While residual medications don’t belong in the water, trace
metals from industrial process waters handled by the recycling industry are, in
contrast, valuable resources. Scientists at the Helmholtz-Zentrum
Dresden-Rossendorf (HZDR) have developed a simple color sensor principle which
facilitates the easy detection of both materials as well as many other
substances. This is the concept: If the analyzed sample shines red, then the
water is ‘clean;’ if its color turns green, however, then it contains the
substances the scientists wish to detect.