We’re flushing gold down the toilet - let’s try another way
Yes, and there are additional reasons to better manage our humanure. We live on a finite planet so we face finite artificial fertilizer https://energyskeptic.com/2022/limits-to-growth-natural-gas-fertilizer-that-feeds-4-billion-of-us/ https://energyskeptic.com/2020/phosphate-production-and-depletion/. We would want to make sure that the more natural treatment options also end up making fertilizer that we can reuse to grow food.
I'm not familiar with how the City accounts for moving water around dollarwise, but we also have to face finite and most likely declining energy. It would be imprudent to assume we will always have sufficient energy to pump water up from Lake Ontario, especially then to just flush it down the toilet or irrigate lawns.
For a City that is supposedly in a Climate Emergency, the bylaw situation is just catastrophic. Unfortunately the bylaws are very difficult to fight legally, partly because there are no Charter Rights to protect the environment or minimize one's energy use. If Toronto were serious about fighting climate change and/or protecting the environment they could pass a bylaw that reads some rights into the Charter when interpreting City Bylaws in the courts. For example a Charter 2e the right to minimize one's energy use. Considering how energy intensive flush toilet are this might give some leverage to challenge the bylaw restrictions on composting toilets. Of course you would have to get to court first. Toronto typically proceeds administratively on bylaws as opposed to bringing charges so bylaws are typically only in court by judicial review which is stacked in favour of the bylaws. Toronto bylaws also need a right to elect charges for those that don't want to knuckle under to administrative enforcement.
I remember once, in the early 80s, yarning with some other young marrieds about the surprises of first housebuyings. Mine was about discovering the holes every six inches around the entire outside, and then the snaking grooves in the floor under the broadloom in the second bedroom. The evening's winner was about a recently purchased house in Parkdale, with the garden shed that turned out to be an outhouse, and no indoor toilet..
A reader just pointed me to a really interesting example of this in China: https://www.researchgate.net/figure/The-Baima-Canal-Eco-machine-Fuzhou-China-To-address-commercial-wastewater-and-sewage_fig1_265205618, which led me to another citizen led project closer to home in NYC: https://www.gessato.com/jerko-the-gowanus-water-vacuum/