Phosphorus recovery from anaerobically digested liquor of screenings

Phosphorus is a limited resource which is predicted to get exhausted at some point during the twenty-first century. However, it is present in wastewaters at concentrations that come close to supplying the nation’s annual requirements for fertiliser. Many papers have addressed the recovery of phosphorus as struvite (magnesium ammonium phosphate hexahydrate) from different types of waste while the most prominent usage of struvite is as a slow-release fertiliser, suitable as a replacement for chemical fertiliser, for agricultural application. In this study, screenings produced during the wastewater treatment process were anaerobically digested to obtain anaerobically digested liquor which was subsequently used for phosphorus recovery in the form of struvite. This was carried out at different concentrations of dry solids. The amount of struvite potential was calculated theoretically using molar ratio calculations of 1:1:1 (Mg:N:P). From the results, it was found that the digestate is high in phosphorus content and can be recovered up to 41%. For struvite yield, 0.27,kg of struvite can be recovered from each kg dry solids of screenings from 3% of dry solids. Screenings thus prove a valuable source of additional phosphorus which current disposal practices fail to exploit

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

Global population growth requires intensification of agriculture, for which a sustainable supply of phosphorus (P) is essential. Since natural P reserves are diminishing, recovering P from wastes and residues is an increasingly attractive prospect, particularly as technical and economic potential in the area is growing. In addition to providing phosphorus for agricultural use, precipitation of P from waste residues and effluents lessens their nutrient loading prior to disposal. This paper critically reviews published methods for P recovery from waste streams (municipal, farm and industrial) with emphasis on struvite (MgNH4PO46H2O) crystallisation, including pre-treatments to maximise recovery. Based on compositional parameters of a range of wastes, a Feedstock Suitability Index (FSI) was developed as a guide to inform researchers and operators of the relative potential for struvite production from each waste

Emerging role of Geographical Information System (GIS), Life Cycle Assessment (LCA) and spatial LCA (GIS-LCA) in sustainable bioenergy planning

Sustainability of a bioenergy project depends on precise assessment of biomass resource, planning of cost-effective logistics and evaluation of possible environmental implications. In this context, this paper reviews the role and applications of geo-spatial tool such as Geographical Information System (GIS) for precise agro-residue resource assessment, biomass logistic and power plant design. Further, application of Life Cycle Assessment (LCA) in understanding the potential impact of agro-residue bioenergy generation on different ecosystem services has also been reviewed and limitations associated with LCA variability and uncertainty were discussed. Usefulness of integration of GIS into LCA (i.e. spatial LCA) to overcome the limitations of conventional LCA and to produce a holistic evaluation of the environmental benefits and concerns of bioenergy is also reviewed. Application of GIS, LCA and spatial LCA can help alleviate the challenges faced by ambitious bioenergy projects by addressing both economics and environmental goals. (C) 2017 Elsevier Ltd. All rights reserved