Technical-economical analysis of selected decentralized technologies for municipal wastewater treatment in the city of Rome

摘要

Several wastewater treatment technologies were evaluated as alternative systems to theudmore traditional centralized continuous flow system to serve decentralized areas of the city of Romeud(Italy). For instance, the following technologies were selected: (1) Constructed wetlands, (2)udMembrane Biological Reactor, (3) Deep Shaft, (4) Sequencing Batch Reactor, and (5) CombinedudFiltration and UV-disinfection. Such systems were distinguished based on the limits they areudpotentially capable of accomplishing on the effluent. Consequently, the SBR and DS were groupedudtogether for their capability to comply with the standards for the discharge into surface watersud(according to the Italian D.Lgs. 152/06, Table 1, All. 5), whereas the MBR and tertiary systemud(Filtration+UVc-disinfection) were considered together as they should be able to allow effluentuddischarge into soil (according to the Italian D.Lgs. 152/06, Table 4, All. 5) and/or reuse (according toudthe Italian D.M. 185/03). Both groups of technologies were evaluated in comparison with the moreudcommon continuous flow treatment sequence consisting of a biological activated sludge tank followedudby the secondary settlement, with final chlorination. CWs were studied separately as a solution foruddecentralized urban areas with limited population.udAfter the analysis of the main technical features, an economical estimate was carried out taking intoudaccount the investment, operation and maintenance costs as a function of the plant's capacity. Theudanalysis was based on real data provided by the Company who manages the entire water system of theudCity of Rome (Acea Ato 2 S.p.A.). A preliminary design of the treatment plants using some of theudselected technologies was finally carried out.