| Title |
Advancd Treatment by Biological Processes - Biological Nutrient Removal |
| Authors |
( Paul F . Greenfield ; Kin Man Ho ; Linda L . Blackall ; Peter R . F . Bell ; Andre Krol ) |
| Abstract |
Biological phosphorus and nitrogen removal and related sludge bulking control in both intermittent cyclic and continuous activated sludge systems are assessed. Experimental results from a laboratory-scale investigation using fermented domestic sewage indicated the advantages of achieving high levels of P ana N removal and good sludge-settling properties using the intermittent cyclic process, as compared to the space-oriented operation of a continuous facility. Accordingly, this cost-effective, simple and reliable technology is receiving wide acceptance as an appropriate technology for not only small treatment applications but in creasingly for large installations. The modified intermittently fed and decanted system incorporating non-mixing sequences produced an effluent quality of NO₃-N$lt;5 ㎎/ℓ, PO₄-P$lt; 1 ㎎/ℓ and NH₃-N$lt;2 ㎎/ℓ, with a nonbulking sludge having a sludge volume index $lt; 120 ㎖/g, despite unfavourable influent characteristics (TCOD:TKN $lt; 7, TKN$gt; 60㎎/ℓ, TP - 7 - 10 ㎎/ℓ and RBCOD $lt;30㎎/ℓ). In contrast, the modified 4-stage Bar-denpho process could not achieve an effluent PO₄-P concentration of $lt; 1 ㎎/ℓ The effluent NO₃-N concentration and sludge volume index (SVI) were always high and occasionally reached 16 ㎎/ℓ and 422 ㎖/g, respectively. The causative filaments were identified to be the low F:M growers - Types 0041/0675. |