screenings_technology
6Pages

The initial step of the water and wastewater treatment plants is the mechanical treatment. Screening equipment are the most important members of this pre-treatment process. Wastewater coming to the treatment plant will occasionally include wood, sticks, rags, and other debris in it. Before further processing, the wastewater must be screened to remove these materials, in order to protect the chemical and biological processes. Also pumps, pipelines are protected by means of these screens. Nevertheless; although screening is acknowledged along with the physical treatment; as a result of their compact construction and purposeful design; screening equipment can be used in various aspects of many applications. Astim designs and manufactures manually cleaned or mechanically raked screens in a wide range of sizes and types for water and wastewater treatment plants and pumping stations. Astim design and manufacturing range for screening equipment covers; • Manually Cleaned Bar Screens and Basket Screens • Mechanically Raked Bar Screens • Belt Screens • Inline Screens • Conveyor Screens • Screening Treatment Systems

MECHANICALLY RAKED Mechanically Raked Bar Screens are proper equipment for full automatic removal of solids from all kinds of water and wastewater. The screens consist of steel bars spaced to catch debris of a certain size. Mechanical rakes scrape the screening bars to carry the debris and discharge them through a chute into transport equipment or into a container. Mechanically Raked Bar Screens can be equipped with electrical control cabinet; with PLC or conventional systems. Additionally to prevent damages due to high screening loads electronically or mechanical torque limiting devices...

Belt Screens are self cleaning screening equipment. These screens consist of a rotating endless belt to catch and remove the debris. Belt Screens are not only used in water and wastewater treatment plants in pretreatment. They are also used in pulp and paper industries for mill effluent screening, fiber recovery, log flume water and wood room effluent screening and other industries such as sea food processing, meat processing, poultries, sugar processing, fruit and vegetable processing, vineyards, breweries, textile industry, paint sludge dewatering, glass ceramics mining industries. Astim...

INLINE SCREENING Many screens can be installed in steel tanks to use as inline screens. Besides Asti m designs and manufactures different type of Wedge-wire Inline Screening Systems in a wide range of sizes. Inline Screening Systems are compact, self cleaning screening equipment. Mainly Inline Screens can be classified as: • Rotating Drum Screen (outer fed) • Rotating Drum Screen (inner fed) Rotating Drum Screen (outer fed) Outer Fed Rotating Drum Screens are continuously operating screening system with automatic cleaning device. They are general purpose self cleaning micro screening...

Conveyor screens are compact screening equipment equipped with a screw conveyor compactor unit. These screens can both be installed in channels or in steel tanks to be used as inline equipment. Conveyor Screens operation is based upon a compact system that allows the combination of screening, washing, transport, compaction and dewatering in a single unit. The Conveyor Screens can also be equipped with every required instrument to become a package unit for screening purpose. Astim designs and manufactures different type of Conveyor Screens in a wide range of These Screens can be classified...

SCREENING TREATMENT The screenings are wastes which must be minimized; reduced in volume as much as possible ano shall be land filled or incinerated. Therefore the aim is to restrict screenings production as far as possible. Screenings content 80% water, partly bound with organic material, 10% other material like hygienic material, plastic articles, cloth, fibers, stones, 5% organic material like paper, food residues etc. and 5% faeces. In order to reduce weight, water has to be pressed out. This means that the most important point is to press the screenings. Since washed screenings can be...