Apparatus for treating a waste stream
An integrated unit operations for the treatment of a waste stream, such as spent caustic, is provided in a single vertical vessel having at least three separate zones: a mixing, a settling, and a mass transfer zone.
1. An integrated treatment vessel for treating waste streams comprising, in combination,
a vertical column having an interior divided into at least a mixing zone, a settling zone, and a mass transfer zone;
a waste stream inlet in liquid communication with the mixing zone;
an off gas outlet in communication with the mixing zone;
an organic stream outlet in liquid communication with the settling zone,
wherein the settling zone has one or more baffles to assist in a separation of aqueous and organic phases;
a liquid transfer line connecting the settling zone with the mass transfer zone;
a vapor line connecting the mass transfer zone to the settling zone;
an inert gas inlet in communication with the mass transfer zone; and
a treated waste stream outlet in liquid communication with the mass transfer zone.
2. The integrated treatment vessel of claim 1 further characterized in that the waste stream inlet is in liquid communication with a neutralization line.
3. The integrated treatment vessel of claim 1 further characterized in that the mixing zone has a means for mixing liquid introduced into the mixing zone through the waste stream inlet.
4. The integrated treatment vessel of claim 3 further characterized in that the mixing means is selected from the group consisting of a powered impeller, a gas sparger, a static mixer and combinations thereof.
5. The integrated treatment vessel of claim 1 further characterized in that at least one pH sensor is in communication with the mixing and settling zones in order to assist in controlling addition of neutralization liquid through a neutralization line and into the waste stream inlet.
6. The integrated treatment vessel of claim 1 further characterized in that the mass transfer zone is configured as a stripping column.
7. The integrated treatment vessel of claim 1 further characterized in that the mass transfer zone comprises packing material or one or more trays.
8. The integrated treatment vessel of claim 1 further characterized in that the mass transfer zone has a recycle stream inlet to allow return of a slipstream of treated waste removed from the treated waste stream outlet.