Determination of heavy metals in industrial wastewaters and their influence on activated sludge biocenose

The paper evaluates the presence and content of traces of heavy metals Hg, Pb, Ni, Cd (total forms) from coal and solid combustion products, the degree of transfer and accessibility in the area of influence of a lignite power plant. The content of toxic heavy metals in residues are characterized by RE Meiji [ 1 (Pb and Hg) and REMeij �1 (Ni and Cd) for the filter ash. Pb and Ni content in the soil exceeds normal values, and Pb exceeds and alert value for sensitive soils around the residue deposit (70.20 mg.Kg-1). The degree of accessibility of the metals in plants (TF), reported at the Khan reference value (0.5), indicates a significant bioaccumulation level for the metals: Cd (1.9) and Hg (0.6) inside the deposit; Cd (0.39) at the base of the deposit, Hg (0.8) in the area of the thermal power plant. The trace levels of heavy metals analyzed by GFAAS and CVAAS (Hg), indicates a moderate risk potential for food safety and quality of life in the studied area.

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Respirometry for determination of the influents SS-concentration

Water Science & Technology ◽

10.2166/wst.1996.0031 ◽

1996 ◽

Vol 33 (1) ◽

pp. 311-323 ◽

Cited By ~ 2

Author(s):

A. Witteborg ◽

A. van der Last ◽

R. Hamming ◽

I. Hemmers

Keyword(s):

Experimental Design ◽

Activated Sludge ◽

Substrate Concentration ◽

Full Scale ◽

Activated Sludge Process ◽

Respiration Rates ◽

On Line ◽

Large Measurement ◽

Set Up

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.

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Quantification of the kinetic differences between communities isolated from completely mixed activated sludge systems operated with or without a selector using a novel respirometric method

Water Science & Technology ◽

10.2166/wst.1994.0567 ◽

1994 ◽

Vol 30 (11) ◽

pp. 255-261 ◽

Cited By ~ 5

Author(s):

Barth F. Smets ◽

Timothy G. Ellis ◽

Stephanie Brau ◽

Richard W. Sanders ◽

C. P. Leslie Grady

Keyword(s):

Oxygen Consumption ◽

Activated Sludge ◽

Physiological Changes ◽

Biodegradation Kinetics ◽

Substrate Removal ◽

Biomass Yields ◽

Selection For ◽

Single Oxygen ◽

Activated Sludge Systems

This study quantified the kinetic differences in microbial communities isolated from completely mixed activated sludge (CMAS) systems that were operated either with or without an aerobic selector preceding the main reactor. A new respirometric method was employed that allowed the determination of biodegradation kinetics from single oxygen consumption curves, thereby minimizing physiological changes to the examined communities during the assay. Results indicated that increased values for Ks and μmax for acetate, phenol, and 4-chlorophenol degradation were measured in the CMAS system operated with a selector. The biomass yields on acetate, phenol, and 4-chlorophenol were very similar in both systems. These findings indicate that the operation of CMAS systems with aerobic selectors may result in the selection for degrading populations with higher Ks and μmax values for both biogenic and xenobiotic organic compounds, and that substrate storage in the selector only partially contributes to increased substrate removal rates.

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Operational Determination of the Activated Sludge Process Using Neural Networks

Water Science & Technology ◽

10.2166/wst.1992.0762 ◽

1992 ◽

Vol 26 (9-11) ◽

pp. 2461-2464 ◽

Cited By ~ 2

Author(s):

R. D. Tyagi ◽

Y. G. Du

Keyword(s):

Neural Network ◽

Neural Networks ◽

Steady State ◽

Activated Sludge ◽

Feedforward Neural Network ◽

Training Data ◽

Activated Sludge Process

A steady-statemathematical model of an activated sludgeprocess with a secondary settler was developed. With a limited number of training data samples obtained from the simulation at steady state, a feedforward neural network was established which exhibits an excellent capability for the operational prediction and determination.

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