Biological filters are commonly employed for the oxidation of carbonaceous and nitrogenous material without the need for expensive power driven machinery. Most filters are circular because this shape accommodates simple rotating distributors that are designed to evenly distribute effluent over the filter surface by the reaction of discharge from the distribution arms.
The Lektratek rotary distributor comprises of a stationary inner column and a rotating outer distribution tank to which two, four or six distribution arms are attached. The distribution tank is completely open thus preventing the accumulation of corrosive gases.
An important feature of the Lektratek rotary distributor is that the top bearing may be inspected and/or removed without detaching the arm stays from the column.
STANDARD ROTARY DISTRIBUTOR
This type of rotary distributor is employed when head conditions permit. The design is such that no seal is required between the stationary and rotating elements as liquid cascades into a distribution tank incorporated in the rotating member thus seal wear is eliminated.
SIPHON ASSISTED ROTARY DISTRIBUTOR
The siphon assisted rotary distributor is employed when only low heads are available. With this design a seal between the stationary and rotating elements is achieved by using an annular siphon between the centre column and the rotating distribution tank therefore the use of a mechanical seal is eliminated thereby reducing maintenance and running costs.
A motorised option is also available, should the flow be such that sufficient reaction of discharge from the distributor arms be limited or inconsistent.
DISTRIBUTION ARM WEIR BOXES
Weir boxes can be fitted to the distributor arms of either model of Lektratek rotary distributor and will isolate half the number of arms to maintain the discharge reaction of the effluent at low flows. At medium to high flow levels all arms will distribute effluent.
Rotary distributors fitted with weir boxes are able to cater for wide variations of the feed flow.
The concept of the dosing siphon is to accumulate very low flows that would otherwise be unable to effectively drive the distributor. The accumulated flow is automatically released to the distributor so that it is either in operation or stopped relative to top and bottom liquid levels.
Three different arrangements of dosing siphon are available, namely direct coupled, trapping weir and trapping head.
MATERIALS OF CONSTRUCTION
The full range of rotary distributors and siphons, designed, manufactured and installed by Lektratek Water Technology, can be supplied with different bases to suit particular requirements and in a variety of materials to suit all operating and environmental conditions.