Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).

A method for desalination of hot supersaturated water having a temperature of between 40° C. and 80°, includes contacting the hot water with a reverse osmosis membrane which is resistant to temperatures of between 40 and 80° C. without a prior cooling step.

A scale suppression apparatus capable of suppressing in a low-priced manner the generation of silica-based scale and calcium-based scale in the influent water, a geothermal power generation system using the same, and a scale suppression method are provided. The apparatus includes a first addition unit configured to add liquid containing a chelating agent and an alkaline agent to influent water flowing through a pipe arrangement to make the influent water higher than pH 7, a second addition unit configured to add an acid substance to the influent water to make the influent water lower than pH 7, and a controller configured to alternatively switch between the operation of the first addition unit and the operation of the second addition unit. The controller controls the switching of the first addition unit and the second addition unit based on the signals output from a scale detection unit and a pH meter.

The invention relates to a compressed salt block and a liquid treatment apparatus provided therein with at least one such compressed salt block. The liquid treatment apparatus comprises a housing adapted to accommodate at least one liquid treatment tank and at least one compressed salt block. The housing comprises a first space portion for accommodating the at least one liquid treatment tank, and a second space portion for accommodating at least partially the at least one compressed salt block; wherein the at least one compressed salt block comprises an extension portion which extends into a space in the first space portion between an external surface of the at least one liquid treatment tank and an inner wall surface of the housing adjacent the external surface of the at least one liquid treatment tank to thereby position the at least one compressed salt block within the housing. The compressed salt block comprises an elongated body having an irregular cross section, the cross section comprising a base side and a functional side opposing the base side, wherein at least a portion of the functional side forms an acute angle to the base side thereby forming the extension portion of the salt block.

A method is disclosed for scaling control in a membrane system operation. The method can be performed by a model in the control system of a plant. The method can include selecting one or more antiscalants corresponding to one or more components of the scale, based on one or more of feed water condition, membrane material, membrane fouling status and a kinetic study relating to a reaction between the antiscalants and the components of the scale. The composition of one or more selected antiscalants can be estimated based on an overall scaling rate constant.

A method is disclosed for scaling control in a membrane system operation. The method can be performed by a model in the control system of a plant. The method can include selecting one or more antiscalants corresponding to one or more components of the scale, based on one or more of feed water condition, membrane material, membrane fouling status and a kinetic study relating to a reaction between the antiscalants and the components of the scale. The composition of one or more selected antiscalants can be estimated based on an overall scaling rate constant.

A scale suppression apparatus capable of suppressing in a low-priced manner the generation of silica-based scale and calcium-based scale in the influent water containing at least a silica component and a calcium component, a geothermal power generation system using the same, and a scale suppression method are provided. The scale suppression apparatus includes a chelating agent and alkaline agent addition unit injecting liquid containing a chelating agent and an alkaline agent into a pipe arrangement through which influent water such as geothermal water or the like flows, and a controller controlling a pump and a valve of the chelating agent and alkaline agent addition unit. The controller controls the injection of the chelating agent and the alkaline agent and stops of the injection based on the signal output from a scale detection unit for detecting a precipitation state of the scale.

A scale suppression apparatus capable of suppressing in a low-priced manner the generation of silica-based scale and calcium-based scale in the influent water containing at least a silica component and a calcium component, a geothermal power generation system using the same, and a scale suppression method are provided. The scale suppression apparatus includes a chelating agent and alkaline agent addition unit injecting liquid containing a chelating agent and an alkaline agent into a pipe arrangement through which influent water such as geothermal water or the like flows, and a controller controlling a pump and a valve of the chelating agent and alkaline agent addition unit. The controller controls the injection of the chelating agent and the alkaline agent and stops of the injection based on the signal output from a scale detection unit for detecting a precipitation state of the scale.

A water treatment device includes a sub-reverse osmosis membrane device having a primary casing and a primary reverse osmosis membrane dividing the primary casing into a primary liquid passing part and a primary permeating part; a low pressure water feed pump feeding seawater to the primary liquid passing part at a pressure that is equal to or lower than an osmotic pressure of the seawater; a main reverse osmosis membrane device having a secondary casing and a secondary reverse osmosis membrane dividing an inside of the secondary casing into a secondary liquid passing part and a secondary permeating part; and a high pressure water feed pump feeding a primary treated liquid, which is a resultant product of the seawater passing through and flowing out of the primary liquid passing part, to the secondary liquid passing part at a pressure higher than an osmotic pressure of the primary treated liquid.

A water treatment device includes a sub-reverse osmosis membrane device having a primary casing and a primary reverse osmosis membrane dividing the primary casing into a primary liquid passing part and a primary permeating part; a low pressure water feed pump feeding seawater to the primary liquid passing part at a pressure that is equal to or lower than an osmotic pressure of the seawater; a main reverse osmosis membrane device having a secondary casing and a secondary reverse osmosis membrane dividing an inside of the secondary casing into a secondary liquid passing part and a secondary permeating part; and a high pressure water feed pump feeding a primary treated liquid, which is a resultant product of the seawater passing through and flowing out of the primary liquid passing part, to the secondary liquid passing part at a pressure higher than an osmotic pressure of the primary treated liquid.