The DynaDisc® filter provides a large area for filtration in a compact process vessel.  The discs are made up of a number of cassette pieces, joined together around a central drum, with a durable filter cloth bonded to the cassette to provide the filtration.  The filter water is then used as the supply of washwater to clean the filter cloth when the headloss through the filter reaches a pre-set level.

Considered engineering design is used to keep the seal length to a minimum and allow quick replacement of cassettes with a minimum of fasteners.  A constant level tank allows any variations of flow rate to be accommodated, and minimises the filtered water retained by the vessel whilst still providing a reservoir for the backwash pump.

A variety of filter cloth can be used within the system to suit the desired application.

Typical uses are for tertiary solids removal in both activated sludge and trickling filter plants, removing both the solids, and the BOD, phosphates and iron associated with those solids. DynaDisc® has also been used in a number of industrial applications including paper and pulp, purification of process water, and cooling water recirculation.

Applications

• Tertiary treatment of wastewater.
• Pulp and paper industry.
• Purification of process water.
• Recirculation of cooling water in the steel industry.

• Can be supplied as freestanding or in situ.
• Fewer parts – theDynaDisc® has 8 or 10 cassettes per disc, which is several times fewer than in disc filters from other manufacturers. This means faster replacement and less weight.
• Filter cloth fastened directly to the cassette body - keeps the seal length to a minimum.
• Strong cassette body – allows high tension on the filter cloth, prolonging its service life.
• Integrated level tank – provides a long level weir for the filtrate which reduces fluctuations at different water flows.
• The filtrate in the level tank is used for backwash – less risk for biological flocks compared to when the backwash water is taken from a much larger concrete tank.
• The chemical solution for cleaning the filter cloth is collected in the level tank, thus reducing acid corrosion of the concrete.

Suitable For Small Or Large Sites

Water to be filtered is guided into the rotor drum and flows by gravity into the filter discs, through openings in the drum, and passes through the filter cloth. Suspended solids are separated and accumulate on the inside of the filter cloth.
When the water level inside the filter increases to a pre-set point, the filter starts rotating and the backwashing of the filter cloth is initiated. The high pressure backwash spray removes the accumulated suspended solids into the reject flume inside the central drum. The suspended solids are then discharged via the reject pipe. 65% of the disc area is submerged in operation, providing a high area through which the flow can pass.

Frequently Asked Questions

Q. What is the headloss through the disc filter?

The operating headloss is between 200 and 300mm, approximately 500mm should be allowed overall for the system.

Q. How often should the filter be chemically cleaned?

This is site dependent; normally this is a 3 to 6 month period.  More frequent chemical cleaning will be required if there is iron dosing within the treatment system as the ferric salts can adhere to the cloth.

Q. What chemical is used in the cleaning process?

Hydrochloric or sulphuric acid is often used, along with an occasional application of sodium hypochlorite if biomass fouling has occurred.