Worldwide Inline Process Control Solutions

Effluent Water Monitoring

Color Removal

In order to meet environmental discharge requirements, it becomes necessary to measure the mill’s effluent and determine the amount of dissolved color. The mill generally treats the problem by using coagulants to precipitate out the color. After this step the effluent is floated in a Dissolved Air Flotation device (DAF) with the aid of a flocculant.

Expensive sampling and analysis can be avoided by using an inline APHA / Hazen color sensor AF26. Alarm functions can be used to alert the operator of excessive levels of contaminant before discharge, helping to avoid penalties and fines from local authorities.

Controlling Chemical Feed to DAF

optek AF26 Dual Channel Absorption Sensor

Monitoring and controlling the DAF unit for color helps optimize the addition of chemicals. Basing the chemical dosage on the color measurement rather than a constant feed rate prevents overdosing. An AF26 color sensor installed in the effluent piping from the DAF unit, or even used in conjunction with a second inline sensor in the feed line, provides automated coagulant and flocculant dosing control. In turn, this significantly cuts down the amount of chemicals needed to properly treat the mill’s effluent water.

Environmental Effluent Monitoring

As environmental regulations become more strict, the need for paper mills to monitor and report their effluent discharges increases. optek inline sensors not only alert plant personnel when color levels are too high, but also provide continuous data logging. This data can be used to report plant effluent efficiency to governmental regulating agencies.


Continuous control of water quality and optimum dosage of flocculant are achievable using optek process photometers. Reduction of polymer consumption and effluent costs gives a rapid return on investment. Additionally, unnecessary fines can be avoided while complying with local authorities and regulations.