Haile et al. Bioresour. Bioprocess.
(2021) 8:35
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Fig. 6 Major wastes generated from pulp and paper mills: a sawdust; b sludge; c waste paper; d inorganic wastes (dregs, lime mud, grits); e Fly ash
such as brucite, larnite, pirssonite, portlandite, and cal- cite are ingredients of the biomass grits. The mineral content of these wastes can be made administered and used for making biomaterials. The successive development in the pulp and paper mill has headed to the release of a large quantity of fly ash (Fig. 6e) as a result of combustion processes of waste bio- mass. The elemental composition survey on fly ash from pulp and paper mills revealed that the ash consists of dif- ferent minerals predominantly iron oxide, silica, and alu- mina. The fly ash also consists of other metal oxides such as oxides of sodium, calcium, magnesium, potassium sulfur, and titanium (Na 2 O, CaO, MgO, K 2 O, SO 3, and TiO 2 ) in variable quantities. Through polymerization, the metal oxides can be converted to biopolymers for diversi- fied end-use. The widely and adopted and conventionally established way of valorization of fly ash is geo-polym- erization. In the polymerization process demand-driven three-dimensional aluminosilicate and similar materials so-called geopolymers are synthesized (Cherian and Sid- diqua 2019; Sjöström and Westermark 1999).
in appropriate ionic liquid, and precipitation of cellulose through the removal of lignin. Another potential source of cellulose is wastewater treatment plants and recycled paper converters. The virgin or waste recycling sludge (Fig. 6b) constitutes cel- lulosic materials. The mill sludge accounts for the main waste from pulp and recycled paper production. Pulp and paper mill sludge is an organic residual generated from wastewater treatments (Faubert et al. 2016). Per unit of paper production 23.4% sludge is generated. The major components of the paper mill sludge are inorganic resi- dues and organic cellulosic fines and fragments (Albu- querque et al. 2015; Abdullah et al. 2015). The organic constitutes in primary sludge mainly consist of cellulosic fibers. A noticeable quantity of cellulose can also be obtained from waste paper (Fig. 6c) which is a release of every paper utilizer with a huge amount from office and related service providers. Directly or as part of recycling residue, the waste paper is considered as a major source of cellu- lose, and using appropriate cleaning and recycling proce- dures the cellulose can be made use of as a raw material for biomaterial synthesis (Kim and Kim 2019). Inorganic wastes (Fig. 6d) namely liquor dregs, calcite mud, and slacker grits are also considered as the major portion of solid waste in the mills (Quina and Pinheiro 2020). These mineral wastes are generated during the chemical recovery process at the pulping mill. The green liquor dregs are obtained The inorganic biomasses con- tain different types of minerals (Bird and Talberth 2008; Leponiemi 2008). The mineral Gipsite and Calcite are present in the dregs and the mud, whereas the minerals
Disposal technique Waste management in pulp and paper mill
The pulp and paper mill generates a large volume of wastes with an estimate of around 100 tonnes per 550 tonnes of pulp production. Though the toxicity of pulp and paper wastes is minimal appropriate disposal tech- nique is required for appropriate management of the land, environment, and allied issues (Monte et al. 2009). As per the environmental policies recommend based on directives of the waste framework the landfill must be
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