Hi David, Something weird is going on with my phreeqc simulations. Biodegradation will work if coupled with dispersion, sorption, and/or gas phase. It will NOT work if I take those processes out. The error I'm getting is that there are negative moles in solution after transport step 9. How can there be negative moles in solution if I have the line "If Benzene <= 0 then goto 200?" I've changed the 0 to 1e-30, 1e-10, etc. and it seems that phreeqc isn't even reading that line. Any suggestions? Attached is my input file (not deck!!):) Thanks a lot, Margaret Dodds
SOLUTION 0 Pulse solution leachate #solution injected units ppb pH 7.0 density 1.00 temp 10.0 Benzene 13.4 Benzdp 0.0 END SOLUTION 1-10 Background solution initially filling column units ppb pH 7.0 density 1.00 temp 10.0 END SELECTED_OUTPUT -file grid2.csv -selected_out true -high_precision false # set value for all indentifiers to follow (lines 1 - 6) -reset true -simulation true -state true -solution true -distance true -time true -distance true -step true -percent_error true -totals Benzene Benzdp -gases Benzene(g) END #SURFACE 1-128 # Surfa_sH2O 20.9 300 20.9 #GAS_PHASE 1-128 # -fixed_volume # -volume 1.0 # Benzene(g) 0.0 # CO2(g) 0.000316 # N2(g) 0.78 # O2(g) 0.2 KINETICS 1-10 Benzene -formula Benzene -1.0 Benzdp 1.0 # -tol 1.0E-25 -M 1.71E-7 -M0 1.71E-7 INCREMENTAL_REACTIONS true RATES Benzene -start 10 Benzene = TOT("Benzene") 20 if (Benzene < 0)then goto 200 30 rate = (-2.5/(60*60*24))*Benzene #day-1 to sec-1 40 moles = rate*TIME 50 if (moles < Benzene) then moles = Benzene 200 SAVE moles -end TRANSPORT Pulsing of Solution 0 -cells 10 -shifts 10 -time_step 4.93E5 -flow_direction forward -boundary_conditions flux flux -length 10*1 -dispersivities 10*0.1 -correct_disp true -diffusion_coefficient 0.3e-9 -stagnant 0 -thermal_diffusion 1 -initial_time 0 -print_cells 10 -print_frequency 1 -punch_cells 1-10 -punch_frequency 1 END
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