Inorganic Acids, Acid Mixtures and Mordants

The pH values of these solutions are less than 6. They are acidic aqueous solutions which must be free of
- Cyanides (otherwise hydrogen cyanide would be formed!),
- ammonium ions (max. allowed 0.1 mol/L), and
- Any kind of organic substances (e.g. solvents, fats and oils).

Used acids containing nitric acid (e.g. nitrant mixtures) must be neutralised and then disposed of as "Washing and rinsing water".

Acidic solutions that do not contain heavy metals or other hazardous substances can be neutralised with sodium hydroxide or sodium hydrogen carbonate in equimolecular quantities and then discharged into the laboratory waste water.

Bases, Alkaline Mixtures, and Mordants
This waste category comprises liquid wastes with a pH greater than 8. These are solutions of alkaline hydroxides that must be free of
- cCanides,
- ammonium ions (max. 0.1 mol/L, otherwise ammonia will be emitted!), and
- Any kind of organic substances (e.g. solvents, fats and oils).

Alkaline solutions that do not contain heavy metals or other hazardous substances can be neutralised with equimolecular amounts of hydrochloric acid and then discharged into the laboratory waste water.

Washing and rinsing water, containing metallic salts
This waste category includes aqueous solutions of metallic salts which must be free from
- Cyanides,
- ammonium ions (max. permitted 0.1 mol/L!), and
- Any kind of organic substances (e.g. solvents, fats and oils).

For these aqueous solutions, significant volume reductions can be achieved by applying concentration measurements.