Application of activated sludge process followed by physical-chemical processes in the treatment of industrial saline effluent for reuse

Milene Carvalho Bongiovani,Márcia Dezotti,Geraldo André Thurler Fontoura

doi:10.4025/actascitechnol.v35i2.13006

Milene Carvalho Bongiovani, Márcia Dezotti + Show 1 more

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https://doi.org/10.4025/actascitechnol.v35i2.13006

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Abstract

The treatment of complex effluent with high salinity and sometimes with toxicity rates from a chemical plant is investigated. Two reactors were monitored continuously: control reactor R1 and reactor R2 adapted for saline effluent with 25h-HRT. The adaptation process to saline effluent (0 - 100%) was effective in removing COD and N-NH4 + , respectively with 70 and 85% efficiency. After adaptation, the sequence coagulation/flocculation (40 mg L -1 PAC coagulant and 0.3 mg L -1 cationic polymer), rapid downflow sand filter (120 m 3 m -2 day) and reverse osmosis to obtain water for reuse was analyzed. Results obtained by coagulation/flocculation and sand filter sequence were satisfactory, mainly with the removal rates of turbidity at 50-65 and 98%, respectively. Average removals of 91, 87, 98 and 98% were obtained for COD, N-NH4 + , TOC and Cl - , respectively, in reverse osmosis, with all parameters below the limits for

Highlights

Due to excessive population growth and intense industrial development during the last decades, environmental problems, such as the pollution of surface and ground water by fertilizers, pesticides, oils, toxic leachate from landfills and great varieties of industrial and domestic effluents, have become more frequent but increasingly critical factors.Pesticides have been used for over 40 years for their effectiveness in controlling a wide variety of pests, diseases and crop-infesting weeds (EPA, 2004; VRYZAS et al, 2011)
The effluent used in current assay came from a pesticide-producing chemical plant producing pesticides and its composition featured high complexity and variability, with high salt contents and sometimes significant toxicity levels (WORLD BANK GROUP, 1998)
Such variability originated from the variety of products manufactured and from a greater production of certain products to the detriment of others according to the season

Summary

Introduction

Due to excessive population growth and intense industrial development during the last decades, environmental problems, such as the pollution of surface and ground water by fertilizers, pesticides, oils, toxic leachate from landfills and great varieties of industrial and domestic effluents, have become more frequent but increasingly critical factors. Pesticides have been used for over 40 years for their effectiveness in controlling a wide variety of pests, diseases and crop-infesting weeds (EPA, 2004; VRYZAS et al, 2011). Technology to society, pesticides have many undesirable effects such as toxicity, carcinogenicity and mutagenicity (KOURAS et al, 1998). Industrial effluents vary quantitatively and qualitatively, depending on the types of products manufactured, and on the raw material processes used. Industries generate complex effluents which are characterized as highly difficult to deal with (COSTA et al, 2003)

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