Innovation, multi-utility service businesses and sustainable cities: where might be the next breakthrough?

A Multi-sectoral Systems Analysis (MSA) model has been constructed for exploring and managing cross-sectoral impacts (both synergies and antagonisms) resulting from technology and policy interventions in the design and stewardship of city infrastructures. This MSA is based on Substance Flow Analysis. It accounts for the flows of water, nitrogen, phosphorus, carbon, and energy into, around, and out of the water, energy, food, waste-handling, and forestry sectors of city-watershed systems. Applications of the MSA to two case studies of the Metropolitan Atlanta Area in Georgia, USA, and the Greater London Area, UK, are compared. The impacts and financial benefits are assessed for four candidate technological innovations in the water sector: urine-separating toilets; pyrolysis of sewage sludge; combined food-waste and wastewater conveyance/treatment; and production of algae-based biofuels from sewage. System-wide environmental sustainability is gauged on four accounts, of attaining progressively more ambitious targets of resource savings/recovery in respect of water, energy, and nutrients (both nitrogen- and phosphorus-based). The paper closes by demonstrating how the MSA can provide assistance in framing questions of a more financial and social nature, i.e., those of ‘Who reaps the rewards?’ and ‘Who bears the costs?’ of the various prospective technological changes and (possibly) breakthroughs.