The nickel plating wastewater treatment process generally includes three links: physical treatment, chemical treatment and biological treatment.
In the physical treatment stage, the suspended solids and sediments in the wastewater can be precipitated by adjusting the pH value of the wastewater, setting up a static sedimentation tank, using sedimentants and filters, etc., so as to reduce the suspended matter in the water.
Common methods in the chemical treatment stage include neutralization precipitation, oxidative precipitation and ion exchange. Among them, the neutralization and precipitation method can use alkaline substances such as sodium hydroxide or calcium hydroxide to neutralize the acidic substances in the wastewater, and then form a precipitate with nickel ions, which can be physically separated through the sedimentation tank. Oxidative precipitation is the use of oxidants such as hydrogen peroxide or potassium permanganate to oxidize nickel ions in wastewater into precipitate, so as to achieve the purpose of removal. Ion exchange is also a common chemical treatment method that adsorbs nickel ions through resin to achieve purification.
The biological treatment stage is to use the biochemical action of microorganisms to degrade organic substances. At present, the commonly used biological treatment methods include aeration activated sludge method, anaerobic biological sieve method and biofilm reactor method. The aeration activated sludge method is to bring wastewater into contact with granular sludge and provide enough oxygen through aeration to enable microorganisms to degrade organic matter. Anaerobic biological sieve is processed in a biofilter bed under anaerobic or anoxic conditions, and microorganisms degrade organic matter through the attachment and growth of biofilms. The biofilm reactor method uses biofilm to attach to the fixed support and provide oxygen through aeration to decompose the organic matter in the wastewater.