Charter for Change: Stryker’s Journey Towards Sustainability

abstract: Charter for Change: Stryker’s Journey Towards Sustainability is a project focused on brining a holistic sustainability strategy to Stryker’s Sustainability Solutions (Stryker). Stryker is a reprocessor and remanufacturer of single-use medical devices. While the inherent business of reprocessing is sustainable by extending the useful life of devices, there should be alignment between the core of the business, the operations and actions that it takes. Through creating and implementing a sustainability charter that outlines environmental goals for Stryker to achieve by 2025, it provides the organization with a systems approach to sustainability and embeds it within the culture. In order for the project to be successful, Senior Leadership had to sign off and make sustainability a top priority for the organization. The sustainability charter allows Stryker to do well by doing good

Enhancement of biogas potential of primary sludge by co-digestion with cow manure and brewery sludge

Anaerobic digestion (AD) has long been used to treat different types of organic wastes especially in the developed world. However, organic wastes are still more often considered as a waste instead of a resource in the developing world, which contributes to environmental pollution arising from their disposal. This study has been conducted at Bugolobi Sewage Treatment Plant (BSTP), where two organic wastes, cow manure and brewery sludge were co-digested with primary sludge in different proportions. This study was done in lab-scale reactors at mesophilic temperature and sludge retention time of 20 d. The main objective was to evaluate the biodegradability of primary sludge generated at BSTP, Kampala, Uganda and enhance its ability of biogas production. When the brewery sludge was added to primary STP sludge at all proportions, the biogas production rate increased by a factor of 3. This was significantly (p<0.001) higher than observed gas yield (337 +/- 18 mL/(L.d)) in the control treatment containing (only STP sludge). Co-digesting STP sludge with cow manure did not show different results compared to the control treatment. In conclusion, Bugolobi STP sludge is poorly anaerobically degradable with low biogas production but co-digestion with brewery sludge enhanced the biogas production rate, while co-digestion with cow manure was not beneficial

A design framework for enabling sustainability in the clothing sector

This article discusses general strategies to enable environmental sustainability within the clothing sector, providing a framework for decision makers involved in the development of programs and policies for this sector. It initially revises the environmental impact of the clothing system and determines its key environmental sustainability priorities. The framework involves five evolutionary strategies for enabling sustainable consumption and production: 1) environmental improvement of flows throughout the supply chain; 2) environmental redesign of existing clothes; 3) design of new clothes intrinsically more sustainable; 4) design of cloth-service systems and 5) promoting life styles towards sufficient consumption. The practical implications of each strategy is analysed based on correspondent ex-post-facto case studies identified in Brazil, using data collected through literature review and desktop research

Supply chain challenges for sustainability: the case of waste textiles as raw materials

Purpose: This paper addresses the growing problem of textile waste in the rapidly developing cities of subSaharan Africa and examines, from a supply chain perspective, the potential for waste textile materials to be transformed into the raw materials for new consumer products. Research Approach: The paper reflects on the outcomes of a field trip to Dar es Salaam in which stakeholders in a hypothesised textile waste supply chain were interviewed and waste textile materials were analysed in order to determine their content and appropriateness for reuse. Findings from the field study have been compared with current literature on logistics and market creation, waste generation, management and recycling in sub-Saharan Africa. Findings and Originality: The findings show that a rudimentary system has been in place for many years to collect and recycle textiles in Dar es Salaam. However, at the same time as textile waste is projected to increase in the city, collection rates are falling. The chief reasons for the falling rates are failures in the ‘modernised mixture’ approach to waste collection employed by Dar es Salaam City Council and market failure for the collected materials. Alternative combinations of ‘modernised mixtures’, incorporating community-based organisations, are likely to increase textile yields from unplanned urban areas but previous high-profile failures in such systems within Dar es Salaam mean there is caution on both sides in entering into such a relationship. The more pressing problem is to identify appropriate end markets for the textile materials, since in a country where recycling is entirely market-driven, failure to do so will undermine any attempt to improve the collection system. Whilst many studies have considered general recycling practices in sub-Saharan Africa, there are few investigations into textile waste. Furthermore, those existing studies do not consider the importance of understanding fibre composition of the materials in order to determine the most appropriate end markets. Research Impact: The research contributes to the growing body of knowledge on ‘bottom of the pyramid’ approaches to sustainable futures. Practical Impact: The work presented considers supply chain problems and offers approaches to tackling the increasing waste management issues of Dar es Salaam and proposes a mechanism for doing so which has the potential to provide income for the poorest sectors of the urban society

Modelling of Temperature in Full-scale Systems: a Review of the Biological Heat Generation Within Windrow Composting

Windrow composting is the most common method for organic solid waste treatment. Temperature is an important state variable in modelling, which could be simulated by estimating the change of heat balance components at any moment. Biological heat energy is the most significant term in the heat balance. In this paper biological heat generation of the composting process are examined and their applicability for a full-scale windrow system is evaluated. It is found that, to date, the accuracy of predicting the rate of substrate degradation has been a major challenge. The use of an inductive approach based on either first-order kinetic expression or empirical kinetics relation was found to be more feasible for practical purposes. However a scale-up correction factor for particular processes and types of substrate may need to be further investigated to narrow the discrepancies of kinetic performances between laboratory and full-scale systems

Resource recovery from wastewater and sludge: modelling and control challenges

Wastewater treatment plants (WWTPs) have been renamed water resource recovery facilities (WRRFs). Our industry is quickly moving from an end-of-pipe environmental protection service to an economic producer of valued products for society. Based on a critical review of resource recovery technologies that are currently applied or in advanced development, it became obvious that most of these technologies are based on physicochemical unit processes (precipitation, volatilization, sorption, …). Current industrial practice for the design and operation of WRRFs is based on mathematical models describing the traditional biological processes. The modeling challenge therefore is to provide practice with proper models for the physicochemical resource recovery processes. The fact that the WRRFs aim at delivering valued products that can partially replace those produced by other means (typically in the chemical industry) leads to a paradigm shift in specifications of the outputs of the facility: no longer treated wastewater and biosolids, but products that have to compete with what is already on the market. The tighter specifications will thus impose a challenge on the process control systems that will be required to guarantee the quality of the products of the WRRFs

Municipal wastewater treatment with pond technology : historical review and future outlook

Facing an unprecedented population growth, it is difficult to overstress the assets for wastewater treatment of waste stabilization ponds (WSPs), i.e. high removal efficiency, simplicity, and low cost, which have been recognized by numerous scientists and operators. However, stricter discharge standards, changes in wastewater compounds, high emissions of greenhouse gases, and elevated land prices have led to their replacements in many places. This review aims at delivering a comprehensive overview of the historical development and current state of WSPs, and providing further insights to deal with their limitations in the future. The 21st century is witnessing changes in the way of approaching conventional problems in pond technology, in which WSPs should no longer be considered as a low treatment technology. Advanced models and technologies have been integrated for better design, control, and management. The roles of algae, which have been crucial as solar-powered aeration, will continue being a key solution. Yet, the separation of suspended algae to avoid deterioration of the effluent remains a major challenge in WSPs while in the case of high algal rate pond, further research is needed to maximize algal growth yield, select proper strains, and optimize harvesting methods to put algal biomass production in practice. Significant gaps need to be filled in understanding mechanisms of greenhouse gas emission, climate change mitigation, pond ecosystem services, and the fate and toxicity of emerging contaminants. From these insights, adaptation strategies are developed to deal with new opportunities and future challenges