When growth isn't backed up by infrastructure...

It's going to happen here too.

It doesn't have to. There is a term worth looking up, http://en.wikipedia.org/wiki/Bioremediation

Bioremediation is the process of encouraging a specific ecosystem to take round that is not much good, and make it safe. The article talks mostly about its role in restoring ground that's been contaminated by industrial processes, but it also works if, say, sewage was pumped onto a dedicated patch of ground, rather than down the sewers.

A much smaller scale example is the Tree Bog: http://en.wikipedia.org/wiki/Tree_bog

Basically, pretty much all plants form a symbiotic relationship with specific soil borne micro-organisms and fungi, and those microbes and fungi consume certain minerals and release chemicals that are harmful to certain pathogens etc. Someone figured out that between willow and comfrey, you can get the right eco-system on the go to very rapidly turn human poo into completely safe compost.

In parts of europe, sewage is routinely dealt with pouring it onto dedicated pieces of ground, where natural processes make it harmless very quickly. I'm not sure how widespread the tree bog is though.

In the UK, we are going to have a massive problem in a few years despite these principles, simply because us Brits (by and large) have become so terrified of change, and so detached from nature, and so obsessed with hygiene that the very idea of a tree bog will have most people physically repulsed, so we'll just have to stick with the status quo until it is broken enough for the masses to actually start considering alternatives.

 

Good for the haulage company if they charge waiting time after 2 hours

 

I feel very optimistic about human waste being recycled somehow, preferably in a way so that the smell is not under our noses.

 

Human waste is currently recycled. Its used for all sorts. Including, much to the shock horror of many, cosmetics.

The solids are separated into their constituent parts, and some becomes fuel, some becomes fertiliser, some goes off to the make-up factories etc.

The trouble is getting it to the sewage works, and from there, getting rid of the mucky water. To get it to the sewage works it goes down massive pipes that run for miles and miles, and regularly clog up so someone gets the unpleasant job of going in with breathing gear and all the rest, and has to scrape caked on poo off the walls. Its not sustainable.

 

I don't know. You'd still need all the pipes, just taking the stuff to more local works instead of fewer centralised ones. Then there's the problem of where to build the extra sewage plants, and the cost, and unfortunately, the smell. It could only possibly work if the local sewage plants were as close as possible to the houses they served, but that would meet a lot of resistance because nobody wants a sewage plant on their doorstep.