Desempenho de um “wetland” vertical aplicado ao tratamento do efluente de um filtro anaeróbio em uma estação de tratamento de águas cinzas claras visando o reúso não potável em edificações residenciais

Abstract

The wetlands have been shown as a viable option for the greywater treatment aiming the building reuse due to the good pollutants removal, the low cost of implantation and operation, as well as minimal environmental impact when compared with another systems. The present study aimed to characterize the physico-chemical and microbiologically the light greywater generated in university building; evaluate the influence of hydraulic and organic loads in removing turbidity and organic matter in a vertical "wetland" used as a post-treatment of an upflow anaerobic filter (AF) treating greywater clear; evaluate the influence of hydraulic and organic loads in the inactivation of thermotolerant coliform in a vertical "wetland" used as post-treatment of an anaerobic filter treating greywater clear, and evaluate the performance and verify the contents of macro and micronutrients present in the biomass of macrophytes used in "wetland" vertical. Were analyzed six periods of experiments, being characterized by the hydraulic retention time (HRT) of 0.25; 0.5; 0.75; 1; 2 e 3 days. The average values of the effluents related to the turbidity the (HRT) studied were 5.2, 4.8 UT, UT 7.0, 5.3 UT 10.3 UT and UT 15, respectively. The average concentrations of TSS were 6.0 mg L-1 , 14.5 mg L-1 , 8.0 mg L-1 , 7.0 mg L-1 , 7.1 mg L-1 and 7.2 mg L-1 , respectively. As for the average COD concentrations were 14 mgO2.L-1 , 25 mgO2.L-1 , 27 mgO2.L-1 , 14 mgO2.L-1 , 27 mgO2.L-1 and 12 mgO2.L-1 and BOD5 were 6 mgO2.L-1 , 11mgO2.L-1 , 23 mgO2.L-1 , 14mgO2.L-1 , 22 mgO2.L-1 and 17 mgO2.L-1 , respectively.The mean density obtained of TC in the VW effluent was 2.7x104 NMP.100mL-1 and the E. coli was6.9x10² NMP.100mL-1 . Finally, the analysis the leaf of macrophyte used in this study resulted in a productivity the 0.298 kg material dry/m2 , with an estimated yield of shoots of 1.9 kg.m-2 . The absorption of macronutrients were: 111 mg.m-2 N; 2.0 mg.m-2 P; 21.4 mg.m-2 K; 8.0 mg.m-2 Ca; 1, 1 mg.m-2 Mg and 1.8 mg.m-2 S. Finally, for micronutrients removals were: 9.9 mg.m-2 Cu; 34.7 mg.m-2 Mn; 144.6 mg.m-2 Fe; 112.1 mg.m-2 Zn and 17.1 mg.m-2 B.It was concluded that the VW showed better performance for the HRT of 3 days over the analyzed periods, making it adequate when used such as post-treatment of an anaerobic filter.