Browsing by Author "Parker, Alison"
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Item Open Access Assessing environmental drivers of fluoride mobilization in groundwater under increased loading of dissolved organic matter from managed aquifer recharge (MAR) Item(Cranfield University, 2022-12-01 15:51) Parker, Alison; Campo Moreno, Pablo; Le Corre Pidou, KristellGeogenic fluoride contamination of groundwater is common in many semi-arid regions, and the impact of managed aquifer recharge (MAR) on increased mobilization of fluoride to the water in these regions is a concern. This work used saturated column experiments to explore the aqueous and mineralogical environmental drivers of fluoride mobilization and how they interact with increased loading of dissolved organic matter (DOM) from infiltrated runoff collected by MAR structures. Groundwater alkalinity was identified as the dominating driver of fluoride mobilization, resulting in increased dissolution of fluorite under all mineral matrix compositions. The influx of a 20 mg/L load of DOM somewhat reduced the mobilization of fluoride from the solid matrix under alkaline conditions, but otherwise did not influence fluorite dissolution compared to unloaded conditions. Environmental drivers were therefore identified as important predictors of fluoride mobilization at groundwater extraction sites, whereas the additional load of DOM to the groundwater resulting from MAR structures does not appear to increase fluoride concentration in the groundwater.Item Open Access Assessing the value of fertilisers derived from container-based sanitation systems(2018-02) Moya Diaz-Aguado, Berta; Parker, Alison; Sakrabani, RubenIt is estimated that 61% of the world population lacks access to safely managed sanitation and that in low-income countries (LICs) only 6.7% of the population is connected to a sewerage network. Container-based sanitation (CBS) systems have shown great potential for increasing access to sanitation in densely populated urban slums given that they do not require permanent infrastructures. Resource recovery is usually an essential part of CBS systems to provide sustainable faecal sludge management. Transforming human excreta into fertilisers creates value from faecal sludge while producing an organic soil amendment, addressing both sanitation and soil fertility challenges. Soil amendments made from organic residues are however known to be difficult to market profitably. This thesis therefore investigated the properties of human excreta derived fertilisers (HEDF) and the opportunities and challenges to their commercialisation in LIC. Nutrient characterisation of composts, anaerobic digestate and vermicompost from two CBS ventures showed significant differences in nutrient content between these three HEDF types. Pathogen and heavy metal analyses demonstrated that there is no pollution threat from HEDF when produced according toWHO guidelines. Field and glasshouse crop trials demonstrated the positive effect HEDF can have on crops and soil health. These benefits however do not currently translate into their commercial value. A case study approach was used to identify barriers and enabling conditions faced by two CBS organisations that successfully produce and sell HEDF. The low market value of compost prevented both organisations from recovering treatment costs from HEDF sales. One major barrier to wider adoption of HEDF use was the lack of regulations or certifications specific to this type of fertiliser. Perception challenges exist because of the potentially harmful components human excreta contain such as pathogens and heavy metals. It is therefore essential to create a way of proving or guaranteeing the quality and safety of HEDF products. The value of qualityassuring schemes for HEDF became evident when applying the Biosolids Assurance Scheme from the UK to HEDF, which helped identify a contamination issue in one of the treatment sites considered.Item Open Access An assessment of microbiological water quality of six water source categories in north-east Uganda(Iwa Publishing, 2010-12-31T00:00:00Z) Parker, Alison; Youlten, R.; Dillon, M.; Nussbaumer, T.; Carter, Richard C.; Tyrrel, Sean F.; Webster, JamesTarget 7C of the Millennium Development Goals is to "halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation". However, the corresponding indicator measures the "proportion of population using an improved drinking water source". This raises the question of whether "safe" and "improved" can be used interchangeably. This paper tests this hypothesis by comparing microbiological water quality in 346 different water sources across the District of Amuria in Uganda to each other and to defined standards, including the WHO drinking water standard of zero TTC per 100ml, and the Ugandan national standard of 50TTC per 100ml. The water sources were grouped into six different categories: boreholes, protected springs, covered hand dug wells, open hand dug wells, open water and roofwater harvesting. The paper concludes that the ranking from the highest to the lowest microbiological quality water was: boreholes, protected springs and roofwater harvesting, open and covered hand dug wells, open water. It also concludes that sanitary surveys cannot be used to predict water quality precisely; however they are an essential component of the monitoring of safe water supplies.Item Open Access An assessment of the microbiological water quality of sand dams in southeastern Kenya(MDPI, 2018-05-01) Quinn, Ruth; Avis, Orlando; Decker, Manon; Parker, Alison; Cairncross, SandySand-storage dams have proven to be a successful water harvesting method and potential solution to water and food security issues in semi-arid regions such as south east Kenya. This paper examines the microbiological quality of water both contained in the sand dam via test holes and abstracted from it through covered wells and scoop holes. In total, the values of thermotolerant coliform (TTC) concentration, turbidity, and pH are presented for 47 covered wells, 36 scoop holes, and 29 test holes, as well as the conductivity values in conductivity in 39 covered wells and 11 scoop holes. The water from test holes and covered wells was microbiologically of better quality than the scoop holes with median TTC levels of 0/100 mL and 159/100 mL respectively. However, the median values of turbidity for both scoop holes (20–30 NTU) and covered wells (5–10 NTU) exceed the World Health Organisation (WHO) guideline values. In addition the conductivity of water from 23% of scoop holes and 26% of covered wells is above the recommended WHO limit. This study also found that sanitary surveys are not a useful indicator of water quality in sand dams; however, they can identify areas in which sanitation and improvement of water sources are needed.Item Open Access Assessment of Traditional Rainwater Harvesting System in Barren Lands of a Semi-Arid Region(Cranfield University, 2021-01-05 10:09) Parker, AlisonField and modelling dataItem Open Access Assessment of traditional rainwater harvesting system in barren lands of a semi-arid region: a case study of Rajasthan (India)(Elsevier, 2022-06-25) Yadav, Basant; Patidar, Nitesh; Sharma, Anupma; Panigrahi, Niranjan; Sharma, Rakesh K.; Loganathan, V.; Krishan, Gopal; Singh, Jaswant; Kumar, Suraj; Parker, AlisonStudy region Dudu station, Rajasthan, India Study focus Rainwater harvesting can be used as a method to recharge aquifers. This can happen with a variety of scales and technologies. One such example is shallow infiltration ponds (Chaukas) which recharge groundwater and increase soil moisture facilitating pastureland development. A HYDRUS-1D model was used to estimate potential groundwater recharge. The model was calibrated using field data from 2019 and validated using data from 2020. The time series of Normalized Difference Vegetation Index (NDVI) was derived at annual scale to assess changes in the vegetation cover. New hydrological insights for the region The modeling revealed that an additional 5% of the rainfall depth was being recharged into the groundwater. In addition, the additional soil moisture was allowing natural grass cover to develop, which could be used by the local community as pastureland. These twin benefits that the local communities are realizing could be scaled up beyond Dudu, to India, and worldwide, as many regions have barren land that is slightly sloping, together with permeable soils, which are the only conditions for the construction of Chaukas. These Chauka systems have helped in sustainable water resources management in these water-stressed regions and the additional livelihood support through developed pastures for animal husbandry.Item Open Access Challenges to the use of fertilisers derived from human excreta: The case of vegetable exports from Kenya to Europe and influence of certification systems(Elsevier, 2019-05-11) Moya, Berta; Parker, Alison; Sakrabani, RubenLand degradation and inadequate faecal sludge management are two major issues in Sub-Saharan Africa (SSA). The transformation of human excreta into soil amendments and their wide-scale adoption could improve soil health and contribute to solving the sanitation crisis in SSA. There are however perception challenges around these fertilisers because of the potentially harmful components they contain such as pathogens and heavy metals, which can be removed with appropriate treatment such as composting. A major barrier to the wide scale commercialisation of human excreta derived fertiliser (HEDF) is the unclear regulations surrounding their use. The aim of this study was to identify barriers to the use of HEDF by farmers participating in the horticultural export market with Kenya as focus area since horticultural exports are a major contributor to the country’s economy. Global GAP is the most widely adopted standard for quality assurance of horticultural crops and the use of human sewage sludge is currently not allowed on certified farms. Interviews with stakeholders along the food export chain highlighted the complex interactions that exist between them and showed that Global GAP certified farmers were not willing to use HEDF on their farms even if local regulations recognise treated sludge as a valid input to agriculture. Several countries (like the UK, Sweden, Australia and the USA) created specific certification or assurance schemes to improve public perception of biosolids. The creation of a similar assurance or certification scheme specific to fertilisers made from source-separated human excreta would be a step into formalising them as a product, establishing production procedures, limits on contaminants content as well as testing protocols. Such a certification scheme could increase the confidence of regulating bodies in HEDF and lead to their acceptance by global farming standards.Item Open Access The characterization of feces and urine: a review of the literature to inform advanced treatment technology(Taylor and Francis, 2015-02-25) Rose, C.; Parker, Alison; Jefferson, Bruce; Cartmell, EliseThe safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On-site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh feces and urine was collected from the medical literature as well as the treatability sector. The data were summarized and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators, and chemical processes was then assessed. Results showed that the median fecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Fecal output in healthy individuals was 1.20 defecations per 24 hr period and the main factor affecting fecal mass was the fiber intake of the population. Fecal wet mass values were increased by a factor of 2 in low income countries (high fiber intakes) in comparison to values found in high income countries (low fiber intakes). Feces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25–54% of dry solids) of the organic fraction of the feces. Undigested carbohydrate, fiber, protein, and fat comprise the remainder and the amounts depend on diet and diarrhea prevalence in the population. The inorganic component of the feces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 L/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions, as well as water, salt, and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus, and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the fecal and urine composition and these variables should always be considered if the generation rate, physical, and chemical composition of feces and urine is to be accurately predicted.Item Open Access Climate change impacts on urban wash services in Ghana.(2017) Boakye, Richard Opoku; Parker, Alison; Hutchings, Paul; Weatherhead, E. KeithThe global water and sanitation sector is faced with numerous problems. Evident from Sub-Sahara Africa is the lack of access to potable water and improved sanitation which has made water coverage and sanitation a worry for most governments in low and middle-income countries. Climate change will exacerbate these problems especially in the urban poor communities. There is therefore the need to investigate how to make urban WASH services climate proof. In line with achieving this aim, part of this work assessed the existing WASH vulnerabilities, assessed the potential impacts of developed hydrological scenarios on the existing vulnerabilities and developed recommendations for various stakeholders using the Rapid Climate Adaptation Assessment (RCAA) methodology. The other part of this work assessed the adaptive capacity of the urban WASH sector by applying the Adaptive capacity wheel (ACW) methodology. In the application of these two methodologies, qualitative empirical data were collected from semi-structured interviews, direct observations and focus group discussions. The empirical data collected helped to understand the stakeholders‟ climate change awareness, the linkages in the local vulnerabilities, and ways to enhance the adaptive capacity of the WASH sector. This research argues that the vulnerabilities of the WASH services are similar within and across the ecological zones in Ghana. These vulnerabilities resulted from intermittent water supply, poorly managed solid waste and lack of spatial planning which are problems in urban poor WASH management. Though these vulnerabilities were arrived by simple hydrological scenario, they show the need for adaptation measures to be incorporated into urban poor WASH planning. To integrate adaptation measures to achieve resilience, this work further argues that the adaptive capacity of the sector can be enhanced by improving the learning capacity and motivation of stakeholders as well as empowering larger-scale institutions to provide structures and guidance at the lower- and individual level.Item Open Access Climate change, population trends and groundwater in Africa(Intl Assn of Hydrological Sciences Press, 2009-12-31T00:00:00Z) Carter, Richard C.; Parker, AlisonGlobal climate change is affecting Africa, as it is every other continent and region of the world. The absolute poverty of a large proportion of the continent's people renders them highly vulnerable to changes in climate. Mitigation of climate change is a global imperative. However, numerous other changes continue apace, notably population growth, natural resource degradation, and rural-urban migration. Probably 50% or more of the continent's population rely on groundwater. This paper explores the relative impacts of changes in climate, demography and land use/cover on groundwater resources and demands. It concludes that the climate change impacts are likely to be significant, though uncertain in direction and magnitude, while the direct and indirect impacts of demographic change on both water resources and water demand are not only known with far greater certainty, but are also likely to be much larger. The combined effects of urban population growth, rising food demands and energy costs, and consequent demand for fresh water represent real cause for alarm, and these dwarf the likely impacts of climate change on groundwater resources, at least over the first half of the 21st century.Item Open Access Conceptual energy and water recovery system for self-sustained nano membrane toilet(Energy Conservation and Management, 2016-08-12) Hanak, Dawid P.; Kolios, Athanasios; Onabanjo, Tosin; Wagland, Stuart Thomas; Patchigolla, Kumar; Fidalgo Fernandez, Beatriz; Manovic, Vasilije; McAdam, Ewan J.; Parker, Alison; Williams, Leon; Tyrrell, Sean; Cartmell, EliseWith about 2.4 billion people worldwide without access to improved sanitation facilities, there is a strong incentive for development of novel sanitation systems to improve the quality of life and reduce mortality. The Nano Membrane Toilet is expected to provide a unique household-scale system that would produce electricity and recover water from human excrement and urine. This study was undertaken to evaluate the performance of the conceptual energy and water recovery system for the Nano Membrane Toilet designed for a household of ten people and to assess its self-sustainability. A process model of the entire system, including the thermochemical conversion island, a Stirling engine and a water recovery system was developed in Aspen Plus®. The energy and water recovery system for the Nano Membrane Toilet was characterised with the specific net power output of 23.1 Wh/kgsettledsolids and water recovery rate of 13.4 dm3/day in the nominal operating mode. Additionally, if no supernatant was processed, the specific net power output was increased to 69.2 Wh/kgsettledsolids. Such household-scale system would deliver the net power output (1.9–5.8 W). This was found to be enough to charge mobile phones or power clock radios, or provide light for the household using low-voltage LED bulbs.Item Open Access Conceptual environmental impact assessment of a novel self-sustained sanitation system incorporating a Quantitative Microbial Risk Assessment approach(Elsevier, 2018-05-26) Anastasopoulou, Aikaterini; Kolios, Athanasios; Somorin, Tosin; Sowale, Ayodeji; Jiang, Ying; Fidalgo, Beatriz; Parker, Alison; Williams, Leon; Collins, Matt; McAdam, Ewan; Tyrrel, SeanIn many developing countries, including South Africa, water scarcity has resulted in poor sanitation practices. The majority of the sanitation infrastructures in those regions fail to meet basic hygienic standards. This along with the lack of proper sewage/wastewater infrastructure creates significant environmental and public health concerns. A self-sustained, waterless “Nano Membrane Toilet” (NMT) design was proposed as a result of the “Reinvent the Toilet Challenge” funded by the Bill and Melinda Gates Foundation. A “cradle-to-grave” life cycle assessment (LCA) approach was adopted to study the use of NMT in comparison with conventional pour flush toilet (PFT) and urine-diverting dry toilet (UDDT). All three scenarios were applied in the context of South Africa. In addition, a Quantitative Microbial Risk Assessment (QMRA) was used to reflect the impact of the pathogen risk on human health. LCA study showed that UDDT had the best environmental performance, followed by NMT and PFT systems for all impact categories investigated including human health, resource and ecosystem. This was mainly due to the environmental credits associated with the use of urine and compost as fertilizers. However, with the incorporation of the pathogen impact into the human health impact category, the NMT had a significant better performance than the PFT and UDDT systems, which exhibited an impact category value 4E + 04 and 4E + 03 times higher, respectively. Sensitivity analysis identified that the use of ash as fertilizer, electricity generation and the reduction of NOx emissions were the key areas that influenced significantly the environmental performance of the NMT system.Item Open Access Data accompanying A randomised controlled feasibility trial of a BabyWASH household playspace: The CAMPI study(Cranfield University, 2021-06-30 10:29) Parker, Alison; Tyrrel, SeanWater, sanitation and hygiene (WASH) interventions should support infant growth but trial results are inconsistent. Frequently, interventions do not consider behaviours or transmission pathways specific to age. A household playspace (HPS) is one intervention component which may block faecal-oral transmission. This study was a two-armed, parallel-group, randomised, controlled feasibility trial of a HPS in rural Ethiopia. It aimed to recommend proceeding to a definitive trial. Secondary outcomes included effects on infant health, injury prevention and women’s time. Methods. November 2019−January 2020 106 households were identified and assessed for eligibility. Recruited households (N=100) were randomised (blinded prior to the trial start) to intervention or control (both n=50). Outcomes included recruitment, attrition, adherence, and acceptability. Data were collected at baseline, two and four weeks. Findings. Recruitment met a priori criteria (≥80%). There was no loss to follow-up, and no non-use, meeting adherence criteria (both ≤10%). Further, 48.0% (95% CI 33.7−62.6; n=24) of households appropriately used and 56.0% (41.3−70.0; n=28) cleaned the HPS over four weeks, partly meeting adherence criteria (≥50%). For acceptability, 41.0% (31.3−51.3; n=41) of infants were in the HPS during random visits, failing criteria (≥50%). Further, the proportion of HPS use decreased during some activities, failing criteria (no decrease in use). A modified Barrier Analysis described good acceptability and multiple secondary benefits, including on women’s time burden and infant injury prevention. Interpretation. Despite failing some a priori criteria, the trial demonstrated mixed adherence and good acceptability among intervention households. A definitive trial to determine efficacy is warranted if recommended adjustments are made. Includes data, protocols and ethical approval documents.Item Open Access Data underpinning research article 'Sand dam contributions to year-round water security monitored through remotely sensed handpump data'(Cranfield University, 2022-12-01 15:20) Nicola Grace Ritchie, Hannah; Holman, Ian; Parker, Alison; Chan, JoannaThe repository contains an hourly abstraction data set collected from 26 sand dam hand pumps in Makueni and Machakos, Kenya via remote sensing, using Water Point Data Transmitters (WDT). The WDT were attached to the handles of the hand pumps in April 2019, and transmit abstraction via an SMS message, generated according to the number of times that the pump is used in an hour. The data set includes date, time, pump location, population size, and variables related to each sand dam (including, size, average distance to reach pump, and livestock usage). The variables are present in their raw form and also in their grouped form, which were used for the modelling in this study. The data was provided by Sand Dams Worldwide and has been approved for publication. The repository also contains an interview data set collected by Joanna Chan (MSc) in 2019 in Makueni and Machakos, Kenya. The interview data was collected at 30 sand dam sites. The data contains questions centred on water use behiours. This data was grouped to provide the variable data present in the abstraction data set. The repository contains an hourly abstraction data set collected from 26 sand dam hand pumps in Makueni and Machakos, Kenya via remote sensing, using Water Point Data Transmitters (WDT). The WDT were attached to the handles of the hand pumps in April 2019, and transmit abstraction via an SMS message, generated according to the number of times that the pump is used in an hour. The data set includes date, time, pump location, population size, and variables related to each sand dam (including, size, average distance to reach pump, and livestock usage). The variables are present in their raw form and also in their grouped form, which were used for the modelling in this study. The data was provided by Sand Dams Worldwide and has been approved for publication. The repository also contains an interview data set collected by Joanna Chan (MSc) in 2019 in Makueni and Machakos, Kenya. The interview data was collected at 30 sand dam sites. The data contains questions centred on water use behiours. This data was grouped to provide the variable data present in the abstraction data set.Item Open Access Delivering innovation and choice in water supply in Kenya's informal settlements(Cranfield University, 2012-09) O'Regan, Jack; Franceys, Richard; Parker, Alison; Bolton, SimonImproved access to water and sanitation in the worlds slums were among the key targets in the Millennium Development Goals. In Kenya, water is generally accessed in slum areas by filling 20l jerrycans at standposts and water kiosks and carrying back to households, with residents paying up to nine times more than utility bulk water prices and spending large parts of their day collecting water. The aim of this research was to assess consumers’ response and reaction to a series of water delivery mechanisms designed to offer a range of service levels and prices in accessing water in informal settlements. The current situation of residents’ access to water in seven informal settlements in Nairobi and Kisumu was assessed via household surveys and interviews with water providers, both municipal utilities and private operators, supplemented with observation of local practises. A series of innovative water delivery techniques were then designed to suit the prevailing conditions intending to offer price differences and volumetric purchase options. Follow up surveys were then carried out. This research has found that offering lower or alternative prices for water services in informal settlements is difficult due to challenges posed by vested interests and those interested in maintaining current high prices for water, and applying a difference in price was easiest in areas with already poor access to water or a new water kiosk. However, residents responded positively to the water delivery service, evidenced by a strong desire for this to continue and a willingness to assist operators in applying group purchases and volumetric purchases. Where it was possible to implement a difference in price corresponding to service level, consumers recognised their ability to move between service levels depending on variable income, their immediate demand and a simple choice.Item Open Access Design and commissioning of a multi-mode prototype for thermochemical conversion of human faeces(Elsevier, 2018-03-23) Jurado Pontes, Nelia; Somorin, Tosin; Kolios, Athanasios J.; Wagland, Stuart; Patchigolla, Kumar; Fidalgo, Beatriz; Parker, Alison; McAdam, Ewan; Williams, Leon; Tyrrel, SeanThis article describes the design and commissioning of a micro-combustor for energy recovery from human faeces, which can operate both in updraft and downdraft modes. Energy recovery from faecal matter via thermochemical conversion has recently been identified as a feasible solution for sanitation problems in low income countries and locations of high income countries where access to sewage infrastructures is difficult or not possible. This technology can be applied to waterless toilets with the additional outcome of generating heat and power that can be used to pre-treat the faeces before their combustion and to ensure that the entire system is self-sustaining. The work presented here is framed within the Nano Membrane Toilet (NMT) project that is being carried out at Cranfield University, as part of the Reinvent the Toilet Challenge of the Bill and Melinda Gates Foundation. For this study, preliminary trials using simulant faeces pellets were first carried out to find out the optimum values for the main operating variables at the scale required by the process, i.e. a fuel flowrate between 0.4 and 1.2 g/min of dry faeces. Parameters such as ignition temperature, residence time, and maximum temperature reached, were determined and used for the final design of the bench-scale combustor prototype. The prototype was successfully commissioned and the first experimental results, using real human faeces, are discussed in the paper.Item Open Access Developing a nutrient recovery process for recovering nutrients in anaerobic digestate in low income countries(Cranfield University, 2015-06) Rose, Christopher; Parker, Alison; Cartmell, EliseIt is estimated that 2.7 billion people worldwide are served by on-site sanitation facilities that require faecal sludge management. Anaerobic digestion is a treatment mechanism that can provide faecal sludge management, methane production and an effluent digestate rich in nutrients. However, there is a paucity of information regarding the composition of the input faecal sludge which hinders the advancement of anaerobic digestion treatment and downstream nutrient recovery together with a lack of knowledge as to how best to recover these output nutrients in a simple process. Following an initial review to collate composition data for fresh faeces and urine, practical studies examined the physical, biological and chemical composition and variation of four different types of faecal sludge from on-site sanitation facilities. Faecal sludge storage strongly influenced the biodegradability and methane production potential in subsequent anaerobic digestion. However, the high concentrations of ammonium observed in faecal sludge (520-1853 mg NH4-N L- 1 ) were highlighted as a key goal for nutrient recovery and the ability of biochar and clinoptilolite as natural adsorbents for ammonium recovery in a drying bed application were investigated through batch and dynamic studies using synthetic and real digestate. Batch tests observed ammonium uptake of 5 and 12.2 mg NH4-N/g for biochar and clinoptilolite respectively whilst under dynamic experimental conditions the most efficient operation for ammonium recovery was at the longest empty bed contact times (354 minutes), ensuring the maximum fertiliser value was obtained (60g NH4-N/kg clinoptilolite). Nevertheless, clogging occurred rapidly at the surface of the media bed (0.04 – 0.5 kg TS/m2 ), consequently a sacrificial sand layer (0.05 m) was included to increase the longevity of the nutrient recovery system (15 fold increase in TS application rates). It has been demonstrated that clinoptilolite can effectively be used as part of a sludge drying bed configuration to recover nutrients from digestate and the saturated media can be used directly as a fertiliser product or blended with the dried sludge to create a balanced nitrogen, phosphorus and potassium fertiliser product (5.9% NH4-N/ 4.2% P/ ≥6.0% K+ ).Item Open Access Diagnosis of an anaerobic pond treating temperate domestic wastewater: An alternative sludge strategy for small works(Elsevier, 2014-01-15) Cruddas, Peter; Wang, K.; Best, D.; Jefferson, Bruce; Cartmell, Elise; Parker, Alison; McAdam, Ewan J.An anaerobic pond (AP) for treatment of temperate domestic wastewater has been studied as a small works sludge management strategy to challenge existing practice which comprises solids separation followed by open sludge storage, for up to 90 days. During the study, effluent temperature ranged between 0.1 °C and 21.1 °C. Soluble COD production was noted in the AP at effluent temperatures typically greater than 10 °C and was coincident with an increase in effluent volatile fatty acids (VFA) concentration, which is indicative of anaerobic degradation. Analysis from ports sited along the AP's length, demonstrated VFA to be primarily formed nearest the inlet where most solids deposition initially incurred, and confirmed the anaerobic reduction of sludge within this chamber. Importantly, the sludge accumulation rate was 0.06 m3 capita−1 y−1 which is in the range of APs operated at higher temperatures and suggests a de-sludge interval of 2.3–3.8 years, up to 10 times longer than current practice for small works. Coincident with the solids deposition profile, biogas production was predominantly noted in the initial AP section, though biogas production increased further along the AP's length following start-up. A statistically significant increase in mean biogas production of greater than an order of magnitude was measured between winters (t(n=19) = 5.52, P < 0.001) demonstrating continued acclimation. The maximum methane yield recorded was 2630 mgCH4 PE−1 d−1, approximately fifty times greater than estimated from sludge storage (57 mgCH4 PE−1 d−1). Anaerobic ponds at small works can therefore enable sludge reduction and longer sludge holding times than present thus offsetting tanker demand whilst reducing fugitive methane emissions currently associated with sludge storage, and based on the enhanced yield noted, could provide a viable opportunity for local energy generation.Item Open Access Do domestic animals contribute to bacterial contamination of infant transmission pathways? Formative evidence from Ethiopia(IWA Publishing, 2019-08-26) Budge, Sophie; Hutchings, Paul; Parker, Alison; Tyrrel, Sean; Tulu, Tizita; Gizaw, Mesfin; Garbutt, CamilaChild stunting is associated with poor water, sanitation and hygiene (WASH), partly due to the effect of infection on intestinal nutrient absorption. WASH interventions, however, show little effect on growth. A hypothesis is that bacterial contamination of hands and floors from domestic animals and their faeces, and subsequent ingestion via infant hand-to-mouth behaviours, may explain this. This formative study used microbial testing and survey and observational data from 20 households in Ethiopia to characterise principle bacterial transmission pathways to infants, considering WASH facilities and practices, infant behaviours and animal exposure. Microbial swabbing showed the contamination of hands and floor surfaces from thermotolerant coliform bacteria. Animal husbandry practices, such as keeping animals inside, contributed significantly (all p < 0.005). There was no evidence that latrine facilities mitigated contamination across infant (p = 0.76) or maternal (p = 0.86) hands or floor surfaces (p = 0.36). This small study contributes to the evidence that animal faeces are an important source of domestic bacterial contamination. The results imply that interventions aiming to reduce pathogen transmission to infants should think beyond improving WASH and also consider the need to separate infants and animals in the home. Intervention studies will be required to determine whether this reduces infant infection and improves linear growth.Item Open Access Do domestic animals contribute to bacterial contamination of infant transmission pathways? Formative evidence from Ethiopia(IWA Publishing, 2019-08-26) Budge, Sophie; Hutchings, Paul; Parker, Alison; Tyrrel, Sean; Tulu, Tizita; Gizaw, Mesfin; Garbutt, CamilaChild stunting is associated with poor water, sanitation and hygiene (WASH), partly due to the effect of infection on intestinal nutrient absorption. WASH interventions however show little effect on growth. A hypothesis is that bacterial contamination of hands and floors from domestic animals and their faeces, and subsequent ingestion via infant hand-to-mouth behaviours, may explain this. This formative study used microbial testing and survey and observational data from twenty households in Ethiopia to characterise principle bacterial transmission pathways to infants, considering WASH facilities and practices, infant behaviours and animal exposure. Microbial swabbing showed contamination of hands and floor surfaces from thermotolerant coliform (TTC) bacteria. Animal husbandry practices, such as keeping animals inside, contributed significantly (all p<0.005). There was no evidence that latrine facilities mitigated contamination across infant (p=0.76) or maternal (p=0.86) hands or floor surfaces (p=0.36). This small study contributes to the evidence that animal faeces are an important source of domestic bacterial contamination. The results imply that interventions aiming to reduce pathogen transmission to infants should think beyond improving WASH and also consider the need to separate infants and animals in the home. Intervention studies will be required to determine whether this reduces infant infection and improves linear growth.