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Zero hunger

How to close nutrient cycles for future Zero Hunger (PICO and Communication session)

EUROSOIL2020CONT-2489

QUALITY ASSURANCE OF RECYCLING PRODUCTS FROM DRY TOILETS FOR USE IN AGRI- & HORTICULTURE THROUGH STANDARDIZATION

Ariane Krause¹, Franziska Häfner^{* 1}

¹Next-generation horticultural systems (HORTSYS), Leibniz Institute of Vegetable and Ornamental Crops (IGZ) e.V., Großbeeren, Germany

Content: Modern anthropogenic activities impact the “Planetary Boundaries”, defining a safe operating space for humanity on earth. Especially for global nitrogen (N) and phosphorus (P) flows, planetary boundaries are already transgressed. The use of synthetic mineral fertilizers in industrial agriculture significantly contributes to linear “shifts” of nutrients, leading to the alteration of natural N and P cycles. These nutrient shifts are based on fixation of atmospheric N and mining of terrestrial P with ultimate discharge of N and P into the hydrosphere, associated with severe environmental risks such as eutrophication. Circular economies (CE) and material cycling within the agroecosystem are therefore crucial to keep environmental impacts of the food system at bay. Ambitious technological improvements, particularly with regards to global N and P applications, are necessary to sustain long-term global food production.

For the production of recycling fertilizer and soil amendments, the EU particularly promotes the use of locally available resources. Urban waste water flows, and specifically human excreta, are considered a significant source for “urban mining” of nutrients. A decentralized treatment of human urine and feces from dry toilets enables the integration of the recycling of nutrients and the elimination of pollutants, including pharmaceuticals. In principle, the EU’s “end-of-life”-criterion promotes the production of bio-based recycling fertilizers. In many European countries however, (processed) human excreta are not yet explicitly mentioned in the legal framework. Political work and a paradigm shift are thus needed to integrate these resources into fertilizer legislation at European and national levels.

In cooperation with the German national organization for standardization (Deutsches Institut für Normung e.V., DIN) we developed a product standard (DIN SPEC) for marketable and quality-assured recycling products made from human excreta, for use as fertilizer in horticulture. The objective was (i) to contribute to quality assurance in modern CEs, (ii) to provide a discussion paper as a decision support at political level, and (ii) to strengthen start-ups and SMEs in establishing their technical innovations on the market for stationary and mobile waterless sanitary technology & services. According to the German fertilizer ordinance, quality assurance must ensure that the application of a recycling fertilizer does not harm soil fertility, damage human, animal and plant health nor endanger the ecosystem.

In this project, we firstly defined the fertilizer products to be covered by the DIN SPEC such as inter alia stored urine, nitrified urine, dried urine powder, struvite, or compost from thermophilic composting of feces mixed with green waste, and thermo-chemically carbonated, pasteurized and/or pelletized feces. We then carried out a risk analysis to derive quality assurance criteria and to define requirements for the characteristics and properties of the recycling products. The requirements/criteria were then specified and quantified by a meta-analysis of existing European and German legal and normative texts and scientific studies. Finally, 20 samples of different recycling products were analyzed and evaluated for a 'proof of concept', with regard to the achievement of the desired quality assurance defined in the DIN SPEC.

Disclosure of Interest: None Declared

Keywords: Circular economy, Human excreta, Multi-criteria requirements, Nutrient cycling, Quality assurance, Recycling fertilizers, Risk assessment, Standardization