Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant
Conventional aerobic sludge stabilization is a power-intensive process. Another major upset is the resulting drop in mixed liquor pH (MLpH). Furthermore, the high concentration of ammonical nitrogen CN"H4-N) , nitrate nitrogen (N03-N), nitrite nitrogen (N02-N) and ortho-phosphate (P04-P) in the...
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| Formaat: | Thesis |
| Taal: | English English |
| Gepubliceerd in: |
2001
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| Onderwerpen: | |
| Online toegang: | http://psasir.upm.edu.my/id/eprint/11164/1/FK_2001_50.pdf |
| _version_ | 1825944871585710080 |
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| author | Hii, Siew Ling |
| author_facet | Hii, Siew Ling |
| author_sort | Hii, Siew Ling |
| collection | UPM |
| description | Conventional aerobic sludge stabilization is a power-intensive process. Another major upset is the resulting drop in mixed liquor pH (MLpH). Furthermore, the high concentration of ammonical nitrogen CN"H4-N) , nitrate nitrogen (N03-N), nitrite nitrogen (N02-N) and ortho-phosphate (P04-P) in the filtrate, could be a strong water-polluting agent. In this study, the anoxic-aerobic stabilization system incorporates, at regular intervals, non-aerated periods during aerobic stabilization. Four different stabilization modes (anoxic-aerobic, anoxic-aerobic with methanol, aerobic with lime control and aerobic) were applied to remove both the mixed liquor volatile suspended solids (MLVSS) and soluble nutrients simultaneously. Both the anoxic-aerobic systems were found to have higher solids decay rate, i.e., 0.064 dai1 and 0.057 dai1, respectively, as compared with lime-controlled (0.049 day-I) and aerobic systems (0.033 day-I). Anoxic-aerobic stabilization also maintained neutral MLpH levels at 'no cost', which is superior to daily lime dosing. The unfavorable environment within the aerobic digester (pH 5.51 - pH 6.59) is believed to retard the endogenous metabolisms of the sludge. The aerobic digester showed a significantly high build-up of NH4-N (95% higher) but lower
concentrations in both anoxic-aerobic and lime-controlled systems. Since both the anoxic-aerobic digesters experienced anoxic conditions on a regular basis, the peak
nitrate were much lower (2.6 mg/L in anoxic-aerobic digester and 1.4 mg/L in anoxic-aerobic digester with methanol). The addition of methanol did accelerate the denitrification process. In contrast, nitrate levels in the lime-controlled digester and aerobic digester were greater than 30.0 mg/L, which do not comply with the World Health Organization standards. Since P04-P is not lost from the digester as gas, the concentration in the four digesters increased with digestion time. The lowest P04-P levels in the lime-controlled digester could be a function of calcium
phosphate fonnation. In contrast, the highest level of P04-P in the fully aerobic digester was due to the low MLpH. Alkalinity was consumed and produced during the anoxic-aerobic stabilization process, thus, there was no net change in the alkalinity level. The experimental results indicate that the anoxic-aerobic digestion system is
definitely a suitable method for the stabilization of sludge, in terms of solids reduction and soluble nutrients removal. |
| first_indexed | 2024-03-06T07:22:42Z |
| format | Thesis |
| id | upm.eprints-11164 |
| institution | Universiti Putra Malaysia |
| language | English English |
| last_indexed | 2024-09-25T03:31:51Z |
| publishDate | 2001 |
| record_format | dspace |
| spelling | upm.eprints-111642024-05-30T06:57:03Z http://psasir.upm.edu.my/id/eprint/11164/ Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant Hii, Siew Ling Conventional aerobic sludge stabilization is a power-intensive process. Another major upset is the resulting drop in mixed liquor pH (MLpH). Furthermore, the high concentration of ammonical nitrogen CN"H4-N) , nitrate nitrogen (N03-N), nitrite nitrogen (N02-N) and ortho-phosphate (P04-P) in the filtrate, could be a strong water-polluting agent. In this study, the anoxic-aerobic stabilization system incorporates, at regular intervals, non-aerated periods during aerobic stabilization. Four different stabilization modes (anoxic-aerobic, anoxic-aerobic with methanol, aerobic with lime control and aerobic) were applied to remove both the mixed liquor volatile suspended solids (MLVSS) and soluble nutrients simultaneously. Both the anoxic-aerobic systems were found to have higher solids decay rate, i.e., 0.064 dai1 and 0.057 dai1, respectively, as compared with lime-controlled (0.049 day-I) and aerobic systems (0.033 day-I). Anoxic-aerobic stabilization also maintained neutral MLpH levels at 'no cost', which is superior to daily lime dosing. The unfavorable environment within the aerobic digester (pH 5.51 - pH 6.59) is believed to retard the endogenous metabolisms of the sludge. The aerobic digester showed a significantly high build-up of NH4-N (95% higher) but lower concentrations in both anoxic-aerobic and lime-controlled systems. Since both the anoxic-aerobic digesters experienced anoxic conditions on a regular basis, the peak nitrate were much lower (2.6 mg/L in anoxic-aerobic digester and 1.4 mg/L in anoxic-aerobic digester with methanol). The addition of methanol did accelerate the denitrification process. In contrast, nitrate levels in the lime-controlled digester and aerobic digester were greater than 30.0 mg/L, which do not comply with the World Health Organization standards. Since P04-P is not lost from the digester as gas, the concentration in the four digesters increased with digestion time. The lowest P04-P levels in the lime-controlled digester could be a function of calcium phosphate fonnation. In contrast, the highest level of P04-P in the fully aerobic digester was due to the low MLpH. Alkalinity was consumed and produced during the anoxic-aerobic stabilization process, thus, there was no net change in the alkalinity level. The experimental results indicate that the anoxic-aerobic digestion system is definitely a suitable method for the stabilization of sludge, in terms of solids reduction and soluble nutrients removal. 2001-08 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/11164/1/FK_2001_50.pdf Hii, Siew Ling (2001) Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant. Masters thesis, Universiti Putra Malaysia. Sewage - Treatment English |
| spellingShingle | Sewage - Treatment Hii, Siew Ling Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title | Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title_full | Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title_fullStr | Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title_full_unstemmed | Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title_short | Anoxic-Aerobic Stabilization of Settled Activated Sludge from A Sew Age Treatment Plant |
| title_sort | anoxic aerobic stabilization of settled activated sludge from a sew age treatment plant |
| topic | Sewage - Treatment |
| url | http://psasir.upm.edu.my/id/eprint/11164/1/FK_2001_50.pdf |
| work_keys_str_mv | AT hiisiewling anoxicaerobicstabilizationofsettledactivatedsludgefromasewagetreatmentplant |