Different strategies, including extension of HRT, dilution, and addition of powdered activated carbon (PAC) and super-powdered activated carbon (S-PAC), were investigated for the quick recovery of nitrifying bacteria activity from the inhibition of coal gasification wastewater (CGW). A lab-scale short-cut nitrogen removal (SBNR) reactor treating CGW, achieving high-levels (90%) of nitrogen removal, was used. After a shock of phenolic compounds (around 250 mg/L) and a failed performance, the results of the batch recovery tests indicated that the PAC and S-PAC addition were the best recovery strategies. In the SBNR reactor, addition of 1 g/L PAC and S-PAC shortened the recovery time from the natural recovery of 32 days to 13 days and 10 days, respectively. FISH assay and the adsorption isotherms revealed that activated carbons absorbed phenolic compounds, reducing the toxicity and allowing for a quick recovery of SBNR treating CGW. S-PAC showed larger adsorption capacity for phenol than PAC.
- coal gasification wastewater
- powdered activated carbon
- recovering inhibition
- short-cut nitrogen removal
- super-powdered activated carbon
- First received 12 January 2015.
- Accepted in revised form 3 April 2015.
- © IWA Publishing 2015