The inhibitory effects of heavy metals and organic compounds on the net maximum specific growth rate of the autotrophic biomass in activated sludge
| Autor: | D. Bixio, Sri Rachmania Juliastuti, Jan Baeyens, E. Lodewyckx, Claude Creemers |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Environmental Engineering
Health Toxicology and Mutagenesis Inorganic chemistry Population Dynamics chemistry.chemical_element Zinc Ethylbenzene chemistry.chemical_compound Respirometry Nitrosomonas europaea Metals Heavy Benzene Derivatives Environmental Chemistry Phenol Biomass Waste Management and Disposal biology Bacteria Sewage biology.organism_classification Pollution Trichloroethylene Activated sludge chemistry Chlorobenzene Solvents Nitrification Nuclear chemistry |
| Zdroj: | Journal of hazardous materials. 100(1-3) |
| ISSN: | 0304-3894 |
| Popis: | A respirometry technique can be applied as an effective method to determine the net maximum specific growth rate of autotrophic biomass under both normal conditions and when inhibition occurs. The net maximum specific growth rate of uninhibited autotrophic biomass, expressed as (mu(A)-b(A)), is approximately 0.8 per day [Proceeding of the International Congress on CHISA, Prague, 2002, p. 1]. Several heavy metals and organic compounds have inhibitory effects. Copper (Cu(2+)) has stronger inhibitory effects than zinc (Zn(2+)), and inhibits the nitrification process by 50% at 0.08 mg/l [(mu(A)-b(A)) = 0.4 per day], while the same concentration of Zn(2+) establishes 12% inhibition only [(mu(A)-b(A)) = 0.75 per day]. Inhibition with Cu(2+) starts at concentrations above 0.05 mg/l, while this is above 0.3mg/l for Zn(2+). The inhibition of the nitrification process is complete at 1.2mg/l for both Cu(2+) and Zn(2+). Among the selected organic compounds tested n the experiments, the degree of inhibition decreases as follow: chlorobenzene>trichloroethylene (TCE)>phenol>ethylbenzene. Chlorobenzene already inhibits the autotrophic biomass at 0.25 mg/l. The nitrification process is totally inhibited by adding 0.75 mg/l of chlorobenzene. TCE has a less inhibitory effect on the nitrification process and 50% inhibition is noticed at 0.75 mg/l TCE. The nitrification process is totally inhibited at 1mg/l TCE. Phenol inhibits the nitrification for 50% at 3 mg/l. The inhibitory effect of phenol is almost constant in the range 4-10 mg/l and complete inhibition is reached at 50 mg/l. The inhibitory effect of ethylbenzene is 50% at 8 mg/l and the autotrophic biomass is totally inhibited at 50 mg/l. Experimental findings are compared with literature data, which generally and significantly overestimate the inhibition threshold concentrations. |
| Databáze: | OpenAIRE |
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