Elizabeth Anne Tilley

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• BASc., MASc., PhD
• Professor (Associate) at ETH Zurich

The purpose of this perspective piece is to advocate for a paradigm shift in biogas research, and argues for the need to centre accountability and justice in household biogas development research and discussion Drawing from biogas literature and the authors' own experiences in South Asia and Southern Africa, the perspective illustrates how a lack o...

For Swiss cities, connecting new migrants to basic services, like waste management, has emerged as an essential challenge toward their social and civic integration. Drawing on an ethnographic approach, this study investigates solid waste management integration within Zürich's Ethiopian and Eritrean migrant communities. Our findings suggest that new...

Abstract Background In Sub Saharan Africa (SSA), approximately 9 million students are enrolled in tertiary education (TE), which is 4% of the total TE enrolment globally. Barriers to higher education in SSA are numerous: poverty, food insecurity, gender, and disability, while the COVID-19 pandemic has worsened the situation. Little is known about t...

Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucidation is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit la...

Despite the widespread global reliance on pit latrines as improved sanitation systems, the decomposition of waste within pit latrines is poorly understood. One area needing elucida-tion is the characterization and function of microbial communities within pit latrines. To address this gap, we characterized the microbial communities of 55 lined pit l...

Blantyre, Malawi’s Queen Elizabeth Central Hospital (QECH), or Queen’s, as it’s known locally, is the country’s largest public hospital. However, Queen’s is not served by regular municipal waste collection. Rather, most hospital waste (infectious and non-infectious) is gathered by grounds staff and openly burned, in several constantly smouldering p...

Within Malawi, and across the Global South, the adoption of stabilised soil blocks (SSBs) as a sustainable alternative to burnt clay bricks, has been hindered by the high cost of stabilisers. The purpose of this article is to evaluate the performance of cement as a stabiliser in soil stabilised blocks, and to propose cement ratios which both reduce...

A significant proportion of South African municipalities, who hold the mandate for providing solid waste management (SWM) services for millions of South Africans, appear to be on the brink of collapse. On the frontlines of municipal failure, the city of Makhanda, following two decades of poor governance and mismanagement, has found itself unable to...

The purpose of this comment is to call for more critical engagement with the potential and practice for biogas investment on the African continent. Over the past two decades, immense amounts of money have been spent by African governments, private individuals, and most conspicuously, international aid agencies and donors, on countless biogas projec...

When soils are phosphorus (P) deficient, external sources in the form of fertilisers have to be applied to increase crop yields. The world depends on mined sources for P fertilisers, and recent reports indicate that an increase in the human population has led to rising demand for P fertilisers, making its future supply uncertain. A low supply of ch...

Background: In Sub Saharan Africa (SSA), approximately 9 million students are enrolled in tertiary education (TE), which is 4% of the total TE enrolment globally. Barriers to higher education in SSA are numerous: poverty, food insecurity, gender, and disability, while the COVID-19 pandemic has worsened the situation. Little is known about the psych...

Process evaluations of environmental health interventions are often under-reported and under-utilized in the development of future programs. The “Hygienic Family” intervention targeted improvements in hygiene behaviors of caregivers with under five-year-old children in rural Malawi. Delivered through a combination of open days, cluster meetings, ho...

In Sub Saharan Africa (SSA) approximately 9 million students are enrolled in tertiary education (TE), which is only 4% of the total number of TE students enrolled globally. The barriers to higher education in SSA are numerous: poverty, gender, and disability, while the COVID-19 pandemic has further worsened the situation. In order to meet the SDGs,...

Supporting low levels of animal product (meat, dairy, and eggs) consumption and food waste can significantly reduce the impacts of unsustainable phosphorus use. In addition, consuming products grown with good on-farm nutrient management practices, including phosphorus recycling can further reduce impacts. These changes can contribute to achieving m...

With the world’s oceans in crisis, citizen knowledge and awareness around riverine and marine waste has become an increasingly crucial topic of study. For most investigations, spatial analysis has centered on the coastline, or most specifically the beach, i.e., the space where most respondents (urban, Northern, middle class), encounter marine litte...

Mzedi dumpsite is the only city-run waste facility in the city of Blantyre, Malawi. Although the entire site is city-owned, the periphery of the dumping site has been used for agricultural purposes for generations, but has become a space of contestation between growers, the city, and dump managers, as unregulated dumping has swelled the boundaries...

The ongoing Covid-19 pandemic has generated an immense amount of potentially infectious waste, primarily face masks, which require rapid and sanitary disposal in order to mitigate the spread of the disease. Yet, within Africa, large segments of the population lack access to reliable municipal solid waste management (SWM) services, both complicating...

African households are often models of sustainability, practicing daily behaviours, which, if even not directly associated by the individual with Western conceptualisations of ‘recycling’ or ‘reuse’, have dramatically positive impacts on the amounts of household waste generated. However, rarely has the African household been given the same consider...

In urban Blantyre, there is ample green-waste and widespread interest in compost, but the feedstock is often contaminated with plastics. If composting is going to become more widely implemented, it must be profitable and ideally, competitive with chemical nutrients, however the time and cost associated with plastics removal is currently a bottlenec...

The removal of excreta or faecal sludge from full pit latrines – pit emptying – is essential to extend the life of the sanitation technology, especially for the millions of users living in the dense, urban areas of the Global South. Unfortunately, pit-emptying is rarely practiced due to factors related to accessibility, disgust, and importantly, co...

The water, sanitation, and solid waste sectors are closely related and have many interactions between their respective service chains in low-and middle-income countries. Currently, these interactions mostly lead to cross-contamination, and opportunities for co-benefits are seldom realized. This review presents the key advancements within each of th...

A R T I C L E I N F O Keywords: Phosphorus Malawi Material flow analysis (MFA) Substance flow analysis software (STAN) Stocks A B S T R A C T Population growth and dietary needs changes have exerted pressure on phosphorus (P) reserves, and the future availability of P fertilisers is uncertain. Most Malawian soils have low P and farmers apply P fert...

In 2014, a gravity-fed rural piped water supply system (GFRPWSS) was constructed in the northern part of Malawi at a cost of $6.8 million (MK5 billion). The system was designed to serve 35,007 people by 2020 but at the time of the study, the ability of water users association (WUA) to operate and maintain the system as well as the financial sustain...

To monitor safely managed drinking water services, an increasing number of countries have integrated water quality testing for Escherichia coli into nationally-representative household surveys such as the Multiple Indicator Cluster Surveys (MICS). However, plastic waste generated during such water quality testing programs, mostly through the use of...

Similar to other poor countries across Africa, Malawi struggles with solid waste management (SWM). Especially considering the high proportion of organic waste, composting is a promising opportunity to tackle the problem. However, composting has had low uptake due to competing fertilizer subsidies, the perceived labour required, and a lack of traini...

Over the past decade, there has been increased awareness and discourse around the inequalities which structure North-South academic collaboration. The purpose of this discussion is to look at the other side of this dynamic: the gatekeeping burden of African scholars in facilitating Northern fieldwork within the African continent. We argue that this...

The interplay between menstrual waste and urban sanitation infrastructure is largely hidden from view. Qualitative research has highlighted socio-cultural aspects of menstruation, but few quantitative studies have mapped the physical situation at scale. This study surveyed 258 women in Blantyre, Malawi about their menstrual absorbent choices, dispo...

Wastewater based epidemiology (WBE) is increasingly used to provide decision makers with actionable data about community health. WBE efforts to date have primarily focused on sewer-transported wastewater in high-income countries, but at least 1.8 billion people in low- and middle-income countries (LMIC) use onsite sanitation systems such as pit lat...

Across the Global South, post-consumer waste glass is an often dumped, and under-utilised resource. Even in Malawi, with widespread return schemes, many barriers exist, inhibiting reuse, and necessitating appropriate solutions. The purpose of this article is to evaluate the performance of post-consumer waste glass as a coarse aggregate within burnt...

Lack of access to safe drinking water on premises remains widespread in low- and middle-income countries. Interventions to improve access to safe water at the point of collection are essential, but water safety at the point of consumption is also an important consideration. This research aimed to 1) improve understanding of household practices in c...

Landfill mining, a process of extracting and processing waste from stored deposits, has been touted within waste management discourses as circular economy strategy for sustainable resource recovery and reuse. However, within the Global South, where many contexts lack engineered landfilles, or even consolidated dumpsites, what relevance does the con...

African households are often models of sustainability, practicing daily behaviours, which, if even not directly associated by the individual with Western conceptualisations of 'recycling' or 'reuse', have dramatically positive impacts on the amounts of household waste generated. However, rarely has the African household been given the same consider...

For those who reside within one of Africa's emerging cities, waste, in the form of litter, is part and parcel of the urban fabric: an element of urban life that must be constantly negotiated, utilised, or, more likely, ignored by city dwellers. But how do individuals 'see' these objects through the quotidian interactions that shape their daily rout...

For those who reside within one of Africa's emerging cities, waste, in the form of litter, is part and parcel of the urban fabric: an element of urban life that must be constantly negotiated, utilised, or, more likely, ignored by city dwellers. But how do individuals 'see' these objects through the quotidian interactions that shape their daily rout...

African households are often models of sustainability, practicing daily behaviours, which, if even not directly associated by the individual with Western conceptualisations of 'recycling' or 'reuse', have dramatically positive impacts on the amounts of household waste generated. However, rarely has the African household been given the same consider...

Blantyre, Malawi has approximately one million people who rely on pit latrines for sanitation and yet there is a limited pit-emptying sector to empty, transport and safely discharge the faecal sludge. Over three years, we monitored the volume of sludge that was safely discharged at the authorized Wastewater Treatment Plants (WWTP) and in parallel,...

Billions of people globally gained access to improved drinking water sources and sanitation in the last decades, following effort towards achieving the Millennium Development Goals. Global progress remains a general indicator as it is unclear if access is equitable across groups of the population. Agenda 2030 calling for `leaving no one behind', th...

Monitoring access to drinking water is complex, especially in settings where on-premises water supply is not available. Although self-reported data are generally used to estimate coverage of access, the relationship between self-reported time travelled and true time travelled is not well known in the context of water fetching. Further, water fetchi...

Waste' is everywhere, a common aspect of daily life in both the West and the Global South. However, the ways in which we as individuals understand it as a problem is far from universal. It does not exist independently from the people it affects, rather , waste, as a problem, is continually made and remade through human practice. The purpose of this...

Using human excreta derived fertiliser (HEDF) in agriculture reduces dependence on diminishing phosphorus rock reserves, improves soil health, and facilitates sustainable nutrient recycling. Such schemes have particular scope for expansion in peri-urban areas of low-income countries, where large quantities of faecal sludge from on-site sanitation s...

Menstrual blood is not just a physical substance; it is laden with symbolism and often powerfully stigmatised. It is important to understand local perceptions and attitudes towards menstrual blood, as well as the preferred practices of menstruating women, in order to design appropriate sanitation and solid waste systems to support menstruation. Fai...

The efficient and sanitary management of infectious waste is an essential part of the humanitarian response to any disaster, including the ongoing Covid-19 pandemic. Unfortunately, in many contexts within the Global South, waste management systems are poorly equipped to handle these waste streams during periods of normalcy, let alone during times o...

Few studies have attempted to measure the differences between self-reported and observed food hygiene practices in a household setting. We conducted a study to measure the level of agreement between self-reported and observed food hygiene practices among child caregivers with children under the age of five years in rural Malawi. Fifty-eight child c...

The purpose of this discussion is to highlight the essential role that solid waste management must play in a humanitarian response towards disasters, in particular the ongoing Covid-19 pandemic. We highlight a number of potential avenues for scholarly investigation into the waste impacts of our response to Covid-19, but in particular, briefly unpac...

Diarrhoeal disease in children under five in low income settings has been associated with multiple environmental exposure pathways, including complementary foods. Conducted from February to December 2018 in rural Malawi, this before and after trial with a control used diarrhoeal disease as a primary outcome, to measure the impact of a food hygiene...

Billions of people globally gained access to improved drinking water sources and sanitation in the last decades, following effort towards the Millennium Development Goals. Global progress remains a general indicator as it is unclear if access is equitable across groups of the population. Agenda 2030 calling for ″leaving no one behind″, there is a n...

Small towns are growing in size and number, but compared to the big cities that fuel economies, or rural areas that feed nations, small towns are generally less prioritized by governments and donors, both because they appear less immediately troublesome and because they defy easy classification. As such, growth has largely been unplanned for and re...

Landfill sites in African cities are rarely engineered, but often unregulated dumpsites with permeable boundaries that that allow both humans and waste to move in and out freely. Mzedi dumpsite is the only city-run waste facility in the city of Blantyre, Malawi, and accepts wastes for about 10% of the population. Although the entire site is city-ow...

Diarrheal disease in under-five children remains high in Sub-Saharan Africa; primarily attributed to environmental pathogen exposure through poorly managed water, sanitation, and hygiene (WASH) pathways, including foods. This formative study in rural Malawi used a theoretical base to determine the personal, social, environmental, and psychosocial f...

Background: Increasing the quantity of water available for consumption and hygiene is recognized to be among the most efficient interventions to reduce the risk of water-related infectious diseases in low and middle-income countries. Such impacts are often associated with water supply accessibility (e.g. distance or collection time) and used to ju...

Diarrhoeal disease remains one of the leading causes of morbidity and mortality in the under-five population, particularly in low income settings such as sub-Saharan Africa. Despite significant progress in sanitation and water access, faecal-oral infections persist in these populations. Therefore, a better understanding of these transmission pathwa...

Informally vended water is an important source of water for marginalized people who do not have access to formal or public sources. In Malawi, hand-tied sachets of water are common but not regulated, and the quality of the water and hygienic practices during packaging are unclear. We analyzed microbial concentrations in the source water (origin), i...

In the city of Blantyre, much of the generated municipal waste is biowaste, typically mixed with other waste fractions and disposed at the city’s dumpsite. Energy and nutrients could be recovered; however, with many biowaste options available, choosing what technology to implement is difficult. Selecting Organic Waste Treatment Technology (SOWATT)...

Insufficient staff, inappropriate collection vehicles, limited operating budgets and growing, hard to reach populations mean that solid waste management remains limited in most developing countries; Malawi is no exception. We estimated the willingness to pay (WTP) for two hypothetical solid waste collection services. Additionally, we tested the imp...

Pit latrines are the most common sanitation option in the developing world. They are simple to build but require periodic emptying which results in widespread dispersion of fecal pathogens in the environment. While much is known about the health risks of fecal-oral exposure, little is known about those resulting from the aerosolization of pathogens...

Poor road networks, inadequate financial resources and low levels of political will mean that many developing countries, especially their unplanned settlements, struggle with solid waste management. Recently, Informal Waste Pickers (IWPs) have been incorporated into waste management cooperatives by formalizing their operations as a strategy to impr...

Highlights of the initial formative results from the SHARE II research project in Malawi

We conducted a choice experiment (CE) to estimate willingness to accept (WTA) values for a planned conditional cash transfer (CCT) programme designed to increase toilet use in South Africa. The payment is made conditional on using a toilet and bringing urine to a central collection point. In a split-sample approach, a segment of respondents were gi...

In the developing world, having access to a toilet does not necessarily imply use: infrequent or non-use limits the desired health outcomes of improved sanitation. We examine the sanitation situation in a rural part of South Africa where recipients of novel, waterless " urine-diverting dry toilets " are not regularly using them. In order to determi...

In the face of increasing phosphorus prices, Nepal, like all agrarian societies is in imminent need of a low-cost, sustainable source of phosphorus and nitrogen. The town of Siddhipur in the Kathmandu valley was selected as a study site to determine the feasibility of establishing a community-scale struvite processing centre using source-separated...

As the number of technologies and programming approaches for improving global sanitation grows, there is an increasing need to evaluate the cost-effectiveness of each so that policy can be driven by informed decisions that consider cost as well as impact. I use data from two different urine-collection programs that were implemented in rural South A...

Despite investment stimulated by the Millennium Development Goals (MDGs), sanitation-related diseases, such as diarrhea, cholera and typhus, remain a leading cause of death of children under five in low-income countries. Prevention of diarrhea requires a combination of access to safe drinking water, good hygiene and adequate sanitation. The sanitat...

Over a billion people in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation technologies. Until now, the management of faecal sludge resulting from these onsite technologies has been grossly neglected. Financial resources are often lacking, and onsite sanitation systems tend to be regarded as temporary sol...

Over a billion people in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation technologies. Until now, the management of faecal sludge resulting from these onsite technologies has been grossly neglected. Financial resources are often lacking, and onsite sanitation systems tend to be regarded as temporary sol...

In recent years there has been a growing body of knowledge exploring the benefits of using sanitation-derived nutrients. Such studies aim to uncover strategies that facilitate nutrient recovery from urine and faecal sludge for agricultural use. This paper presents the findings of a study which assessed the willingness to handle and use urine in agr...

Sanitation has evolved from a purely technical discipline to one that includes social, environmental, economic and, increasingly, gender considerations. However, blurry notions of gender are frequently offered in the sanitation literature. Although it has been recognized that gender-responsive sanitation does not mean ‘toilets for women’, substanti...

Regarding multi-criteria decision analysis (MCDA), the problem of generating alternatives has not received the attention it deserves. Most research is currently devoted to the problem of alternative selection, where it is assumed that a set of appropriate alternatives is already given. This paper addresses the generation of potential alternatives i...

Struvite precipitation is a simple technology for phosphorus recovery from source-separated urine. However, production costs can be high if expensive magnesium salts are used as precipitants. Therefore, waste products can be interesting alternatives to industrially-produced magnesium salts. We investigated the technical and financial feasibility of...

The goal of this chapter is to outline a method of conceptualizing the components of, and interdependencies between technologies which comprise a system. Within a system boundary, technical and operational responsibilities can be identified to improve the overall system efficiency to remove gaps and redundancies. The chapter begins with a short des...

Human urine has the potential to be a sustainable, locally and continuously available source of nutrients for agriculture. Phosphate can be efficiently recovered from human urine in the form of the mineral struvite (MgNH4PO4·6H2O). However, struvite formation may be coupled with the precipitation of other constituents present in urine including pat...

Safe drinking water and basic sanitation are key elements of the Millennium Development Goals, a United Nations initiative. The microbial quality of drinking water is inherently linked to sanitation practices because fecal pathogens are the most common source of drinking water contamination in developing countries. Filtration of water through soil...

The Community-Led Urban Environmental Sanitation (CLUES) approach presents comprehensive guidelines for the planning and implementation of environmental sanitation infrastructure and services in disenfranchised urban and peri-urban communities. The planning approach builds on a framework which balances the needs of people with those of the environm...

This research investigated the possibility of transferring phosphorus from human urine into a concentrated form that can be used as fertilizer in agriculture. The community of Siddhipur in Nepal was chosen as a research site, because there is a strong presence and acceptance of the urine-diverting dry toilets needed to collect urine separately at t...

Reaching the Millennium Development Goals for Sanitation is a challenge. To address this challenge, numerous technological innovations have been developed. But with so many innovations and a wide range of existing technologies appropriate in different settings, difficulties with communication and knowledge dissemination hinder informed decision-mak...

Reaching the Millennium Development Goals for Sanitation is a challenge. Numerous technological innovations have been developed in the last decade but, with innovation comes an increasing lack of consistency and increased communication difficulties. This is especially true in rural and peri-urban West Africa, where there is a desperate need for fea...

In previous work, synthetic urine was used as a readily available proxy for real urine for determining the factors which affect the recovery of struvite from urine. Based on these findings with synthetic urine, we recovered struvite from real urine and, thus, showed that a) the synthetic urine served as an adequate model for determining the process...

In laboratory experiments using synthetic urine the effect of temperature, faecal contamination, dilution and headspace on urine to be used as a feedstock for struvite recovery were examined. The effects of adding different quantities of magnesium on the amount of phosphorus that could be removed from solution was also examined. An average of 62% o...

Too often, standardized groupings of sanitation and treatment technologies are imposed in situations where they may not be appropriate. The Household-Centred Environmental Sanitation (HCES) approach instead emphasizes that the needs and means of households should be put first, and a collaborative process involving all stakeholders should steer the...