Sustainable nitrification in fluidised bed reactor with immobilised sludge pellets

Abstract

Sustainable immobilised microbial pellets were developed with water-borne polyurethane (WPU) material together with powdered activated carbon (PAC) and activated sludge as microbial inoculums for nitrification or partial nitrification. The nitrification performance and the influencing factors were studied with lab-scale aerobic fluidised bed reactors (FBR) under various temperature conditions. During the start-up period, quickly increasing the influent ammonium concentration from 40 to 320 mg N·ℓ -1 led to a stable nitrification performance with high nitrite accumulation (>80%). Characterisation of the FBR performance indicated that the desired partial nitrification could be achieved at pH 7.8-8.5, dissolved oxygen (DO) 3-5 mg·ℓ -1 and temperature between 24 and 29°C. Addition of organic carbon (glucose) improved the ammonium removal but decreased the nitrite accumulation ratio significantly. TOC concentration above 800 mg·ℓ -1 was not able to cause the inhibition of the heterotrophs over the nitrifiers. PCR-DGGE results indicated the presence of Nitrosomonas (ammonia-oxidising bacteria) and Nitrobacter (nitrite-oxidising bacteria) in the immobilised pellets.

Simulation of Bubble Behavior Characteristics in a Rolling Fluidized Bed with the Addition of Longitudinal Internal Members

“…After the gas-solid bubbling fluidized bed is applied to rolling environments such as floating platforms and ships in the ocean, the rolling amplitude, rolling period, and apparent gas velocity will affect the bubble behavior [15]. Considering the periodic effects of the rolling process on the gas-solid flow in the fluidized bed [19], as well as the gas-solid interactions, a novel longitudinal internal member was designed, as shown in Figure 2a [26], which was mounted at the position shown in Figure 1a, with its bottom 100 mm from the bottom of the fluidized bed. As shown in Figure 2a, the longitudinal internal members consist of a lower support plate structure, a middle curved plate structure, and an upper support plate structure.…”

Construction of Nitrification Model With Nitrifying Coal Ash in Aerobic Treatment of High Strength Wastewater

“…(Chaali et al, 2021;Parker et al, 2002;Li et al, 2013;Han & Park, 2012). After enrichment, the nitrifying carrier were also widely used for improving sustainable nitrification in lab-scale and full-scale (Wang et al, 2013;Liu et al, 2018). However, the nutrients utilization mechanism of nitrifying carrier should be focused, and a better understanding of nutrients availability is essential to control aquatic environment.…”

Isolation and characterization of nitrogen removal bacteria from sewage and fecal sludge of dairy cow farms in Cu Chi, Ho Chi Minh City, Vietnam

“…Anammox is a type of ammonia oxidation under an anoxic condition that was first discovered in 1999. Anammox bacteria oxidize ammonia to nitrogen gas by using nitrite as an electron acceptor but not produce nitric oxide and nitrous oxide, which is considered intermediate products of the denitrification [3][4][5]. Besides the nitrifying-, denitrifying-and anammox-bacteria have just mentioned, bacteria that are able to assimilate ammonia, nitrite and nitrate have also been reported [6][7][8].…”