An integrated device and method for treating toxic and refractory wastewater are provided. The integrated device includes an adjusting pool, a first-stage reactor, a second-stage reactor, a third-stage reactor, a coagulation sedimentation pool, and a biochemical reaction pool that are sequentially connected in series, and further includes an aeration blower. Each of the first-stage reactor and the third-stage reactor is an advanced oxidation reactor, and the second-stage reactor is a Fenton reactor. The coagulation sedimentation pool includes 2 to 4 stages, and each stage of the coagulation sedimentation pool includes a coagulation tank, a primary sedimentation tank, and a secondary sedimentation tank that are connected in series. The biochemical reaction pool includes an anoxic tank, an aerobic tank, a settling tank, and a clean water tank that are connected in series. The wastewater treatment method combines the integrated device for treating toxic and refractory wastewater with reasonable process parameters.

A method of removing organic pollutants in water by zero-valent iron enhanced hypochlorite includes the steps of: adjusting a pH of raw water containing organic pollutants to 4.0˜9.0; adding zero-valent iron solid and hypochlorite to the raw water in a mixer; and turning on the mixer to carry out stirring reaction. The method constructs a Fenton-like system through the redox reaction in the heterogeneous micro-interface region that occurs between zero-valent iron and hypochlorite which produces a variety of active oxidizing species with high occurrence, improves the shortcomings of the traditional Fenton method, broadens the applicable range of pH, and increases the removal efficiency of pollutants in water by 35˜95%.

A method and system for treating contaminated water are described. The method comprises receiving, in a first chamber, contaminated water with injection of a modifier; in a first chamber, treating the contaminated water with at least one of air or oxygen and simultaneously treating the contaminated water with ultraviolet radiation; in a second chamber, receiving fluid from the first chamber and treating the received fluid with at least one of oxygen or ozone; in a third chamber, receiving fluid from the second chamber and treating the received fluid with ultraviolet radiation; and discharging water from the third chamber using a discharge pump.

Provided herein are processes for the removal and/or recovery of a target metal from a liquid sample, said process comprising: [1] applying acoustic cavitation to the liquid; and [2] adding an iron (II) salt, or a precursor form thereof, to the liquid sample and allowing Fenton oxidation reaction to occur between the iron and hydrogen peroxide in the liquid, thereby producing hydroxyl radicals; thereby producing a target metal salt or metal oxide having a reduced solubility in the liquid sample, leading to removal of the target metal from the liquid sample. The use of metal ligands in such processes is also described, as well as systems for performing such processes. Methods, processes, and systems for removing organic contaminants from a liquid sample are also described.

An industrial waste salt resourceful treatment method comprises the following steps: the industrial waste salt is sequentially subject to dissolving, chemical pre-purification, deep purification, organic matter concentration reduction, adsorption and oxidation decolorization and multi-effect evaporative crystallization to respectively obtain sodium sulfate, sodium chloride and sodium nitrate crystals; the crystallization temperature of sodium sulfate is in a range of 75° C. to 85° C.; the crystallization temperature of sodium chloride is in a range of 60 to 70° C.; and the crystallization temperature of sodium nitrate is in a range of 45° C. to 55° C. An industrial waste salt resourceful treatment device is further provided.

A system for treating printed circuit board wastewater (PCB) includes a production system, a pretreatment system, a biochemical system, a recovery system and a concentrated water treatment system. The production system is configured for producing process water and auxiliary water from tap water. The pretreatment system is configured to pretreat different wastewater samples separately. The biochemical system is configured to decompose the pretreated wastewater. The recovery system is configured to treat wastewater from the pretreatment system and the biochemical system to obtain process water and feed concentrated water to the concentrated water treatment system. The concentrated water treatment system is configured to treat the concentrated water to meet a discharge standard. A treatment method for the PCB wastewater is also provided.

The present invention discloses an electrocatalytic Fenton oxidation-electrochemical oxidation coupling process and apparatus for efficient treatment of chemical wastewater, and belongs to the field of sewage treatment. The process includes an electrocatalytic Fenton oxidation step, an electrochemical oxidation step, and a pH adjustment step. A spacing between a cathode and an anode in the electrocatalytic Fenton oxidation step is controlled, so that oxygen produced at the anode reacts at the cathode to produce H.sub.2O.sub.2. The treatment requirements can be met without external aeration or external addition of H.sub.2O.sub.2, and meanwhile, the efficiency of COD removal by electro-Fenton oxidation is effectively improved. Further, by connecting a pH adjusting tank with the electrocatalytic Fenton oxidation-electrochemical oxidation coupling apparatus in series, a coupling treatment process with near-zero production of iron sludge is realized.

The present disclosure relates to the field of resource utilization-oriented treatment technologies for wastewater, and more particularly, to a resource utilization-oriented treatment method for a spent electroless nickel plating bath. The method includes oxidation de-complexation, synchronous precipitation of nickel and phosphorus, secondary precipitation of nickel, and resource utilization of sodium salt. In the present disclosure, in a reaction process, no sludge is generated to avoid secondary pollution to the environment. Further, the present disclosure has the advantages of short flow and less chemical use, greatly reducing treatment costs. In this way, this method is a low-cost and clean resource utilization-oriented treatment method capable of achieving resource utilization-oriented recovery of nickel, phosphorus, sodium, sulfate radical, or chlorine in the spent electroless nickel plating bath.

A water treatment composition for treating organic wastewater is provided. The water treatment composition includes a bulk catalytic material and an oxidant. The bulk catalytic material includes iron atoms or ions, manganese atoms or ions, and magnesium atoms or ions.

A gas diffusion electrode includes a carbon fiber tube, a support layer, and a catalyst layer. The carbon fiber tube is straight and functions as a substrate. The support layer includes a carbon black-polytetrafluoroethylene (PTFE) coating, and is disposed on the substrate. The catalyst layer includes carbon black, anhydrous ethanol, and PTFE, and is disposed on the support layer. The gas diffusion electrode has a diameter of 3-20 mm and a length of 50-500 mm.