Treatment of Grit from Sewage Treatment Plants

Q: "Can sewer grit be washed together with sewage treatment plant grit?"

"HUBER has solutions for the processing of sewer grit and grit from sewage treatment plants as well as road sweepings. Depending on the quantities and composition of the material to be processed as well as other general conditions, we design a tailor-made HUBER solution for grit treatment."

Q: "What are the characteristics of a good grit washing system?"

"A good grit washing system is characterised by its ability to wash out the organic substances in the grit so that the loss on ignition in the washed grit is < 3%. In addition to the effective separation of organic and mineral components, the retention of fine sands is also decisive in practice, which is taken into account in the design of HUBER Grit Washing Plants."

Q: "What happens to the grit from the grit chambers within a wastewater treatment plant?"

"In order to be landfilled, the grit must be further treated before. Depending on the size of the sewage treatment plant and the amount of grit, grit classifiers or grit washers are used. The state of the art is now the grit washer."

Q: "What is the difference between a grit washer and a grit classifier?"

"Both the grit washer and the grit classifier are fed with a grit-water mix. In the machine, the grit is separated from the water.\r\nIn contrast to the grit classifier, the grit washer is able to wash the separated grit. This means that the separated grit is freed from organic components as far as possible. The grit washer thus produces grit that is almost free of organic matter, whereas the separated grit in the grit classifier may contain a considerable amount of organic matter."

Q: "Why is grit washing needed?"

"In municipal wastewater treatment, grit is separated in a grit trap. This separation takes place by sedimentation, i.e. the grit settles in the grit chamber after sufficient retention time. However, since there are not only mineral substances such as grit in the wastewater, but also many organic solids, these also settle to a greater or lesser extent. As a result, when the grit is discharged from the grit chamber, it sometimes contains a large amount of organic solids. This contamination of the grit with organic matter hinders, among other things, cost-effective landfilling or reuse of the grit.\r\nGrit washing with a HUBER Grit Washer RoSF4 solves this problem and produces clean grit with an organic content of less than 3% loss on ignition, the HUBER Grit Washer RoSF G4E reduces the organic content to \u2264 5%."

Grit washing for Reduction of the Organic Matter Contained in Grit

Grit and mineral substances from the grit chambers of municipal wastewater treatment plants usually contain a large to very large proportion of organic substances, which have settled in the grit chamber together with the grit.

Grit washing has become an established process for the treatment of grit from grit chambers over the last decades. HUBER Grit Washing Plants have been in operation worldwide for more than 25 years and have set the standard for modern and efficient processing of grit from wastewater treatment plants to produce a valuable product for reuse.

HUBER Coanda Grit Washer RoSF4

Reliable reduction of the organic content of the grit to < 3%

The loss on ignition of the washed grit is less than 3%

The HUBER Grit Washer RoSF4 T washes the classified grit from a HUBER Circular Grit Trap HRSF

HUBER Grit Washer RoSF G4E reduces the organic content in grit to < 5%

Grit washing plants with container for the washed grit

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Process

The Target of Grit Treatment

Due to the proportion of organic substances, the heterogeneous grit-organic mixture has a relatively low dry residue of 40 – 70 % DR and a relatively high loss on ignition of up to 80 %.

The purpose of a well-performing grit treatment system is to first remove the grit down to a grain size of 0.20 mm and then to separate the valuable material sand and the mineral fraction from the organic contaminants mentioned.

The treatment of grit produces a valuable resource with a low loss on ignition (< 3 %) and a high dry residue (> 90 %). This reduces disposal costs and provides a product that can be reused as a secondary raw material.

Products

Machines for Treatment of Grit from Sewage Treatment Plants

Case Studies

HUBER Solutions in Operation

Targeting the fine sand: Grit Trap GritWolf® passes first endurance test in Texas

Reliable grit treatment with the use of HUBER machines

HUBER supplies the machines for the mechanical treatment stage of the worlds’ largest wastewater treatment plant project

Grit washing in grit trap: Complete Plant plus grit washing plant

Grit Recycling at the Largest German WWTP

1000 COANDA Grit Washing Plant installations

Test stand to determine the separation efficiency of the HUBER Grit Trap GritWolf® at 40°C in South Padre Island, TX

Targeting the fine sand: Grit Trap GritWolf® passes first endurance test in Texas

HUBER Grit Trap GritWolf® proves its efficiency in the separation of fine sand down to a grain size of 75 µm in a test run at South Padre Island in Texas.

HUBER's first small grit treatment plant in France for treatment of sewer grit and road sweepings

Reliable grit treatment with the use of HUBER machines

In November 2014, a HUBER Grit Treatment System RoSF5 was installed on WWTP Castres for treatment of sewer grit and road sweepings.

WWTP Atotonilco is built on an area of 1.580.000 m³

HUBER supplies the machines for the mechanical treatment stage of the worlds’ largest wastewater treatment plant project

The largest sewage treatment plant under construction in the world lies in the Mexican Tula Valley of Hidalgo. HUBER SE will supply the complete equipment for the mechanical pre-treatment stage and in this way contribute significantly to the future improvement of the country’s water shortage problems.

Grit washing in grit trap: Complete Plant plus grit washing plant

Complete Plants are complete systems for the mechanical treatment of small to medium amounts of wastewater from 10 to 300 l/s. Basically, a Complete Plant consists of two main components: screen and grit trap. As an option, other systems can be added, such as screenings treatment units, aeration systems or a grease trap.

Pair of 20 m³ slurry receiving tanks with Ro 8 screw conveyors

Grit Recycling at the Largest German WWTP

The hydraulic capacity of the wastewater treatment plant Emschermündung is 30 m³/s. This is a gigantic flow, larger than of any other German, perhaps even European, wastewater treatment plant.

Since the plant’s inflow is an open river, one can easily imagine the huge freight of debris, leaves and grit arriving within a few hours after storm events.

The management of the Emschergenossenschaft decided to provide a grit treatment system, and they want to recycle their large amount of grit as construction material, e.g. for pipe or road bedding.

1000 COANDA Grit Washing Plant installations

1000 COANDA Grit Washing units sold impressively demonstrate that this plant is being accepted as the standard solution in mechanical wastewater treatment

Media

Videos and Animations

Video: HUBER Grit Treatment System RoSF5 at WWTP Frankfurt-Niederrad

Video: HUBER Grit Treatment System RoSF 5 at major WWTP "Emschermündung"

Video: HUBER Grit Treatment System RoSF 5 - grit recycling at WWTP Schwarzenberg

Animation: HUBER Grit Treatment System RoSF 5

Video: HUBER Grit Treatment System RoSF5 at WWTP Frankfurt-Niederrad

Video: HUBER Grit Treatment System RoSF 5 at major WWTP "Emschermündung"

Video: HUBER Grit Treatment System RoSF 5 - grit recycling at WWTP Schwarzenberg

Animation: HUBER Grit Treatment System RoSF 5

Process and components: A universally usable and economical process of grit preparation

Downloads

Customer Information and Documents

Brochure: HUBER Solutions for Grit Treatment and Mineral Waste

More information needed?

Feel free to contact us

FAQ

Frequently Asked Questions

HUBER has solutions for the processing of sewer grit and grit from sewage treatment plants as well as road sweepings. Depending on the quantities and composition of the material to be processed as well as other general conditions, we design a tailor-made HUBER solution for grit treatment.

A good grit washing system is characterised by its ability to wash out the organic substances in the grit so that the loss on ignition in the washed grit is < 3%. In addition to the effective separation of organic and mineral components, the retention of fine sands is also decisive in practice, which is taken into account in the design of HUBER Grit Washing Plants.

In order to be landfilled, the grit must be further treated before. Depending on the size of the sewage treatment plant and the amount of grit, grit classifiers or grit washers are used. The state of the art is now the grit washer.

Both the grit washer and the grit classifier are fed with a grit-water mix. In the machine, the grit is separated from the water.

In contrast to the grit classifier, the grit washer is able to wash the separated grit. This means that the separated grit is freed from organic components as far as possible. The grit washer thus produces grit that is almost free of organic matter, whereas the separated grit in the grit classifier may contain a considerable amount of organic matter.

In municipal wastewater treatment, grit is separated in a grit trap. This separation takes place by sedimentation, i.e. the grit settles in the grit chamber after sufficient retention time. However, since there are not only mineral substances such as grit in the wastewater, but also many organic solids, these also settle to a greater or lesser extent. As a result, when the grit is discharged from the grit chamber, it sometimes contains a large amount of organic solids. This contamination of the grit with organic matter hinders, among other things, cost-effective landfilling or reuse of the grit.

Grit washing with a HUBER Grit Washer RoSF4 solves this problem and produces clean grit with an organic content of less than 3% loss on ignition, the HUBER Grit Washer RoSF G4E reduces the organic content to ≤ 5%.