Views: 888 Author: Yosun Publish Time: 2024-11-28 Origin: Site
Lamella clarifier is a device used in wastewater treatment to filter and remove sludge. The principle is that under the action of gravity, solid particles are aggregated into larger particles, and solid particles in suspension are removed by precipitation. Sedimentation tanks occupy an important position in wastewater treatment and in sludge treatment, such as wastewater treatment in petrochemical, food, pharmaceutical and other industries. Sedimentation tanks are used to remove suspended solids and colloidal substances from sewage. Sedimentation tanks can rapidly settle suspended matter in sewage to the bottom of the tank for further dewatering. There are many types of sedimentation tanks, and the commonly used ones are inclined tube sedimentation tank, advection mixer, inclined plate sedimentation tank, inclined tube sedimentation tank, and so on.
Below we will learn about several commonly used types, as well as their characteristics and scope of use.
Inclined tube lamella clarifier is a kind of lamella clarifier composed of three parts, its basic principle is to set up the water distribution area on the inclined tube, through the inertia of the water flow and the gravity of the inclined tube itself, so that the suspended particles in the water will settle down under the effect of gravity to achieve the purpose of solid-liquid separation. There are two kinds of inclined tube sedimentation tank: single-layer and multi-layer, and the number of layers of inclined tube in multi-layer is 3~4 layers.
Inclined tube sedimentation tank has the advantage of strong processing capacity, suitable for sewage water plant with a large amount of water. The disadvantage of the inclined tube sedimentation tank is that it covers a large area and has a short service life. In general, it is not suitable for treating high concentration wastewater and high turbidity raw water.
Inclined plate sedimentation tank utilizes the flow rate of water to separate the sediments from the water by utilizing the principle of gravity settling, which passes the water through the small holes of the inclined plate to make it separate quickly. It is widely used in all kinds of industrial wastewater, domestic sewage, washing water of construction projects, car washing water and pre-treatment of all kinds of industrial wastewater.
Inclined plate clarifier generally consists of two parts: plate and hole, the plate is inclined and the water flow direction is opposite to the inclined pipe. The outlet of the inclined pipe type is set at the bottom of the sedimentation tank, and the angle of inclination is generally 10°~15°, and the water flow rate is about 180~240m3/h.
Inclined plate clarifier can be divided into plate and frame type and floating box type according to the structure form. Plate and frame type is suitable for sedimentation tanks with larger sedimentation volume, and floating box type is suitable for sedimentation tanks with smaller sedimentation volume. In addition, there are many forms of inclined plate sedimentation tanks such as folding flow type, flat push type, perforated pipe type and so on.
The main advantage of lamella clarifier over other clarifying systems is the large effective settling area caused by the use of inclined plates, which improves the operating conditions of the clarifier 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 clarifier to be located and operated inside, reducing some of the common problems of algae growth, clogging due to blowing debris accumulation and odour 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 clarifier which allow a greater influent flow rate and thus a more time efficient clarification process. Lamella clarifier 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 may be improved by the addition of flocculants and coagulants. These chemicals optimize the settling process and cause a higher purity of overflow water by ensuring all smaller solids are settled into the sludge underflow.
Whilst the lamella clarifier has overcome many difficulties encountered by the use of more traditional clarifier, there are still some disadvantages involved with the configuration and running of the equipment. Lamella clarifier are unable to treat most raw feed mixtures, which require some pre-treatment to remove materials that could decrease separation efficiency. The feed requires initial processing in advanced fine screening and grit and grease removal to ensure the influent mixture is of an appropriate composition
