A system includes a filtration vessel, a filtration input gauge, a filtration output gauge, a solvent vessel, an acid vessel, a water vessel, a computer, and a control system. The filtration vessel includes gravel configured to filter a produced water to create a filtered water. The filtration input gauge is configured to measure an inlet pressure of the produced water flowing into the filtration vessel. The filtration output gauge is configured to measure an outlet pressure of the filtered water flowing out of the filtration vessel. The computer is communicably connected to the filtration input gauge and the filtration output gauge and is configured to determine a differential pressure based on the inlet pressure and the outlet pressure. The control system is communicably connected to the computer and is configured to prevent the produced water from flowing to the filtration vessel and allow solvent, acid, and water to flow to the filtration vessel when the computer determines the differential pressure is greater than a pre-determined value.

A filter unit is provided for filtering a liquid. The filter unit is intended to be connected to a cap including a first liquid passage and a second liquid passage 114. The filer unit includes: a canister; and a filter cartridge rotatably arranged within the canister, the filter cartridge includes a first filter connection for liquid to pass through, the first filter connection is intended to be connected to the first liquid passage in the cap, wherein the canister is intended to be rotatably attachable to the cap such that, when the canister is attached to the cap by a rotating action, the filter cartridge is stationary to the cap.

A filter unit is provided for filtering a liquid. The filter unit is intended to be connected to a cap including a first liquid passage and a second liquid passage 114. The filer unit includes: a canister; and a filter cartridge rotatably arranged within the canister, the filter cartridge includes a first filter connection for liquid to pass through, the first filter connection is intended to be connected to the first liquid passage in the cap, wherein the canister is intended to be rotatably attachable to the cap such that, when the canister is attached to the cap by a rotating action, the filter cartridge is stationary to the cap.

An underdrain filtered water collection system includes: a pair of opposing drainpipes, each drainpipe having a plurality of collection drains; and a diffuser screen. The diffuser screen can slide within an outlet in each of the collection drains. A diffuser screen for a pressure vessel containing filter media includes: a screen pipe; a solid plate coupled to a base of the screen pipe; and a winged diffuser arranged around an outer circumference of the solid plate. The winged diffuser includes a plurality of foldable wings. The screen pipe includes a mesh screen having preconfigured interstices therethrough. Feed water flows through the screen pipe where it is directed by an inner surface of the solid plate to flow in a diffused flow through the interstices of the mesh screen and the wings.

A backwash filtration system comprising a backwash discharge port, a sedimentation collection and separation system, and a final filtration chamber. The backwash discharge port is coupled with a pool filter system and is configured to pass backwashed water from the pool filter system to the sedimentation collection and separation system. The sedimentation collection and separation system has a plurality of sedimentation chambers that are vertically stacked and a plurality of baffles configured to reduce the migration of sediment within the sedimentation chambers. A path for water flow passes down sequentially through each of the sedimentation chambers. The final filtration chamber receives the backwashed water from the sedimentation collection and separation system, filters the backwashed water through a final filtration medium, and passes the filtered water to a water return line of the pool filter system or to a pool of water.