Abstract
In the external nitrification (EN) biological nutrient removal (BNR) activated sludge (AS) system, the nitrification process is removed from the BNR activated sludge system and performed eexternallyf on an integrated nitrifying trickling filter (NTF). As such, optimum design and operation of the NTF is essential for reliable performance of the ENBNRAS system. Although information on the design and operation of NTFs is available in the literature, this experience is not directly applicable to the NTF in the ENBNRAS system. To address this deficiency, a full-scale ENBNRAS prototype was implemented at the Daspoort Wastewater Treatment Works (DWWTW) in Tshwane, South Africa. In this investigation an average apparent nitrification capacity of approximately 1.25 to 1.29 gN per m2 of media surface area per day [gN/(ms2Ed)] ammonia removal was determined for 2 existing rock media TFs retrofitted as NTFs in the prototype ENBNRAS system (nominal surface area of 45 ms2/m3 for the rock media). This nitrification capacity corresponded to a removal efficiency of about 14 mgN/. (96%), or 149 kgN/d, of the influent ammonia load applied to the NTFs (average influent flow rate of 10 M./d). General concordance was found with corresponding nitrate and nitrite production and alkalinity usage measurements, which substantiated the observed removal performance. This paper details determination of the nitrification capacity of the 2 rock media NTFs used in the prototype ENBNRAS system.
Highlights
In the external nitrification (EN) biological nutrient removal (BNR) activated sludge (AS) system, the nitrification process is removed from the BNR activated sludge system and performed ‘externally’ on an integrated nitrifying trickling filter (NTF) system (Hu et al, 2000; 2003)
Information on the design and operation of NTFs is well established in the literature (Boller and Gujer, 1986; Lutz et al, 1990; Parker et al, 1989; 1995), this experience is limited to tertiary treatment applications
This paper describes determination of the nitrification capacity of the rock media NTFs used in this implementation
Summary
In the external nitrification (EN) biological nutrient removal (BNR) activated sludge (AS) system, the nitrification process is removed from the BNR activated sludge system and performed ‘externally’ on an integrated nitrifying trickling filter (NTF) system (Hu et al, 2000; 2003). Information on the design and operation of NTFs is well established in the literature (Boller and Gujer, 1986; Lutz et al, 1990; Parker et al, 1989; 1995), this experience is limited to tertiary treatment applications. NTF design for tertiary treatment typically recommends plastic media, flooding capability for predator control, forced ventilation, continuous dosing and a well clarified secondary treated effluent as influent (Parker et al, 1989;1995). NTF performance as an integral unit process within ENBNRAS systems, in combination with an upstream internal settling tank (IST), is lacking. Where such information has been developed, it has been within the area of research investigating the potential for anoxic P-uptake during denitrification (e.g. Wanner et al, 1992; Bortone et al, 1996; Kuba et al, 1996). The main advantage of anoxic P-uptake is purportedly in using the same substrate for
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
