title: Novel design and optimisation of a nitritation/anammox set-up for ammonium removal from filtrate of digested sludge.
abstract: Although the anammox process is extensively applied for the treatment of NH4-rich wastewater, new technical solutions overcoming the operational difficulties remain an important task. An innovative design of anammox-based set-up was employed to improve sludge settling under high ammonium load. The set-up included a completely mixed bioreactor with suspended and immobilised activated sludge. To prevent sludge flotation, recycled suspended sludge was additionally treated in an aerated tank at dissolved oxygen (DO) concentration of 1.5 ± 0.2 mg/l followed by processing in a flow-homogeniser. Introduction of these elements resulted in a 3.5-fold increase in total nitrogen removal efficiency (TNRE). The bioreactor achieved maximal TNRE of 86% corresponding to total nitrogen removal rate of 0.77 kg N/m3/d under defined optimal conditions: temperature of 35 ± 2°C, DO of 0.6 ± 0.2 mg/l, hydraulic retention time of 12 h, and dose of suspended sludge of 1.5 ± 0.1 g total suspended solids (TSS)/l. A weakly attached sludge was first described as a technologically important factor. Suspended, weakly and firmly attached sludge exhibited the highest heterotrophic, nitrifying, and anammox activities, respectively. New probes were constructed to detect anammox bacteria by fluorescence in situ hybridisation. Probe for Candidatus 'Jettenia' could be recommended for widespread use.
authors.affiliation: a Wastewater and Sludge Treatment Division of Engineering and Technology Centre , JSC Mosvodokanal , Moscow , Russia.
authors.forename: Yury
authors.initials: Y
authors.lastname: Nikolaev
authors.affiliation: b Winogradsky Institute of Microbiology , The Research Center of Biotechnology of Russian Academy of Sciences , Moscow , Russia.
authors.forename: Anna
authors.initials: A
authors.lastname: Kallistova
authors.affiliation: a Wastewater and Sludge Treatment Division of Engineering and Technology Centre , JSC Mosvodokanal , Moscow , Russia.
authors.forename: Marina
authors.initials: M
authors.lastname: Kevbrina
authors.affiliation: a Wastewater and Sludge Treatment Division of Engineering and Technology Centre , JSC Mosvodokanal , Moscow , Russia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dorofeev
authors.affiliation: a Wastewater and Sludge Treatment Division of Engineering and Technology Centre , JSC Mosvodokanal , Moscow , Russia.
authors.forename: Anton
authors.initials: A
authors.lastname: Agarev
authors.affiliation: c Centre 'Bioengineering' , The Research Center of Biotechnology of Russian Academy of Sciences , Moscow , Russia.
authors.forename: Andrey
authors.initials: A
authors.lastname: Mardanov
authors.affiliation: c Centre 'Bioengineering' , The Research Center of Biotechnology of Russian Academy of Sciences , Moscow , Russia.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Ravin
authors.affiliation: a Wastewater and Sludge Treatment Division of Engineering and Technology Centre , JSC Mosvodokanal , Moscow , Russia.
authors.forename: Michail
authors.initials: M
authors.lastname: Kozlov
authors.affiliation: b Winogradsky Institute of Microbiology , The Research Center of Biotechnology of Russian Academy of Sciences , Moscow , Russia.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Pimenov
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis* / Q000378:metabolism; D000693:Anaerobiosis; D052837:Chemoautotrophic Growth; D009584:Nitrogen / Q000032:analysis; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen
keywords: Nitritation/anammox process; intermediate aeration; reject water; sludge flotation; sludge homogenisation