The present invention provides a multi plate screw press sludge dewatering machine and a helical shaft thereof. The multi plate screw press sludge dewatering machine includes fixed rings, movable rings, the helical shaft, a sludge inlet tank and a sludge discharging tank; the helical shaft adopts a variable diameter variable pitch helical shaft, a lead angle arrangement sequence of a helical blade of the whole helical shaft is gradual reduction from the sludge discharging tank to the sludge inlet tank, and the lead angle arrangement sequence is gradually reduced from 16°-22° to 6°-14°; a pitch of the helical shaft is gradually increased along a direction from the sludge inlet tank to the sludge discharging tank; a diameter of a shaft body of the helical shaft is gradually increased along with a direction of the sludge discharging tank from a ⅓ position of a shaft length; and blockage prevention plates are arranged on two sides of the bottom of the helical blade. The helical shaft in the present invention is specially designed, so that the pitch is more reasonable, a helical angle is gentler, frictional resistance when sludge passes through the helical shaft may be effectively reduced, and phenomena of shaft blockage and shaft sticking of the sludge may be reduced.

A membrane separation process is described. The process comprises pumping of a fluid stream through a membrane module to produce a permeate during a plurality of membrane operating cycles. Each membrane operating cycle comprises a filtration cycle and a relaxation cycle. Concentration polarisation is controlled during the process by controlling duration of filtration cycles and relaxation cycles to relatively short duration to maintain the degree of concentration polarisation below a target.

An apparatus is for injuring or killing undesired organisms in water in a channel. The apparatus has an insert which is arranged to be releasably attached to the channel on the inside of the channel, a plurality of electrodes that are attached to the insert, the insert being formed from an electrically insulating material and the plurality of electrodes being connected to a power-supply unit. A method for using the apparatus in the channel is described as well.

A water-treating ceramic filter unit comprising a filter having pluralities of flow paths partitioned by porous ceramic cell walls and plugs alternately sealing the one-side or other-side ends of the flow paths; a housing containing the filter such that water to be treated is supplied from one end of the filter, and that the treated water is discharged from the other end of the filter; and seal members disposed on the outer edge portions of both end surfaces of the filter for longitudinally sandwiching and fixing the filter to the housing; the maximum of a gap between a side surface of the filter and the housing being equal to or less than the equivalent diameter of the flow paths.

Exemplary embodiments describe apparatuses and related processes for improving mixing and sheer in a fixed film reactor. One process can include recycling at least a portion of a biogas product through at least one sparger below a fixed film zone in the fixed film reactor at conditions sufficient for mixing and sheering the film from an internal structure within the fixed film zone. Often, a cross-sectional area of the fixed film zone fills at least about 90% of a cross-sectional area of the fixed film reactor.

A subsea desalination template includes subsea desalination module zones and module fluid couplings. A desalinated water outlet is in fluid connection with the module fluid coupling in the subsea desalination module zone. Subsea desalination modules with reverse osmosis cartridges are in fluid connection with a subsea template fluid coupling, a seawater inlet section, and a concentrated seawater outlet section. A transport pump assembly for desalinated water in a pump module is in fluid connection with the subsea desalination template and the desalination modules. A seawater circulation pump is in fluid connection with a seawater side of the at least one reverse osmosis cartridge. A desalinated water pipeline conveys fluid from the desalinated water transport pump assembly to a location above sea level.

A closed conduit system for use in a water supply system includes a recirculating unit configured to connect to an isolated section between a first point and a second point of the water supply system. The recirculating unit includes a first filter unit defining a first closed circuit including the isolated section and adapted to perform a first treatment. A second filter unit defines a second closed circuit including the isolated section and is adapted to perform a second treatment. At least one pump is capable of generating a flow of water through the first and the second closed circuit, and a valve selectively controls flow through either the first or the second closed circuit.

In a wastewater treatment plant a rag seeding tank is included in a process drain to collect hair and fibers which have passed through headworks of the plant. The hair and fibers tend to join together into large masses downstream of the headworks and can be damaging to process zones, particularly membrane zones. The rag seeding tank includes cartridges filled with surfaces that fibers and hair will attach to, so that hair/fiber rags grow in the seeding tank and are removed therefrom rather than causing problems downstream.

In a geothermal plant, alternately injecting an acid composition and a caustic composition removes or inhibits scale build-up.

A water treatment method includes a microbubble generating step (S101) of generating microbubbles in water to be treated containing at least calcium ions and producing water to be treated containing microbubbles, a water softening step (S102) of crystallizing calcium ions contained in the water to be treated containing the microbubbles as calcium carbonate and removing the calcium carbonate, and a reverse osmosis membrane treatment step (S103) of separating the water to be treated, from which the calcium carbonate has been removed, into reverse osmosis membrane treated water and reverse osmosis membrane concentrated water using a reverse osmosis membrane.