Is phosphorus recovery from waste water feasible?
Phosphorus (P) recovery from waste water must become a predominant goal of all countries to face the limited resources of this essential nutrient. The induced crystallisation of calcium phosphates straight from the waste water phase applying tobermorite-rich calcium silicate hydrate compounds (CSH) from the construction industry as the trigger material has proved to be a suitable method. Laboratory and semi-technical scale experiments were carried out in fixed bed, stirred reactor and expanded bed mode. P-loads of the crystallisation substrates of up to 13 wt-% total P (P-tot) (30 wt-% P2O5) were achieved. Recycling options of the generated products, both as substitute for phosphate rock in the phosphate industry and as a new fertiliser in agriculture, were demonstrated. Indicative operating and investment costs were estimated for conversion of conventional waste water treatment plants (WWTP) designed for nutrient removal and P-precipitation with iron and aluminium reagents to the proposed new crystallisation technology for simultaneous P-removal and P-recovery.
Berg
U
U
Institute for Technical Chemistry, Water Technology and Geotechnology Division (ITC-WGT), Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Knoll
G
G
Kaschka
E
E
Weidler
P G
PG
Nüesch
R
R
D017610:Calcium Compounds / Q000737:chemistry; D003247:Conservation of Natural Resources / Q000191:economics / Q000379:methods*; D003365:Costs and Cost Analysis; D003460:Crystallization; D005308:Fertilizers; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D017640:Silicates / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000191:economics / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*
D017610:Calcium Compounds; D005308:Fertilizers; D017640:Silicates; D014874:Water Pollutants, Chemical; D010758:Phosphorus; C031293:calcium silicate