Fundamental and application of aerobic granulation technology for wastewater treatment（2）

Source： | Date: 2011-05-04 | Hits:

Keywords:

Keyword

Biogranulation; Aerobic granules; Aerobic granulation; Microbial structure; Diversity; Mechanism of granulation;

Operatinal condition.

Introduction

Aerobic and anaerobic granulations involve cell-to-cell interactions that contain biological, physical and chemical

phenomena. In selective environment, microorganisms are capable of attaching to each other and aggregate.

Through self-immobilization of microorganisms, granules are formed. These dense microbial aggregates consist of

various bacterial species and typically contain millions of organisms per gram of biomass. These bacteria are

expected to play different roles in degrading wastewater containing various organic chemicals and removing of

nutrients. As compared to conventional activated sludge flocs, granular sludge has regular, denser and stronger

microbial structure and good settling ability. These characteristics result in high biomass retention and withstand

high-strength wastewater and shock loadings.

In the Netherlands, granular sludge was discovered in 1976 in a 6m³ pilot plant at the CSM sugar factory in Breda.

Granular sludge with good settling ability and methanogenic activity has now been extensively applied to anaerobic

wastewater treatment system and studied in the upflow anaerobic sludge blanket (UASB) reactor. Anaerobic

granular sludge is a dense microbial community that typically includes millions of organisms per gram of biomass.

None of the individual species in these microecosystems is capable of completely degrading the influent wastes.

Complete degradation of industrial waste involves complex interactions between the resident species. Thus, granular

sludge reactors are desirable in wastewater biological treatment processes because a very high number of organisms

can be maintained in the bioreactor. Therefore, large volumes of waste can be treated in compact bioreactors.

However, some drawbacks of the anaerobic granulation technology include the need for a long start-up period, a

relatively high operation temperature and unsuitability for low strength organic wastewater. Anaerobic granulation

technology is not suitable for the removal of nutrients from wastewater. In order to overcome those weaknesses,

research has been devoted to the development of aerobic granulation technology.

The development of aerobic granules was first reported by Mishima and Nakamura (1991) in a continuous aerobic

upflow sludge blanket reactor. Aerobic granules with diameters of 2 to 8 mm were developed, with good settling

properties. Aerobic granulation has been observed in sequencing batch reactors (SBRs) (Morgenroth et al., 1997;

Beun et al., 1999; Peng et al., 1999; Etterer and Wilderer, 2001; Tay et al., 2001a; Liu and Tay, 2002). It has been

utilized in treating high-strength wastewaters containing organics, nitrogen and phosphorus, and toxic substances

(Jiang et al., 2002; Moy et al., 2002; Tay et al., 2002e; Lin et al., 2003). However, the granulation process of aerobic

sludge has not been well studied.

Pre: Fundamental and application of aerobic granulation technology for wastewater treatment（1）

Next: Fundamental and application of aerobic granulation technology for wastewater treatment（3）

News

Products

ZDG Series vacuum vibrating dryer（Specially for lithium battery)
YQJ Series Rotary Disc Dryer（Horizontal rotary disc dryer/Horizontal rotary disc paddle dryer)
LDG Series Vertical single-conical ribbon mixer dryer
HYD Series Rotary Calciner (calcination kiln)
GWD Series high temperature belt calciner
FWD Series Multi-functions filter washing drying machine
FGBX series Sealed -Circuit Circulation Fluidizing Dryer
HDT Series Post Hopper Mixer( Post Bin Blender)