Caracterização das águas utilizadas e residuárias do processo de reciclagem de papel.

Abstract

The use of large amounts of water by the paper industry is causing concern, because the generation of high volumes of liquid effluents, with significant concentrations of organic material, which can harm the receiving water body. In this work the water flow was monitored together with physical and chemical parameters in samples from the water used and the effluents generated in a recycling paper industry (IPELSA S/A), located in Campina Grande - Paraiba State - Northeast of Brazil. The work comprised a monitoring program and daily cycles profiles with measurements of hydraulic (flow) and physical-chemical parameters (temperature, pH, turbidity, electric conductivity, BOD5, COD, total, settable and suspended solids and its fixed and volatile fractions, alkalinity, hardness, chloride, sulfate, sodium, potassium, magnesium, calcium, carbonate and bicarbonate). The height of the liquid in a V notch (for flow calculation) and the temperature were measured during sample collection. The other analyses were carried out in the laboratory of the Sanitary and Environmental Engineering Area (AESA - DEC -CCT - UFPB - CAMPUS I I , Campina Grande - PB). The monitoring was accomplished in 7 months (jan-jul/99), with monthly samples collected between 13 and 15 hours. Results were evaluated through descriptive statistics, variance analysis (ANOVA: one way) with GT-2 method and multiple correlation analysis (SPSS for Windows 8.0). The daily cycle studies comprised a one day factory operation staring at 08 a.m. and ending 06 a.m. next day, with sample collection every 2 hours, aiming the study of the final effluent behavior and to evaluated the pollution power discharged in the receiving body. The monitoring showed that the water used in the process, coming from the Bodocongo dam, was highly modified, particularly to parameters such as BOD5, COD and total, suspended and settable solids. The incorporation of microfibers, originated during the paper sheet formation, introduced in the final effluent a high load of organic and solid material raising turbidity, BOD5 and COD to 560 Tu, 943 mg/L and 3.145 mg/L, respectively, and introducing a flow between 33,7 and 95,9 m3/h. Positive and significant correlations were observed among several parameters particularly those related to organic matter, such as COD and BOD5 (a = 0,01 and r = 0,557), COD and TS (a = 0,01 and r = 0,558), COD and TSS (a = 0,01 and r = 0,722), turbidity and BOD5 (ct= 0,05 and r = 0,547), demonstrating that microfibers were the main cause of the observed alterations in the effluent in relation to water used in the process. The studies of daily cycles showed a wide variation in most of the parameters, not being possible to observe among the two experiments, coincidence among maximum and minimum flow values as well as in the concentrations of the analyzed parameters, resulting the release in the Bodocongo stream of high organic loads (BODs, COD) and solids loads (TS, SS and SSeat).