Turbidity monitoring

Chemical addition is typically used with clarification to improve both the utility and performance of the unit operation. Coagulants and flocculants are generally used to improve the ability to settle particles in the clarifier. Jar tests are used to determine the proper dosage of chemicals and streaming current detectors or turbidity monitors are used to monitor performance and control chemical dosage. Chlorine is often used to improve the removal of organics and color in the clarifier. Chlorine also provides disinfection of the make-up water to prevent the clarifiers from going septic. 

Turbidity Monitoring The turbidity of feed water and filtrate is monitored. An intact membrane would be expected to show a 90% reduction of turttdily from feed to filtrate (DWl, 2001). 

Turbidity Gauges These operate with visible light beams and detectors. They are used to monitor feed and effluent turbidity. 

GC Jeffrey, RH Ottewill. Reversible aggregation Part reversible flocculation monitored by turbidity measurements. Colloids Polymer Sci 266 173-179, 1988. 

Introduction of chemical sensors for water quality monitoring. This includes parameters like turbidity, color, surface tension, detergent concentrations, pH-value etc. Optoelectronic systems are used to monitor the turbidity of washing water, which then determines the number of rinsing cycles (aqua-sensor system). 

Optoelectronic systems for monitoring the turbidity of washing water allow the number of flushing cycles to be adapted to the actual need. (Aqua-sensor system). 

Quantitative determination and monitoring of many species in solution over a wide range of concentrations (10 7 - 1 M) relative precision 0.1-5%. Titrations are especially useful for coloured or turbid samples or for mixtures. 

A lot of substances and components are present in wastewaters and can be measured, especially the emerging pollutants. However, in practice, the aggregate parameters (BOD, COD, TSS,...) and the physico-chemical ones (temperature, pH, dissolved oxygen, conductivity, turbidity,...) are more often monitored. The only specific compounds generally considered are the N and P forms, and in case of industrial wastewaters, some specific pollutants such as organics (phenolics, hydrocarbons,...) or metallic compounds. 

Relatively far from the present topic and well known, the on-line measurement of the physical and aggregate properties of wastewater does not present any problem. Conductivity, temperature, turbidity and oxido-reduction potential (ORP) are easily measured by well-designed sensors, because these parameters are also used for treatment process control. In practice, turbidity is more used for the treatment of natural water, and ORP for the biological treatment of wastewater. However, conductivity and temperature are often monitored at the same time as the other parameters in this section. 

S. Barnes, J. Gillian, A. Diederich, D. Burton and D. Ertl, In process monitoring of polymorphic form conversion by Raman spectroscopy and turbidity measurements. Am. Pharm. Rev., 11, 80, 82-85 (2008). 

Assays. The turbidity of E. coli extracts and alfalfa extracts was quantitated spectrophotometrically at 600 nm and 680nm respectively. GUS activity was assayed as outlined by Novel and Novel (75), except that activity was monitored at 400 nm (6° = 9.6 X 10 ). Peroxidase activity was determined at 37°C with o-tolidine using a final concentration of 0.67 mM o-tolidine-HCl (Sigma Chemical Co., St. Louis, MO) and 1 mM H2O2 in 20 mM sodium phosphate buffer pH 7.1. The change in absorbance was... 

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