Reducing household waste : A social practice perspective on Swedish household waste prevention

This thesis studies household waste prevention from a social scienceperspective. Swedish waste management is efficient in handling wastebut has not succeeded in reducing its quantities, even though theissue of waste prevention is being raised at both international andnational levels.The aim of this thesis is to study and analyse the practice ofhousehold waste prevention. I seek to understand and explainhow it may be possible for households in their everyday to reducethat waste. With understanding comes an aspiration to mitigatewhatever impedes households from reducing their waste. A secondaim is therefore to apply these new understandings and make policysuggestions as to how household waste prevention can be promotedand supported. My research questions are:• How is everyday household waste prevention as a practicenarrated and discussed? And how can this practice andthe activities in it be understood in connection with socialstructures?• What obstacles and opportunities do households experience inconnection with the practice of everyday waste prevention?• What policy suggestions can be drawn from these findings? Household waste prevention has in earlier research often beenstudied from a waste management perspective, juxtaposing it withrecycling. These studies has identified a need to approach the areafrom a consumption perspective. Sustainable consumption has,however, in general failed to incorporate disposal as a practicesin itself, in that disposal involves competence in knowing what todo with certain things, as well as relation between things and theirmeanings. This runs the risk of leaving waste and waste preventionas part of consumption scarcely researched. It is in this identified gapthat I place my study.In order to address my questions, two studies were carried out.The first is presented in Article I, ‘Household practices of disposal –Swedish households’ narratives for moving things along’. The datawas gathered using in-depth interviews with Swedish households not explicitly devoted to waste prevention. The study focused oneveryday disposal activities. The second study, presented in Article II,is called ‘The practice of household waste minimisation’. This studycollected data from Swedish bloggers engaging in waste-minimisationpractices, sometimes called ‘zero-waste bloggers’, focusing on howthese forerunners describe practising waste minimisation in theireveryday.In both studies I used sociological theories of how humans asactors relate to the social structures and how humans act in theireveryday. The theories applied were derived from the extensive workof Anthony Giddens on structuration and late-modernity. As I placehousehold activities at the centre of my study, I have also appliedtheory of practice. My analysis starts off with the claim that waste is an unintendedconsequence of keeping up shared practices: in other words, thathousehold waste production is neither deliberate nor completelyvoluntary. For waste prevention practices to happen, the prevailingidea that recycling alone is good enough needs to be challenged.There need to be other opportunities to act, such as buying secondhandclothes, unpackaged groceries, repairable electronics etc. Theseopportunities need to be normalised, meaning that they need tobe socially spread and accepted. They also need to be reasonablyconvenient, as in not demanding too much time and effort. The studyof the minimising forerunners reveals that these households have tostruggle in their everyday to minimise their waste. This implies thathousehold waste prevention is not supported by the social structuresin Sweden and, therefore, will not increase by itself.I move on to suggest a new model for the understanding ofsustainable consumption. This model takes the perspective of practicetheory and presents four stages of consumption: need, obtain, use anddispose. All four stages should be recognised as possible situationsfor interventions. There is also a need for a holistic perspective onconsumption, where none of the stages is studied in isolation fromthe rest.I conclude the thesis by pinpointing the identified major obstaclesto household waste prevention, and by suggesting necessary changesin order for household waste prevention to become a shared practice

The practice of household waste minimisation

This article presents a study of Swedish waste minimisation bloggers, often called zero waste bloggers. Through the lens of practice theory, the study shows that household waste is an unintended consequence of maintaining shared practices. The studied bloggers choose to maintain shared practices such as dressing well and buying takeaway lunch, but still manage to reduce their household waste. Waste reduction is acted out by altering some of the activities of which practices are made up by, such as applying the circular wardrobe and bringing their own food container. This becomes possible as the households reflect on their own consumption practices and thereby perceive opportunities to reduce their waste. Apart from lacking opportunities, waste minimisation is challenged by firmly established norms, such as shopping and the perception that recycling is good enough. Activities may also be challenged by other actors who inevitably get involved as activities change. This study suggests that if waste prevention is to become a shared practice more opportunities for waste prevention need to be normalised

Lifecycle assessment of a system for food waste disposers to tank - A full-scale system evaluation

An increased interest for separate collection of household food waste in Sweden has led to development of a number of different collection-systems - each with their particular benefits and drawbacks. In the present study, two systems for collection of food waste in households were compared; (a) use of food waste disposers (FWD) in kitchen sinks and (b) collection of food waste in paper bags for further treatment. The comparison was made in relation to greenhouse gas emissions as well as primary energy utilization. In both cases, collected food waste was treated through anaerobic digestion and digestate was used as fertilizer on farmland. Systems emissions of greenhouse gases from collection and treatment of 1 ton of food waste (dry matter), are according to the performed assessment lower from the FWD-system compared to the reference system (-990 and -770 kg CO2-eq./ton food waste dry matter respectively). The main reasons are a higher substitution of mineral nitrogen fertilizer followed by a higher substitution of diesel. Performed uncertainty analyses state that results are robust, but that decreasing losses of organic matter in pre-treatment of food waste collected in paper bags, as well as increased losses of organic matter and nutrients from the FWD-system could change the hierarchy in relation to greenhouse gas emissions. Owing to a higher use of electricity in the FWD-system, the paper bag collection system was preferable in relation to primary energy utilization. Due to the many questions still remaining regarding the impacts of an increased amount of nutrients and organic matter to the sewage system through an increased use of FWD, the later treatment of effluent from the FWD-system, as well as treatment of wastewater from kitchen sinks in the reference system, was not included in the assessment. In future work, these aspects would be of relevance to monitor

Technical evaluation of a tank-connected food waste disposer system for biogas production and nutrient recovery

In this study, a tank-connected food waste disposer system with the objective to optimise biogas production and nutrient recovery from food waste in Malmö was evaluated. The project investigated the source-separation ratio of food waste through waste composition analyses, determined the potential biogas production in ground food waste, analysed the organic matter content and the limiting components in ground food waste and analysed outlet samples to calculate food waste losses from the separation tank.It can be concluded that the tank-connected food waste disposer system in Malmö can be used for energy recovery and optimisation of biogas production. The organic content of the collected waste is very high and contains a lot of energy rich fat and protein, and the methane potential is high.The results showed that approximately 38% of the food waste dry matter is collected in the tank. The remaining food waste is either found in residual waste (34% of the dry matter) or passes the tank and goes through the outlet to the sewer (28%). The relatively high dry matter content in the collected fraction (3-5% DM) indicates that the separation tank can thicken the waste substantially.The potential for nutrient recovery is rather limited considering the tank content. Only small fractions of the phosphorus (15%) and nitrogen (21%) are recyclable by the collected waste in the tank. The quality of the outlet indicates a satisfactory separation of particulate organic matter and fat. The organic content and nutrients, which are in dissolved form, cannot be retained in the tank and are rather led to the sewage via the outlet