System And Process For Removing Particulate From A Coal Fired Power Waste Stream

1 . A closed loop system for removing particulate from a coal fired power waste stream comprising:

a) at least one boiler, including wash water inlets;

b) at least one submerged flight conveyor, including a horizontal section for receiving wash water and an incline dewatering section adjacent to the horizontal section;

c) a bleed line for draining wash water from the submerged flight conveyor adjacent the joint between the horizontal and incline sections;

d) a filter connected to the bleed line for removing particulate from the wash water; and

e) a return pump for feeding the filtered wash water to the wash water inlets.

2 . A system for processing particulate from a wash stream in a coal fired power waste stream comprising:

a) a submerged flight conveyor including substantially horizontal section and an inclined section;

b) a plurality of scrapers rotating through at least the horizontal section;

c) a bleed line proximate the joint between the horizontal and incline sections; and

d) a filter connected to the bleed line for removing particulate from the coal fired power waste stream.

3 . The closed loop system of claim 2 wherein the filter is a bag filter.

4 . The closed loop system of claim 2 wherein at least a portion of the coal fired power waste stream is dewatering by the incline section of the submerged flight conveyor.

5 . The closed loop system of claim 2 wherein at least a portion of the coal fired power waste stream is pretreated with at least one of a pH adjustment, coagulant and flocculent to precipitate dissolved metal therefrom.

6 . A method for treated a wash water waste stream from a coal fired boiler comprising:

a) receiving the wash water waste stream into a submerged flight conveyor, the submerged flight conveyor comprising substantially horizontal and inclined portions;

b) treating a first portion of the wash water waste stream with a series of lamella plates so as to capture particulate therefrom;

c) removing a second portion of the wash water waste stream from the submerged night conveyor via a bleed line for processing in a thickening tank and filter to capture particulate therefrom;

d) returning water removed from the second portion of the wash water waste stream in the thickening tank and filter to the submerged night conveyor;

e) removing an overflow portion of water from the submerged flight conveyor to a surge tank;

f) removing a portion of the water from the surge tank to supply wash water to create the wash water waste stream in a coal fire boiler;

g) returning the remainder of the water from the surge tank to the submerged flight conveyor; and

h) removing settled particulate from the wash water waste stream via the inclined portion of the submerged flight conveyor.