Total Value of Phosphorus Recovery

Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies

Economic and agronomic evaluation of using excreta-derived plant nutrients sources (latrine dehydrated and pasteurised pellets, struvite and nitrified urine concentrate) as agricultural fertilisers.

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.Faecal sludge can be recycled and processed into usable products such as the Latrine Dehydrated and Pasteurised (“LaDePa”) pellets and urine into Nitrified Urine Concentrate (NUC) and struvite, which can be used as fertilisers. The financial costs and benefits and the agricultural-effectiveness of using LaDePa, NUC and struvite as fertilisers in South Africa and the wider sub-Saharan African region have not been empirically quantified. A study was carried out using experimental data to quantitatively establish the cost-effectiveness of using LaDePa, NUC and struvite for maize production. The costs per hectare of using these products to meet crop nutrient requirements for maize and achieve a specified target yield were determined and compared with the costs per hectare of using recommended commercial fertilisers. The financial feasibility was determined using partial budgets. The income per hectare of using these products was determined and compared with that of the commercial fertilisers. Pot trials in a tunnel were also carried out to determine the agricultural-effectiveness of the products compared with the commercial fertilisers and crop growth parameter results analysed statistically using GenStat. The results showed that LaDePa, NUC and struvite are financially viable, if used in place of the organic fertiliser studied. Their net income (gross income less total calculated costs) per hectare was also higher compared with that of commercial fertilisers analysed. On the agronomic side, the products also proved to be very effective for crop growth and might be better than the assessed commercial fertilisers. On top of being a viable nutrient source, LaDePa is even more cost-effective if it is used as a soil amendment to improve soil physical properties. The use of NUC and struvite as nitrogen and phosphorus sources, respectively, was shown to be financially viable. If one is to add the environmental benefits of recycling waste products as fertilizers, the products will be even more economically viable. However, there is a need for more research on consumer acceptance of the agricultural goods produced this way

A technological and economic exploration of phosphate recovery from centralised sewage treatment in a transitioning economy context

Phosphate is one of the substances which wastewater treatment works (WWTW) have to lower in order to meet the South African regulatory discharge standard of 1 mg/L. Wastewater is increasingly viewed as a ‘water-carried waste’, presenting opportunities for resource recovery. South Africa has commenced its transition to a low-carbon and resource-efficient economy, all whilst it struggles to provide universal access to basic needs and is faced with massive infrastructure maintenance as well as upgrading backlogs in the sanitation sector in particular. Although phosphate recovery methods exist, there is little evidence to indicate that these techniques would be economically viable or socially accepted in South Africa. This paper explores the potential for centralized recovery of nutrients, through the conceptual design and techno-economic pre-feasibility assessment of two phosphate recovery options, at the largest WWTW in the Western Cape, South Africa. This assessment revealed that the digestate stream at the 200 ML/d Cape Flats WWTW (CFWWTW) has the potential to produce ~470 kg/d of struvite fertilizer, whilst recovering 4–8% of the plant’s costs in 20 years. When contrasted with the more familiar, yet less sustainable, chemical precipitation process, low-grade and high-grade struvite production establishment costs are 10 and 25 times higher, respectively. Still, to reduce effluent phosphate loading to within regulated standards, the low-grade struvite production option at an estimated net present cost of R25.4 million over a 20-year lifetime is more affordable than chemical precipitation at a net present cost of R51.2 million. Low-grade struvite production is thus concluded to be technically feasible and the economically most affordable option from a lifecycle-costs perspective. Although it is a simple process, it is not cheap. Municipalities will need to consider the lower operating costs, as well as the environmental benefit of producing a useful phosphate fertilizer, over the immediate capital investment, if they decide to install such an operation.Keywords: nutrient recovery; struvite; techno-economic assessment; phosphate recovery; South Afric

Modelling the benefits of urine diversion for resource recovery: a case study of Arba Minch, Ethiopia

Urine diversion provides a possibility of linking environmental sanitation and agricultural production. In order to support decision making with regard to the implementation of dry, urinediverting toilets (UDDT), material flow analysis (MFA) can represent a useful tool. This paper presents the use of a material flow analysis for water, sanitation and organic waste applied to the city of Arba Minch, Ethiopia. Mass flows as well as nitrogen and phosphorus flows are assessed. The results highlight the potential for reduced environmental pollution as well as the recovery of valuable nutrients through the application of urine and compost. Different implementation pathways are modelled including uncertainty analyses. The results show that the replacement of nitrogen and phosphorus fertiliser currently required within the system boundaries is possible at UDDT implementation rates between 20 and 50%. If more households are equipped with UDDTs, excess nutrients can be delivered to surrounding areas with higher farming intensities

User-acceptance of sanitation technologies in South Africa and Malawi

There is a great need for the planning and implementation of sanitation technologies (STs) to take into consideration the user-acceptance factor and, therefore, limit resource wastage. This article aims to determine whether the pattern of relative importance of the factors that affect sanitation technology user-acceptance (STUA) is similar across study areas located in South Africa and Malawi with respect to the STs rolled out. Information from the study is especially critical for resource conservation, considering the recent relatively poor performance of the South African economy (a 7% slump) in 2020. Desktop research methods, using data from previous studies, were used to perform an analysis of the significance of the underlying factors that influence STUA. These were based on a systematic review that uses a structured protocol for literature review, together with the snowball approach. The methodology proposed by the Water Research Commission (WRC) under the sanitation suitability index was used to perform the sanitation technology comparisons. This article adds value to previous research in that, unlike previous research studies, it considers several relevant researched technologies to establish whether there exist similar patterns of relative significance of factors that influence STUA. Reliability, health, user- and technical acceptability were the predominant influencers of STUA. Education, training, and technical support are necessary throughout the sanitation project life cycle.&nbsp

'What is to be sustained for whom?': Equity as a key to sustainable sanitation in South African informal settlements

Universal access to sustainable and equitable sanitation is a Sustainable Development Goal on the 2030 Agenda for Sustainable Development. The South African government has taken strides to try and meet both international and domestic development goals with its Free Basic Sanitation policy, for which a national implementation strategy was developed in 2008. Although the policy was formulated at a national level, municipal governments are delegated the authority to ensure service delivery at the local level. Municipalities have adapted and interpreted the policy to suit their own contexts. In particular, they have attempted to address the challenge of providing sanitation services to informal settlements using different approaches with varying degrees of success and often without explicit consideration or guidance for how to incorporate sustainability and equity principles. The aims of this thesis are thus to explore how the concepts of sustainability and equity can be applied to improve municipal sanitation services in South African informal settlements and to explore how various dimensions of sanitation and equity relate to sanitation. A comparative case study method using the lens of sustainability and equity was used to critique the approaches to providing sanitation services to informal settlements in three of South Africa's largest municipalities: eThekwini (Durban), Johannesburg and Cape Town. Each municipal case study incorporated an embedded case study that was used to examine sanitation services in selected informal settlements at a programme, project or settlement level. Primary data was collected using interviews and field visits. Secondary data was obtained from national and municipal records such as water and sanitation department reports, census data from Statistics South Africa, and municipal geographical information system databases. Findings from the thesis indicate that there is a need to better incorporate multiple stakeholders' perspectives on what sustainable and equitable sanitation services should be like. Strengths and weaknesses of each municipality's approach to sanitation service provision were compared and used to identify factors relating to sustainability and equity. A major conceptual gap identified in sanitation service delivery approaches is the need to emphasise equity as a core tenet of sustainability, especially in a socio-economic context of extreme inequality. This thesis makes a contribution towards knowledge by highlighting the importance of equity to support sustainable sanitation service delivery in South African informal settlements, adding new perspective into different dimensions of equity in sanitation and a suggested framework for how they could be incorporated into M&E practices

Perception and impact of micropollutants in urine-based liquid fertilizer on crop production: A comprehensive review of Eco-sanitation practices

Large-scale sustainable agriculture presents a formidable challenge globally, resulting in severe food insecurity for approximately 52% and 48% of people living in rural and urban areas, respectively. An estimated 690 million individuals suffer from hunger annually due to the high cost of chemical fertilizers and other factors. To reduce costs, source-separated urine offers a promising alternative for crop production, despite containing more nitrogen and phosphorus than traditional fertilizers. However, human urine also contains pharmaceuticals and micropollutants with adverse effects on human health and the environment. Human urine provides essential micronutrients for plant growth, with studies showing similar nutrient concentrations between concentrated urine and mineral fertilizers. Nevertheless, the presence of heavy metals and other contaminants in urine raises safety concerns. While urine diversion toilets can safely collect urine, their use as a liquid fertilizer requires careful consideration due to the presence of disease-causing organisms, pharmaceuticals, and metabolites that contribute to water and soil contamination. Consumers and farmers alike worry about the safety of crops fertilized with urine, given the perception of disease-causing pathogens. This review explores the impact of urine and chemical fertilizers on plant yield as well as the effects of heavy metals, pharmaceuticals, and microplastics on human health and the environment. Various methods to remove antibiotics from urine, such as membrane bioreactors combined with complex chemicals and physicochemical processes, were also examined. These methods, including activated powdered carbon, nano-filtration, ozone, and ozone/UV, target specific antibiotics and their metabolites to ensure the safety of urine-derived fertilizers

Governance:Governance Frameworks for Wastewater Management

MVZ specimen catalog numbers and views represented. (XLSX 495 kb

Assessing the value of fertilisers derived from container-based sanitation systems

It 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