How Much Does Odor Management Cost in a Water Resource Facility in Europe? Analysis of the results of a survey of 400 facilities in Spain

In 2020, the Odor Subgroup of the Spanish Association of Sanitary Waters disseminated a survey among its associates to evaluate the state of odor management in Spain, circumscribing it to those facilities with more than 10,000 hab-eq. The survey consisted of 57 questions in 10 sections: WWTP characteristics (10 questions), Sewage network characteristics (2 questions), WWTP deodorization systems (10 questions), Sewage network deodorization systems (1 question), WWTP operation and maintenance (13 questions), Sewage network operation and maintenance (12 questions), Regulations (2 questions), Incident management (4 questions), Design (1 question) and Investment (2 questions). A total of 394 responses were received, representing 43% of the total number of WWTPs in Spain and 60% representativeness if the number of equivalent inhabitants served by these infrastructures is considered. The analysis of the results shows a wide variability between the level of odor management in the different WWTPs. This difference is attributed to the absence in Spain of a state regulation that could provide homogenization capacity, there being only autonomous regulation in specific Autonomous Communities and, on occasion, municipal regulations. This lack of regulation is partially made up for by the bidding specifications for the operation of sanitation systems, which require control and mitigation measures from the operating companies. Although this represents an added value for society, it is considered that it can generate an imbalance between the level of service received by the different populations affected by the odor emitted from the Water Resource Recovery Facilities. In the same way, there is an underestimation of the economic allocation necessary for the correct management of the odor to eliminate the nuisance produced, in addition to reducing the emission of polluting gases into the atmosphere. The aim of this paper is to present the analysis of the results of this survey.