| Author | Chaudhary, Durgananda Singh |
| Call Number | AIT Thesis no.EV-93-08 |
| Subject(s) | Water--Purification--Coagulation
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Natural organic matters are ubiquitous in aqueous environment. Humic substances are naturally occuring organic macromolecules formed by a complex series of biochemical
reactions among carbohydrates, proteins, lignin, and tannin of the decaying animals and
vegetable matters. Humic substances are of great concern in Water treatment technology
because of health, aesthetics and associated operational problems. The formation of
carcinogenic trihalomethanes and other toxic halogenated molecules from reactions between
organic matter and chlorine, is one of the main problems caused by organic matter.
The present study has aimed to assess the impairment caused by humic and tannic
acids in the conventional water treatment process of "Coagulation-Flocculation", and to
evaluate the removal efficiency of these organics by Alum and Cat-FlocT2, a cationic
polyelectrolyte as coagulants.
Alum was found to be very effective in both organics and turbidity removal, whereas
. Cat-FlocT2 was not effective for either. But the Cat-FlocT2 with alum of 20 mg/L dose, was
found to be effective in very narrow pH range of about 4.75-5. The pH of the suspension was
observed to be the most crucial factor that determine the coagulant dose and the removal
of organics and turbidity. The optimum pH for organics and turbidity removal was found to
be around 5. For both Alum and Cat-FlocT2 with alum, the optimum conditions for organics
removal nearly coincide with that for turbidity removal.
Humic acid was found to have more affinity towards adsorption on kaoline clay in
acidic condition than tannic acid. Whereas tannic acid was observed to have more tendency
to form complexes in alkaline conditions than humic acid. |
| Year | 1993 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Visvanathan, C.; |
| Examination Committee(s) | Tanaka, Shuzo;Schroder, Hans; |
| Scholarship Donor(s) | Government of Austria; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1993 |