Advanced treatment of petrochemical wastewater by combined ozonation and biological aerated filter

Abstract

The secondary effluent from a petrochemical wastewater treatment plant was treated by biological aerated filter (BAF) before and after ozonation, namely BAF1 and BAF2, respectively. The results showed that BAF2 fed with the ozonized secondary effluent exhibited a high efficiency in degrading organic pollutants. The removal efficiency of COD and NH-N was 6.0 ± 3.2 and 48.2~18.6% for BAF1 and 12.5 ± 5.8 and 62.1~40.9% for BAF2, respectively, during the whole operation. The integration system of ozonation and BAF could tolerate a higher organic loading rate. When HRT decreased from 4 to 1 h, COD removal efficiency decreased from 12 to 4% for the BAF1 system, but it kept almost unchanged at high levels of 27-32% for the ozonation-BAF2 system, with around 20% removal by ozonation. The biomass in BAF2 exhibited a higher activity of protease, DHA, and SOUR than that in BAF1. The organic pollutants in influent and effluent of BAF were mainly ester compounds, which were difficult to biodegrade by BAF. The predominant genera in BAF1 were Gemmatimonadaceae uncultured, Thauera, and Thiobacillus, while the dominant genera in BAF2 were Nitrospira, Gemmatimonadaceae uncultured, and Flexibacter, respectively. Overall, BAF2 performed better than BAF1 in organic pollutant removal and microbial activity. The ozonation process was vital for BAF to treat petrochemical secondary effluent.

Degradation of Thiol Collectors Using Ozone at a Low Dosage: Kinetics, Mineralization, Ozone Utilization, and Changes of Biodegradability and Water Quality Parameters

“…Liu et al [10] observed fast degradation of butyl xanthate at high O 3 dosage of 145.59 mg/(min•L), but the O 3 utilization was not concerned. As the reagent concentration in flotation pulps is usually 10 −3 -10 −4 mol/L [27], the pollutant concentration in flotation effluents is much lower than that of pharmaceutical effluents and petrochemical wastewaters [28,29]. In ozonation, a lower concentration of organics usually leads to a declined O 3 decomposition rate, resulting in lower ozone utilization.…”

A bioaugmentation agent allowing the advanced treatment of refractory refinery wastewater in a biological aerated filter and analysis of its microbial community

“…The phylum Proteobacteria is well known as being prominent in BAFs used to treat wastewater from coking and petrochemical plants . It includes a broad variety of aerobic, anaerobic and facultative bacteria that can degrade a wide spectrum of organic pollutants, as well as remove nitrogen and phosphorus during wastewater treatment .…”

“…The phylum Proteobacteria is well known as being prominent in BAFs used to treat wastewater from coking and petrochemical plants. 41,42 It includes a broad variety of aerobic, anaerobic and facultative bacteria that can degrade a wide spectrum of organic pollutants, as well as remove nitrogen and phosphorus during wastewater treatment. 43 The filamentous phylum Chloroflexi is ubiquitous among microbial populations in petroleum refinery and coking wastewater treatment plants, 37,44 where it plays a critical role in the degradation of soluble microbial products, including organic carbohydrates and other cellular components.…”

Advanced Treatment of Effluent Extended Aeration Process Using Biological Aerated Filter (BAF) With Natural Media: Modification in Media, Design, and Backwashing Process

“…The most important materials used in BAF media are sand, concrete, clay, shale, polyethylene, polystyrene, and plastic materials (Abou-Elela et al, 2019, Bilotta andBrazier, 2008). The diameter of these media is about 4 mm, operating at 10 h hydraulic retention time (Ding et al, 2018, Blumenthal et al, 2000, Amin et al, 2018.…”