Designing a circular business model from industrial by-products: A case study on paper mill sludge

The circular economy (CE) emphasises the optimisation of resource yields by keeping products, components and materials at their highest utility and value. This recently popularised concept has created awareness within businesses, government and policymakers. However, there is a discourse that the concept lacks scientific rigour and has primarily been led by practitioners such as policy makers, social scientists and business consultants. Resources in the CE concept are referred to as biological nutrients and technical nutrients. Based on the CE resource recovery model, biological nutrients such as organic waste/by-products are expected to return to the system. However, the current waste management sector is not equipped with how to innovate and/or create value from resources termed as waste/by-products. Whilst CE is a commendable strategy with insightful case studies, the philosophy currently lacks robust design guidance that can provide businesses with the tools and tactics required to meet the agenda. Therefore, this EngD research applies design thinking innovation methodology to an existing business faced with the challenge of adopting a circular business model for resource recovery. The EngD research is based on Ecoganix, an organic waste treatment company. Ecoganix manages Paper Mill Sludge (PMS), a by-product derived from the waste-water treatment of paper mills. In the UK, a million tonnes of PMS is currently produced annually. The management of PMS is an environmental challenge and the second highest cost for the sector after energy consumption. The PMS is collected by Ecoganix from 7 paper mills in the UK for use as soil improvement on farm land . The current management system of PMS is unsustainable and short-term. Moreover, the market is highly competitive due to increasing recycling rates and competitive pricing. Nonetheless, this material PMS is rich in organic cellulose fibres and inorganic minerals. Thus, a design thinking methodology is used to create new value streams of materials from this byproduct...[cont.]Sustainable Materials and Manufacturin

Exploring new horizons for paper recycling: A review of biomaterials and biorefinery feedstocks derived from wastepaper

Paper is a perfect example of the circular economy as it remains the furthermost recycled product in Europe, creating significant environmental benefits and raw materials resources to the industry. Indeed, maintaining a consistent level of quality whilst limiting the environmental footprint of the product has become a major challenge for the industry. In this direction, paper is proving to be the promising feedstock for biorefinery and biomaterials. The future of paper recycling is slowly going beyond fibre recovery to address the needs of other industries because for the earth's environmental well-being various paper products need to be recycled and reused persistently. In this article, we outline the ambitious use of wastepaper (WP) for high-value applications such as; production of cellulose nanocrystals (CNC), composite reinforcement, high performance electrical components and biofuels

Antimicrobial Agents: Antibacterial Agents, Anti-biofilm Agents, Antibacterial Natural Compounds, and Antibacterial Chemicals

The surge in antimicrobial resistance coupled with the decline in the antimicrobial drug pipeline calls for the discovery and development of new agents to tackle antibiotic resistance and prevent a return to a post-antibiotic era. Several factors account for resistance of microbes; some are natural and others are acquired. Natural selection, presence of efflux pumps, impermeable cell wall, biofilm formation and quorum sensing are some of the factors. Though it is difficult to outwit the pathogens, the discovery and development of compounds with pleiotropic modes or mechanisms of action different from the conventional drugs currently being used can help us tackle antimicrobial resistance. Natural products have been known to be a rich source of bioactive compounds with diverse structures and functional group chirality. Various reports indicate medicinal plants with antibacterial, anti-biofilm, efflux pump inhibition, wound healing effects or properties and others used for upper respiratory and urinary tract infections. There is an urgent need to research into natural products particularly plants for antimicrobial agents including antibacterial agents, anti-biofilm agents, antibacterial natural compounds and antibacterial chemicals. This chapter throws more light on such antimicrobials

Combating Biofilm and Quorum Sensing: A New Strategy to Fight Infections

Biofilms are structured aggregates of bacterial cells that are embedded in self-produced extracellular polymeric substances. Various pathogens initiate a disease process by creating organized biofilms that enhance their ability to adhere, replicate to accumulate, and express their virulence potential. Quorum sensing, which refers to the bacterial cell-to-cell communication resulting from production and response to N-acyl homoserine lactone signal molecules, also plays an important role in virulence and biofilm formation. Attenuation of microorganisms’ virulence such that they fail to adapt to the hosts’ environment could be a new strategic fight against pathogens. Thus, agents or products that possess anti-biofilm formation and/or anti-quorum sensing activities could go a long way to manage microbial infections. The incidence of microbial resistance can be reduced by the use of anti-biofilm formation and anti-quorum sensing agents

Properties of cellulose nanofibre networks prepared from never-dried and dried paper mill sludge

Paper mills yield large volumes of sludge materials which pose an environmental and economic challenge for disposal, despite the fact that they could be a valuable source for cellulose nanofibres (CNF) production. The aim of the study was to evaluate the production process and properties of CNF prepared by mechanical fibrillation of never-dried and dried paper mill sludge (PMS). Atomic force microscopy (AFM) showed that average diameters for both never-dried and dried paper sludge nanofibres (PSNF) were less than 50 nm. The never-dried and dried sludge nanofibres showed no statistical significant difference (p > 0.05) in strength ∼92 MPa, and ∼85 MPa and modulus ∼11 GPa and ∼10 GPa. The study concludes that paper mill sludge can be used in a dried state for CNF production to reduce transportation and storage challenges posed on industrial scale

Executive bonus compensation and financial leverage: do growth and executive ownership matter?

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Purpose: This study examines the impact of executive bonus compensation on a firm’s financial leverage policy and the extent to which this compensation–leverage relation is moderated by firm growth and executive ownership. Design/method/approach: Using data from 213 non-financial and non-utility UK FTSE 350 firms for the period 2007-2015, generating a total of 1,784 firm-year observations, panel econometric methods are employed to test our model. Findings: Drawing insights from agency theoretic view, we uncover that managerial cash bonus compensation is negatively and significantly related to financial leverage. However, stock bonus compensation has a positive and significant impact on leverage. We also observe that compensation–leverage is moderated by both firm growth and executive ownership. Our results remain robust to alternative econometric models. Originality/value: While this paper builds on the risk-motivated argument of executive bonus compensation literature, it is the first – to the best of our knowledge – to explore the bonus compensation-corporate financial leverage and, particularly, examine the extent to which firm growth and corporate executive ownership matter in this relationship

Structural packaging foams prepared by uni-directional freezing of paper sludge cellulose nanofibres and poly (vinyl alcohol)

Porous foams from cellulose nanofibres (CNF) and poly-vinyl alcohol CNF/PVA were prepared by uni-directional freezing to create a homogeneous pore structure. The CNF was derived from paper mills sludge (PMS), a by-product of paper manufacturing waste-water treatment. Sodium tetraborate decahydrate (borax) was used as a crosslinking agent. The density of the CNF/PVA foams were 0.03 g cm−3 with a compressive strength of 116 kPa at 20% strain. The foams were competitive to commercial expanded polystyrene (EPS) foam

Measuring Coverage in MNCH: Validating Women’s Self-Report of Emergency Cesarean Sections in Ghana and the Dominican Republic

Background: Cesarean section is the only surgery for which we have nearly global population-based data. However, few surveys provide additional data related to cesarean sections. Given weaknesses in many health information systems, health planners in developing countries will likely rely on nationally representative surveys for the foreseeable future. The objective is to validate self-reported data on the emergency status of cesarean sections among women delivering in teaching hospitals in the capitals of two contrasting countries: Accra, Ghana and Santo Domingo, Dominican Republic (DR). Methods and Findings: This study compares hospital-based data, considered the reference standard, against women’s self-report for two definitions of emergency cesarean section based on the timing of the decision to operate and the timing of the cesarean section relative to onset of labor. Hospital data were abstracted from individual medical records, and hospital discharge interviews were conducted with women who had undergone cesarean section in two hospitals. The study assessed sensitivity, specificity, and positive predictive value of responses to questions regarding emergency versus non-emergency cesarean section and estimated the percent of emergency cesarean sections that would be obtained from a survey, given the observed prevalence, sensitivity, and specificity from this study. Hospital data were matched with exit interviews for 659 women delivered via cesarean section for Ghana and 1,531 for the Dominican Republic. In Ghana and the Dominican Republic, sensitivity and specificity for emergency cesarean section defined by decision time were 79% and 82%, and 50% and 80%, respectively. The validity of emergency cesarean defined by operation time showed less favorable results than decision time in Ghana and slightly more favorable results in the Dominican Republic. Conclusions: Questions used in this study to identify emergency cesarean section are promising but insufficient to promote for inclusion in international survey questionnaires. Additional studies which confirm the accuracy of key facility-based indicators in advance of data collection and which use a longer recall period are warranted

Properties of cellulose nanofibre networks prepared from never-dried and dried paper mill sludge

Paper mills yield large volumes of sludge materials which pose an environmental and economic challenge for disposal, despite the fact that they could be a valuable source for cellulose nanofibres (CNF) production. The aim of the study was to evaluate the production process and properties of CNF prepared by mechanical fibrillation of never-dried and dried paper mill sludge (PMS). Atomic force microscopy (AFM) showed that average diameters for both never-dried and dried paper sludge nanofibres (PSNF) were less than 50 nm. The never-dried and dried sludge nanofibres showed no statistical significant difference (p > 0.05) in strength ∼92 MPa, and ∼85 MPa and modulus ∼11 GPa and ∼10 GPa. The study concludes that paper mill sludge can be used in a dried state for CNF production to reduce transportation and storage challenges posed on industrial scale

Continuous and sustainable cellulose filaments from ionic liquid dissolved paper sludge nanofibres

The textile industry is resource intensive, which has a significant impact on global emissions and waste pollution. To meet the demand of textiles over a third of fibres used in manufacturing are sourced from fossil fuels. As the global demand for textiles continues to grow, manufacturers have having to seek innovative approaches to providing sustainable regenerative cellulose fibres. However, the latest climate change pressures on the textile industry has uncovered grave environmental issues associated with traditional regenerative cellulose production such as the viscose manufacturing process. The viscose process the required intensive use of hazardous chemicals which leads to water pollution and ecotoxicity. In addition, if forestry products are unsustainably sourced for the viscose production this can lead to resource scarcity and deforestation. To provide a holistic solution for mitigating these challenges this study uses the by-products of paper manufacturing dissolved in an ionic liquid to produce regenerated cellulose filaments. Paper mill sludge (PMS) is a cellulosic by-product typically used on animal bedding and land spreading. The material has been dissolved in an ionic liquid - 1-ethyl-3-methylimidazolium diethyl phosphate - with the aid of a co-solvent dimethyl sulfoxide (DMSO) - and spun into continuous filaments for textile production. The mechanical properties of paper sludge filaments are found to be competitive with commercial viscose, which is promising for their drop-in replacement. It is also demonstrated that by increasing the concentration of the PMS from 9% to 12.4%, an improvement of the filament properties can be achieved; an increase in modulus from ~19 GPa to ~ 26 GPa and ~ 223 MPa to ~ 282 MPa. These values are shown to be competitive with other commercial, less sustainable, regenerated cellulose fibre