A method of processing a workpiece having a first surface and a second surface opposite the first surface includes: generating a first beam of laser pulses having a pulse duration less than 200 ps at a pulse repetition rate greater than 500 kHz, directing the first beam of laser pulses along a beam axis intersecting the workpiece, and scanning the beam axis along a processing trajectory. The beam axis is scanned such that consecutively-directed laser pulses impinge upon the workpiece at a non-zero bite size to form a feature at the first surface of the workpiece. One or more parameters such as bite size, pulse duration, pulse repetition rate, laser pulse spot size and laser pulse energy is selected to ensure that the feature has a processed workpiece surface with a mean surface roughness (Ra) of less than or equal to 1.0 μm.

Method and apparatus pertaining to the production of hydrogen sulfide using sodium salts recycle. Sodium sulfate is reacted with a carbon containing stream to produce sodium sulfide and carbon dioxide. The sodium sulfide is blended with elemental sulfur and water. The blend is subjected to elevated temperatures and pressures to result in the production of hydrogen sulfide and sodium sulfate. A mixing apparatus, such as a bubble column reactor, has been found to be especially useful. The hydrogen sulfide can be used for removing metal from effluents.

A process is disclosed for treating water, such as wastewater, with ozone under alkaline and acidic conditions to decompose and remove acrolein and acrolein byproducts from the water and/or wastewater. The process is able to lower the concentration of acrolein and acrolein byproducts from water to a sufficiently low level suitable for discharge to a municipal sewer collection system with reduced occurrence of the decomposition by-products of acrolein converting back to acrolein in the water. One embodiment of the process treats contaminated water containing acrolein with ozone by sparging or bubbling ozone through the contaminated water. The contaminated water can be treated with ozone where the contaminated water is initially adjusted to a pH greater than 7.0 for a time to convert at least a portion of the acrolein to 3-hydroxypropanal to obtain a partially treated water. The pH of the partially treated water is then adjusted to a pH below 7.0 while continuing the ozone treatment for a time sufficient to react with and decompose the 3-hydroxypropanal to inhibit the conversion of 3-hydroxypropanal back to acrolein.

A method of removing boron from water to be treated includes subjecting the water to be treated to reverse osmosis membrane treatment, subjecting at least part of permeated water after the reverse osmosis membrane treatment to cation-removing treatment, and measuring a concentration of boron in the resulting permeated water after the cation-removing treatment, in which a measured value for the concentration of boron is used to regulate at least one of: (a) the recovery rate of water to be treated in the above reverse osmosis membrane treatment, (b) the temperature of the water to be treated, (c) the pH of the water to be treated, (d) the supply pressure of the water to be treated, which pressure is applied to the reverse osmosis membrane during the reverse osmosis membrane treatment, and (e) when the reverse osmosis membrane used for the reverse osmosis membrane treatment should be changed.

A method of removing boron from water to be treated includes subjecting the water to be treated to reverse osmosis membrane treatment, subjecting at least part of permeated water after the reverse osmosis membrane treatment to cation-removing treatment, and measuring a concentration of boron in the resulting permeated water after the cation-removing treatment, in which a measured value for the concentration of boron is used to regulate at least one of: (a) the recovery rate of water to be treated in the above reverse osmosis membrane treatment, (b) the temperature of the water to be treated, (c) the pH of the water to be treated, (d) the supply pressure of the water to be treated, which pressure is applied to the reverse osmosis membrane during the reverse osmosis membrane treatment, and (e) when the reverse osmosis membrane used for the reverse osmosis membrane treatment should be changed.

An ion removal device includes a hard water storage section configured to store hard water; and a fine bubble generation means configured to generate fine bubbles and supply the bubbles to the hard water storage section, wherein, in the hard water storage section, metal ions in the hard water are adsorbed to the fine bubbles to be removed from the hard water.

A water-permeable device. The device has a supporting layer and a water-permeable membrane. The water-permeable membrane includes graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers. The interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation. Also disclosed are systems and methods for water treatment.

A water-permeable device. The device has a supporting layer and a water-permeable membrane. The water-permeable membrane includes graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers. The interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation. Also disclosed are systems and methods for water treatment.

Various embodiments relate to methods and systems for removing phosphorus and/or nitrogen from water. A method of removing phosphorus and nitrogen from water includes passing starting material water including nitrogen and phosphorus through an elevated pH phosphorus removal stage. The method includes passing the water through an electrolytic nitrogen removal stage. The method includes passing the water through a galvanic phosphorus removal stage. The water produced by the method has a lower phosphorus concentration and a lower nitrogen concentration than the starting material water.

A water treatment system is provided with a nitrogen-containing organic compound oxidizing device that treats the first-stage treatment water after filtration and removal of cation ions. An oxidant-containing water stream and an inorganic bromide-containing water stream are respectively added into a pipeline that conducts the first-stage treatment water and then pass through an in-pipe mixer and a mixing unit, whereby to oxidize the nitrogen-containing organic compounds in the first-stage treatment water and then form the second-stage treatment water for output.