The invention relates to a water treatment plant comprising: means for supplying water for treatment, wherein said water has been coagulated previously, a flocculation-decantation device having means for dispensing at least one flocculant reagent, means for dispensing at least one ballast, means for extracting decantation sludge, means for discharging the treated water, means for separating said ballast contained in the ballasted sludge, and means for recycling the ballast that has been cleaned in this manner back into the flocculation-decantation device, characterised in that: said flocculation-decantation device has a single tank in the lower portion of which a stirring mechanism is arranged; wherein said single tank comprises slats in its upper portion; and said slats are separated from the stirring mechanism by a distance “d” which is between approximately 0.5 metres and approximately 3 metres. The invention also relates to a method using said plant.

A method and system of providing seawater into a subterranean formation, including adding chloride salt having a metal cation to the seawater (having sulfate), precipitating sulfate salt (of the metal cation and sulfate), removing the sulfate salt as precipitated to give treated seawater having less sulfate than the seawater, and injecting the treated seawater into the subterranean formation.

A method of desulfating seawater includes adding a produced water to a sulfated seawater, forming a first precipitate, separating the first precipitate from the sulfated seawater, measuring the sulfate ion concentration of the desulfated seawater, adding a precipitating agent to the sulfated seawater, and separating a second precipitate from the sulfated seawater. Another method of desulfating seawater includes determining concentrations of sulfates in a sulfated seawater and a precipitating agent in a produced water, adding the produced water to the sulfated seawater based on the determined concentrations of sulfates in the sulfated seawater and the precipitating agent in the produced water, forming a first precipitate, separating the first precipitate from the sulfated seawater, measuring the sulfate ion concentration of the desulfated seawater, adding a precipitating agent to a sulfated seawater, and separating a second precipitate from the sulfated seawater.

Defining one treatment cycle as comprising a filtration step J for using a filter membrane to filter water to be treated in a filtration tank and a filtration stopping step K for stopping filtration, this method, for administering a coagulant in water treatment that involves repeating the treatment cycle C1 to C5 to treat water to be treated, starts administration of the coagulant into the filtration tank when the membrane load index becomes greater than or equal to a first threshold value, wherein the membrane load index is defined as the amount of increase in transmembrane pressure per unit time in the filtration step J.

A system for treating metal-contaminated wastewater includes a primary treatment sub-system, a secondary treatment sub-system, and a tertiary treatment sub-system. The tertiary treatment sub-system includes a reactor tank, a source of ballast material, a source of coagulant, a solids-liquid separator, and a controller configured to recycle ballasted solids from the solids-liquid separator to the reactor tank an amount sufficient to generate metal hydroxide floc in the reactor tank to reduce a concentration of dissolved metal in the reactor tank.

A system and method for treating reverse-osmosis (RO) concentrated water with high temporary hardness. The system includes a crystallization unit, a precipitation unit, a dewatering unit, and a programmable logic controller (PLC) system. The crystallization unit, precipitation unit and dewatering unit are connected in series, and the PLC system is configured to control pumps, valves, and displays in the crystallization unit, precipitation unit and dewatering unit. The crystallization unit includes a storage tank and a crystallization reactor communicated therewith. The crystallization reactor is provided with a pH meter, a liquid-level gauge, and a stirrer. A connection pipe between the crystallization reactor and the RO concentrated water is provided with an inlet pump and a inlet valve. A connection pipe between the crystallization reactor and the storage tank is provided with a feeding pump and a feeding valve.

According to one or more embodiments, sulfate ions may be removed from seawater to form an injection fluid by a method including passing the seawater and formation water to a mixing tank. The seawater may comprise sulfate ions. The formation water may comprise barium ions. The seawater and formation water may be passed to the mixing tank in a ratio determined by a computerized geochemical model. The method may further include mixing the seawater and formation water to form a mixed fluid and passing the mixed fluid to a clarifier, where a barium sulfate precipitate may be formed and at least a portion of the barium sulfate precipitate may be separated from the mixed fluid. The method may further include passing the mixed fluid to a microfiltration system, where at least a portion of the barium sulfate precipitate may be removed from the mixed fluid to form an injection fluid.

A vacuum-flocculation-solidification integrated apparatus for waste mud and a using method thereof are provided, and the apparatus includes an outer support truss, a vacuum barrel wall, a flocculation stirring device, and a rotary spraying solidification device. The using method of the apparatus includes: flattening a site and installing a support truss and a vacuum barrel wall; assembling a flocculation stirring device and then hoisting and installing to a top of the vacuum barrel wall; checking an air tightness; adding an APAM flocculant, starting the flocculation stirring device and a vacuum pump; starting an air compressor; and squeezing solidified soil from soil outlets. Beneficial effects of apparatus are that: multiple procedures of flocculation, vacuum drainage, solidification and discharging soil for the waste mud are continuously performed; a solidification agent is fully mixed with solidified soil through rotary spraying; and the apparatus is convenient to be disassembled, reassembled, and reused.

Provided for example is a system and method for real-time monitoring or controlling wastewater or sludge dewatering or thickening processes. The system and method can also enable operators to remotely monitor their own system off-site.

Methods for flocculating solid particles in a provided suspension including specifying a target charge density of the suspension at which the solid particles flocculate; providing a flocculant having a charge density; determining, at a plurality of measuring times, the suspension charge density present in the suspension in the course of a titrimetric analysis, measuring the flow potential; determining, at respective of the measuring times, a quantity of the flocculant needing to be added to ensure optimal flocculation based on the target charge density, the flocculant charge density, and the suspension charge density present at the respective measuring time; and subsequently adding the determined quantity of flocculant into the suspension; and systems therefor. The methods and systems can provide the actual demand of flocculant needed for efficient flocculation in a continuous flocculation method of a suspension.