A new phosphate-selective sorbent for the Rem Nut~reg; process. Laboratory investigation and field experience at a medium size wastewater treatment plant

摘要

P-control technologies for municipal wastewater are essentially based on "destructive" methods, that lead to formation of concentrated solid-phases (sludge), usually disposed-off in controlled landfills. Ion exchange, as a "non-destructive" technology, allows for selective removal and simultaneous recovery of pollutants, which can be recycled to the same and/or related productive lines. In this context, the REM NUT~® process removes nutrient species (HPO_4~=, NH_4~+, K~+) present in biologically oxidised municipal effluents and recovers them in the form of struvites (MgNH_4PO_4; MgKPO_4), premium quality slow release fertilisers. The main limitation to the extensive application of this ion exchange based process is the non-availability of selective exchangers for specific removal of nutrient species. This paper illustrates laboratory investigation and pilot scale development of a so-called "P-driven" modified REM NUT scheme based on a new phosphate-selective sorbent developed at Lehigh University, PA, USA.