Pulp Plant Research Articles

Experimental Study on the Start-Up Stage of Wheat Straw Pulp and Paper Wastewater Treatment in Immobilized and Suspended Biomass Combination Processing

The study on the start-up of the pilot-scale immobilized and suspended biomass combination processing to treat the comprehensive effluent from a wheat straw pulp and paper plant was performed. The carrier packing selected in this experiment is a new type of microbial carrier (modified polyurethane foam plastic packing) which dosing rate was 20% of the reactor volume. The low quantity of inoculation sludge way is used to start the system. The test results show that the removal efficiency of COD and SS by the immobilized and suspended biomass combination technology system after a weak or so can be stable, as the effluent SS was below 50mg/L, the removal rate of 95% or more and the effluent COD was below 260mg/L, the removal rate of 85% or more. From start to 10th day, the attached sludge concentration on biomass conversion was more than 20g/L, while the microscope observation to biological adherent microbes suspended sludge and carrier phase indicated abundant microbial species. The fact indicates that the start-up can be finished in 10 days.

KP設備老朽化への対応

KP設備老朽化への対応

Insights from simulation of CIL/CIP circuit Part 2 – Simulation studies

In Part 1 of this paper, the development of a semiempirical model of a carbon in leach (CIL)/carbon in pulp (CIP) plant for recovery of gold and silver was detailed. With appropriate practical parameters, the model was able to reproduce typical tank profiles for gold and silver contained in the solids, solution and active carbon. The model was used in a series of simulations to explore the influence on plant performance of: (1) circuit design encompassing tank size and number, and tankage configuration; (2) using some of the initial tanks for leaching only (CIP); (3) the impact of a thickener recycling a percentage of tailings solution to the head of the circuit; (4) leaching and adsorption parameters; (5) operational parameters such as ore feed rate and percent solids in the slurry; and (6) rate of countercurrent movement of active carbon. The results of these simulations highlight factors which need to be considered in the design and optimisation of a CIL/CIP circuit and provide an insight into identifying deficiencies in performance and the possible ways to counteract them by manipulation of the factors above.

Mites (Arachnida: Acari) collected on rubber trees Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg. in Santana, Amapá state, Brazil

The purpose of this study was to elaborate a preliminary list of the mite species associated with rubber trees in the municipality of Santana, in the state of Amapá, Brazil. Two collections of rubber tree leaves were conducted on May 2nd and June 5th , 2010. Twenty-five plants were sampled at random. Three leaves were collected per plant, from the lower third of the crown. The samples were placed in paper bags, packed in an isothermal box chilled gel-based pulp plant (Gelo-X(®)), and transported to the Entomology Laboratory at Embrapa Amapá, in Macapá. The leaflets were examined under a stereomicroscope, and the mites found on the adaxial and abaxial surfaces of the leaves were collected with a stilet, mounted on microscope slides in Hoyer's medium, and later identified. We collected a total of 1,722 mites of 10 families: Acaridae, Cunaxidae, Eriophyidae, Iolinidae, Phytoseiidae, Stigmaeidae, Tarsonemidae, Tenuipalpidae, Tydeidae, and Winterschmidtiidae, in addition to unidentified species of the suborders Oribatida and Astigmatina. The family Phytoseiidae represented only 2.90% of specimens collected, but showed the highest species richness (5 species). The only representative of Tenuipalpidae was Tenuipalpus heveae Baker, 1945, but 81.13% of the mites collected in this study belonged to this species.

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.

Coupling of solar-assisted advanced oxidative and biological treatment for degradation of agro-residue-based soda bleaching effluent

This study evaluates the effect of integrated solar-assisted advanced oxidation process (AOP) and biological treatment on the extent of degradation of effluents from chlorination (C) and first alkaline extraction (E(1)) stages of soda pulp bleaching in agro-residue-based pulp and paper mill. Biodegradation of the effluents was attempted in suspended mode using activated sludge from the functional pulp and paper industry effluent treatment plant acclimatized to effluents in question. The photocatalytic treatment was employed using zinc oxide (ZnO) in slurry mode for decontamination of effluents in a batch manner and the degradation was evaluated in terms of reduction in chemical oxygen demand. The biological treatment (24h) of C and E(1) effluent resulted in 30 and 57% of degradation, respectively. Solar-induced AOP of C and E(1) effluents resulted in 53 and 43% degradation under optimized conditions (2.5gL(-1) ZnO at pH8.0) after 6h of exposure. For C effluent, a short duration of solar/ZnO (1h) prior to biological treatment reduced the time required at biological step from 24 to 12h for almost same extent (92%) of degradation. However, sequential biological treatment (24h) followed by solar/ZnO (2h) resulted in 85.5% degradation. In contrast, in the case of E(1) effluent, sequential biological (24h)-solar/ZnO (2h) system effectively degrades effluent to 95.4% as compared to 84.8% degradation achieved in solar/ZnO (2h)-biological treatment (24h) system. In the present study, the sequencing of photocatalysis with the biological treatment is observably efficient and technically viable process for the complete mineralization of the effluents.

Results of multiyear studies on the dynamics of pollution of lake Baikal by polycyclic aromatic hydrocarbons in the area waste water discharge from the Baikal Pulp and Paper Plant

New data on the concentration and spatial distribution of the benz(a)pyrene and polycyclic aromatic hydrocarbons in bottom sediments in the testing area of the Baikal Pulp and Paper Plant (BPPP) waste water discharge in 1981–1988 and 2010 are presented in this paper. The bottom sediments in this section of the lake are strongly polluted with polycyclic aromatic hydrocarbons.

Potential of Lignosulphonate of Eucalyptus Lignin from Pulp Plant as Dispersant in Gypsum Paste

Eucalyptus lignin was isolated from kraft black liquor through acidification by using H2SO4. To effectively utilize black liquor waste from pulp plant, lignin was converted into sulphonated hydroxymethylated phenolized sulphuric acid lignin compound (SHP-SAL), which is soluble in water. SHP-SAL was obtained through the sequence of (1) phenolation of sulphuric acid lignin (SAL) into phenolized sulphuric acid lignin (P-SAL), (2) hydroxymethylation of P-SAL into hydroxymethylated phenolized sulphuric acid lignin (HP-SAL), and (3) sulphonation of HP-SAL into SHP-SAL. The derived lignin of SHP-SAL characterized by infrared spectrometry showed a significant absorption at 630 cm-1, which indicates the presence of S−O bond, and absorption at 1118 and 1059 cm-1, which are characteristics of C−O bonds in lignosulphonates. Assessment of SHP-SAL as a dispersant in gypsum paste was done according to C230-90 ASTM standard. The synthesized SHP-SAL has approximately 60% higher dispersability than those of commercial sodium lignosulphonate (comm. SLS) and commercial calcium lignosulphonate (comm. CLS). It is equal to the dispersability of sulphonated naphthalene formaldehyde (SNF), one of the high-performing sulphonate compounds.

Pulp and Paper Treatment Plant Upgrade A Case Study on Developing Best Solution

Pulp and Paper Treatment Plant Upgrade A Case Study on Developing Best Solution

Performance of a pilot-scale membrane process for the concentration of effluent from alkaline peroxide mechanical pulping plants

A pilot-scale membrane process for the concentration of effluent from an alkaline peroxide mechanical pulping (APMP) plant was investigated. Specifically, the cross-flow velocity and volume reduction were optimized again for a higher flux and a lower system energy consumption. A mathematical model was established to obtain the optimal parameters. Estimates were obtained of the expected savings in energy and water. The obtained optimal concentration conditions were: molecular weight cut-off at 10,000 Dalton, trans-membrane pressure at 3 bar, feed temperature at 50 oC, cross-flow velocity at 2 m/s, and volume reduction at 0.9. The average permeate flux under these conditions was 43.21 l/m2.h. The total solids content was increased from 25.47 g/L in the feed to 128.36 g/L in the concentrate. The permeate had low total solids content of 11.03 g/L, Chemical Oxygen Demand of 9180 mg/l, and Biochemical Oxygen Demand of 5870 mg/L. Such qualities would allow the permeate to be reused in the APMP process after a light biochemical treatment. With this new membrane concentration process, about 1402 kWh energy can be saved and 22 m3 effluent discharge can be reduced for each ton of pulp produced.

Characterization of the Different Abaca-Based Agro-Ecosystems in Leyte, Philippines

This study was conducted to provide baseline data on the agro-ecosystem characteristics needed by the development planners and policymakers specifically for under-utilized and neglected crops, such as abaca, at the east-central portion of the Philippine archipelago. The results revealed that the most common companion crops for abaca were anii (Erythrina fusca), narra (Pterocarpus indicus), coconut, fruit trees, and other forest trees. Among the areas sampled, biomass and fiber yield performance of abaca ranges from 200 kg/ha to 1,200 kg/ha, which is far below the potential and attainable yield. These areas were located along the central mountain range of the island (i.e., Leyte Cordillera). The main consumers of the produced raw fiber were the two pulping plants in the province, which can be considered as an advantage to those farms that are located nearest to it. Among the areas surveyed, soil samples had loam texture that ranged from sandy loam to clay loam and were slightly acidic, with pH of 4.44–6.38. Samples in the mountain area of Ormoc city (i.e., Site No. 03) showed the lowest pH, higher percentage of organic carbon, and lower extractable phosphorus. However, among the areas surveyed, more than three-fourths had higher exchangeable bases that resulted to higher cation exchange capacity values.

Composition of the bacterial biota in slime developed in two machines at a Canadian paper mill

During the process of papermaking by pulp and paper plants, a thick and viscous deposits, termed slime, is quickly formed around the paper machines, which can affect the papermaking process. In this study, we explored the composition of the bacterial biota in slime that developed on shower pipes from 2 machines at a Canadian paper mill. Firstly, the composition was assessed for 12 months by DNA profiling with polymerase chain reaction coupled with denaturing gradient gel electrophoresis. Except for short periods (2-3 months), clustered analyses showed that the bacterial composition of the slime varied substantially over the year, with less than 50% similarity between the denaturing gradient gel electrophoresis profiles. Secondly, the screening of 16S rRNA gene libraries derived from 2 slime samples showed that the most abundant bacteria were related to 6 lineages, including Chloroflexi, candidate division OP10, Clostridiales, Bacillales, Burkholderiales, and the genus Deinococcus. Finally, the proportion of 8 bacterial lineages, such as Deinococcus sp., Meiothermus sp., and Chloroflexi, was determined by the Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization in 2 slime samples. The results showed a high proportion of Chloroflexi, Tepidimonas spp., and Schlegelella spp. in the slime samples.

ENVIRONMENTAL RISKS RELATED TO ACCIDENTS AT PULP AND PAPER PLANTS: THE CASE OF THE MANTUROVO PULP AND PAPER PLANT PROJECT

The paper presents approaches to quantitative and spatial assessment of emergency environmental risks at new sites of pulp and paper production using mathematical statistics, probability theory, and cartographic modeling. Damage assessment is based on the type and sphere (atmosphere, soil, and underground and surface waters) of impact. Although damage assessment considers governmentally approved methodology, the formula suggested for the assessment contains some suitable improvements. In addition, a brief characterization of technological process at pulp and paper plants provides objective substantiation of possible accident scenarios. Conclusions discuss economic and social benefits of pulp and paper plants versus their ecological disadvantages.

Designing an Economical Membrane Process to Concentrate the Effluent from Alkaline Peroxide Mechanical Pulping Plants

Using a multi-effect evaporation system to concentrate the effluent from alkaline peroxide mechanical pulping (APMP) plants is known to require a high energy consumption. In order to improve the situation, a polyethersulfone (PES) membrane was used to concentrate the effluent of APMP plants beforehand. An orthogonal experimental design was applied and a mathematical model was established to optimize the filtration parameters. An estimation of potential energy and water savings from this new concentration process was developed. The optimal filtration conditions obtained were: molecular weight cut-off at 10,000 Dalton, trans-membrane pressure at 3 bar, feed temperature at 50oC, cross-flow velocity at 420 rpm, and volume reduction factor at 0.93. The average permeate flux under these conditions was 45.31 l/m2.h. The total solids content was increased from 14.74 g/l in the feed to 95.04 g/l in the concentrate. The permeate had low total solid contents of 8.75 g/l, Chemical Oxygen Demand of 6696 mg/l, and Biochemical Oxygen Demand of 4383 mg/l. Such qualities would allow the permeate to be reused in the alkaline peroxide mechanical pulping process. With this new concentration process, about 4840.6 kWh energy can be saved and 23.3 m3 effluent discharge can be reduced for each ton of pulp produced.

Using a membrane filtration process to concentrate the effluent from alkaline peroxide mechanical pulping plants

Using a multi-effect evaporation system to concentrate the effluent from alkaline peroxide mechanical pulping (APMP) plants is known to require a high energy consumption. In order to improve the situation, a polyethersulfone membrane was used to concentrate the effluent of APMP plants beforehand. An orthogonal experimental design was applied and a mathematical model was established to optimize the filtration parameters. An estimation of potential energy and water savings from this new concentration process was developed. The optimal filtration conditions obtained were: molecular weight cut-off at 10,000 Dalton, trans-membrane pressure at 3 bar, feed temperature at 50oC, cross-flow velocity at 420 rpm, and volume reduction factor at 0.93. The average permeate flux under these conditions was 45.31 l/m2.h. The total solids content was increased from 14.74 g/l in the feed to 95.04 g/l in the concentrate. The permeate had low total solid contents of 8.75 g/l, Chemical Oxygen Demand of 6696 mg/l, and Biochemical Oxygen Demand of 4383 mg/l. Such qualities would allow the permeate to be reused in the alkaline peroxide mechanical pulping process. With this new concentration process, about 4840.6 kwh energy can be saved and 23.3 m3 effluent discharge can be reduced for each ton of pulp produced.

Dynamics of sulfur-containing admixtures in the atmosphere around a point source—the Baikal Pulp and Paper Plant on the southeast coast of Lake Baikal

A complex of organic and inorganic sulfur compounds have been measured for the first time in the vicinity of a point anthropogenic source—the Baikal Pulp and Paper Plant (BPPP) on the southeast coast of Lake Baikal; their spatial distribution and possible chemical transformation depending on the meteorological conditions and the time of day have been estimated. It is shown that the different heights of the emission of the sulfur compounds by departments of the plant and the coal thermal power station are responsible the different behavior of the corresponding admixtures in the plant’s surrounding.

Toxicity and recalcitrant compound removal from bleaching pulp plant effluents by an integrated system: anaerobic packed-bed bioreactor and ozone

Effluents originated in cellulose pulp manufacturing processes are usually toxic and recalcitrant, specially the bleaching effluents, which exhibit high contents of aromatic compounds (e.g. residual lignin derivates). Although biological processes are normally used, their efficiency for the removal of toxic lignin derivates is low. The toxicity and recalcitrance of a bleached Kraft pulp mill were assessed through bioassays and ultraviolet absorption measurements, i.e. acid soluble lignin (ASL), UV(280), and specific ultraviolet absorption (SUVA), before and after treatment by an integrated system comprised of an anaerobic packed-bed bioreactor and oxidation step with ozone. Furthermore, adsorbable organic halides (AOX) were measured. The results demonstrated not only that the toxic recalcitrant compounds can be removed successfully using integrated system, but also the ultraviolet absorption measurements can be an interesting control-parameter in a wastewater treatment.

Evaluation of the anaerobic degradation of black liquor from a Kraft pulp plant with addition of organic co-substrates

The purpose of this study was to assess the anaerobic degradation of black liquor with and without additional carbon sources. Batch experiments were conducted using black liquor, from an integrated pulp and paper mill adding ethanol, methanol and nutrients. The PCR/DGGE technique was used to characterize the structure of the microbial community. The addition of extra sources of carbon did not significantly influence the degradation of black liquor under the conditions evaluated and the microbial community was similar in all experiments. It was observed an increase in some members of the archaeal in reactors that had the best efficiencies for removal of black liquor (around 7.5%). Either ethanol or methanol can be used as co-substrates because the produce the same quantitative and qualitative effect.

Combination of an anaerobic process with O3, UV and O3/UV for cellulose pulp bleaching effluent treatment

Recent studies have shown that partial oxidation by advanced oxidation processes (AOP) is able to transform hard-to-degrade compounds and increase their biodegradability. In this work, anaerobic treatment was followed by ozonation, UV radiation and ozonation in the presence of UV radiation, to treat bleaching effluents from a cellulose kraft pulp plant. The anaerobic reactor (horizontal anaerobic immobilized sludge bed, HAISB) was used as a pretreatment to reduce the effluent organic load before applying AOP. The ozone treatments were applied in three different pH environments (3, 8 and 10) with retention times of 10, 30, 45 and 60 min. COD and adsorbable organic halogens (AOX) removal efficiencies at the HAISB were approximately 50%, while the BOD removal efficiency reached 80%. Ozonation promoted further removal of AOX and COD so that the combined efficiency reached 96% for AOX and 70% for COD. In the oxidation process, BOD was either removed in small quantities or actually increased, as intended, so th...

Study on the Possibilities to Use Ashes, EAF Dust and Lime Sludge as Neutralising Agent in Bioleaching

Studies were conducted to investigate the possibilities to use combustion ashes, electric arc furnace (EAF) dust and lime sludge as neutralising agent with reference to a commercial grade slaked lime. To maintain optimum pH during biooxidation of pyrite the acid produced has to be neutralised. Batch bioleaching was performed on a pyrite concentrate in 1-L reactors, using a mixed mesophilic culture at a temperature of 35oC. Neutralising agents were added regularly to ad- just pH to the desired level of 1.5. The ashes used were Bioash, Waste ash and Coal & Tyres ash, representing ashes gen- erated from combustion of biomass, a mixture of wood chips and municipal waste, and a mixture of coal and tyres. The dust used was an EAF dust produced in a scrap-based steel plant, while the sludge used was Mesalime produced in a pa- per and pulp plant. The study aimed to investigate the possibility to replace the conventionally used lime or limestone with by-products, based on their neutralising capacity and to observe eventual toxic effects on the bacterial activity. The bioleaching effi- ciency was similar for all the neutralising agents used except Waste ash, when compared with slaked lime. The extent of pyrite oxidation was in the range 69-75% for all neutralising agents, except Waste ash, which had a pyrite oxidation of 59%. The Waste ash contained a large number of potentially toxic elements and the chloride concentration of 11% proba- bly had a negative effect as observed on the lower redox potential and pyrite oxidation. The EAF dust has a good potential to be used as neutralising agent in bioleaching processes for zinc recovery from zinc sulphides, due to the high content of zinc, however the chlorides present should be removed prior to its use. The neutralising capacity, as determined by the amount needed for neutralisation during bioleaching, were rather high for EAF dust, Bioash and Mesalime with 37 g, 33 g and 29 g, respectively as compared with 22 g needed for slaked lime. However, Waste ash and Coal & Tyres ash had lower neutralising capacities with 81 g and 57 g needed, respectively. It is concluded that the replacement of lime or limestone with ash, dust or lime sludge can render considerable cost savings to the bioleaching operation. In addition, it is a means for sustainable use of natural resources, which would provide oppor- tunities to recycle elements present in them like for example zinc.