Suspended carrier technology allows upgrading high-rate activated sludge plants for nitrogen removal via process intensification

Abstract

The Oxley Creek wastewater treatment plant is a conventional 185,000 EP BOD removal activated sludge plant that is to be upgraded for nitrogen removal to protect its receiving water bodies, the Brisbane River and Moreton Bay. Suspended carrier technology is one possible way of upgrading this activated sludge wastewater treatment plant for nitrogen removal. Freely moving plastic media is added to the aeration zone, providing a growth platform for nitrifying bacteria and increasing the effective solids residence time (SRT). This paper presents the results from operating a pilot plant for 7 months at the Oxley Creek WWTP in Brisbane, Australia. Natrix Major 12/12 plastic media, developed by ANOX (Lund, Sweden), was trialed in the pilot plant. The pilot plant was operated with a mixed liquor suspended solids concentration of 1220 mg/L and a total hydraulic residence time of 5.4 hours, similar to the operating conditions in the full-scale Stage 1&2 works at the Oxley Creek WWTP. The plastic carriers were suspended in the last third of the bioreactor volume, which was aerated to a DO setpoint of 4.0 mg/L. The first third of the bioreactor volume was made anoxic and the second third served for carbon removal, being aerated to a DO setpoint of 0.5 mg/L. The results from the pilot plant indicate that an average effluent total inorganic nitrogen concentration (ammonia-N plus NOx−N) of less than 12 mg/L is possible. However, the effluent ammonia concentrations from the pilot plant showed large weekly fluctuations due to the intermittent operation of the sludge dewatering centrifuge returning significant ammonia loads to the plant on three days of the week. Optimising denitrification was carried out by lowering the DO concentration in the influent and in the carbon removal reactor. The results from the pilot plant study show that the Oxley Creek WWTP could be upgraded for nitrogen removal without additional tankage, using suspended carrier technology.

Biohydrogen production from glucose in upflow biofilm reactors with plastic carriers under extreme thermophilic conditions (70°C)

“…However, it requires a long start-up period (e.g., 120 days) if granules are formed inside the reactor itself (Chang et al, 2002;Chen et al, 2006). On the other hand, carriers have been successfully used in various systems for wastewater treatment in both lab-scale and fullscale systems as the solid support for microbial attachment (Rodgers and Zhan 2004;Von Munch et al, 2000). In addition, no investigation on feasibility of using biofilm reactor for biohydrogen production has been previously reported.…”

Development of a membrane‐assisted hybrid bioreactor for ammonia and COD removal in wastewaters

“…1 Some representative examples of laboratory-and full-scale hybrid systems are the Pegasus, 2 the Biolift reactor, 3 a hybrid biofilm airlift-activated sludge reactor 4 and an activated sludge system in which a plastic support was added to the reactor in order to promote nitrification. 5,6 The control of the suspended solid concentration and the retention of the biofilm media have been reported as the main operational problems of these technologies.…”

Bat for fiskeopdræt i norden

“…Fordelen ved MBBR-processen er dens kompakthed, som vaesentligt overstiger de faste mediers med hensyn til specifik overfladeareal samt processens selvrensende evne til at opretholde en relativ tynd biofilm på ydersiden af mediet. Det størst opnåelige specifikke overfladeareal vurderes teoretisk at ligge omkring 500 m2/m 3 (Lazarova, 2000) (Øde-gaard, 1994) (AEsøj, 1998) (Rusten, 1995) (Münch, 2000), men det skal anføres, at en del af det beregnede areal (ca. halvdelen) afskaermes fra konvektiv strømning, hvilket resulterer i vaesentlig reduceret omsaetning på grund af kraftig påvirkning fra den hydrauliske filmdiffusion, som dannes over biofilmen.…”