This study evaluates, under field conditions, the efficiency of a permeable reactive barrier (PRB) with compost and brown coal to remove trichloroethylene (TCE) (109 µg/L) from contaminated groundwater. Three stainless steel boxes (1.2 × 0.5 × 0.5 m) with the brown coal-compost mixture at three different mixing ratios of 1:1, 1:3, and 1:5 (by volume) were installed to simulate the PRB. Groundwater from the TCE-contaminated aquifer was pumped into the system at a flow rate of 3.6 L/h. Residence times in the boxes were of: 25, 20, 10 h, respectively. Effluent samples were analyzed for TCE and its daughter products: dichloroethylene (DCE), vinyl chloride (VC) and ethane. During the 198-day experimental period TCE concentrations in groundwater decreased below ≤1.1 µg/L, i.e., much lower than groundwater and drinking water standards in Poland. After 16 days cis-1,2-DCE was monitored indicating possible reductive dechlorination of TCE. However, complete transformation of TCE into non-toxic byproducts was not evidenced during the time of experiments, indicating that reductive dechlorination slowed down or stopped at DCE, and that the designed residence times were not long enough to allow the complete dechlorination process.

As a result of the implementation of the Water Framework Directive and the Groundwater Directive, and the consequent restriction of Polish law regulations, groundwater contamination with trichloroethylene (TCE) and tetrachloroethylene (PCE) was detected at numerous sites in Poland, including groundwater in the vicinity of the waterworks in Nowa Dęba. It is expected that the problem will growth with time as it was observed in the other European countries and the USA in the 80's and 90's, after implementation of drinking water standards for TCE and PCE. Consequently, there is an increasing need to investigate these sites and the effects of contaminants in groundwater, especially on these sites where groundwater is used as a resource of drinking water.