Treatment performance comparison between regular O3–BAC and O3–BAC with rear sand filtration: verification in a full-scale study

Abstract

Background: To improve the microbial safety of drinking water, an arrangement of O 3-BAC with rear sand filtration (O 3-BAC-sand) has been proposed. In this study, efforts were devoted to evaluate the benefits and drawbacks of O 3-BAC-sand in a full-scale water treatment plant. The performance of the two configurations was compared in terms of particles, turbidity, COD Mn and typical odorants and pesticides. Results: The O 3-BAC-sand yielded lower turbidity but higher COD Mn (by approximately 7%) in the finished water than regular O 3-BAC (sand-O 3-BAC). Both systems removed odors in raw water; however, sand-O 3-BAC was more effective on septic and musty odorants. The total pesticide removals by sand-O 3-BAC and O 3-BAC-sand were 78% and 72%, respectively; though the latter had shorter activated carbon durable years. Conclusion: The re-location of the sand filter would sacrifice the BAC efficiency in removals of organic matter and micropollutants. This tradeoff is a result of the loss of the particulate organic matter removal by sand filters, because locating the sand filter behind BAC causes particle load increase on BAC; some measures of enhanced coagulation should be suggested to improve the turbidity and particle removal. The study will be helpful for improvement of the O 3-BAC process in drinking water treatment.

Effect of Flow Configuration on Nitrifiers in Biological Activated Carbon Filters for Potable Water Production

“…This was likely associated with the better particle removal performance in down-flow filters, resulting from mixed effects of diffusion, interception, and sedimentation. However, this phenomenon could be reversed by relocation of sand filters after BAC units. , In the present work, higher gene copy numbers of total bacteria and Nitrospira as well as higher relative abundances of AOB and Nitrospira were observed in the up-flow filters relative to the down-flow filters, implying enhanced biodegradation and biotransformation capabilities in up-flow filters. These results are in agreement with the previous studies that reported higher COD Mn removal efficiency and improved ammonia removal ability in pilot-scale up-flow filters relative to down-flow filters. , Up-flow filters are characterized with enhanced oxygen supply and higher mass transfer rates by maintaining a stable expanded bed, which can promote the microbial growth.…”

The Auxiliary Effect of Different Bacterial Groups on the Degradation of Organic Matter in Refinery Wastewater by Bacillus Licheniformis

“…The wastewater samples used in this study are all taken from the second wastewater treatment plant of a refinery wastewater treatment plant [4]. The water intake point is located at the entrance of the biochemical reaction tank of the wastewater treatment plant.…”

Biofiltration for treatment of recent emerging contaminants in water: Current and future perspectives

“…Numerous WTPs apply BAC after the conventional treatment or as a sand filter replacement to remove conventional and emerging contaminants. However, for some WTPs (in subtropical region), sand filtration is placed after BAC in order to remove turbidity sloughing off from BAC and provide additional barrier for reducing the biological risk (Guo et al, 2016; Yang et al, 2019).…”