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Thesis - faculty.ait.ac.th - Asian Institute of Technology

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Table 3.1 Composition <strong>of</strong> Simulated Le<strong>ac</strong>hate<br />

Parameters Concentration<br />

pH<br />

7.8-8.2<br />

COD (mg/L)<br />

8,000±1,000<br />

BOD/COD<br />

0.40±0.05<br />

NH4-N (mg/L)<br />

1,700±100<br />

TKN (mg/L)<br />

1,900±100<br />

TDS (mg/L)<br />

12,000±1,000<br />

Note: Pb concentration is below 0.3 mg/L, which has no effect on microbial toxicity.<br />

3.3 Seed Study<br />

3.3.1 Yeast and B<strong>ac</strong>terial Sludge<br />

a) Yeast Sludge<br />

The mixed yeast sludge comprises <strong>of</strong> a mixture <strong>of</strong> wild yeast varieties <strong>th</strong>at exist in<br />

<strong>th</strong>e raw wastewater and which quantitatively propagate under normal enrichment<br />

conditions. The procedure for enrichment <strong>of</strong> yeasts was carried out <strong>ac</strong>cording to <strong>th</strong>e<br />

Standard Me<strong>th</strong>ods for <strong>th</strong>e examination <strong>of</strong> water and wastewater (APHA, et al., 1998). The<br />

yeast strains were selected based on competition among different organisms present in<br />

wastewater (Nishihara Ltd., 2001) by <strong>th</strong>e enrichment culture technique. Figure 3.2<br />

illustrates <strong>th</strong>e procedure for enrichment <strong>of</strong> yeast.<br />

Seed Seed yeast yeast sludge sludge<br />

(from (from sediments sediments) )<br />

Filling<br />

Aeration Aeration 24 24 h h<br />

MLSS<br />

Completion Enriched Completion Enriched culture<br />

> 3,000 mg/L<br />

Figure 3.2 Diagram Illustrating <strong>th</strong>e Enrichment Procedure<br />

55<br />

< 3,000 mg/L<br />

Drawing<br />

Settling

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