The technology consists of sand filters impregnated with special bacteria which absorb or precipitate something over eighty percent of heavy metals such as zinc, copper and aluminium. Moreover, unlike with existing technologies, that absorption rate can be maintained indefinitely, due to the continuous cleaning system incorporated in the filter. That system is not only highly effective but it also refrains from inflicting any damage on the bacteria themselves, which continue to grow on the sand thanks to a continuous feeding process. This technology offers a cheap, cost-effective way for companies such as metal processing and mining companies to abide by the latest European environmental regulations and thereby minimize the amount of tax they pay for discharging heavy metals. Moreover, the reduction in pollution represents good news for the environment in general and human health in particular, heavy metals being suspected carcinogens. There even exists the possibility of reclaiming and reusing the metals from the sludge released in the filter-washing process, thus eliminating completely the problem of their safe disposal.