The treatment of urban waste water results in the production of biosolids. This byproduct may be landfilled, incinerated, composted to use as fertilizer, or applied directly to land. Each alternative involves different costs and greenhouse gas emissions. A study of biosolids management options in central Ohio focused on ways of making this activity carbon neutral. Four cases were considered: a base case that represented current operation: a techno-centric design that considers various technological options; a techno-ecological synergy design that considers ecological alternatives such as lengthening the timber cycle and planting new forests; and a TES design with feedback where wood is used to replace some of the fossil resources. Typical costs and net CO emissions are listed in Table 20.6. 

Table 20.6:

Sketch the approximate Pareto curves for the three cases and compare them with the base case. Are there win-win opportunities in developing synergies with nature?

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Table 20.6 Cost and net CO₂ emissions for biosolids management in central Ohio. Case Base case Techno-centric TES without feedback TES with feedback Cost (million US) 9.80 6.23 8.09 7.05 8.75 6.34 6.77 7.61 5.94 6.04 Net CO₂ emissions (tons) 42,818 36,696 23,134 27,000 101 36,594 11,756 -4500 36,012 24,370