Environmental Engineering Reference
In-Depth Information
measurements in a wide variety of small sample applications in environmental
engineering and life sciences.
Keywords
Needle-type sensors
·
Multi-analyte sensors
·
MEMS
·
In
situ
measurements
·
Biofilms
·
Dissolved oxygen sensor
·
Oxidation reduction potential
sensor
·
Phosphate sensor
List of Abbreviations
ASTM:
American society for testing and materials
COM:
Commercially available millielectrode
CCD:
Charge couple device
COD:
Chemical oxygen demand
DO:
Dissolved oxygen
EBPR:
Enhanced biological phosphorus removal
EDM:
Electrical discharge machining
EPS:
Extracellular polymeric substances
FISH:
Fluorescent
in situ
hybridization
HOC:
Hydrophobic organic compound
HRT:
Hydraulic retention time
IC:
Integrated circuit
ISFETs:
Ion-sensitive field-effect transistors
LOC:
Lab-on-a-chip
ME:
Conventional pulled-glass pipette microelectrode
MEA:
Microelectrode Array
MEMS:
Microelectromechanical systems
MLSS:
Mixed liquid suspended solids
ORP:
Oxidation reduction potential
PAOs:
Phosphate accumulating organisms
PCB:
Printed circuit board
SBR:
Sequencing batch reactor
SRT:
Sludge retention time
UEA:
Utah Electrode Array
6.1 Introduction
Microbial cells attach firmly to almost any surface in soil or in aquatic environ-
ments. The immobilized cells grow, reproduce, and produce extracellular polymeric
substances which frequently extend from the cell forming a tangled matrix of fibers
that provide structure to the assemblage. This structure is termed a
biofilm
[1], and
its formation can be categorized into three steps, as shown in Fig. 6.1. First, free
bacteria attach to substratum and form a thin layer called “micro-colonies.” In the
second step, the attached bacteria aggregate together on the substratum with the
help of extracellular polymeric substances (EPS). Finally, fully developed biofilms
