Physical/Chemical Methods

 

To ensure possibility of dumping it is necessary, in some cases, especially with galvanic, mordanting and hardening processes, to implement detoxication and stabilization to transform them to stabilized form. Contaminants contained in waste are altered by a chemical, eventually physical/chemical reaction and transformed to nontoxic form with permanently lowered maceration of dangerous extracts.

 

Removal of waste by demulsification is done by acid or alkaline process. Both ways lead to nullification of emulsifier effect to dissolve oil substances in water. Done by addition of additive to emulsion of oil substances. Additives used in this process are coagulation or demulsification reagents. Acidic coagulation employs Aluminium Sulphate with pH 4 – 6, alkaline coagulation Iron Sulphate with pH 8 - 9. This is followed by flocculant addition which leads to separation of solid and fluid phases. The solid phase is then concentrated in filter press and afterwards removed in incineration plant or in landfill for dangerous waste. The fluid phase is than taken to a sewage clarification plant.

 

The chemical reaction between acidic and alkaline dilution takes place done during neutralization. Acidic waste is neutralized by sodium solution or milk of lime and opposite alkaline waste by acids. The best way to neutralize these waste waters is so-called auto-neutralization. Where if it´s technologically possible, both kinds of waste waters mix together and only the leftover is neutralized by reagent. Products of this reaction are respective salt and water. Those are than utilized by sedimentation and separation. Sediments are then concentrated in filter press or decanter hydroextractor. Neutralization is mostly used for utilization of industrial wastes which are concentrated strong acids, alkalines and lyes, which in most cases also contain heavy metals. 

 

Solidification is process where a solid matrix is created from mix of wastes, binder and other additives. Waste and bonding agent are formed into solid monolithic corpus, which leads to significant cut-down of surface area of utilized waste.