China 
Africa 
Explore chapters and articles related to this topic
Downstream Processing
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
The mechanical device which is specially used in solid/liquid separation using the principle of pressure driven which is provided by a slurry pump is called a plate and frame filter press. The frame contains an open space inside which the slurry reservoir is maintained for filtration and an inlet to receive the slurry. The plate has a studded or grooved surface to support the filter cloth and an outlet. The system is usually made of aluminium alloy. The mechanism of the plate and frame filter press is based on surface filtration. The slurry enters the frame by pressure and flows through the filter medium. The filtrate is collected on the plates and sent to the outlets. A number of frames and plates are used so that the surface area increases and consequently large volumes of slurry can be processed simultaneously with or without washing. Filter presses are used in a huge variety of different applications including the food industry, the mining industry, the pharmaceutical industry, the chemical industry, wastewater treatment etc.
Pressure Filtration
Published in Glenn M. Tillman, Wastewater Treatment, 2017
There are several types of filter presses available but the most common type consists of vertical plates that are held in a frame and are pressed together between a fixed and moving end.A cloth filter medium is mounted on the face of each individual plate.The press is closed and sludge is pumped into the press at pressures up to 225 psi and passes through feed holes in the trays along the length of the press.Filter presses usually require a precoat material such as incinerator ash or diatomaceous earth to aid in solids retention on the cloth and to allow easier release of the cake.
Sludge conditioning
Published in Bhola R. Gurjar, Vinay Kumar Tyagi, Sludge Management, 2017
Bhola R. Gurjar, Vinay Kumar Tyagi
In the descender, the treated sludge is settled with the aid of a peripheral drive decanting mechanism. The decantrate is drawn off via weirs at the top of the decanting tank and returned to the primary treatment. The low-pressure raw pump transfers the treated sludge having approximately 90% moisture content, into the treated sludge holding tank. The treated sludge is drawn from holding tank by a hydraulically operated flow control pump specially designed for the maintenance of constant pressure when charging filter presses. The filter press is designed to produce a low moisture content cake, this being achieved by pumping sludge under pressure into the press chamber. After a pressing cycle, which last approximately 4 h, the cake is discharged into tanks and is used as a landfill on adjacent site. Cake moisture is 50–55%, its volume representing about 8% of the volume of treated sludge.
Techniques for harvesting, cell disruption and lipid extraction of microalgae for biofuel production
Published in Biofuels, 2021
Filtration uses filters for harvesting microalgae and requires the application of pressure by a suction pump to allow the fluid to flow through the membrane [20]. This method is mostly useful for organisms ˃70 μm such as Coelastrum and Spirulina, but most of the microalgae giving high amounts of lipid contents, like Botrycoccus, Scenedesmus, Dunaliella and Chlorella, are ˂30 μm, making this technique unprofitable. The micron size of the algae is a serious hurdle, as it increases the thickness of the algal layer over the membrane, which leads to clogging, the major drawback of filtration. It also restricts the application of a faster flow rate to the system. The condition worsens due to the production of EPSs, produced during stress conditions such as nutrient deprivation, leading to the formation of a jelly-like layer on the filtered material which causes increased resistance of the fluid to flow. This necessitates the frequent removal and cleaning of the membranes. Clogging or fouling can be avoided by several methods. The first one uses a reverse-flow vacuum system, in which the pressure operates from above. This makes the process less vigorous, avoiding algal cell disruption. The second process uses a direct vacuum with a paddle above the filter, providing agitation that prevents the particles from depositing on the medium. Pressure filtration uses plate and frame filter presses, or pressure vessels containing filter elements. The high-pressure mechanism allows the algal suspension to move through the filtration system. Rectangular plates are present on both sides of the filter press, supported by a fixed and a movable head. The filtration cycle involves filling the press, keeping the press under pressure, opening the press, washing and discharging the cake, and closing the press. The plates in the filtration unit are firmly held to cope with the pressure. Several designs of pressure vessel filtration have been devised, such as rotary-drum pressure filters, cylindrical-element filters, vertical tank vertical leaf filters, horizontal tank vertical leaf filters, and horizontal leaf filters [44].