Raw sewage sludge needs to be thoroughly digested (basically left to detiorate and breakdown either aerobically or anerobically) for a long period of time, before it could even be considered safe for growing food crops. It contains all sorts of nasty pathogens that could be very harmful or even devastating to humans if fruit or veggy crops that it was applied to are ingested.
I worked in the wastewater field for over 30 years, so am well aware of the good, the bad, and the smelly of this subject. We had a HUGE storage pit (over 3 acres in area, and approximately 50-60 feet deep) where we pumped and stored aged sludge to further breakdown. We'd let it settle out, pump the excess water off the top, and then pump in more aged sludge.....repeating continuously. When the sludge in the pit would reach near maximum capacity.....after several years of sitting.....we hired a company to come in, dredge the pit, haul it off in 5000-6000 gallon tanker trucks, and land apply it to farm fields in our area......200K-300K gallons of sludge per day (that's roughly 270+/- dry tons).
The farm fields would have soil tests and analysis done before application, and then after the thoroughly digested sludge (now referred to as bio-solids at this point of the treatment process) was 'knifed in' (applied about 12 inches below the surface of the field), a predetermined amount of lime would be spread over that field to balance out the pH. Normally, the field was done in the fall after the crop was harvested, so the bio-solids would have all winter to work it's wonders.
As far as using it on your families veggie gardens.....I wouldn't! You're better off using well composted
cow or horse manure. Less of a risk for pathogenic contamination.
That's the only 'commercial' fertilizer that I use on my lawn and gardens......twice a year. It's all natural, and won't 'burn' your lawn if accidentally applied to heavily. And unlike chemical fertilizers, it won't build up chemical salts in the soil, that will eventually destroy instead of benefit, your lawn. My neighbor has been fertilizing his lawn with the chemical cr*p for years now, and always wonders why his lawn isn't nearly as nice and lush as mine. Other than our fertilizers, both lawns are taken care of exactly the same....same mowing, watering (or actually lack thereof), amount of sun/shade, etc. I've tried to get him to change over to Milorganite, but he's set in his chemical ways.