void findSFLinkQual(int i, double tStep)
//
// Input: i = link index
// tStep = routing time step (sec)
// Output: none
// Purpose: finds new quality in a link at end of the current time step for
// Steady Flow routing.
//
{
int j = Link[i].node1;
int p;
double c1, c2;
double lossRate;
double t = tStep;
// --- for each pollutant
for (p = 0; p < Nobjects[POLLUT]; p++)
{
// --- conduit's quality equals upstream node quality
c1 = Node[j].newQual[p];
c2 = c1;
// --- apply first-order decay over travel time
if ( Pollut[p].kDecay > 0.0 )
{
c2 = c1 * exp(-Pollut[p].kDecay * t);
c2 = MAX(0.0, c2);
lossRate = (c1 - c2) * Link[i].newFlow;
massbal_addReactedMass(p, lossRate);
}
Link[i].newQual[p] = c2;
}
}
double getReactedQual(int p, double c, double v1, double tStep)
//
// Input: p = pollutant index
// c = initial concentration (mass/ft3)
// v1 = initial volume (ft3)
// tStep = time step (sec)
// Output: none
// Purpose: applies a first order reaction to a pollutant over a given
// time step.
//
{
double c2, lossRate;
double kDecay = Pollut[p].kDecay;
if ( kDecay == 0.0 ) return c;
c2 = c * (1.0 - kDecay * tStep);
c2 = MAX(0.0, c2);
lossRate = (c - c2) * v1 / tStep;
massbal_addReactedMass(p, lossRate);
return c2;
}
void treatmnt_treat(int j, double q, double v, double tStep)
//
// Input: j = node index
// q = inflow to node (cfs)
// v = volume of node (ft3)
// tStep = routing time step (sec)
// Output: none
// Purpose: updates pollutant concentrations at a node after treatment.
//
{
int p; // pollutant index
double cOut; // concentration after treatment
// double cLost; // concentration lost by treatment //(5.0.017 - LR)
double massLost; // mass lost by treatment per time step
// --- set global variables for node j
if ( Node[j].treatment == NULL ) return;
ErrCode = 0;
J = j; // current node
Dt = tStep; // current time step
Q = q; // current inflow rate
V = v; // current node volume
// --- initialze each removal to indicate no value
for ( p=0; p<Nobjects[POLLUT]; p++) R[p] = -1.0;
// --- determine removal of each pollutant
for ( p=0; p<Nobjects[POLLUT]; p++)
{
// --- removal is zero if there is no treatment equation
Treatment = &Node[j].treatment[p];
if ( Treatment->equation == NULL ) R[p] = 0.0;
// --- otherwise evaluate the treatment expression to find R[p]
else getRemoval(p);
}
// --- check for error condition
if ( ErrCode == ERR_CYCLIC_TREATMENT )
{
report_writeErrorMsg(ERR_CYCLIC_TREATMENT, Node[J].ID);
}
// --- update nodal concentrations and mass balances
else for ( p=0; p<Nobjects[POLLUT]; p++ )
{
if ( R[p] == 0.0 ) continue;
// --- removal-type treatment equations get applied to inflow stream
if ( Treatment->treatType == REMOVAL )
{
// --- if no pollutant in inflow then cOut is current nodal concen.
if ( Cin[p] == 0.0 ) cOut = Node[j].newQual[p];
// --- otherwise apply removal to influent concen.
else cOut = (1.0 - R[p]) * Cin[p];
// --- cOut can't be greater than mixture concen. at node
// (i.e., in case node is a storage unit)
cOut = MIN(cOut, Node[j].newQual[p]);
}
// --- concentration-type equations get applied to nodal concentration
else
{
cOut = (1.0 - R[p]) * Node[j].newQual[p];
}
// --- mass lost must account for any initial mass in storage //(5.0.017 - LR)
massLost = (Cin[p]*q*tStep + Node[j].oldQual[p]*Node[j].oldVolume - //(5.0.017 - LR)
cOut*(q*tStep + Node[j].oldVolume)) / tStep; //(5.0.017 - LR)
massLost = MAX(0.0, massLost); //(5.0.017 - LR)
// --- add mass loss to mass balance totals and revise nodal concentration
massbal_addReactedMass(p, massLost);
Node[j].newQual[p] = cOut;
}
}
