LCA-based decision support for plant short-term control: Technical, economic and carbon-footprint assessments of a pump system in wastewater treatment plants

Pumping systems account for a very relevant share of the energy consumption of infrastructures for water supply, treatment, use and disposal. For example, in wastewater treatment plants (WWTPs) hydraulic pumps are responsible... [ view full abstract ]

Pumping systems account for a very relevant share of the energy consumption of infrastructures for water supply, treatment, use and disposal. For example, in wastewater treatment plants (WWTPs) hydraulic pumps are responsible on average for more than 12% of the total energy demand of a plant. Acting on the correct sizing and operational control of the pumping system has therefore a high potential impact on the energy efficiency of WWTPs.

This paper presents a simplified implementation of a decision support tool to estimate the efficiency of the pump system of a hypothetical WWTP and assess the environmental and economic payback times of some selected scenarios.

The environmental costs are estimated here solely in terms of lifecycle carbon emissions of the scenarios, including the energy use in each scenario, the installation of a new pump and the disposal stage of the old pump.

The simulated example shows a situation in which the environmental payback time is significantly lower than the economic one. This methodology is suitable to be applied in pump systems also outside WWTPs, regardless the plant’s size or layout. Moreover, the system prospects to be even more interesting if implemented as a web-based tool where the plant managers can very quickly assess possible sub-optimal efficiencies in the pump system and estimate the suitability of pre-defined correction actions. In particular, the advantages of a system like the one described in this paper can be particularly relevant if extended to other energy demanding appliances in the plant (such as air blowers, and stirrers).