@misc {
    orvium-649fee2ee31917f67e1c10b4,
    title = "Coupling Urine Diverting Flush Toilets with Anaerobic Co-Digestion in the Global South - Modelling Climate Benefits in Kpong, Ghana",
    abstract = "In the Global South, urine diverting dry toilets have been successfully tested as feasible tools toincrease sanitation coverage. However, many people desire flush toilets. Some approaches to treatwastewater from flush toilets have been implemented successfully, yet many sanitation projectshave failed because operation and maintenance costs were too high. Biogas production fromwastewater can be seen as a tool that benefits operators directly and tangibly, reducing thelikelihood of sanitation projects to fail due to economic reasons once in operation. However,decentralized treatment systems in the Global South that can cope with larger quantities offlushwater do not provide reliable gas retrieval mechanisms. Fixed-dome digesters (FDDs) canprovide a simple retrieval mechanism without the need for electricity or moving parts, allowing forsustainable gas collection. However, they are not used for treatment of diluted wastes, as this wouldmake them unreasonably large. Urine diverting flush toilets (UDFTs) can save large quantities ofwater due to reduced flushwater consumption for urinations and could therefore enable thecombination of flush toilets with biogas collection.For a specific trade center with a size of 120 person-equivalents in Ghana, the economic andgreenhouse gas (GHG) mitigation benefits of using this combination were compared against astandard anaerobic wastewater treatment approach without biogas collection. It was analyzed howflushwater consumption and co-digestion with food waste affect operational benefits, increasedinvestment costs, and space consumption. This was done by comparing the influences of thedifferent treatment elements used in the two approaches, namely the FDD, Imhoff tank, anaerobicbaffled reactor, urine storage and composting of food waste as an alternative to co-digestion in theFDD. A key underlying assumption was that all water and nutrients would be properly reused.Theoretical calculations were performed using URWARE wastewater data and treatment modellingapproaches that were combined with DEWATS engineering guidelines. An emission modellingapproach was set up to investigate how different flushwater and food waste quantities affectemissions from the compensation tank of the FDD. Additionally, effects of varying LPG and carbonprices as well as effects of leaks and lack of flaring were shown and it was investigated how resultscould be translated to differing user populations.It was found that about 700 USD can be saved per year but additional initial investment cost wouldbe as large as 13,600 USD. Still, 32% of initial investment costs were attributed to urine storage,which may not be needed in some cases. GHG emissions from construction would amortize alreadyafter 1.7 years and 200 tCO2-eq could be mitigated after 20 years of operation. Adjustment with acarbon price of 100 USD tCO2-eq-1 would allow for economic amortization after 8.6 years, resultingin economic savings of 20,400 USD after 20 years of operation. Food waste dosage did not affectthis result significantly, showing that co-digestion is not needed if this carbon price would be ineffect. In conclusion, UDFTs are a powerful tool to mitigate GHG emissions and ensure continuedtreatment system operation in the Global South, however technology diffusion will require adequatefunding mechanisms that can cope with the increased investment costs.",
    keywords = "Anaerobic Digestion, Urine-diverting flush toilets, Wastewater, Greenhouse gas emissions",
    author = "Felix Giglberger",
    year = "2023",
    doi = "10.13140/RG.2.2.18281.16487",
    language = "English",
    url = "https://dapp.orvium.io/deposits/649fee2ee31917f67e1c10b4/view",
}