Here is an example of applying a filter to a dc chart: http://jsfiddle.net/djmartin_umich/5Lvcq/
I simply added the code that Lars referred to after the dc.renderAll().
First retrieve the chart svg:
var defs = rowChart.svg().append("defs");
Next define the filter:
var filter = defs.append("filter")
.attr("id", "drop-shadow")
.attr("height", "150%")
.attr("width", "200%");
filter.append("feGaussianBlur")
.attr("in", "SourceAlpha")
.attr("stdDeviation", 5)
.attr("result", "blur");
filter.append("feOffset")
.attr("in", "blur")
.attr("dx", 5)
.attr("dy", 5)
.attr("result", "offsetBlur");
var feMerge = filter.append("feMerge");
feMerge.append("feMergeNode")
.attr("in", "offsetBlur");
feMerge.append("feMergeNode")
.attr("in", "SourceGraphic");
Finally, apply the filter to the rows:
rowChart.selectAll("rect")
.style("filter", "url(#drop-shadow)");
Hopefully the example at http://jsfiddle.net/djmartin_umich/5Lvcq/ helps you get going.