First published in 1994 - (the costs are not updated)
Companies should consider factors like the demand for land and capital, the desired filtrate quality and level of automation in the selection of water and waste water filter.
Programmable Logic Controller
Filtration is the easiest way to remove solids from the flow of water and wastewater. In water purification systems, filtration are used to working in the public service suspended or reduced water treatment systems for reuse or solid increase in sludge dewateringApplications.
Filter selection begins for a company determines the filtration required or the quality filtered water, will decide whether, filtrate disposed of or reused; identify the amount of space available and calculated the amount of capital available for the purchase, management and maintenance of the system , decide whether the system automatically or manually, and believes that all relevant requirements for the control of water pollution.
The amount of solids removal, or the quality of filtered waterdefines the desired type and size of the required filter, most of them with different levels of automation and price ranges available.
appropriate filter thread of the flow velocity and quantity, size and type of solids are removed determined. particle size and levels of filtering to filter the water and solids with different sizes of filter paper and measuring the total content of solids to be determined from filtered water.
Solids remaining filtered water is the same size or smaller than the previousfilter paper and used the display to be used by media filter opening size. (A filter manufacturer or laboratory can be hired to perform this procedure.) The amount of solids in water or wastewater can be determined by laboratory analysis of total solids, can flow can be determined from plant records or a meter inline flow.
The following equation is used to load solid (how quickly the filter with the load of solids), calculated: solid (lb / hr) = Flow (gal / min) x total solids content (ppm) x(8.34/60/1, 000,000).
After loading the solids, filters and filter media area opening size has been determined, the time required before cleaning or back-washing, to be calculated, and the fate of the waste filtrate was determined.
backwash In other words, according to a filter, where the waste water go? Undertow often requires up to 10% of the total volume filtered, the ratio of 10:1. For example, would be 379 m3 (100,000 gal) of filtered water produced 38 m3 (10,000 gal)Backwash contains concentrated solid and may require additional treatment.
Po 'water must be treated before filtering. oily waste water, for example, tends to agglomerate or rapidly between filter media and requires conditioning prior to filtration. filtering of fine-grade securities are subject to pollution from organic growth, yeast and other microorganisms by testing bank or consultation with the manufacturers of filter on some applicationsrecommended.
Y-strainer
Y-filters are the easiest, cheapest ($ 30 to $ 100) filters, but have a small filter area and require regular maintenance. They are typically used on small pipes to these protective devices such as seals, pumps and nozzles of solid construction.
Bag Filter
Bag filters are typically larger than Y-strainers. These filters are pockets of selected pore sizes that are enclosed in a pressure vessel with a removable lid for cleaning. They are easy toUse in various sizes are filtering, and are relatively inexpensive, especially for final filtration or solid applications with low loads. Bag filters shall not exceed 203 mm (8 inches) in diameter, for larger diameter, an on-line bank is used with multiple filters in one housing.
The price of carbon or stainless steel filter housing bag varies depending on the size, from $ 100 for a 51 mm (2.) Package for $ 3000 for a 1219 mm (48-in.) Housing. Filter bags range in price from $ 6 to $ 10pore sizes 25-800 microns. The pockets are pleated or straight. Pleated pockets offer space, but they cost more than double those flat included. The disadvantages are high maintenance costs for systems that are underdesigned bag filter or high load of solids and the cost of replacement bags.
Vacuum filters
Vacuum filter with a vacuum in slow rotation (negative pressure) liquid drum pulls dirt from the outside of the drum and the media on the insidethe drum. The vacuum is usually coagulate the waste stream with a system of charging for pre-treatment before filtration filters packed. The advantage of this filter is its ability to filter a range of effluents. The disadvantages are the system slow throughput and high costs can be found with the media filter, which must be applied to the treatment tank game immediately before vacuum filtration. In addition, the increase in the total sludge volume of filter media up to 60%.As the costs of the vacuum filter usually covers the pre-treatment, a group that processes 19 m3 / d (5000 l / d) can cost $ 60,000.
Cyclone
Cyclone separators are relatively new. Because they have higher speeds than vacuum filters, create a significant amount of energy, the centrifugal force to filter wastewater through different media formats. The filter uses a rotating means of micro fixed size, such as diatomaceous earth, filter the waste stream. The advantages of the cycloneThe separators are their ability to filter particles of variable capacities of different sizes, the manipulation and production of dry sludge cake as a vacuum filter for about the same cost (about 60.00). Inherited disadvantages are similar to those of vacuum filters, filter materials, namely high costs and the volume of sludge.
Plate-and-frame presses
Plate and frame presses are batch processes in which they are kept in solid sheets with a hydraulic press pre-coated with diatomaceous earth filter media. Printing sizedepends on the total volume of solids loading. Liquid (psi 25, 50, 75 and 100) in the press with a pneumatic diaphragm pump in steps of 172, 345, 517 and 690 kPa load. The press is at 690 kPa (100 psi) caused a pressure of water are displaced. After water is removed, the filter is "jumped" with the air, opening the sludge can be removed from the plates. The cake is usually at least 35% solids. The boundaries of the plate and frame presses include a processing time of at least4 hours, a large space, an escape skill, only the volume of plaque, and the operating time required to clean the dishes. Therefore, when waste water contains high levels of solids, the print must be large. filter presses range in size from 0,014 to more than 2.8 m3 (0.5 to more than 100 FT3). Print An.028-M3 (1-FT3) costs $ 3,500, and a 2.3 m3 (80-ft) press costs $ 100,000. large presses require automatic loading controls, gear plate, mud trucks and other equipment,Cost another $ 100,000. The advantage of filter presses is their ability, constant, pastries, which are often required to produce landfill.
A leaf spring filter
Multi Plate filters use specially modified spring plates work with nuances that give the required micron-size hole. The discs, which are held together with a spring-loaded to allow water to flow through and retain the filtered particles as small as 2 microns. These filters areback-flushed with water based on a pressure difference, and are all equipped with an option to save water or air-assisted backwash, water and rubbing plate filter increases. This continuous on-line filters are typically configured in pairs (one for filtering, one for back-washing). The amount of water used for backwashing, approximately 10% of the total flow of filtered. Air-assisted rinsing save an extra 3% to 5% water, but needs air. The programmableLogic Control-based filters allow you to adjust the time duration between the surf and undertow. The filters cost $ 4,500 per couple, and the controller will cost an additional $ 5,000, but a bank of up to 12 filters to control.
Multimedia Sand Filter
Multimedia sand filters traditionally used to treat the water, but can also be used for waste water which is full of irregular solids treated. This three-dimensional system in a much better filtering of other filters, becauseboth use the bed surface and depth, to remove particles as small as 0.45 micron.
An online analyzer measures the amount of suspended particles passing through the filter. Solid increase past or break the filter, start a predetermined level of suspended solids washing. Backwashing can be supported by air to save water, but be careful not to fan the media with the filtered material. These filters usually offer couples a continuous online service.It also acts as a final filter for water with solids uniform. Saving water is obtained when the control and regulation of air-assisted flushing systems are used, A 0.19-nil/min (50-gal/rnin) Pair of sand filter media and backwash controller with a header assembly costs about $ 15,000.
have with the variety of available filters and control scenarios that are ready should do some research in advance of their waste streams is not a problem, a system ofmeet their needs.
The clarification of wastewater treatment optionsprogrammable logic controller