The standard applies to all types of wastewater with a sulphide content of at least 0.1 mg/l. When determining dis olved sulphide, interference due to sulphite and thiosulphate occurs at SO2 contents greater than 10 mg/l and at S203 contents greater than 10 mg/l; Sodium hydrosulfite also interferes. Sulphites, thiosulphate and hydrosulphite can interfere with the determination of the total sulphide content. The photometric determination is dis urbed by iodide if there is more than 1 mg of iodide in the solution whose extinction is measured.
NEN 3235 8.3-1978 history
1978NEN 3235 8.3-1978 Test methods for waste water. Photometric rietermination of sulphide content