The more I consider current practice in water and sanitation (particularly in my own city - Brisbane, Queensland, Australia) the more ludicrous it becomes...
Most of our potable water is sourced from dams in the hinterland. There are plans to build another dam over a hundred kilometres North of Brisbane. Yet the storm water that falls on the city of Brisbane (mostly on impervious, paved surfaces is channelled to the Brisbane River, mixes with the estuarine, brackish water and flows out to sea.
A de-salination plant 100 kilometres South, draws saline water from the ocean and uses electricity to purify the sea water and pump it into the so-called "water grid".
Taking a relatively solid reside, which contains some of the most harmful bacteria known to humanity and making a 1-2% slurry, solution, pumped hundreds of kilometres to centralised sewage treatment plants is a very inefficient use of electicity and potable water.
In Brisbane, we currently purify the sewage treatment plant effluent with an energy intensive process called Continuous Mirofiltration, followed by reverse osmosis. The lunacy continues with the purified water being pumped over 70 kilometres to be used to cool the exhaust from the steam turbines of a coal fired power station.
My background is in industrial water treatment (steam generation, heat rejection, process water, corrosion mitigation, anti-scalants, emulsion breaking etc). When I apply the principles of "cleaner production" to domestic sewage treatment, the first thing that needs to be done is separation of waste streams.
In other words, no.1's need to be kept separate from no.2's.
Adding a concentrated source of Nitogen, Phosphorus and trace quantities of endrocrine disruptors to this mix is sheer stupidity, considering the difficulty ond expense of removing the N.P and endrocrine disruptors from the dilute stream.
So what is the alternative?
I understand that Urine-separating toilets have been used as an effective source control measure in many parts of Europe for years. The No.1's can be collected and used beneficially as fertiliser and are a precursor to many industrial chemicals including ammonia, pool chlorine and/or bleach.
The No.2's contain many pathogens, which can be disinfected through dessication and/or heat. Once treated, this residue is a useful soil conditioner and source of organic material. It could even be digested and the biogases could be used to generate electricity.
There is billions of dollars tied up in the infrastructure that perpetuates this system. There is inertia and resistance to change. So just because this is the way it is always been done, does not mean we have to keep doing it this way.
Subvert the dominant paradigm. Lobby your local Authorities and install a urine separation toilet.