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Objectives of Biological Treatment1. Transform dissolved and particulate p
biodegradable constituents into acceptable end products.
2. Capture and incorporate suspended and nonsettleable colloidal solids into a biological floc or biofilm.T f d t i t (N & P)3. Transform and remove nutrients (N & P)
4. In some cases, remove specific trace organic constituents and compounds.
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BiodegradasiSalah satu faktor yang berpengaruh pada Salah satu faktor yang berpengaruh pada pertumbuhan mikroba: Oksigen (aerob, anaerob, fakultatif)Masing‐masing mengikuti mekanisme yang berbeda
Biodegradasi AerobFungsi OksigenFungsi Oksigen1. Electron acceptor
Fungsi oksigen bisa digantikan oleh senyawa lain, eg. Nitrat, sulfat, hidrogen. Biodegradasi tetap berlangsung meskipun oksigen terbatasPolutan + O2 CO2 + H2O + biomassa
2. Reaksi enzymatisBiodegradasi berhenti jika oksigen tidak ada
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Biodegradasi AnaerobPolutan CH4 + CO2 + biomassaDua tahap prosesDua tahap proses
Organic acid
Methane formingBacteria
CH4 and CO2
CO2 and CH4
H2S
Second Stage
Organic matter
Acid forming Bacteria (fakultatif) First
Stage
•Anaerob•Sensitif thd pH
Masalah umum: organic shock loading
Anaerob vs AerobAnaerob:
Kelebihan KeterbatasanProduksi biomassa (sludge) rendah dan stabilKebutuhan nutrient rendahTdak memerlukan energi untuk aerasiMenghasilkan gas metan (sbg bahan bakar)Organic loading rates (org/vol waktu) tinggi
Proses sensitif, khususnya dari organic shock loadingWaktu start‐up relatif lama (pertumb mo lambat)Perlu post‐treatment
(org/vol.waktu) tinggiSludge tetap aktif meskipun tdk ada umpan dalam waktu lama
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Types of aerobic processesType Comon name Use
Suspended th
Activated sludge } BOD removalgrowth Aerated lagoonAerobic digestion
} BOD removalStabilization, BOD removal
Attached growth
Trickling filterRotating biological contactor }BOD lcontactorPacked bed reactor
}BOD removal
Hybrid (combined) suspende & attached
Trickling filter/ Activated sludge
BOD removal
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Effect of filamentous organisms in activated sludge on morphology and settleability: a) and b) inter‐floc bridging; c) and d) diffuse floc structure bar = 100 micrometers
a) pin floc; b) small, weak flocs; c) flocs contining filamentous organisms; d) flocs containing filamentous organism “network" or “backbone.“ Bar = 10 micrometers
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Aerated lagoon
Aerial view of theVeazie Sanitary District's aerated lagoon system.
Trickling filterRotating biological contactor
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Trickling filterA trickling filter consists of a fixed bed of rocks, gravel, slag, polyurethane foam, sphagnum peat moss, or plastic media over which sewage or other wastewater flows downward and is contacted with a layer or fil f i bi l li film of microbial slime covering the bed media.
A typical complete trickling filter system
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Trickling filterThe process mechanism involves:
• adsorption of organic p gcompounds in the sewage or other wastewater by the layer of microbial slime,
• diffusion of air into the slime layer to furnish the oxygen required for the biochemical oxidation of the organic gcompounds to release carbon dioxide gas, water and other oxidized end products.
Rotating biological contactor
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Types of anaerobic processesType Comon name Use
Suspended growth
Anaerobic contact processAnaerobic digestion
BOD removalgrowth Anaerobic digestion
Stabilization, solid destruction, pathogen kill
Attached growth Anaerobic packed and fluidized bed
BOD removal, stabilization
Sludge blanket Upflow anaerobic sludge blanket
BOD removal (esp. high strength)blanket strength)
Hybrid (combined) suspende & attached
Upflow sludge blanket/attached growth
BOD removal
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