Natural Organic Matter in SA
Waters: Characterisation and
treatability- our capabilities
“Sustainable
water
resource”
Nanotechnology and Water Sustainability
Unit (NanoWS @ UNISA)
 Multi-disciplinary research unit focussing on:
•
•
•
•
nanotechnology (nanomaterials) for water treatment
advanced water treatment technologies (membranes)
optimisation of conventional water treatment technologies
water reuse, wastewater reclamation, “new water” from AMD
 The researchers in the group and collaborators include
materials scientists, analytical chemists, applied chemists,
nanoscience research specialists, materials engineers,
biosciences engineers, water and environmental engineers
RESEARCH FOCUS AREAS
• Nanostructured Membranes, Composites and
nanocomposites
• Toxicology, nanotoxicology and development
of analytical methods and protocols
• Urban Water Cycle (Water reclamation, reuse,
NOM, and drinking water treatment)
• Bioremediation and analysis (Constructed
wetlands and biotoxins analysis)
• Community Engagement (Training)
STRUCTURE OF NOM
CHEMICAL DESCRIPTION OF NOM
FRACTIONS
(i) Hydrophobic acid:
carboxylic acids of five to nine
carbons, one and two-ring aromatic
carboxylic acids, aromatic acids, one
and two-ring phenols and tannins.
(iv) Hydrophilic acid:
aliphatic acids of less than five
carbons, hydroxyl acids, sugars, low
molecular weight alkyl monocarboxylic
acids and dicarboxylic acids.
(ii) Hydrophobic base:
are proteins with one and two-ring
aromatic amines except for pyridine and
high molecular weight alkyl.
(v) Hydrophilic base:
Amphoteric proteinaceous materials
containing amino acids, amino sugars,
peptides and proteins.
(iii) Hydrophobic neutral:
a mixture of hydrocarbon and carboxyl
compounds.
(vi) Hydrophilic neutral:
aliphatic amides, alcohols,
aldehydes, esters, polysaccharides and
ketones with less than five carbons.
NOM IN THE ENVIRONMENT
Hydrophobic
HPO
Tannic acid
Humic Acid
Transphilic
TPI
Terpenoid
3-Acetonedicarboxylic acid
Hydrophilic
HPI
Amino Sugars
D-xylose
NOM IN THE WATER TREATMENT TRAIN
Disinfection
Ferric
HPO
HPI
Coagulation
Disinfection
social).
byproducts
Flocculation
(Health
Colour, undesirable taste and odour
quality).
and
DBPs
(water
Corrosion of distribution network (Costs).
High disinfectant demand (Costs).
Eutrophication (Environmental)
Effluent
What do we need to know about NOM to
understand its treatability?
• DOC concentration at
How much coagulant
source
do we need?
• Charge load
• Zeta potential (charge
How do we
removal)
optimise the
process?
• Membrane fouling
How much DOC
will remain?
What DBPs will
form?
• Fractionation
• No idea! (yet)
NOM CHARACTERIZATION
CHARACTERIZATION OF NOM
Isolation and/or concentration of NOM from source waters.
Fractionation into groups (fractions) of compounds with similar
physical or chemical characteristics.
To identify which fractions dominates the NOM.
Develop and employ methods to remove
problematic fractions.
Use of NOM fractions to investigate the effects of NOM on
various water treatment processes and health effects.
NOM FRACTIONATION
Dissolved organic carbon
Humic
• Hydrophobic NOM
• High aromatic content
• High UV254
NonHumic
• Hydrophilic NOM
• Less aromatic (aliphatic)
• Lower UV254
FRACTIONATION OF NOM (PRAM)
HPO
NaOH
NaOH
TPI
HPI
HPO
Fraction
NOM sample
C18
TPI Fraction
HPI
Fraction
CN/NH2
DISINFECTION BY-PRODUCT FORMATION
(POTENTIAL)
NOM + free chlorine
THMs + HAAs + cyanogen halides + other DBPs
SIMULTANEOUS FEEM ABSORBANCE
TYPICAL RAW SURFACE WATER FEEM