Thesis - faculty.ait.ac.th - Asian Institute of Technology
Thesis - faculty.ait.ac.th - Asian Institute of Technology
Thesis - faculty.ait.ac.th - Asian Institute of Technology
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TKN Removal<br />
(%)<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
4.5 O<strong>th</strong>er Studies<br />
Figure 4.35 TKN Removal in MBR Process at 16 and 24 h HRT<br />
4.5.1 Biodegradability <strong>of</strong> <strong>th</strong>e Le<strong>ac</strong>hate<br />
Wi<strong>th</strong>out Ammonia Stripping Wi<strong>th</strong> Ammonia Stripping<br />
BMBR-16h BMBR-24h YMBR-16h YMBR-24h<br />
Landfill le<strong>ac</strong>hates are usually compared to complex industrial wastewater streams<br />
which contain bo<strong>th</strong> toxic organic and inorganic contaminants (Krug and McDougall, 1988).<br />
Toxic and hazardous compounds can originate from landfill le<strong>ac</strong>hate as a result <strong>of</strong> soluble<br />
components <strong>of</strong> solid and liquid wastes being le<strong>ac</strong>hate into surf<strong>ac</strong>e and groundwater.<br />
The COD present in any wastewater can be categorized into two fr<strong>ac</strong>tions:<br />
biodegradable and non-biodegradable COD. The non-biodegradable COD has two subfr<strong>ac</strong>tions<br />
consisting <strong>of</strong> dissolved non-biodegradable organics and suspended nonbiodegradable<br />
organics. The same way, <strong>th</strong>e biodegradable COD has two fr<strong>ac</strong>tions<br />
comprising dissolved readily biodegradable organics (Ss) and suspended slowly<br />
biodegradable organics (Xs) (Ekama, et al., 1986; Vanrolleghem, et al., 1999).<br />
Respirometric me<strong>th</strong>od could be effective in measuring <strong>th</strong>e biodegradable component <strong>of</strong> <strong>th</strong>e<br />
landfill le<strong>ac</strong>hate. During <strong>th</strong>e feed period <strong>th</strong>e rate <strong>of</strong> supply <strong>of</strong> Ss is due to <strong>th</strong>at added via <strong>th</strong>e<br />
influent feed and <strong>th</strong>at realized to <strong>th</strong>e liquid via hydrolysis <strong>of</strong> Xs. After <strong>th</strong>e supply <strong>of</strong> Ss from<br />
<strong>th</strong>e feed ceases; OUR immediately drops to <strong>th</strong>e value, which is fixed by <strong>th</strong>e rate <strong>of</strong> Ss<br />
supply from <strong>th</strong>e hydrolysis <strong>of</strong> slowly degradable particular COD, Xs. In a batch test, an<br />
exponential decrease can be observed in respirogram after an initial peak formed due to <strong>th</strong>e<br />
presence <strong>of</strong> Ss in <strong>th</strong>e le<strong>ac</strong>hate. The concentration <strong>of</strong> Xs can also be assessed in a similar<br />
way (Kappeler and Gujer, 1992).<br />
To find out <strong>th</strong>e biodegradable component present in <strong>th</strong>e le<strong>ac</strong>hate, a le<strong>ac</strong>hate substrate<br />
concentration <strong>of</strong> 43.2 mg COD/L was injected into respirometer containing a sludge<br />
concentration <strong>of</strong> 924 mg VSS/L. OUR was measured at a temperature <strong>of</strong> 30 o C. The<br />
variation in OUR wi<strong>th</strong> time is shown in Figure 4.36. The readily biodegradable COD<br />
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