Green liquor dregs effect on Kraft mill secondary sludge composting

Zambrano, M.; Pichún, Consuelo; Alvear, Marysol; Villarroel, Mario; Velasquez, Ivan; Baeza, Jaime; Vidal, Gladys

doi:10.1016/j.biortech.2009.09.049

Cited by 29 publications

(10 citation statements)

References 49 publications

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“…The neutralization of wastewater by GLD may also cause operational problems by increased recirculation of NPE as a result of burning the wastewater sludge in the recovery boiler. Zambrano et al (2010) performed composting experiments with Kraft mill secondary sludge, by using GLD as a pH-stabilizing additive. Their results show that the sufficient dosage of dregs is 5e8 w-%, and that this amount does not hinder the microbial degradation of organic matter.…”

Section: Criticality Of Non-process Elementsmentioning

confidence: 99%

Separation, treatment and utilization of inorganic residues of chemical pulp mills

Kinnarinen

Golmaei

Jernström

et al. 2016

Journal of Cleaner Production

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a b s t r a c tThe major inorganic solid residues of chemical pulp mills include green liquor dregs, various lime residues, recovery boiler fly ash, and salt cake produced at the chlorine dioxide generator. Only a small proportion of these residues is currently utilized outside the mill area: landfill disposal and reuse at the mill are the most typically applied methods. The situation should be improved in the future for environmental and economical reasons. The focus of this review is on the separation of inorganic pulp mill residues to enhance the possibilities of their utilization. Solid-liquid separation operations, such as filtration and sedimentation, and the associated treatment processes, are described in close detail. The review aims at recognizing the most promising residues for utilization, as well as enhancing the understanding of the material balance of chemical pulp mills. The review also covers the most potential industrial applications for the utilization of residues, as well as the possibilities of using them as raw material in value-added products.

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Section: Criticality Of Non-process Elementsmentioning

confidence: 99%

Separation, treatment and utilization of inorganic residues of chemical pulp mills

Kinnarinen

Golmaei

Jernström

et al. 2016

Journal of Cleaner Production

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“…The addition of a moderate amount of GLD (5-8 wt %) with kraft mill sludge did not show a negative effect on the biological activities during the composting process [58].…”

Section: Co-compostingmentioning

confidence: 83%

Inorganic Waste Generated in Kraft Pulp Mills: The Transition from Landfill to Industrial Applications

Quina

Pinheiro

2020

Applied Sciences

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Kraft pulp mills produce the main raw material for paper, while several waste products are generated in large quantities in the process. This review study addresses four of the main inorganic wastes formed by this industry, namely green liquor dregs (GLD), slaker grits (SG), lime mud (LM) and boiler fly ash (BFA), which are still mostly discarded in landfills. A brief overview of a typical industrial process was included to outline the waste generation points. The main chemical and physical properties are indicated for highlighting the most relevant characteristics to determine which applications may be considered in each case. An in-depth literature review allowed the identification of the main applications that have been tested mainly at the laboratory scale and some at an industrial scale. The applications are grouped into construction materials, geotechnical, environmental, agricultural and others. This assessment shows that the circular economy and the sustainable development goals of the UN are important issues for organizations in general, and the pulp mill in particular. In fact, this industry has managed to close the chemicals loops, recover energy and reduce water consumption in the process. However, the current situation of inorganic waste can still be improved if industrial applications are developed to avoid landfill.

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“…According to these assays, and using pH 4.5 as a reference, dregs and grits have an ANC of about 16 mmol H + /g. The high buffer capacity of the dregs is well known 56 , and it has been studied as an alternative liming material in soil 25 . The maintenance of the dregs´ alkaline condition, used as remediation of acid mine drainage in a long-term project, suggests a strong potential for this application 57 .…”

Section: Resultsmentioning

confidence: 99%

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

Farage

Quina

Gando-Ferreira

et al. 2020

Sci Rep

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Mining is an essential human activity, but results in several environmental impacts, notably the contamination of ground and surface water through the presence of toxic substances such as metals and sulfates in mine drainage. permeable reactive barriers (pRB) have been applied to remediate this environmental impact, but the high costs associated with the maintenance of this system are still a challenge. the main objective of this study was to evaluate the use of kraft pulp mill alkaline residues, known as dregs and grits, as material for pRB, and to determine their capacity for retaining copper and sulfate. the work was carried out in laboratory adsorption kinetics assays, batch assays and column tests. tests for elemental characterization, point of zero charge, acid neutralization capacity, total porosity, bulk density and moisture of the dregs and grits were conducted. the results showed high retention of Cu due to a chemical precipitation mechanism, notably for dregs (99%) at 5 min in adsorption kinetics. The grits presented similar results after 180 min for the same assay. Sulfate retention was effective at pH below 5, with an efficiency of 79% and 89% for dregs and grits, respectively. Dregs presented the best results for acid drainage remediation, notably with a solid:liquid (S:L) ratio of 1:10.Acid mine drainage (AMD) is caused by the oxidation of sulfur-bearing materials in the presence of oxygen and water, resulting in sulfate and metals solubilization and forming acidic solutions 1-4 . Active and inactive mining activities for metals, such as copper, lead, zinc, gold, silver and uranium, provoke potential degradation of the environment by the presence of different contaminants, particularly due to metals and sulfates in acid drainage 5 . Indeed, the acid drainage formation is an important environmental aspect of mining practices. The sulfate concentrations may reach 2,400 to 20,800 mg/L 6,7 , well above the limit of 250 mg/L established by the World Health Organization 8 . It might cause damage not only to human health but also to the environment, and depreciation of structures and equipment 2,9 , resulting in high costs for control and management by the mining companies 2,10 . Copper concentration may be in the range from 77 to 615 mg/L, with higher values in the Cu mines 1,11 . Other metals such as Al, Mn, Fe, Mg, and Zn are also commonly found in AMD in these mines 10,12 .AMD remediation can be actively accomplished off-site with the pumping of the contamination plume to a treatment plant, or passively on-site with the use of permeable reactive barriers (PRB), with lower installation and maintenance costs. It can be carried out with the flow directed to the system, by the Funnel model, or the grid-type, by the installation of a perpendicular barrier to the contamination plume 13,14 . The PRB was first proposed in Canada in the 1990s 13,15 , with different materials used as adsorbent media, from single barriers with only one material to composites of different materials, or multiple sequential barrier...

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Green liquor dregs effect on Kraft mill secondary sludge composting

Cited by 29 publications

References 49 publications

Separation, treatment and utilization of inorganic residues of chemical pulp mills

Separation, treatment and utilization of inorganic residues of chemical pulp mills

Inorganic Waste Generated in Kraft Pulp Mills: The Transition from Landfill to Industrial Applications

Kraft pulp mill dregs and grits as permeable reactive barrier for removal of copper and sulfate in acid mine drainage

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