Lamella clarifier

Lamella Clarifier

A lamella clarifier (inclined-plate clarifier) is designed to remove particulates from liquids. They are often employed in primary water treatment in place of conventional settling tanks. They are used in industrial water treatment. Unlike conventional clarifiers they use a series of inclined plates. These inclined plates provide a large effective settling area for a small footprint. The inlet stream is stilled upon entry into the clarifier. Solid particles begin to settle on the plates and begin to accumulate in collection hoppers at the bottom of the clarifier unit. The sludge is drawn off at the bottom of these hoppers and the clarified liquid exits the unit at the top by weir.

Advantages of ACHME Clarifier

The main advantage of ACHME lamella clarifiers over other clarifying systems is the large effective settling area caused by the use of inclined plates, which improves the operating conditions of the clarifiers in a number of ways. The unit is more compact usually requiring only 65-80 % of the area of clarifiers operating without inclined plates. Therefore where site footprint constraints are of concern a lamella clarifier system is preferred. The reduced required area allows the possibility for the clarifiers to be located and operated inside, reducing some of the common problems of algae growth, clogging due to blowing debris accumulation and odor control, that occur when the machinery is outdoors. Operation within an enclosed space also allows for a better control of operating temperature and pressure conditions. The inclined plates mean the clarifier can operate with overflow rates 2 to 4 times that of traditional clarifiers which allow a greater influent flow rate and thus a more time efficient clarification process. Lamella clarifiers also offer a simple design without requiring the use of chemicals. They are therefore able to act as pre-treatment for delicate membrane processes. Where necessary flocculants may be added to promote efficiency.

Lamella clarifier performance can be improved by the addition of flocculants and coagulants. These chemicals optimise the settling process and cause a higher purity of overflow water by ensuring all smaller solids are settled into the sludge underflow.

A further advantage of the lamella clarifier is its’ distinct absence of mechanical, moving parts. The system therefore requires no energy input except for the influent pump and has a much lower propensity for mechanical failure than other clarifiers. This advantage extends to safety considerations when operating the plant. The absence of mechanical parts results in a safer working environment, with less possibility for injury.

INHOUSE DESIGN FACILITY

We have number of proprietary lamella clarifier designs. Inclined plates may be based on circular, hexagonal or rectangular tubes. Some possible design characteristics include:

·         Tube or plate spacing of 50 mm

·         Tube or plate length 1–2 m

·         Plate pitches between 45° and 70° allow for self-cleaning, lower pitches require backwash ^[4]

·         Minimum plate pitch 7°

·         Typical loading rates are 5 to 10 m/h

·         MAIN PROCESS CHARACTORSTICS

Lamella clarifiers can handle a maximum feed water concentration of 10000 mg/L of grease and 3000 mg/L of solids. Expected separation efficiencies for a typical unit are as follows:

·         90-99% removal of free oils and greases under standard operation conditions.

·         20-40% removal of emulsified oils and greases with no chemical amendment.

·         50-99% removal with the addition of chemical agent(s).

·         Treated water has a turbidity of around 1-2 NTU.

The surface loading rate (also known as surface overflow rate or surface settling rate) for a lamella clarifier falls between 10–25 m/h. For these settling rates, the retention time in the clarifier is low, at around 20 minutes or less, with operating capacities tending to range from 1–3 m³/hour/m² (of projected area).