The way Western societies dispose of their sewage is crazy. What could have been an excellent fertiliser and soil conditioner becomes instead an environmental catastrophe. Industry uses 70,000 chemicals in commercial quantities, any of which can turn up in the sludge left behind in modern sewage processes. It is possible to compost your household wastes into a smell-free product that can be used as agricultural fertiliser.
Larger buildings can use anaerobic digesters producing fertiliser.
Water should be higher priced so that the market works to keep it clean, rather than contaminating it. Each machine typically involves a series of cylinder-contained ecologies which are linked by connector tubes filled with water. Wastes generated by the organisms in one cylinder flow down the tubes and then become food for those that inhabit the next cylinder. In this way, waste compounds are broken down using sunlight as the primary source of energy. In Providence, Rhode Island, for example, OAI have set up a sewage treatment plant that uses snails to break down the heavy metals used in the manufacture of costume jewellery.