ABSTRACT

Wet-chemistry analyzers and autotitrators are jokingly called "chemist in the box" devices because they automatically and accurately perform the operations which a laboratory chemist would perform manually to gain the same end result. Autotitrator-based closed-loop control systems are used on those neutralization applications where the wastewater is buffered and therefore pH measurement alone is insufficient to determine the neutralization agent requirement. When used for process control, the autotitrator can be continuous or batch-type. Recognizing that continuous analysis may not be necessary for alarm or on/off control purposes on streams that are relatively stable, automatic batch analyzers have also been developed. High-precision, automatic colorimetric analyzers perform in the same manner as does the chemist. Colorimetric analyzers are generally equipped with automatic zero and standardization features. The simpler continuous colorimetric analyzers are generally limited to analyses requiring no more than two or three reagents that can be added simultaneously.