As effluent water quality regulations have become more stringent, the need for an online continuous effluent monitoring system has continued to grow. Continuous monitoring of effluents from the discharge points of industrial units at the outlets of effluent treatment plants/ Waste Water Treatment plants. The analysers continuously generate data at intervals of one second to few minutes.

CBCP has issued directions u/s 5 of the E(P) act to the units for installation of online monitoring system for strengthening monitoring and self-regulation. Failure to comply with the directions may lead to closure of the units. Industrial units are required to submit the compliance data online and thereafter separate submissions in hard copies will be phased out. For effluent PH, BOD, COD, TSS, flow, chromium, ammoniacal nitrogen, fluoride, phenol, cyanide, temperature, aox and arsenic are the parameters which require continuous monitoring depending on the industry.

The major advantages of on-line monitoring systems over traditional laboratory based and portable field methods are:

Online monitoring systems provide continuous measurement of data for long periods of time, at the monitoring site of interest, without skilled staff being required to perform the analysis.

All the major steps in traditional analysis like sample collection, preservation, transportation, sample pre-treatment, calibration, reagent addition and sample analysis procedures are usually automated in on-line analysers.

In case of sudden disturbance in the system, compared to conventional methods the on-line analysers provide timely information for taking immediate corrective/preventive steps.