For the screenings dewatering at:

• Waste water treatment plants
• Sewage treatment plants
• Combined storm water overflows
• Water reclamation facilities
• Various screening dewatering applications

Screw Compactor
The Brackett Green® Screw Compactor is designed to remove excess liquid from screenings and to discharge them to a suitable container for disposal. The Screw Compactor may be located inside the traveling band screen, placed adjacent to the screenings discharge trough, or arranged to accommodate feed from a number of conveyed sources. This conventional process is utilized for the primary purpose of compressing and delivering the dewatered screenings to a dumpster, conveyor or bagging unit as desired. Installations where fine screens capture significant amounts of biological material, washing nozzles can be added to break down organics and return them to the channel for biological digestion. Brackett Green’s screw compactors significantly reduce the volume of screenings in both domestic screenings and combined storm water applications. For ease of transport and process containment, each compactor can be fitted with a discharge bagger.

The Problem
Screenings of Mixed Debris: Rags, Cotton Products, Fiber, Plastics, Paper, Hair, Fecal Matter, Oils/Fats/Grease. Designers of municipal wastewater treatment plants normally avoid the use of fine screens at the headworks due to concerns over removal of the organic matter and the potential interruption of the downstream treatment processes. Additional concerns arise from landfill restrictions pertaining to the disposal of free and absorbed water, fecal contamination of screenings and the accompanying odor problems that arise from screenings collection and storage. The everchanging regulations and discharge restrictions now present the engineer with the problem of balancing headworks screenings, handling equipment and downstream treatment processes.

The Solution
Brackett Green engineers have spent more than a century designing and building screen and screenings conditioning and dewatering equipment. The Brackett Green Screw Compactor is designed to remove excess liquid from screenings and to discharge them to a suitable container for disposal. Extraction rates of 50% to 55% moisture reduction are expected with an equivalent reduction in weight of 65% to 85% and in volume of 70% to 75%. Optional spray nozzles can be installed to wash, break down and separate the organic solids from the inorganic debris and discharge it by gravity back to the inlet channel. Brackett Green’s Compactors can be installed inside a traveling band screen or located directly at the discharge point adjacent to the screen,
delivering dewatered screenings to a dumpster, conveyor or bagging unit.

The Process
Fine screenings are flushed by water and received through a debris trough or pipe (1&5) for collection and dewatering. The inlet hopper (2) may be positioned directly inside the traveling band screen or outside, directly under or adjacent to the discharge of a screen. The compactor consists of a heavy duty horizontal tube (6) in which is fitted a helical screw. Debris is transported and compressed by the screw. As the screenings are compressed, the liquid is allowed to drain out through holes in the bottom of the pan and gravity discharged back to the inlet channel. The screw shaft is carried in a single bearing fitted at the drive end. When required, the screw compactor discharge is often fitted with an extension pipe (7) to provide either horizontal or elevated discharge of the dewatered screenings. Discharge can then be transferred to a dumpster,
(8) discharge conveyor or a bagging unit for disposal.

Other Features
Screw Compactors that are not installed in the interior of a traveling band screen are designed to stand on a floor with no special civil works involved other than drilling for holding down bolts. The inlet hopper (2) may be positioned directly under the discharge of a band screen and a drain pipe is all that is necessary for the discharge of liquid back to headworks. Spray jets can be provided in the collecting hopper if required to assist with screenings washing. Acompact Drive Unit (3) comprises a totally enclosed motor coupled to a shaft mounted gearbox. The complete unit is readily accessible for maintenance. An optional Brush Screen (4) is often utilized in a dewatering system to reduce the volume of free water entering the inlet hopper, reducing the size of the screw. Upon request, Brackett Green can provide overload protection and highly recommends that each Screw Compactor be protected against overload damage by current sensing devices in the control panel.

All Dimensions in Inches
Screw Press Model	Total No. of Flight Pitches	A	B	C	E	F	G	Motor Power Hp
200/6	6	14 5/16	14 15/16	58 3/8	40 5/8	15 3/4	211/4	1.5
200/9	9	14 5/16	14 15/16	79 5/8	61 7/8	15 3/4	42 1/2	1.5
200/11	11	14 5/16	14 15/16	93 13/16	76 1/16	15 3/4	56 11/16	1.5
300/6	6	14 5/16	19 11/16	94 15/16	54 5/16	17 11/16	29 1/2	3
300/9	9	14 5/16	19 11/16	105 9/16	88 3/16	17 11/16	59 1/16	3
300/11	11	14 5/16	19 11/16	125 1/8	107 14/16	17 11/16	88 5/8	3
400/6	6	33 7/16	14 9/16	102 3/8	76 5/16	29 1/2	39	7.5
400/9	9	33 7/16	14 9/16	141 3/8	115 1/4	29 1/2	77 15/16	7.5
400/11	11	33 7/16	14 9/16	167 3/8	141 1/4	29 1/2	103 15/16	7.5
500/6	6	25 9/16	31 1/2	94 7/8	59 1/16	63	47 1/4	10
500/9	9	25 9/16	31 1/2	142 1/8	106 5/16	63	94 1/2	10
500/11	11	25 9/16	31 1/2	173 5/8	137 13/16	63	126	10