A resin-wafer electrodeionization (RW-EDI) apparatus for purifying water for coffee brewing comprises a cathode; an anode; and multiple porous solid resin wafer exchange units arranged in a stack between the cathode and the anode, and an air distributor adapted and arranged to aerate the water to be purified. Each unit comprises a monovalent cation exchange membrane (CEM), an anion exchange membrane (AEM), and an ion exchange resin wafer between the CEM and the AEM, which is in contact with, and in fluid flow connection with the CEM and AEM. Each resin wafer comprises a cation exchange resin and an anion exchange resin. The units are oriented with the CEM facing the cathode and the AEM facing the anode, with space between the units defining ion concentrate chambers. Bipolar ion exchange membranes separate the anode and cathode from their nearest resin wafer exchange units.

Header-equipped air diffusion devices includes, in the header, an air storage unit, on its lower end including inlet(s) for water to be treated, and air supply part(s) and air sending part(s) on the air storage unit upper section. The air diffusion device's air sending part and horizontal tube are connected, air sent from the header being diffused by the air diffusion device, and air sending in the air storage unit is above the air supply part's air supply port. The air storage portion's partition portion, with a 50+mm height, partitions the upper portion into an air supply and an air feeding portion side. The partition portion forms a cylindrical portion and an upper plate portion and the air storage portion's trunk portion serves as part of the air supply portion, and an opening end on a lower end side of the partition portion serves as the air supply port.

An electrochlorination system includes an electrolyzer fluidically connectable between a source of feed fluid and a product fluid outlet, and a sub-system configured to one of increase a pH of the feed fluid, or increase a ratio of monovalent to divalent ions in the feed fluid, upstream of the electrolyzer.

A water treatment control system includes an aerobic tank in which aerobic treatment is carried out, an aerobic tank aeration device that aerates to-be-treated water in the aerobic tank, a membrane filtration tank including a separation membrane that filters the to-be-treated water treated in the aerobic tank, a membrane filtration tank measurement instrument that measures the ammonia concentration of the to-be-treated water in the membrane filtration tank, as a membrane filtration tank ammonia concentration measurement value, and an aerobic tank aeration air volume calculation device that sets the aerobic tank aeration air volume of the aerobic tank aeration device on the basis of the membrane filtration tank ammonia concentration measurement value.

A membrane module includes a housing. The housing includes a housing, comprising: a first plurality of porous hollow fiber membranes, and a second plurality of porous hollow fiber membranes different from the first plurality of porous hollow fiber membranes. The first plurality of porous hollow fiber membranes has a first length, and the second plurality of porous hollow fiber membranes has a second length that is at least 1.1 times greater than the first length. The membrane module can be used in separation methods, such as membrane distillation methods.

Vacuumed gap membrane distillation (VAGMED) modules, and multi-stage VAGMED systems and processes using the modules are provided. In an embodiment, the membrane distillation modules can comprise: a) a condenser including a condensation surface; b) a first passageway having an inlet for receiving a first feed stream and an outlet through which the first stream can pass out of the first passageway, the first passageway configured to bring the first feed stream into thermal communication with the condensation surface; c) an evaporator including a permeable evaporation surface allowing condensable gas to pass there through; d) a second passageway having an inlet for receiving a second feed stream and an outlet through which the second feed stream can pass out of the second passageway, the second passageway configured to bring the second feed stream into communication with the permeable evaporation surface; and e) an enclosure providing a vacuum compartment within which the condenser, the evaporator and the first and second passageways of the module are contained.

Vacuumed gap membrane distillation (VAGMED) modules, and multi-stage VAGMED systems and processes using the modules are provided. In an embodiment, the membrane distillation modules can comprise: a) a condenser including a condensation surface; b) a first passageway having an inlet for receiving a first feed stream and an outlet through which the first stream can pass out of the first passageway, the first passageway configured to bring the first feed stream into thermal communication with the condensation surface; c) an evaporator including a permeable evaporation surface allowing condensable gas to pass there through; d) a second passageway having an inlet for receiving a second feed stream and an outlet through which the second feed stream can pass out of the second passageway, the second passageway configured to bring the second feed stream into communication with the permeable evaporation surface; and e) an enclosure providing a vacuum compartment within which the condenser, the evaporator and the first and second passageways of the module are contained.

A membrane distillation system includes a hollow fiber aerator configured to provide gas bubbles to a relatively cool permeate stream so that the relatively cool permeate stream contains gas bubbles when it contacts a porous and hydrophobic membrane in a direct contact membrane distillation process. The system can further include an additional hollow fiber aerator configured to provide gas bubbles to a relatively hot feed stream so that the relatively hot feed stream contains gas bubbles when it contacts a porous and hydrophobic membrane in a direct contact membrane distillation process.

A biological reactor system treats concentrated contaminated water with a combination of upflow and downflow bioreactors that are downstream from a reverse osmosis or other concentrator. The system may have a fail safe configuration where flush water may be introduced to the reactors in the event of a power failure or when taking the reactors offline. Many reverse osmosis systems introduce antiscalant treatments upstream so that the reverse osmosis filters do not scale. However, such treatments result in superconcentrated conditions of the antiscalants in the contaminated water processed by the bioreactors. A flushing system may deconcentrate the bioreactors to prevent the antiscalants from precipitating and fouling the bioreactors.

A biological reactor system treats concentrated contaminated water with a combination of upflow and downflow bioreactors that are downstream from a reverse osmosis or other concentrator. The system may have a fail safe configuration where flush water may be introduced to the reactors in the event of a power failure or when taking the reactors offline. Many reverse osmosis systems introduce antiscalant treatments upstream so that the reverse osmosis filters do not scale. However, such treatments result in superconcentrated conditions of the antiscalants in the contaminated water processed by the bioreactors. A flushing system may deconcentrate the bioreactors to prevent the antiscalants from precipitating and fouling the bioreactors.