"Milorganite" search will get one dedicated and a few mentions in other topics. It is for those who never heard of it, processed and dried waste water sludge, made and sold as fertilizer by the city of Milwaukee.
There are some concerns about drug, chemical and hormonal residue(s) in the product and it's not recommended for use on food crops for that reason.
They say it is the leftover "dead" microbes from the treatment process which is true in part. I was a wastewater operator for near 14 years and know full well what's left over.
They also use a de-watering polymer in end processing. These polymers may be toxic to aquatic life as labeled (the specific type/brand they use is not known to me), and earthworms, according to my own trials years ago when our facility changed processes. Worms won't touch dewatered sludge with polymer, even when composted with sawdust. That does not fill me with confidence for the safety of it.
All that said, plants love the stuff. I have personally used quite a bit of the equivalent over the years for various things, one of the best was some sunflowers with stalks near the size of coke cans and 12 ft tall.
Our old treatment facility was built around 1970 and was a big round tank with an inner clarifier. The outer ring, divided by three walls, served as aeration via airlifts in two portions and waste sludge containment in another.
Every year, there would be tomato seeds sprout along the splash line of the outer ring, the roots only having a few rusty cracks to cling to, some would survive and grow up and over the wall, nearly to the ground. They also made big fruits but nobody, not even I would eat them.
That old sludge would be drained off periodically to sand pit drying beds. When I arrived at the city and started the care of the place, there was a huge pile of dried sludge mixed with sand under a pole shed with concrete floor. I found worms really liked this stuff and they started processing. Soon there were rows of worms and then the flood came...
Well, back on topic. What really is Milorganite? Basically it's dead microbes, living microbes and dried human waste with all the microbe digestible components gone out of it, given the process is functioning well. It's full of plant available nutrients, plus residues of everything else that goes down the drains and through the bodies of people and sometimes animals and/or their parts.
So I'm now going to tell you a big secret lol. If you ever have made compost tea, you have made liquid Milorganite. It's the same process of aeration of the same microbes present in wastewater facilities within a nutrient rich solution.
We put molasses in as the additional food source for compost/worm tea so the bugs will keep multiplying as they eat up the food. I forget just how fast they do multiply/die but it has a lot to do with temperature and other factors.
There. Now you have a Milorganite substitute without fear of all the nasties. Your own liquid quality as fertilizer will depend on the components used of course. I have some brewing in a five gallon pail right now with compost, worm castings, pelleted organic fertilizer and molasses. It will be filtered and used in my sprayer as needed out of the bucket and be diluted to a weak tea color. I'll keep it going out in the garage all winter.
You know it's working well when there are no foul odors. That's a sign of good aerobic activity. Milorganite stinks because it has gone from aerobic to anaerobic in the drying process or end storage, as some processes use anaerobic bacteria in some processes and holding tanks.
One may be surprised at having the ability to add stinky things to an aerated bucket and notice how quickly the smell goes away. A well functioning facility has no foul odor at all, same as a good compost tea bucket.
If your DIY starts to smell foul, increase the air. Foaming is to be expected, those are the microbes multiplying and dying. So keep the bucket level to no more than 4 gallons to allow for the "head" of foam you will get, or it will spill out in the floor lol.
It doesn't store well, that is if you want to keep it good smelling. Should be applied fresh to roots and foliar spray, full of aerobic bacteria, and chitin present if quality worm casts are used. :)