Humic Substances Present In water

Hydrology presentationSubmitted To: DR Zakir Hussain.

What are Humic Substances?

Humic substances are major components of natural organic matter (NOM) in the soil as well as geologic organic deposits such as lake sediments, peat, brown coals and shales.

NOM:

It is the matter composed of organic compounds that has come from the remains of the animals and plants and their waste products in the environment.

Humic substances in soil are divided into three main fractions: HUMIC ACIDFULVIC ACIDHUMIN

Composition:

Difference between Humic Acid and Fulvic Acid:

Structure of Humic Substances

Formation Characteristics and Extraction of Humic Substances

Three Theories to explain it Lignin Theory Polyphenol Theory Sugar Amine Condensation

Formation

Formed by the microbial degradation of dead plant matter such as lignin and charcoal.

Characteristics

fDark Coloured Acidic

Aromatic

HydrophilicComplex Weight

Methods for Extraction Include Freeze Drying Liquid Extraction Anion Exchange Ultrafiltration Adsorption Method using Charcoal or organic non organic resins.

Extraction

The extractions were carried out with 0.5 M KOH for 3 h, at a ratio of 1:20 (m/v) under a nitrogen atmosphere. The Humic Substances

were separated by centrifugation.

“Measure of dissolved oxygen required to decompose the organic matter in water biologically’”

Normally, it is measured over 5 days.Rapid waters can rapidly replenish Oxygen supply due

to its fast flow. Lakes are less efficient at doing this.Pure water BOD = 1 ppm Polluted water BOD = 5 ppm or above

What Is BOD?

With the help of BOD we can remove organic matter / Humic substances from

water..Example?

How to remove humic substances from water?

Over six hundred organic compounds have been detected in water, mostly from human activity (Tebbutt, 1993).

Examples: Benzene,

chlorophenols ,pesticides ,trihalomethanes and polynuclear aromatic hydrocarbons (PAH).

Pesticides Is a significant problem in many countries .For example

Belgium and Europe.

TRACES ORGANICS

Trace organics can be detected using gas chromatography, although this is made difficult by the sheer number of compounds to be detected.

They are removed from drinking water supplies using activated carbon filters, or sometimes oxidation by ozone.

DETECTION OF TRACES ORGANICS:

The complexation of metals with humic materials in natural

waters:

High molecular weight compounds of humic and fulvic acids occur in small concentrations in natural surface waters and ground water.Generally described, as polymers with molecular weights from 300 to 30,000.chemical and biological processes that tend to produce complex chemical structures that are more stable than the original material.

The complexation of metals with humic

materials in natural waters:

one of the more important

characteristics of humic substances is their

ability to form water soluble and water in

soluble complexes with metal ions and hydrous oxides and to interact with clay minerals and

various organic compounds.

the stability constants of

their complexes with

ca,mg,co,ni,cu,zn,cd and hg have been determined

at pH 8.0

In fresh water more than 90% of the copper and mercury was found to be complexed by humic materials.In sea water >99% of the humic material is complexed by calcium and magnesium because of their relatively high concentrations.

The metals may be transported in flowing ground water, followed by destruction of the metal humic substance bound at elevated temperature, and this is thought to give rise to the formation of ore deposits.

The contribution of humic substances to the acidity of coloured natural waters

The dissociation behavior of two combined fulvic, humic acid extracts was studied and it was found that the dissociation of the humic varied in a predictable manner with pH.Using a carboxyl content of 10 μeq/ mg humic organic carbon, and mass action quotient calculated from sample pH,the ionic balances of three highly coloured Nova Scotia rivers were estimated.

Removal of humic substances by coagulation: The adsorption of NOM on oxides depends significantly on

complex formation reactions between specific sites on oxides surfaces and functional groups on the NOM

coagulant requirements can and often are set by the total organic carbon concentration in a water source.

there is a stoichiometric relationship between the required coagulant dosage and the TOC of the water to be treated.

Impact of humic substances on human

Humic acid Humic acid is a chemical produce by decaying plants.

It is also a major constituent of many upland streams and ocean water.

BENEFITS OF HUMIC ACID Humic acid is use for stimulating the immune system.

Humic acid is also for treating acute infection , chronic infection and Latent infections.

Bad effect of humic acid Humic acid when present in drinking water can react with the chemical used in the

chlorination process to form disinfection by product such as dihaloacetonitriles.

Fulvic acid Fulvic acid is formed when plants and animals decompose.

Fulvic acid is a yellow-brown substances found in natural material such as soil, peat, coal, and bodies of water such as streams or lakes.

Benefits of fulvic acid People take fulvic acid by mouth for brain disorder such as Alzeimers diseases as well as

respiratory tract infections cancer ,fatigue heavy metal toxicity and preventing condition in which the body tissues do not receive enough oxygen.

Bad effect of fulvic acid The anti-inflammatory properties of the substance reduce the itching associated with the

skin condition. Fulvic acid might block reactions in the body that cause allergy symptoms.