SLUDGE QUALITY FROM MUNICIPAL WASTEWATER TREATMENT PLANTS IN SWEDEN – PAST AND FUTURE TRENDS
The current debate concerning land application of sewage sludge is briefly reviewed. Of major concern in the public debate today is the presence of organic micro-pollutants in the sludge. Sludge quality data from Swedish plants related to trends in contents of heavy metals, PCB and DDT are discussed. A large decrease can be noted. This is mainly due to an efficient control and regulation of wastewater from large industries. From the compiled data over organic priority pollutants in sludge and sewage water, no clear sources can so far be pointed out, mainly due to the limited data material. However, it indicated that neither by authorities uncontrolled industries, workshops, petrol stations etc. nor households cannot be excluded as important sources for this group of pollutants.