| Author | Nguyen, Thi Yen |
| Call Number | AIT Thesis no. EV-94-20 |
| Subject(s) | Environmental auditing--Vietnam
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Science, School of Environment, Resources & Development |
| Publisher | Asian Institute of Technology |
| Abstract | An envirorunental audit with the focus on the waste water and effluent toxicity was
conducted at COGIDO, an integrated modified soda pulp and paper mill in Bien Hoa Industrial
Estate, Vietnam. Besides, general data on the Vietnamese pulp and paper industry were
provided.
The pollution load from the mill was relatively high with wastewater flow: 22,600 m3
/d,
CODr.: 17.98 t/d, BOD: 2.72 t/d, SS: 8.56 t/d, color: 20.14 t/d and AOX: 2.93 kg/tor 49.86
kg/d. The water consumption was 550 m3
/t in which 340 m3 per ton produced pulp and 210
m3 per ton paper. The fiber was recovered and the white water was partly recycled by using
two settling conics. However, the fiber loss was in the order of 13% and only a small amount
of white water was reused (500 m3
/d). A sedimentation basin with a volume of 12,000 m3 was
used for treatment of the wastewater discharged from the bleaching-pulping plant, before
discharge into the Dong Nai River. The SS removal efficiency was found to be in the order
of 50% and the CODr. removal was less than 10% after a two-day retention period. Microtox,
Selenastrum capricornutum and L. aequinoctialis acute toxicity tests were run to evaluate the
toxicity of the effluents from the bleaching plant and the three final effluents discharged from
COGIDO into the Dong Nai River. EC50 values varied in the range of 1-40% for Microtox,
0.5-15% for Selenastrum capricornutum and 9-60% for Lemna aequinoctialis tests.
Selenastrum capricornutum was the most sensitive among tested organisms to the toxic
wastewater substances discharged. The wastewater from COGIDO, a modified soda pulp and
paper mill without a chemical recovery system, was toxic to L. aequinoctialis, meanwhile, the
wastewater from BAPACO, a kraft pulp and paper mill with a recovery system, was not. The
wastewater discharged from the bleaching-pulping plant was the most significant both in terms
of pollution load and toxic load. The black liquor discharged from the private semi-chemical
pulp plant based on raw material of fresh tail bamboo, was the most polluting and toxic in
terms of pollution factor. These two wastewater streams should be target for pollution
reduction measures.
A simple water quality survey was also carried out in the Dong Nai River in order to make
a quick assessment of the envirorunental impact from the mill on the receiving water body.
The mill was found to have a minor and local effect on the recipient water which was non-acute-toxic to the tested organisms. However, it might have chronic toxic effects on the aquatic
life.
The study proposes some alternatives to be implemented in order to control pollution and
to improve process efficiency. |
| Year | 1994 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Reutergardh, Lars Bertil
|
| Examination Committee(s) | Stoll, Uwe ;Bengtsson, Bengt-Erik ;Wise, Donald L.
|
| Scholarship Donor(s) | The Federal Republic of Germany (DAAD) |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1994 |