C. Vandenbrink et Wj. Zaadnoordijk, NONEQUILIBRIUM TRANSPORT AND SORPTION OF ORGANIC-CHEMICALS DURING AQUIFER REMEDIATION, Hydrological sciences journal, 42(2), 1997, pp. 245-264
Aquifer remediation operations are often behind schedule. Usually, a r
ather sharp concentration decrease shortly after the start of an opera
tion is followed by a situation in which hardly any concentration decr
ease is observed. Furthermore, the concentration increases after stopp
ing the groundwater recovery. These phenomena are caused by so-called
tailing. An important cause of tailing is the phenomenon that equilibr
ium is not reached for some of the transport and sorption processes in
volved. To predict these effects of tailing, IWACO has developed a pro
gram SORWACO, which describes the behaviour of solutes along a path li
ne. Processes for which equilibrium is reached quickly as well as proc
esses for which equilibrium is reached only slowly are taken into acco
unt. The program has been verified against breakthrough curves observe
d in column experiments reported in the literature. The program parame
ters were calibrated using the data of several experiments. The result
ing set of parameter values accurately described the transport for dif
ferent flow velocities. The fact that quite good results can be obtain
ed without a lot of data from a specific site makes the program a valu
able tool for the design of remediation operations. The program is esp
ecially useful when extensive input data are not available so that det
ailed three-dimensional or stochastic models cannot be applied. The us
e of the program is illustrated by means of a case study. The progress
was monitored and the data show good correspondence with the predicti
ons of the program.