Methods for forming a treated water may comprise: obtaining a produced water comprising at least a divalent metal ion from a subterranean formation; introducing an accelerator into the produced water; wherein the accelerator comprises a zwitterionic compound; introducing a carbon dioxide gas into the produced water; allowing the carbon dioxide gas to react with the divalent metal ion in the presence of the accelerator to form a carbonate salt of the divalent metal ion; and removing the carbonate salt of the divalent metal ion from the produced water to form a treated water having a lower divalent metal ion concentration than the produced water.

Provided are methods for recovering phosphate from wastewater by treating the wastewater with calcium containing compounds to raise its pH to near neutral values in order to precipitate calcium phosphate compounds, such as brushite, from the wastewater.

Disclosed herein is a liquid pod comprising a liquid composition comprising at least two of a Solvent A, a Solvent B, an Active, a Modifier, and an Adjuvant, wherein the water treatment liquid composition is disposed within a packet comprising a water-soluble polymer film.

The present invention discloses a method for nitrogen removal of wastewater, which achieves the perfect combination of COD removal (Fenton oxidation) and nitrogen removal (Feammox) of wastewater, thereby avoiding the waste of reagents in traditional Fenton oxidation treatment of wastewater.

Disclosed herein is a liquid pod comprising a liquid composition comprising at least two of a Solvent A, a Solvent B, an Active, a Modifier, and an Adjuvant, wherein the water treatment liquid composition is disposed within a packet comprising a water-soluble polymer film.

A grinding wastewater pretreatment method has the following steps: S1, taking grinding wastewater and adjusting the pH to 7 using sodium hydroxide or sulfuric acid; S2, adding a demulsifier to the grinding wastewater, stirring, filtering, and collecting a filtrate; S3, adding magnetic nanoscale ferroferric oxide particles and an adsorbent to the filtrate, stirring, allowing to settle, and collecting an upper solution; S4, adding aluminum sulfate and cationic polyacrylamide for sludge dewatering to the upper solution, stirring, and allowing to settle; and S5, passing a filtered liquid through a cotton filtration layer and a ceramic nanofiltration membrane layer in sequence, resulting in pretreated grinding wastewater. The pretreatment method provided by the invention can efficiently remove suspended solids in grinding wastewater.

A method for reducing a toxicity of wastewater, including: selecting a working electrode based on a biochemical oxygen demand to chemical oxygen demand (B/C) ratio of the wastewater; constructing a microbial electrochemical system using the graphite rod or the biochar/MoS.sub.2-modified graphite rod as the working electrode; adding a culture solution including the wastewater, sediment, a phosphate buffer solution, and a carbon source to the microbial electrochemical system, cultivating and enriching an electroactive biofilm on the surface of the working electrode in the microbial electrochemical system using chronoamperometry, and periodically refreshing the culture solution until the electroactive biofilm reaches a stable and mature state; and after formation of the electroactive biofilm, introducing the wastewater into the microbial electrochemical system with a matured electroactive biofilm, applying an external voltage to the working electrode, and operating the microbial electrochemical system under intermittent polarization switching between open-circuit and closed-circuit modes.