Enhancing the removal of hazardous pollutants from coke‐making wastewater by dosing activated carbon to a pilot‐scale activated sludge process

Abstract

BACKGROUND: Powdered activated carbon (PAC) was investigated for its ability to remove six polycyclic aromatic hydrocarbons ( 6PAHs) (fluoranthene, benzo[b + J]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[g,h,i]perylene), trace metals and colour from coke-making wastewater when dosed to a pilot-plant activated sludge process (ASP). The ASP had a volume of 0.68 m 3 and was operated to simulate the full-scale ASP treating coke wastewater from a steel works. Operational conditions included a flow rate of 0.78 m 3 day −1 , a hydraulic retention time of 21 h, a sludge retention time of 38 days and a temperature of 27 ∘ C. The ASP was operated for a control period before PAC was dosed directly into the aeration cell at a dose of 400 mg L −1 .RESULTS: Powdered activated carbon addition resulted in a 20% increase in removal efficiency of the 6PAHs. Removal efficiency of trace metals was variable, but increased for nickel, chromium and cadmium by 22.6%, 20.5% and 12.4%, respectively. Improvement in colour removal efficiency was marginal at 5%. CONCLUSION: PAC addition allowed the improvement of treatment efficiencies in the ASP process at relatively low capital and operational costs, which may assist in reaching tighter effluent emission limits set for the industry.

Nitrogen removal from coke making wastewater through a pre-denitrification activated sludge process

“…Burmistrz and Burmistrz (2013) reported 255-312 µg/L for the sum of 16 PAHs whilst Zhang et al (2012a) reported much higher concentrations of 5470 ± 907 µg/L for the sum of 18 PAHs. Raper et al (2017) reported the sum of 6 PAHs at 179 ± 35 µg/L therefore being more comparable to the values reported by Burmistrz and Burmistrz (2013). Trace metals have been reported at 4216 µg/L (Raper et al, 2017).…”

“…Raper et al (2017) reported the sum of 6 PAHs at 179 ± 35 µg/L therefore being more comparable to the values reported by Burmistrz and Burmistrz (2013). Trace metals have been reported at 4216 µg/L (Raper et al, 2017).…”

Enhancing the removal of pollutants from coke wastewater by bioaugmentation: A scoping study

“…Coke wastewaters are typically characterized by ammonia concentrations of 50–500 mg L –1 , thiocyanate (SCN – ) concentrations of 100–400 mg L –1 and phenol concentrations of 60–400 mg L –1 . The sum of six polycyclic aromatic hydrocarbons (Σ6PAHs: sum of fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3‐cd]pyrene and benzo[g,h,i]perylene) was previously reported at 179 ± 35 µg L –1 . Total trace metals (sum of Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb) also were reported at a concentration of 4216 µg L –1 with individual trace metal concentrations ranging from 0.13 µg L –1 (Cd) to 3612 µg L –1 (Fe) .…”

Factors controlling adsorption of recalcitrant organic contaminant from bio‐treated coking wastewater using lignite activated coke and coal tar‐derived activated carbon

“…Coking wastewater is produced during the coke‐making process, and bio‐treatment effluent still contains a certain level of bio‐refractory organics . These include PAHs, heterocyclic compounds and long‐chain alkanes, which pose hazardous threats to the environment, when the effluent is used for coke quenching and gas washing .…”

“…Coking wastewater is produced during the coke-making process, and bio-treatment effluent still contains a certain level of bio-refractory organics. 1,2 These include PAHs, heterocyclic compounds and long-chain alkanes, which pose hazardous threats to the environment, when the effluent is used for coke quenching and gas washing. 3,4 The character of these recalcitrant organic contaminants (ROC) may also lead to the generation of disinfection byproducts and/or serious membrane fouling in the advanced treatment process.…”