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Trace and bulk organics removal during ozone–biofiltration treatment for potable reuse applications
Author(s) -
Sundaram Vijay,
Pagilla Krishna
Publication year - 2020
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.1002/wer.1202
Subject(s) - chemistry , ozone , biofilter , environmental chemistry , effluent , water treatment , pulp and paper industry , filtration (mathematics) , wastewater , environmental engineering , waste management , environmental science , statistics , mathematics , organic chemistry , engineering
This study investigated impact of ozone/biological activated carbon (BAC) filtration design and operational parameters on contaminants of emerging concern (CEC) and bulk organics removal over 450 days of operation. Two parallel BAC filters with identical media and influent were maintained, each at a different empty bed contact time of 10 and 20 min. This study captured the CEC removal performance of a BAC filter over an extended operational period after treating 65,000 bed volumes. Ozone system was operated at ozone dose to TOC ratio range of 0.9–2. Biofilter with lower EBCT (10 min) and exhausted media resulted in poor removals of Tris(2‐chloroethyl) phosphate (TCEP), perfluorooctanoic acid (PFOA), sucralose, meprobamate, N,N‐diethyl‐m‐toluamide (DEET), and cotinine. Biofilter with higher EBCT (20 min) and remaining adsorptive effects resulted in significant (84% or more) removal of all CECs that were detected in the ozonated effluent. Increasing both ozone dose and BAC EBCT resulted in increased removal of UV absorbance (UVA 254 ). The evaluation of impact of ozone:TOC ratio and BAC EBCT on CEC removal, bulk organics (TOC), and UVA 254 performed in this study confirmed the importance of these two parameters on overall success of nonreverse osmosis (RO) potable reuse projects. Practitioner points Ozone–BAC biofiltration is feasible strategy for indirect potable reuse water reclamation. Ozone–BAC empty bed contact time is a critical design parameter. Adsorption and biodegradation are both important mechanisms for trace organic contaminant removal in BAC.