7.5 Characterization of Municipal Wastewater
97
7.5 Characterization of Municipal Wastewater
Before going for any laboratory study on municipal wastewater, the same was characterized for all the relevant parameters. The parameters selected for characterization of the raw municipal wastewater are pH, total alkalinity, chemical oxygen
demand (COD), biochemical oxygen demand (BOD3 at 27 °C), total solids (TS),
total suspended solids (TSS), total dissolved solids(TDS), total Kjeldahl Nitrogen
(TKN), PO
3−
4 and NO
2−
3 . The purpose of characterization of wastewater was to
study the nature of the same and to know the present strength of the wastewater. The
detailed characterization of the municipal wastewater was performed in the laboratory following the Standard Methods (1998) and the results of same are tabulated in
Table 7.1.
7.6 Acclimation of Biomass and Its Enrichment
For the sake of acclimation, the sludge from one ASP unit was collected and then it
was fed with gradually increasing amount of municipal wastewater. The municipal
wastewater was fed under batch mode to a bucket of 10-L liquid volume over 21 days.
The progress of acclimation was monitored by taking sample at the beginning and
at the end of a particular batch period. There are two phases of monitoring Phase A
during summer and Phase B during monsoon.
The parameters, viz. pH, MLSS, COD and BOD3 at 27 °C were regularly
measured at every 24 h interval from initial feeding. The purpose of monitoring
in two phases is to see the effect of seasonal fluctuations on biological acclimation.
It was observed in Phase B, i.e., in rainy season, the municipal wastewater was found
diluted resulting in lower value of initial COD compared to Phase A. Under Phase
A, initial COD value was in the range of 127–278 mg/l, whereas the final COD value
ranged from 51–150 mg/l. The initial COD value for Phase B was observed to be
between 64 and 112 mg/l, whereas the final COD value ranged from 12 to 26 mg/l.
The BOD to COD ratio was found to be in the range of 0.7–0.8 during the acclimation
study. The pH value was observed satisfactorily in the range between 7.1 and 7.7 in
both Phase A and Phase B throughout the acclimation period. The MLSS (biomass)
concentration was measured at the initial and the final stage of the batch acclimation
and the average value was noted. The results of the acclimation study are shown in
Table 7.2.
The variation of initial and final COD profile in the periodic batch study for Phase
A is shown in Fig. 7.2 and that of Phase B is shown in Fig. 7.3.
97
7.5 Characterization of Municipal Wastewater
Before going for any laboratory study on municipal wastewater, the same was characterized for all the relevant parameters. The parameters selected for characterization of the raw municipal wastewater are pH, total alkalinity, chemical oxygen
demand (COD), biochemical oxygen demand (BOD3 at 27 °C), total solids (TS),
total suspended solids (TSS), total dissolved solids(TDS), total Kjeldahl Nitrogen
(TKN), PO
3−
4 and NO
2−
3 . The purpose of characterization of wastewater was to
study the nature of the same and to know the present strength of the wastewater. The
detailed characterization of the municipal wastewater was performed in the laboratory following the Standard Methods (1998) and the results of same are tabulated in
Table 7.1.
7.6 Acclimation of Biomass and Its Enrichment
For the sake of acclimation, the sludge from one ASP unit was collected and then it
was fed with gradually increasing amount of municipal wastewater. The municipal
wastewater was fed under batch mode to a bucket of 10-L liquid volume over 21 days.
The progress of acclimation was monitored by taking sample at the beginning and
at the end of a particular batch period. There are two phases of monitoring Phase A
during summer and Phase B during monsoon.
The parameters, viz. pH, MLSS, COD and BOD3 at 27 °C were regularly
measured at every 24 h interval from initial feeding. The purpose of monitoring
in two phases is to see the effect of seasonal fluctuations on biological acclimation.
It was observed in Phase B, i.e., in rainy season, the municipal wastewater was found
diluted resulting in lower value of initial COD compared to Phase A. Under Phase
A, initial COD value was in the range of 127–278 mg/l, whereas the final COD value
ranged from 51–150 mg/l. The initial COD value for Phase B was observed to be
between 64 and 112 mg/l, whereas the final COD value ranged from 12 to 26 mg/l.
The BOD to COD ratio was found to be in the range of 0.7–0.8 during the acclimation
study. The pH value was observed satisfactorily in the range between 7.1 and 7.7 in
both Phase A and Phase B throughout the acclimation period. The MLSS (biomass)
concentration was measured at the initial and the final stage of the batch acclimation
and the average value was noted. The results of the acclimation study are shown in
Table 7.2.
The variation of initial and final COD profile in the periodic batch study for Phase
A is shown in Fig. 7.2 and that of Phase B is shown in Fig. 7.3.