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ONSITE TREATMENT METHODS FOR REMOVAL AND RECOVERY OF MACRONUTRIENTS (N/P) FROM WASTEWATER. Sukalyan Sengupta Professor & Chairperson Civil & Environmental Engineering Department University of Massachusetts Dartmouth. SOME I/A SYSTEMS TO REDUCE NITROGEN IN ONSITE EFFLUENT.
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ONSITE TREATMENT METHODS FOR REMOVAL AND RECOVERY OF MACRONUTRIENTS (N/P) FROM WASTEWATER SukalyanSengupta Professor & Chairperson Civil & Environmental Engineering Department University of Massachusetts Dartmouth Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
SOME I/A SYSTEMS TO REDUCE NITROGEN IN ONSITE EFFLUENT Heterotrophic Denitrification • Requires an organic carbon source for energy metabolism and cell synthesis: • C in wastewater + NO3- N2 + C5H7O2N Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Waterloo Biofilter Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
AquapointBioclere Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Technology Influent Total Nitrogen (mg/L) as N Effluent Total Nitrogen (mg/L as N) % Of Nitrogen Removal Conventional Title 5 System 34.6 26.6 23 Waterloo Biofilter 35.1 12.5 64 Amphidrome 35.3 12.1 66 Biomicrobics MicroFAST 34.1 14.6 57 ECO-RUCK 34.8 34.9 UP Nitrogen Removal Efficiencies of a Title 5 System and 4 I/A Techs. Influent Total Nitrogen = NH4+ + NOx + DON + PON UP = Unsatisfactory Performance BOD5 - Average = 180 mg/L Total Suspended Solids – Average = 150 mg/L Hydraulic Loading Rate = 0.74 gal/ft2/day– Based on NSF 40 protocol
SULFUR-OXIDIZING DENITRIFICATION 55S0 + 20CO2 + 50NO3- + 38H2O +4NH4+ 4C5H7O2N + 55SO42- + 25N2 + 64H+ ADVANTAGES: • High nitrate removal efficiencies • Elemental sulfur, which is a by-product of oil processing, is less expensive than ethanol or methanol • No external carbon source is required, minimizing the possibility of carry-over of excess organic carbon into the effluent • Sulfur oxidizing denitrification can take place under aerobic conditions, no need to deoxygenate the influent • Less sludge produced due to lower biomass yields • Autotrophic sulfur oxidizing denitrifying bacteria produce less N2O (a greenhouse gas) than heterotrophic denitrifying bacteria Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
SOLID-PHASE SOURCES OF ALKALINITY • Limestone • Marble Chips • Crushed Oyster Shell Both laboratory-Scale and Field-Scale Tests Performed Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Massachusetts Alternative Septic System Test Center (MASSTC) • At Otis ANG Base Sandwich, MA. • Assessment of Innovative/Alternative on-site wastewater technologies. • Pilot scale bioreactor tests run for 18 months.
MASSTC Pilot Tests Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
FIELD - SCALE TEST RESULTS Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
FIELD - SCALE TEST RESULTS Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
FIELD - SCALE TEST RESULTS Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
FIELD - SCALE TEST RESULTS Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
FIELD - SCALE TEST RESULTS Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
CONCLUSIONS • High denitrification rates could be achieved in a sulfur-oxidizing bioreactor system treating nitrified wastewater with an EBCT of eight hours and sufficient pH buffering. • Crushed oyster shell is the most suitable solid-phase buffer in sulfur-oxidizing autotrophic denitrification systems based on the criteria of (i) dissolution rate, (ii) effluent turbidity, and (iii) economics.. • Material characterization studies (SEM, EDX, and XRD) clearly demonstrate that in crushed oyster shell, (i) the presence of various crystalline phases of calcite (CaCO3), (ii) nano-flakes of calcite, and (iii) the binding action of shell proteins to calcite, contribute to controlled release of buffer and its suitability for this application scenario. • pH and alkalinity can act as process-control variables. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
USE OF BIORETENTION SYSTEMS TO CONTROL NONPOINT SOURCES OF NITROGEN Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Stormwater Structural Best Management Practices* • Swales • Wetlands • Infiltration basins • Media filters • Porous pavement • Bioretention systems • Data available on flow reduction, travel time delays, solids and organics removal • Little data on nutrient removal • Conventional bioretention systems: • 70-85% P, 55-65% TKN, < 20% NO3- /NO2- *UNH stormwater center 2007 annual report
Five Distinct Regions: • Ponding: maintains hydraulic loading • Top Soil & Mulch • Nitrification: aerobic sand layer • Denitrification • Autotrophic (Sulfur + Oyster) • Heterotrophic (wood chips and sand mix – Denyte) • Stone Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Nitrification NH4+ + O2 + CO2 NO3- + H+ + H2O + new cells • Inorganic electron donor (NH4+) • O2 is electron acceptor • Carried out in aerobic sand layer • Autotrophic metabolism (inorganic C source – CO2) • Alkalinity consumed during process Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Heterotrophic Denitrifying Bioreactor Organic carbon + NO3- + H+ N2 + CO2 + H2O + new cells • Organic electron donor • Wood chip/sand mixture • NO3- electron acceptor • Process generates alkalinity • High growth and denitrification rates Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Autotrophic Denitrifying Bioreactor 55S0 + 20CO2 + 50NO3- + 38H2O +4NH4+ 4C5H7O2N + 55SO42- + 25N2 + 64H+ • Mixture of Sulfur and Crushed Oyster Shell • Autotrophic metabolism • Low biomass generation • Excellent packing material • Process consumes alkalinity – oyster shell provides alkalinity source
Methods: Laboratory Storm Events • Feed – literature values based on urban runoff (Davis et al., 2001; Hsieh and Davis, 2005) • Application – average W Mass storm event & 0.75% bioretention surface area • Influent & effluent: pH, TALK, BOD, COD, TSS, VSS, TN, NH4+, NO3-, NO2- Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Total N Removal in Simulated Storm Event Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Nutrients: Simulated Storm Event • Excellent N and P removal similar to those observed in other studies. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Organics & Solids: Simulated Storm Event • Some generation of organics and solids due to leaching from organic material, production of soluble microbial products. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Field Site: Putnam CT • Dairy farm in Putnam, CT • Runoff from barn conveyed to detention pond • Reactors used to treat detention pond water
Total Nitrogen Removal N P BOD TSS CH4 CH4 CO2 Concentration of TN over time during typical field test Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Field Tests – Nutrients Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Field Results – Organics, Solids & Metals • * Approximately 56% TN, 14% TP and 55% COD removal due to removal of solids • Hydrolysis of dissolved and particulate organic N appears to be rate limiting. • Current research focused on pretreatment to remove organic C, and hydrolyze organic N. • ND =Non-Detect, Detection Limit = 0.10 mg/L by AA flame method. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Change in Sampling Procedure A battery operated timer was installed to control the influent flow to the field reactors for dosing the units at scheduled intervals for better activation of the microbial community and to more closely simulate conditions expected of a bio-retention system. Operating Parameters • Flow Rate: 100 ml/min • Days of Operation: Tuesday, Thursday, Saturday • Time of Operation: 8:00 , 9:00, 10:00, 11:00,12:00 • Duration: 21 minutes on • 39 minutes off • Loading Rate: 0.035 cm3/cm2-min • Sample Collection: 11:00, 12:00 Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Field Tests – Nutrients Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Field Tests – Organics, Solids, & Microbial Contaminants Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Conclusions – Bioretention Systems • Initial steps taken in developing a low cost, low maintenance, passive system for total N removal in stormwater. • Laboratory results indicate >90% TN removal achievable for runoff from developed land, fertilized fields. • Treatment of runoff from livestock operations challenging – low rates of organic N hydrolysis. • Bench scale tests currently focused on increasing ammonification rates. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Selective Removal of Phosphorus from Wastewater Combined with Its Recovery as a Solid-Phase Fertilizer Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
P Limits: 70µg/L – Boise 42 µg/L – Spokane 10 µg/L - Everglades Chemical Precipitation:Moles Al/Fe/Mole P 100 – 200 Sludge disposal?? Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Phosphorus Supplies • Phosphorus is being consumed faster than geological cycles can replenish it. • Approximately 80% of global phosphorus deposits are concentrated in three countries: Morocco, China, and the US. • Some studies predict global supplies of phosphorus may start running out at the end of this century. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Physical-Chemical Adsorption/ Sorption • Removal mechanisms: • Electrostatic interaction • Lewis acid-base interaction/Ligand exchange • Materials Studied: • Metal hydroxides (Al, Fe, Zr, etc.) • Alum sludge • Blast furnace slag • Fly-ash • Gas concrete Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Ligand Exchange • Oxides of polyvalent metals exhibit strong ligand (Lewis bases) sorption properties (Lewis acids) through formation of inner sphere complexes. • Ortho-phosphate molecules containing one or more lone pairs of electrons in the highest occupied molecular orbital depending on the degree of dissociation are strong ligands. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Development of Polymeric Ligand Exchangers (PLEs) • Limitations faced: • Granular metal oxides lack the mechanical strength and attrition resistance properties for prolonged operation. • Commercial anion exchangers show poor selectivity for phosphate over other competing anions, like sulfate. • Development of PLEs: • PLEs combine the sorption affinity of these metal oxides with the durability and mechanical strength of the ion exchanger. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Iron-Oxide-Impregnated PLE H N N N H N N N Cu2+
Schematic of Complexation of Phosphate Competing sulfate and chloride ions only form outer sphere complexes due to Coulombic interaction. This reverses the tendency of preferential uptake of sulfate over phosphate by the resin. Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011
Effect of SO42- Presence on PO43- Sorption Global Innovation Imperatives, IWSWQ, Delhi, Jan. 17-20, 2011