Resources Recovery from Wastewater Treatment Plants: Full-Scale Optimization by Using a Mathematical Model Including Greenhouse Gas Emissions

Wastewater treatment plants (WWTPs) have the advantage of reducing pollutants discharged into the environment. However, WWTPs impose a burden on the environment with direct, indirect, and external indirect greenhouse gas emissions. Reducing this burden caused by WWTPs is an important step for sustainable development especially when technologies aimed to recover resources are applied. Indeed, considering the resources such as water, organic matter, nitrogen, phosphorus, and biopolymers in the wastewater content, WWTP can be viewed as resource recovery, not a burden. Within the scope of the European Union Horizon 2020 “Achieving wider uptake of water-smart solutions — WIDER UPTAKE” project, which aims to overcome the existing barriers to resources recovery from wastewater with the concept of circular economy, improvement and optimization modelling studies were implemented at the Corleone WWTP (Italy). The aim is to minimize sludge production and reuse the treated water and sludge in agriculture. In this study, Corleone’s WWTP was mathematically modeled by using the activated sludge model (ASM) family. The model has been constructed by using GPS-X simulation software (Hydromantis). Model calibration was done by using measured continuous and discrete data, including water quality and quantity. A step-wise Monte Carlo calibration procedure was adopted for model calibration based on a sensitivity analysis. The emission reduction techniques such as automatic control systems (optimization of aeration and pumping) and metabolic techniques (implementing oxidation-sedimentation-anoxic (OSA) concept) were tested by validating the model using a long-term dataset. Keywords: ASM, GHG emissions, mathematical modelling, optimization, OSA