Energy efficient nutrient recovery fromhousehold wastewater using struviteprecipitation and zeolite adsorptiontechniquesA pilot plant study in Sweden

摘要

The most N and P abundant part among the domestic waste components is thetoilet wastewater; especially urine. Urine separation has been proposed to achieve maximumrecovery and recirculation of nutrients in Sweden. However, storage, transportation of largeamounts of urine, as well as spreading and hygienic aspects connected to handling of urineand faeces are still main obstacles in achieving full system efficiency. A decade of academicresearch on struvite precipitation and zeolite adsorption techniques aimed to solve someof these problems and 3 years of collaboration with Split Vision Development AB resulted in acommercially available, energy efficient system developed and tested in laboratory scale andin a pilot plant.This paper presents the results from one-year testing of a pilot plant installed andintegrated in a family house in northern Sweden. The pilot plant is based on the combinedstruvite precipitation and zeolite adsorption processes. The nutrient rich end-productobtained in the unit called SplitBox is vacuum-dried (fully hygienised) and this dryingprocess connects the SplitBox to the energy system of the house. Moreover, spill-energyfrom wastewater and ventilation is efficiently reused. The pilot study shows 90–98% P and95–98% N recovery from toilet wastes using urine separating toilet and SplitBox techniqueand a total energy saving of ca 50% for the household after one year operation.