Locally backwashing portions of filter media allows a simple and effective design of intake and pretreatment units, as well as their integration. An enclosure is used to limit portions of filter media and backwash them locally by suction, utilizing filtered water from adjacent filter media as the back wash water. Wastewater is produced at small amounts that allows efficient sludge treatment. This design enables water pretreatment at the intake unit, simplifying overall plant design and preventing damage to organisms living outside the intake unit.

A filtration device comprising a media basket, a baseplate, and a canister. The media basket is affixed to the baseplate. The canister has a cavity therein and is detachably coupled with the baseplate to enclose the media basket. The media basket contains a porous filtration material that efficiently removes contaminants from liquid. The device is configured to establish a first siphon to convey liquid from outside the device into the canister cavity through a canister pipe when a liquid level outside the filtration device is higher than the top of the weir in the canister pipe and configured to establish a second siphon to convey liquid from canister cavity through the top of a center riser pipe and out an outlet pipe when the first siphon has been established and the liquid level outside the filtration device is higher than the top of the center riser pipe.

An apparatus for removing impurities from water and/or wastewater and a method of installing a fluid distribution system in the apparatus. In the most preferred form of the invention, the fluid distribution system is an air scour system for directing air through the filter bed to assist in cleaning of the filter bed to remove impurities trapped in the filter bed during a service run. In the most preferred form, the method of installing the fluid distribution system in the filter bed is performed by imparting a force to the filter bed to permit the fluid distribution system to be installed in the filter bed without removing media. The fluid distribution system is preferably configured to permit the fluid distribution system to be readily installed in the filter bed and at an optimum orientation.

The present disclosure relates to a filter apparatus (1) for mechanically filtering a liquid (W). The filter apparatus (1) includes a filter chamber (5) for containing a plurality of filter elements (7) that form a filter pack (29) for filtering the liquid. The filter chamber (5) has a liquid inlet (12) and a liquid outlet (14). The filter apparatus (1) includes means for introducing air into the filter chamber (5) through one or more air inlets (25) to agitate the filter elements (7). The filter chamber (5) is substantially sealed and the air introducing means (22) may be configured to draw air into the filter chamber (5) as liquid is drained from said filter chamber (5). In certain embodiments, the filter chamber (5) may have a substantially constant profile or a substantially continuously tapered profile along its longitudinal axis (X-X). The present disclosure also relates to methods of filtering a liquid (W).

An air grid for supplying air under pressure. The air grid may be used as an air scour system for a filter for removing at least some impurities (e.g., foreign matter of any nature including a solid, a liquid or a gas) from water or wastewater or as an aerator for aerating wastewater in an aeration tank or basin. The air grid includes an adapter for permitting in field adjustment of one or more components (e.g., drop pipe) of the air grid. Preferably, the adapter houses a portion of an air supply header and a portion of a drop pipe such that the air supply header is disposed above the drop pipe. The adapter may include a detachable sealing assembly. A tool may be provided for inserting and/or removing one or more components of the air grid from the operation environment.

A horizontal-flow sand filtration pool and a water treatment process thereof. The horizontal-flow sand filtration pool includes a pool body, a raw water inlet assembly, a sand filtration bed, a filtered water outlet assembly, an aeration assembly, and a back washing assembly; the raw water inlet assembly includes a water inlet pipe and a water distribution device that supplies raw water to the sand filtration bed; the water inlet pipe is connected with the water distribution device, the water distribution device is provided in the sand filtration bed, and a plurality of water outlet channels are uniformly distributed on the vertical surface of the water distribution device; the filtered water outlet assembly includes a water collector and a water outlet pipe; the water outlet pipe is communicated with the water collector; the back washing assembly includes a back washing pipe and a drainage pipe.

An underdrain assembly in a wastewater filtration unit for providing even distribution of liquid and gas during filter backwashing operations and the uniform collection of filtered water during the normal operation of the filtration unit is provided. The underdrain assembly is provided with a flat, concrete plate with a perimeter matching the shape of the filtration unit. The concrete plate has a plurality of holes with individual PEX tubes in each hole extending from the concrete plate top surface through and protruding below the plate.

The invention is directed to methods of providing backwash processes for a synthetic compressible medium filter system. More specifically, the system may include a backwash pump and air blower, and the processes may include at least three sequences of: air and water wash; air purge; and medium compression. The backwash process may be triggered by one or more of a pressure, time point, and/or turbidity set point. The air and water wash sequence may include breaking and washing the medium. The air purge sequence may include removing substantially all of the air entrapped in the medium by providing a backwash water flow for a period of time; and a medium compression sequence compressing the medium while avoiding exposing the medium to air, including introducing raw water and where the backwash and raw water provide enough energy to compress the medium without introduction of air into the medium.

A water treatment filter backwash process control system, comprising a control system that receives filter level data and filter backwash turbidity data. The control system having a filter level set point, wherein the filter level set point corresponds to a desired filter media bed expansion. The control system having a filter backwash turbidity set point, wherein the control system controls the filter backwash process by, while monitoring the filter backwash turbidity, sending one or more output signals that are used to control a backwash inlet liquid flow in order to maintain a desired media bed expansion, and stop the backwash inlet liquid flow when the filter backwash turbidity set point is reached.

The filtration system of the present invention comprises first and second filtration tanks. The first filtration tank has a first floating filter media layer, a first upper screen with a first aperture ratio, a first inlet, a first backwash water supply source, and a first backwash water outlet means. The second filtration tank has a second floating filter media layer, a second upper screen with a second aperture ratio, a second inlet, an inflow blocking mechanism capable of blocking inflow of water to be treated through the second inlet, a second backwash water supply source, and a second backwash water outlet means. The first aperture ratio is smaller than the second aperture ratio.