Particulate-biofilm, expanded-bed technology for high-rate, low-cost wastewater treatment: Nitrification

Abstract

The performance of a particulate-biofilm, expanded-bed process for nitrification of activated sludge final effluent (ASFE) is reported for a plant receiving mixed industrial and domestic wastewater. The support material for the particulate-biofilms was glassy coke, to which the nitrifying bacteria attached and formed a highly active biofilm. An average nitrification rate of 1.7+/-0.6 kg m(expanded bed)(-3)d(-1) was recorded during operation of the bioreactor, which had a hydraulic residence time of 15 min. On average, the ASFE contained 12.6+/-3.7 g m(-3) NH3-N, which was reduced to 2.6+/-3.3 g m(-3) NH3-N. Furthermore, transfer of 10-12% of the oxygen in air was achieved using counter-current aeration. This investigation has demonstrated that a high rate of nitrification can be achieved with a particulate-biofilm, expanded-bed process. It has also demonstrated that the process can operate without backwashing and still remove particulate material from the ASFE feed.

Simultaneous removal of ammonia, P and COD from anaerobically digested piggery wastewater using an integrated process of chemical precipitation and air stripping

“…The further removal of NH 3 -N and total P from anaerobically digested liquor can be conducted using air stripping [8][9][10][11][12] and struvite precipitation [13][14][15][16]. Compared with the usually used biological processes [17][18][19][20][21][22][23][24][25], the physicochemical method cannot only remove ammonia and P, but also recover them as valuable products such as NH 3 and MgNH 4 PO 3 , which can be used as fertilizers. In addition, these processes are a time and energy-saving process.…”

Air stripping of ammonia in a water-sparged aerocyclone reactor

“…Moreover, wastewaters containing ammonia are often toxic, which makes their biological treatment unfeasible [2]. Such adverse effects of ammonia promote the development of various techniques for its removal for instance, biological nitrification-denitrification [3,4], air stripping [5][6][7][8][9], struvite precipitation [10][11][12][13], membrane separation [1], catalytic liquid-phase oxidation [2], and selective ion exchange [14].…”

Using porous ceramic media in the upflow packed-bed reactor (UPBR) system for nitrogen removal via autotrophic nitrification and denitrification

“…The calculated specific nitrification rate resulted 1.73-2.29 kg NH 4 + -N m −3 CERAMED-L d −1 , with a F/M ratio in the range 0.08-0.31 g NH 4 + -N g −1 VS d −1 , and was higher with respect to rates reported by other investigators. [25,26] The nitrification efficiencies shown in Figure 4(a) and (b) were plotted as a function of volumetric NH 4 + -N loading rates, and a linear regression is presented in Figure 4(c). The nitrification efficiency profiles for EBCTs of 6 and 8 h, for the UPBR-n, exhibited a significant (R 2 = 0.93 and 0.99) linear relationship with the volumetric NH 4 + -N loading rate.…”