A process to remove nitrates and chrome from water. The process includes the steps of passing incoming nitrate and chrome contaminated water through a nanofiltration membrane. Retentate liquid rejected from the nanofiltration membrane is pumped to effluent or returned to the nanofiltration membrane. Permeate from the nanofiltration membrane is sprayed through a well screen upper collector above an open atmospheric bed having strong base ion exchange resin. The permeate is pumped through the ion exchange resin and through a gravel layer beneath the resin. The strong base ion exchange resin is periodically regenerated.

A filtration system has a filter element with a filtration membrane, a feed inlet and a concentrate outlet on a first side of the membrane and a permeate outlet on a second side of the membrane. A feed line with a feed shutoff valve is in fluid communication with the feed inlet, and a concentrate return line with a concentrate shutoff valve is in fluid communication with the concentrate outlet. A feed pump is in fluid communication with the feed inlet via the feed line and the feed shutoff valve, and a backwash pump is in fluid communication with the permeate outlet. In a priming phase of a backwash operation, the feed shutoff valve and the concentrate shutoff valve are closed and the backwash supply is operable to deliver fluid to the filtration element and equalize pressure between the first side and the second side of the filtration membrane.

A membrane-based air separation module includes an inlet configured to receive supply air, a first hollow fiber membrane configured to substantially remove water from the supply air to form an anhydrous air stream, and a permeate port configured to exhaust the water removed by the first hollow fiber membrane from the air separation module. The air separation module also includes a second hollow fiber membrane positioned downstream of the first hollow fiber membrane configured to receive the anhydrous air stream and substantially remove oxygen from the anhydrous air stream, an oxygen-enriched air outlet configured to exhaust the oxygen removed by the second hollow fiber membrane from the air separation module, and a nitrogen-enriched air outlet configured to supply a stream of nitrogen-enriched air to a fuel tank of an aircraft.

A water treatment device (1) includes a primary unit (U1) having a plurality of primary elements (E1) as reverse osmosis membrane devices disposed in parallel to each other to separate water to be treated (SW) supplied from an upstream side into primary condensed water (CW1) and fresh water (FW1); a pump (P) which feeds the water to be treated from the upstream side of the primary unit to supply the water to be treated to the primary unit; a secondary unit (U2) having secondary elements (E2) as reverse osmosis membrane devices, the secondary elements being provided in smaller number than the primary elements and disposed in parallel to each other to separate the primary condensed water into secondary condensed water (CW2) and fresh water (FW2); and a reflux unit (2) which refluxes a part of the secondary condensed water between the primary unit and the secondary unit.

A membrane-based air separation module includes an inlet configured to receive supply air, a first hollow fiber membrane configured to substantially remove water from the supply air to form an anhydrous air stream, and a permeate port configured to exhaust the water removed by the first hollow fiber membrane from the air separation module. The air separation module also includes a second hollow fiber membrane positioned downstream of the first hollow fiber membrane configured to receive the anhydrous air stream and substantially remove oxygen from the anhydrous air stream, an oxygen-enriched air outlet configured to exhaust the oxygen removed by the second hollow fiber membrane from the air separation module, and a nitrogen-enriched air outlet configured to supply a stream of nitrogen-enriched air to a fuel tank of an aircraft.

An acidic treatment liquid processing apparatus includes: a tank having an interior space; a diaphragm permeable to a metal cation and separating the interior space of the tank into a first chamber and a second chamber; a first electrode disposed in the first chamber; a second electrode disposed in the second chamber; a power supply configured to apply a voltage while using the first electrode as an anode and the second electrode as a cathode; a first liquid passing part configured to pass an acidic treatment liquid containing a dichromate ion and a metal cation into the first chamber; and a second liquid passing part configured to pass an acid aqueous solution into the second chamber.