Issues and guidelines for treated wastewater reservoirs design and operation

The potential wastewater stabilisation during the storage phase might improve significantly water quality therefore making appropriate to use this hydraulic component also as part of the treatment line of a reuse system. An experimental research was carried out in a small farm reservoir, receiving treated wastewater, aimed at investigating design and management parameters (depth, surface/volume ratio, incoming/outcoming flows), and role of operational indexes, like MRT (mean retention time) and PFEn (percentage of fresh effluents). Guidelines for proper design and operation were developed aiming at achieving higher removal efficiency and a more homogeneous quality of the reservoir effluent during the irrigation season. A mass balance model was developed and a simulation was carried out to verify the effectiveness of the proposed management criteria by calculating corresponding MRTs and PFEn.