Estudo da qualidade de água residuária doméstica pós-tratada em fluxo descendente intermitente.

Abstract

This research investigated the performance of the post-treatment of septic tank effluent sand filters intermittent flows, to obtain a treaty with sewage quality suitable for reuse in irrigation. The sewage was coming from the classes of block II of the Center for Science and Technology Agrifood (CCTA), the Federal University of Campina Grande (UFCG). The input flow control in the system was also quantified. The experimental system was composed of a septic tank of three sand filters with intermittent flow and a storage box. The three aerobic sand filters were filled with gravel and sand at the following ratio: 10 cm crushed base # 1, 50 cm in the middle portion sand and crushed stone No. 5 0 cm in the upper portion. The sand used in the three filters was the same, being sieved through a sieve with a diameter of 0.50 mm. The first filter received 200 L / day (50 L each 6am) of effluent from septic tank, the second filter received 150 L / day (50 L every 8h) filter and the third received 100 L / day (50 L each 12pm). There were measurement campaigns, from November / 2014 to February / 2015 to characterize the effluents in the physical, chemical and microbiological aspects as processing indicators of water quality. The parameters analyzed were: OD, temperature, turbidity, pH, EC, color, total hardness, Ca, Mg, chlorides, N, Na, K, P, COD, BOD 5, CT, CTT and E. coli. The analysis of variance (ANOVA) was performed to compare the concentrations of all the parameters in the effluent, at 5% significance level. Temperature, turbidity, EC, color, total hardness, Ca, Mg, chlorides, Na, K, P, COD, BOD 5, CT, CTT and E. coli showed no statistically significant differences. The OD showed significant. The N, much significance and the pH, extreme statistical significance. The filters reduced the concentrations of nutrients, organic matter and pathogenic microorganisms, but with reduced flickers adopted times could not find statistical differences between treatments. These values were not compatible with those recommended for agricultural use, according to CONAMA resolution.