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NAERINGSPH-Nærings-phd

Source separation and on-site wastewater treatment technologies for improved food security and green development

Alternative title: Teknologiutvikling av bærekraftig behandling for kildeseparerende avløp for ressursgjenbruk

Awarded: NOK 1.8 mill.

Project Number:

252510

Project Period:

2015 - 2018

Funding received from:

Organisation:

This research project aimed to contribute to a novel sustainable approach in which resources contained in wastewater are treated, recovered and reused, in an efficient and safe manner, in areas close to the source of generation. The project considered source-separation of domestic wastewater streams into blackwater and greywater and treating them separately according to their properties. For the blackwater stream, experiments were conducted with two bench-scale biogas reactor units to assess the potential of blackwater for recovery of energy and as pre-treatment for recovery of nutrients. These two mini reactors are in operation for the last two years without critical failures. The experiences from these two years experiment show that this type of reactor retains more than 90% of suspended solids and converts 60-65% of the organic matter contained in the blackwater into biogas while significantly reducing sludge production. The methane content of the biogas is in the range of 69 to 82%, indicative of high burning value. Based on these results a full-scale reactor is under development and Ecomotive AS plans to take a first pilot installation into operation in begin of 2018. Simultaneously, a post-treatment system is designed to treat the effluent from the reactors and produce a hygienically safe liquid fertilizer with high concentration of plant available N and P. This system demonstrated the potential of developing a combined treatment and resource recovery approach for sustainable source-separated blackwater treatment, which can play a significant role towards a circular economy. The system significantly removed effluent organic matter and suspended solids resulting clear and transparent effluents, while preserving more than 77% of soluble N and 87% P in the liquid phase that can be reused as a nutrient solution. Integration of UV after Filtration resulted complete removal of E. coli. Therefore, combing UASB with Filtration and UV units as novel post-treatment steps opens up the opportunity of reusing valuable resources from blackwater as raw materials. Moreover, as part of on-site greywater treatment system, a post-treatment systems was developed to improve the treatment efficiencies and effluent quality of package treatment plants that can be applicable for vulnerable areas or for areas where discharge requirements are very stringent. The system resulted an overall efficiency of more than 95% for all the parameters investigated. For coliform bacteria and E. coli, the overall system reached a reduction of 4?5 log10 units. The effluent quality from this source-separating and multi-barrier biofilter treatment system complies with the Norwegian discharge limits. The assessment results revealed that with integration of UV, the system can be used in drinking water source catchments with minimal or no environmental and health related risks. Currently, a sideline experiment is being carried out aiming at concentrating and transforming the nutrients from treated blackwater into valuable products. Hygienically safe liquid fertilizers produced from blackwater is used for production of microalgae biomass. The potentials of microalgae as a sink for N and P and for removal of residual micropollutants and producing high quality effluent is being evaluated.

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This research project aims to contribute to a novel sustainable approach in which resources contained in wastewater are locally recovered and reused in an efficient and safe manner. The project will consider households and communities as sources of sustainable production units of water, energy, nutrients and food from the wastewater they generate. Source separation of the different wastewater streams and treating this valuable resource in situ and subsequent resource recovery is an attractive domestic wastewater management option. This require development of novel, more simple and self-sustaining technologies. Using these technologies, the organic matter in the wastewater will be converted into biogas that can be used as energy source in the households and communities. Hygienically safe liquid fertilizers and bio-solids produced as by-products will contribute to local agricultural production. The treated water can be recycled for non-potable purposes and be an alternative source to the local water demand. The overall objective of the research project is, therefore, to develop and combine processes for efficient treatment and recovery of resources from source-separated household wastewater and assess the contribution to food security, green economy and ensure a safe living environment. Data will be collected to characterize, analyze and monitor the combined systems, to describe relevant materials, process properties and product features with respect to different reuse applications and to optimize and evaluate the performance and reliability of the technology. At the end of the project, a robust, compacted and integrated technology that can combine both wastewater management and by-product use is anticipated.

Publications from Cristin

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Funding scheme:

NAERINGSPH-Nærings-phd