Search results for "paper industry"

Behavior of carbohydrate-based material in black liquor during heating

2004

One industrial softwood Kraft black liquor was heat-treated (at 175 ?C and 190 ?C for 15-60 min) together with laboratory-made soda-AQ (wheat straw and reed canary grass) and Kraft (reed canary grass) black liquors (at 190 ?C for 30 min). The feedstock black liquors were characterized with respect to their polysaccharide (mainly xylem) and aliphatic carboxylic acid contents before and after the heat treatments. It was noted that, due to the higher amount of polysaccharides in the non-wood black liquors (8.2-16.6% of d.s) compared to that in the softwood black liquor (1.4% of d.s), the heat treatment in the former case resulted in a 5-30% increase in the amount of aliphatic acids formed by v…

Screening pretreatment methods to enhance thermophilic anaerobic digestion of pulp and paper mill wastewater treatment secondary sludge

2013

Abstract The effect of hydrothermal (150 °C for 10 min and 70 °C for 40 min), enzymatic (Accelerase 1500, 0.07 g/g volatile solids (VS)), ultrasound (45 kHz for 30 min) and chemical pretreatments (HNO3 at pH 3 and NaOH at pH 12) alone or in combination on the chemical composition and methane yield of the pulp and paper mill secondary sludge was studied in batch assays at 55 °C. In total, 12 different pretreatment combinations were compared. Chemical analyses showed that all pretreatments except for HNO3 and ultrasound pretreatments improved the organic matter solubilization. Among the studied pretreatments, hydrothermal (150 °C, 10 min) pretreatment alone or in combination with enzymatic an…

Bleaching of color of kraft pulp mill effluents and natural organic matter in lakes

2002

In situ changes in the color of lake water and biologically treated kraft pulp mill effluents mixed in lake water were examined in three lakes. In 1.7 m3 enclosures, the color (400–700 g Pt·m–3) of the mixture of pulp mill effluent and lake water remained similar for 4 months in darkness, whereas exposure to solar radiation resulted in 17–42% bleaching of color. During the summer stratification of a humic lake, the color (160 g Pt·m–3) of hypolimnetic water remained similar to that found during spring turnover, but the color of epilimnion decreased 13%. The measured rates of photochemical bleaching of color by solar radiation could explain the decrease of epilimnetic color. Attenuation of …

Characterization of totally chlorine-free effluents from kraft pulp bleaching III

1999

Abstract Chemical changes in the dissolved high-molecular-mass material from silver birch (Betula pendula) kraft pulp during the oxygen–alkali delignification stage (O) and the subsequent totally chlorine-free (TCF) bleaching sequence (X–Z–EOP–AZ–EP–S) were investigated by analytical pyrolysis (pyrolysis–gas chromatography/mass-sensitive detector (Py–GC/MSD)). In addition, the pyrolysis data were subjected to chemometric analysis, resulting in a rapid method for determining with reasonable accuracy, for example, the mass proportion of carbohydrates and lignin in the effluents from each of the treatment stages. The method was calibrated by chemical analysis on the same effluents.

Carbon Dioxide as Chemical Feedstock. Edited by Michele Aresta.

2010

Soda-AQ pulping of reed canary grass

2001

Abstract Delignification of reed canary grass (Phalaris arundinacea L.) was carried out by conventional soda-anthraquinone (AQ) pulping under varying conditions selected according to an orthogonal experimental design with four factors (cooking parameters) at three levels each L9 (34). The influence of these four parameters, i.e. effective alkali, EA (12, 15, and 18% on oven dried (o.d.) reed, as NaOH), maximum temperature (145, 155, and 165°C), time to maximum temperature (70, 90, and 110 min), and time at maximum temperature (0, 15, and 30 min) on the pulp properties (yield, kappa number, and viscosity) was studied. Results indicated that, with respect to delignification, EA was the most i…

Shedding light on biogas: a transparent reactor triggers the development of a biofilm dominated by Rhodopseudomonas faecalis that holds potential for…

2019

AbstractConventional anaerobic digesters intended for the production of biogas usually operate in complete darkness. Therefore, little is known about the effect of light on microbial communities operating in anaerobic digesters. In the present work, we have studied through 16S rRNA gene amplicon Nanopore sequencing and shotgun metagenomic sequencing the taxonomic and functional structure of the microbial community forming a biofilm on the inner wall of a lab-scale transparent anaerobic biodigester illuminated with natural sunlight. The biofilm was composed of microorganisms involved in the four metabolic processes needed for biogas production. The biofilm proved surprisingly rich in Rhodops…

Microbial communities in full-scale woodchip bioreactors treating aquaculture effluents.

2021

Woodchip bioreactors are being successfully applied to remove nitrate from commercial land-based recirculating aquaculture system (RAS) effluents. In order to understand and optimize the overall function of these bioreactors, knowledge on the microbial communities, especially on the microbes with potential for production or mitigation of harmful substances (e.g. hydrogen sulfide; H2S) is needed. In this study, we quantified and characterized bacterial and fungal communities, including potential H2S producers and consumers, using qPCR and high throughput sequencing of 16S rRNA gene. We took water samples from bioreactors and their inlet and outlet, and sampled biofilms growing on woodchips a…

Potential of Baltic Region Peat in High Added-value Products and Environmentally Friendly Applications - A Review

2021

The present review is dedicated to using of peat on the example of fen peat in high added-value products and applications. Mainly, but not limited, last decade literature was analysed from the perspective of innovation potential of peat applications in environmental technologies on examples of studies from the Baltic Sea region. Paper covers a wide range of applications of peat products started from agriculture to medicine and cosmetics. A separate chapter is devoted to the deep-processed peat product - humic substances (humate, humic and fulvic salts and acids). Generalised dependence of product extraction rate and its properties, depending on the process parameters are provided. Widely ar…

Modeling the influence of potassium content and heating rate on biomass pyrolysis

2017

This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing. The shrinking particle model considers internal and external heat transfer limitations and incorporates catalytic effects of potassium on the product yields. Modeling parameters were tuned with experimentally determined char yields at high heating rates (>200 K s−1) using a wire mesh reactor, a single particle burner, and a drop tube reactor. The experimental data demonstrated that heating rate and potassium …