3.3.4. Toxicity evaluation

most abundant active species is given in Table 3. Both heterotrophic and autotrophic bacterial

Figure 11. Gel sequence and DGGE banding results of active spices in different biofilter levels. Names of referred bacteria

species are present in the biofilter with a predominance of heterotrophic population.

Figure 10. Media samples from different heights of the biofilter.

386 Phenolic Compounds - Natural Sources, Importance and Applications

are listed in Table 3.

Toxicity evaluation of leachate before and after treatment was performed in the Centre d'Expertise en Analyses Environnementales de Québec using the Microtox test on two species susceptible to the toxicity, which are daphnia and algae. Results are presented in Table 4. Toxicity evaluation confirmed that effluent was not toxic for algae and daphnia. It was confirmed also that algae were stimulated in the presence of diluted (5.6% V/V) effluent.

### 3.4. Pilot unit profiles comparison

Figures 12 and 13 illustrate the profiles performance comparison. COD (feed) was the influent COD and COD (Out) was the effluent COD in column 1 without bacterial activity. The variation of BOD in the woodwaste influent and in the biofilter effluent showed high biofilter performances.

The pH distribution in column 1 (without bacterial activity) and in column 2 (biofilter) is presented in Figure 14.


Table 4. Toxicity evaluation of leachate before and after treatment.

### 3.5. Mini-columns COD profile comparison

The mini-columns COD decreased in the first 10 days of operation from 1896 mg L−<sup>1</sup> as a fed COD influent to 968 mg L−<sup>1</sup> for the first column (without bacterial activity) and 737 mg L−<sup>1</sup> for

Figure 12. COD profiles comparison in woodwate leachate influent and in both columns with and without bacterial activity.

Figure 13. Treatment efficiency and BOD performance in the biofilter.

3.5. Mini-columns COD profile comparison

activity.

Table 4. Toxicity evaluation of leachate before and after treatment.

Concentration % V/V Influent Effluent

388 Phenolic Compounds - Natural Sources, Importance and Applications

56 100 100 99 0 1 0 42 100 100 99 0 0 0 24 99 100 99 0 0 0 18 30 40 99 0 0 0 13.5 25 30 99 0 0 0 10 25 30 99 0 0 0 7.5 20 20 99 0 0 0 5.6 10 5 80 0 0 −1.7 Control 0 0 0 0 0 0

The mini-columns COD decreased in the first 10 days of operation from 1896 mg L−<sup>1</sup> as a fed COD influent to 968 mg L−<sup>1</sup> for the first column (without bacterial activity) and 737 mg L−<sup>1</sup> for

Figure 12. COD profiles comparison in woodwate leachate influent and in both columns with and without bacterial

Daphnia Algae Daphnia Algae

% Mortality % Immobility % Inhibition % Mortality % Immobility % Inhibition

Figure 14. pH distribution in column 1 (without bacterial activity) and in column 2 (biofilter).

Figure 15. Mini-columns COD profiles comparison.

the second one (mini-biofilter). After 10 days of operation, the mini-biofilter COD fluctuated due to the biomass adaptation and then decrease in time at 254 mg L−<sup>1</sup> (Figure 15). COD concentration of the two mini-columns increased at the 37th day of operation. This increase may due to the media saturation. COD of mini-column without bacterial activity was set at COD concentration influent while that of the mini-biofilter decreased to reach 285 mg L−<sup>1</sup> values at the steady state with 84.9% of COD removal.
