Influence of flow velocity on performance of a low loaded downflow biofilter

• Autorzy: Albuquerque, A.

Warianty tytułu

PL

Wpływ prędkości przepływu na wyniki pracy nisko obciążonego biofiltru spływowego

• Języki publikacji: EN

Abstrakty

EN

Laboratory tests were carried out to assess the influence of flow velocity on the performance of a downflow biofilter treating a domestic wastewater with low concentration of organic carbon. Flow velocities ranged from 0.26 to 0.65 m h-1, corresponding to hydraulic retention times from 19.5 to 48.6 minutes, and the incoming organic load ranged from 41.5 to 47.0 g C m-3 h-1. The performance of the biofilter, filled with puzzolane grains, was analysed in terms of total organic carbon (TOC) removal and total suspended solids (TSS) removal. The effect of varying flow velocity on biofilter performance was analysed taking into account the hydrodynamic characteristics observed in two media sections (TM - P1 and TM - P2) and for the total media depth. The highest TOC removal efficiency was observed for the lower velocity reaching 40.2% of the total incoming organic load. For velocities between 0.39 and 0.65 m h-1 the total organic load removal rate (rv C) was stable with values ranging from 26.3 to 33.6 g C m-3 h-1 corresponding to TOC removal efficiencies from 28.6 to 37.8%. In the upper filter section (TM - P1) a higher removal of organic carbon (deltaC) and TSS (deltaTSS) was observed, which seemed to be related to the occurrence of large dispersion conditions and the likely presence of completely mixed regime. The TSS removal was stable within the range of applied flow rates and seemed to not be influenced by the flow velocity. However, to maintain a good performance the biofilter should be washed every five days of the operating period. The results showed that this type of device would be very useful to reduce the residual organic and solid loads present in secondary treated domestic wastewaters minimizing environmental impacts on receiving waters. The final effluent characteristic indicated that in can be used for some reuse purposes. These last conclusions make admit thas this type of biofilter may be used as a useful tool to help water resources authorities to fulfil some objectives defined by the European Water Directive (Directive 2000/60/EC).

PL

Aby ocenić wpływ prędkości przepływu na wyniki pracy nisko obciążonego biofiltru spływowego, oczyszczającego ścieki domowe o niskim stężeniu węgla organicznego przeprowadzono badania laboratoryjne. Prędkości przepływu były w przedziale od 0,26 do 0,65 mh-1, co odpowiada hydraulicznym czasom zatrzymania od 19,5 do 48,6 minut, a ładunek organiczny był w przedziale od 41,5 do 47,0 gCm-3h-1. Wyniki pracy biofiltru napełnionego ziarnami pucolanowymi, były analizowane pod względem usuwania całkowitego węgla

Słowa kluczowe

PL

prędkość przepływu; biofiltr spływowy; oczyszczanie ścieków

EN

flow velocity; downflow biofilter; organic carbon

• Czasopismo: Zeszyty Naukowe. Budownictwo / Politechnika Śląska
• Rocznik: 2004
• Tom: z. 102
• Strony: 31-41
• Opis fizyczny: Bibliogr. 12 poz.

Twórcy

autor

Albuquerque, A.

• University of Beira Interior, Covilha, Portugal

Bibliografia

• 1. Akunna J., Bizeau C., Moletta R., Bemet N., Héduit A.: Combined organic carbon and complete nitrogen removal using anaerobic and aerobic upflow filters. Water Science and Technology, V. 30, N.° 12, 1994, p. 297-306.
• 2. Albuquerque A.: Contribuição para o estudo da remoção de carbono residual em filtros biológicos de leito imerso e fluxo descendente. PhD Thesis, University of Beira Interior, Covilhá 2003, Portugal, p.441 (in Portuguese).
• 3. Albuquerque A., Santana F.: Hydrodynamic behaviour of a biological packed bed under different hydraulic and organic loading. 2nd International Conference on Applications of Porous Media 2004 (ICAPM 2004), Évora 2004, Portugal, 24 - 27 May 2004, p. 319-327.
• 4. Apha: Standard methods for the examination of water and wastewater. 19lh edition, American Public Health Association, American Water Works Association, Water Environment Federation, Washington DC 1995, USA, p.1220.
• 5. Crites R., Tchobanoglous G.: Small and decentralized wastewater management systems. McGraw-Hill International Edit., New York 1998, USA, p. 1084.
• 6. Fdz-Polanco F., Garcia P., Villaverde S.: Adsorption and diffusion effects on the residence time distribution of submerged biofilters. Env. Technology, 17, 1996, p. 687-696.
• 7. Grady JR W., Daigger G., Lim H.: Biological wastewater treatment. 2nd Edition, Marcel Decker, Basel 1999, Switzerland, p. 1076.
• 8. Inag: Águas residuais urbanas. Technical report (in Portuguese). Instituto da Agua, MAOT, Lisboa 2000, Portugal (http://snirh.inag.pt/snirh/dados_sintese/insb/insb.html).
• 9. Karamanev D., Belanger M., Chavarie C.: Hydrodynamic characteristics of a trickling bed of peat moss used for biofiltration of wastewater. The Canadian J. Chem. Eng., 1994, 72, 6, p. 411-417.
• 10. Nouvion N., Block J., Faup G.: Effect of biomas quantity and activity on TOC removal in a fixed-bed reactor. Water Research, 1987, V. 21, N°. 1, p. 35-40.
• 11. Silva G., Franson R., Gonsalves R.: Filtros biológicos percoladores para pós-tratamento de efluentes anaerobios em pequeñas comunidades. In Actas do XXII Congresso Brasileiro de Engenharia Sanitaria, Joinville 2003, Santa Catarina, Brasil, p. 6 (in Portuguese).
• 12. Tay J., Show K.: Media-induced hydraulic behaviour and performance of upflow biofilters. Journal of Env. Eng., 124, 8,1998, p. 720-729.