Effect of prefermentation on inert COD fractions in BNR systems

    Authors

    G. Eremektar; A. A. Randall;T. McCue

    Comments

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    Abbreviated Journal Title

    Fresenius Environ. Bull.

    Keywords

    BNR systems; modified UCT systems; prefermentation unit; inert COD; fractions; 2-STAGE TREATMENT; FATE; Environmental Sciences

    Abstract

    Biological nutrient removal systems (BNR) such as the Modified UCT (MUCT) process have an anaerobic, anoxic, and an aerobic zone for both biological phosphorus and nitrogen removal. In addition a prefermentation unit can be used to enhance these removals. In BNR systems the anaerobic zone is where volatile fatty acids (VFAs) are sequestered and transformed to polyhydroxyalkanoates (PHAs) and release of phosphorus occurs. In subsequent anoxic and aerobic zones PHA is degraded and phosphorus uptake occurs. The presence of high levels of VFAs in the anaerobic phase result in elevated amounts of PRA formation and phosphorus release. Prefermentation converts readily degradable influent COD to VFAs, and enhances PHA formation and anaerobic phosphorus release. In addition other fractions of the wastewater which also affect BNR performance are transformed. In this context, the changes in inert COD fractions of domestic wastewater treated with prefermentation were compared with those in the non-prefermented wastewater. Changes in the inert COD fractions of the raw domestic wastewater were subjected to fractionation. The prefermented and non-prefermented wastewaters fed two parallel and identical MUCT systems. The experiments discussed in this paper were done for a COD limited/septic wastewater. The fractionation procedure was done according to Germirli et al [1]. The COD fractions in wastewaters are defined: initially inert particulate (XI), initially inert soluble (SI), particulate inert metabolic products (Xp), soluble residual metabolic products (Sp). The results show that the inert soluble fraction (sum of S, and Sp) was reduced from 11% of total influent COD (C-T0) to 7%. This has potential ramifications on process performance.

    Journal Title

    Fresenius Environmental Bulletin

    Volume

    13

    Issue/Number

    10

    Publication Date

    1-1-2004

    Document Type

    Article; Proceedings Paper

    Language

    English

    First Page

    1033

    Last Page

    1035

    WOS Identifier

    WOS:000225520100026

    ISSN

    1018-4619

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