The Concern about Hazardous Waste Management

1. cause of mass life and material damage and loss (disability, death, fire, explosion);

2. cause of environmental damages: potential water, solid, and air pollution (underground and surface drinking water);

3. cause of potential increased chemical bioaccumulation that is hard for biodegradability (chlorine containing chemicals);

4. cause of long term irreversible health risks (mutagenicity, teratogenicity, and carcinogenicity)

5. high concern of trans-boundary movement of toxic wastes;

6. cause of massive toxic health damages.

Hazardous Waste Treatment

Different technical options and alternative methods can be employed for the treatment. The end result needs to focus on making the waste non-harmful or less hazardous, reduce its volume and texture, separate for re-use, and isolate it for final disposal.

Treatment methods include:

A. Physical methods: drying, screening, grinding, evaporation, sedimentation, filtration, fixation, etc.

B. Chemical methods: Oxidation, reduction, neutralization, hydrolysis, etc.

C. Biological methods: composting, aerobic and anaerobic decomposition, activated sludge, enzyme treatment, etc.

D. Thermal methods: incineration, boiling, autoclaving, UV treatment, microwave use, etc.

Hazardous Waste Disposal:

The hazardous waste, after treatment, can be ultimately disposed using the following methods:

a) Land farming: the treated waste can be used as a fertilizer or soil conditioner with the approval of concerned regulatory entities;

b) Deep well injection: a special kind of drilled well is prepared for such purposes. Brine (40% salt solution) is usually disposed in this manner. Precautions for water

pollution need to be a concern.

c) Surface impediment: encapsulation, fixation, or containment of the waste. This method involves arresting or demobilizing the movement or migration of the waste by containing it in a hard core: clay soil, thermoplastics polymers, non-corrosive metallic containers (carbon-steel tanks), cement, lime, fire glass, rocks.

d) Ocean dumping: was mostly practiced from 1945 to the 1970s. Despite the existing public protest, this method continuous to be an alternative for the waste generators.