No one can know what will come out of the treatment system into the sludge at any given moment. EPA's 503 regulations are meaningless as a mechanism for protecting land, people, and other life forms from the hazards of sewage sludge. It is of course true that our species has gone far already toward fundamental disruption of the metabolisms of living organisms, including humans. And separation at the source is the only way to begin to prevent the trouble now caused by this ill-mixed mess of matter. Communities need to take the political initiative to insist that failing septic systems must be fixed up by on-site technologies.
Many options exist for on-site remediation of failing or polluting septic systems.
These should be funded by the Clean Water Act, whose public funds are presently only available for sewers. Second, sludge which is still being produced by existing treatment plants should either be isolated in secure storage or processed through the use of advancing technologies such as gasification. So, avoiding sewers to begin with is the first serious act of cost saving. EPA has placed a 20 year limit on the spreading of sludge on farmland. It is unconscionable to use life this way.