Bioprecipitation as a Bioremediation Strategy for Environmental Cleanup 33

Table 2.5. Ex-situ reactor designs for bioprecipitation (Adapted from Kaksonen and Puhakka 2007, Kiran et al. 2017,

Speece 1983).

Method

Design

Advantages & Disadvantages

Continuously

Advantages:

Stirred Tank

- High performance

Reactor (CSTR)

- Reliable

Disadvantages:

- Poor biomass retention

Anaerobic Contact

Advantages:

Press (ACP)

- Good biomass retention

Disadvantages:

- Breakdown of flocs and sludge due to high shear

force

Upflow Anaerobic

Filter Reactor

(UAFR)

Advantages:

- Good sludge retention

- Low shear force

Disadvantages:

- Channeling due to shear force

- Large pressure gradients

Downflow

Advantages:

Anaerobic Filter

- Utilizes gravitation force

Reactor (DAFR)

- Good sludge retention

- Low shear force

Disadvantages:

- Channeling due to shear force

- Large pressure gradients

Fluidized-Bed

Advantages:

Reactor (FBR)

- Large surface area for biofilm

- Good biomass retention

- Small pressure gradients

- No channeling or clogging

- Large mass transfer rates

Disadvantages:

- Biomass loss due to shear force

- Energy requirement

Table 2.5 contd. ...