290 likes | 438 Views
Ochre Pelletising and use for phosphate Removal from sewage effluent 2 nd February 2005 Jonathan Aumônier. Introduction. Pelletising Process Lab results – phosphate removal Micrographs Windlestone trial Planned work. Requirements for Pellets. Physical Strength – (Crush and handling)
E N D
Ochre Pelletising and use for phosphate Removal from sewage effluent 2nd February 2005 Jonathan Aumônier
Introduction • Pelletising Process • Lab results – phosphate removal • Micrographs • Windlestone trial • Planned work
Requirements for Pellets • Physical Strength – (Crush and handling) • Resistance to degredation in water • Resistance to degredation through biological activity • Size • Retained Reactivity of Ochre • Retained Phosphate Capacity • High Porosity • No “Film” or “Matrix” Binder System • No Leaching of metals
Extrusion Trial ‘Z’ Blade Mixer-Extruder Cutting Extruded Product Mixer Blades
Pan Pelletising Water & Liquid Binder Powder Feed Pan Angle Θ Product Θ Rotational Speed ω Small Pellets Water & Liquid Binder Powder Feed Large Pellets
Pelletising Equipment Dust Extraction Vibrating Hopper 70cm Diameter Pelletising Pan Variable Speed Helical Feed Screw ASDA Washing-up Bowl
Ochre Sources and use Skinningrove - initial physical test Silwood - MScs - 1st Nafferton Farm trial Acomb - Current lab work - 2/3 of Windlestone pellets - Some to Leitholm Polkemet - 1/3 of windlestone pellets - Leitholm Horden - 1/3 of Leitholm - ESL Nafferton Farm - Stock of pellets
Phosphate remover from solution with varying initial P – after 24 hours P removed (mg/l) Initial P (mg/l) Data from Lawrence Bowden
Rate of phosphate sorption Phosphate load on pellets (mg_P/g) Time (s) Data from Lawrence Bowden
Rapid P Sorption tests Feed Concentration 1 mg/l P Solution Concentration (mg/l P) Residence time (s) Data from Frances Brett
Phosphate removed from solution with varying ionic strength of KCl 100% % Removal 80% Molar strength of solution KCl Data from Lawrence Bowden
Windlestone trial details(Horizontal Flow) • Feed taken from site final effluent • Initial rate 2.7 m3/hr reduced to 0.75 m3/hr • 0.96 m3 of pellets • Contact time 7½min increased to 24 min • Sampled input and output every 25 hr
Windlestone trial details(Vertical Flow) • Feed taken from site final effluent • Flow Rate 0.75 m3/hr • 0.88 m3 of pellets • Mean contact time 90 second (unsaturated flow) • Mean contact time 25 minutes (fully saturated flow) • Sampled input and output every 25 hr
Ochre pellet reaction vessel: Windlestone WWTW – Horizontal Flow Effluent percolates through ochre Inflow Outflow Gravel Images: Jonathan Aumônier Slide: Kate Heal
Final STW Sump at Windlestone Outlet from Trial Inlet for Trial
Results for Windlestone Trial(Horizontal Flow) Feed Phosphate Mg/l P Removal Fraction Date
Windlestone spot resultsResults from samples after maintenance to clear the overflow
Ochre pellet reaction vessel: Windlestone WWTW – Vertical Flow Inlet Pipe From Pump In-line Strainer Inlet Sample Line Spray Bars
Spray Bar Inlet - 0.75 m3/hr 500mm Saturated Zone U Bend Outlet Ochre pellet reaction vessel: Windlestone WWTW – Vertical Flow
Results for Windlestone Trial(Vertical Unsaturated Flow) 0.75 m3/hr mean residence time 90 sec Feed Phosphate Mg/l P Removal Fraction Date Mean Removal 26%
Planned Work • Continue Windlestone trial with saturated flow • More locations • Laboratory tests on ochres and binders • Laboratory continual flow trials