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MBBR followed by microfiltration and reverse osmosis as a compact alternative for advanced treatment of a pesticide‐producing industry wastewater towards reuse
Author(s) -
Cao Sandra M. S.,
Dezotti Marcia,
Bassin João P.
Publication year - 2016
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22542
Subject(s) - effluent , reverse osmosis , moving bed biofilm reactor , chemical oxygen demand , microfiltration , environmental science , wastewater , total suspended solids , powdered activated carbon treatment , industrial wastewater treatment , sewage treatment , nanofiltration , pulp and paper industry , reuse , chemistry , waste management , environmental engineering , activated carbon , adsorption , membrane , biofilm , biochemistry , organic chemistry , biology , bacteria , engineering , genetics
The treatment of a chemical industry wastewater with the goal of reuse was evaluated in a three‐step process. First, the industrial waste stream underwent biological treatment in a two‐stage moving‐bed biofilm reactor (MBBR) system, which allowed achieving average effluent chemical oxygen demand (COD), dissolved organic carbon (DOC), ammonium, total nitrogen (TN), and total suspended solids (TSS) concentrations of 45.5, 27.2, 1.0, 34.2, and 210 mg/L, respectively. Salt and TSS concentrations after the MBBR process were still not compatible with the requirements for effluent reuse and the silt density index (SDI 15 ) was found to be > 6.5, making a direct reverse osmosis (RO) application impractical. By employing microfiltration (MF) downstream of the biological treatment, no salt removal was observed, but the SDI 15 was reduced to around 2, enabling final RO application. Long‐term RO experiments conducted at different pressures (1.5–3.0 MPa) showed that biofouling became more severe under higher pressures, leading to the enhancement of the permeate flux drop. Rejection of DOC, TN, and salt by RO corresponded to 97.8 %, 89 %, and 99 %, respectively. The combined MBBR/MF/RO process allowed the production of a high‐quality effluent appropriate for direct reuse in the industry as feed water in cooling towers, steam boilers, and general industrial process activities.