How does the cost of wastewater treatment scale?

Question

Is it the case that some of the energy expenditure associated with wastewater treatment is more proportional to the amount/type of waste than to the amount of treated water (meaning that my water has a lower marginal cost than a unit of water used for washing/flushing)?

When I say "energy expenditure," I'm also interested in embodied energy of treatment chemicals. I'm particularly interested in US cities.

If you want to include analysis of "fixed-cost" things like building the plant, precluded alternative land uses due to the plant, etc., feel free.

Answer 1

On an industrial scale, wastewater treatment costs vary on region, labor and desired water quality. Capital costs are the costs forthe physical assets of the project. Capital costsare part of the fixed component of the total cost. They arenormally incurred one time but also includecost of rehabilitation or replacement of equipments during the life of the system. Over all about 1.2 Million dollars per Million gallon/per day set up.