Custos de operação e manutenção de ETE por reator anaeróbio e lodos ativados com desnitrificação

Abstract

This research presents studies on operation and maintenance costs (O&M) of an wastewater treatment plant (WWTP) with anaerobic reactor and denitrification activated sludge, located in the city of Natal - RN. Its objective is to make a composition of O&M costs and to analyze their relation with the volumetric parameters, number of inhabitants benefited and loads removed. In this study various components of O&M costs were identified, which are related to the activities necessary to the operation of the WWTP during the period ranging from July 2016 to December 2018, also being grouped into 4 cost groups. The O&M costs per cubic meter of treated sewage over the years 2016, 2017 and 2018 amounted to the average values of R$ R$ 0,34 ± 0,01∙m-³, R$ 0,31 ± 0,04∙m-³ e R$ 0,40 ± 0,04∙m-³, respectively. Costs related to the personnel and energy consumption figured, in all the analyzed months, as the first and the second most representative components in the total cost. Among the sectors responsible for energy consumption, the blowers are noteworthy, given that they contributed with 65.43% in this aspect. Costs for removal of organic matter, ammonia nitrogen and E. coli (log) have also been calculated and exposed. Finally, this study recommends as suitable the implementation of improvements in the personnel and energy groups, as they account for over 75% of all the WWTP O&M costs.