Recovery of N and P from Urine by Struvite Precipitation Followed by Combined Stripping with Digester Sludge Liquid at Full Scale

Abstract

A novel ammonia stripping method, including a CO 2 pre-stripper was used to treat a mix of supernatant liquor from an anaerobic digester and urine in order to recycle nitrogen as ammonium sulfate at full-scale in the WWTP Kloten/Opfikon. Waste streams were not generated, since the ammonia was recovered as a marketable nitrogen fertilizer, turning a waste product into a valuable product. The efficiency of this system was increased by means of the addition of pre-treated urine collected separately at EAWAG building. The separation step was performed by the use of water free urinals and urine diversion flush toilets. An increase of 10% in the liquid flux with the addition of the urine translated into a 40% increase of the ammonia concentration in the inlet of the stripping unit. The achievement of these percentages generated a proportional increase in the fertilizer production. The urine pre-treatment was carried out by adding magnesium to produce a precipitate of struvite. The first experiments with the combined treatment showed the feasibility of the combination of the separation and pre-treatment steps. OPEN ACCESSWater 2013, 5 1263

Phosphorus recovery as struvite from farm, municipal and industrial waste: Feedstock suitability, methods and pre-treatments

“…Nepal (Ronteltap et al, 2007;Gell et al, 2011;Grau et al, 2012) without the need for any pre-treatments.. Human urine contains156-460 mg L -1 of P and is low in heavy metals (Ganrot et al, 2007;Morales et al, 2013). Struvite can easily be precipitated from urine urea by addition of Mg, since it is naturally deficient in Mg. Commercial struvite recovery units handling municipal wastewater sludge are in operation in countries like Japan, Canada, England, USA, Australia, Germany, The Netherlands and…”

“…Urine can be used without any pre-treatment prior to P recovery. Further, urine-derived struvite is free of heavy metals and its inherent alkaline nature requires no addition of an external base (Hug and Udert, 2013;Morales et al, 2013).…”

Effects of Precipitation and Topography on Total Phosphorus Loss from Purple Soil

“…With the development of modern agriculture technology, the use of chemical fertilizers and pesticides in agriculture is increasing and the chemical composition becomes more complicated, which lead to wide range of nonpoint source (NPS) pollution after long-term accumulation in the soil [1][2][3]. Due to the large area of cultivated land and multi-sources, widespread and difficulty in processing of NPS pollution, it has been the main type of water pollution when point source pollution control is becoming more and more effective [4][5][6].…”

Concurrent hydrogen production and phosphorus recovery in dual chamber microbial electrolysis cell

“…These processes are effective for struvite precipitation; however, the operation cost is too high. Using chemical addition to raise the solution's pH can account for up to 97% of struvite cost (Jaffer et al, 2002;Morales et al, 2013).…”

“…These processes are effective for struvite precipitation; however, the operation cost is too high. Using chemical addition to raise the solution's pH can account for up to 97% of struvite cost (Jaffer et al, 2002;Morales et al, 2013).Microbial electrolysis cells (MECs) are a new and promising approach for hydrogen (H 2 ) production from organic matter, including wastewater and other renewable resources. In MECs, electrochemically active bacteria oxidise organic matter and generate CO 2 , electrons and protons.…”