(-1).