pH/ORP Monitoring Articles

  • Case study - Increased capacity & stringent effluent limits met in a small footprint

    This Idaho Wastewater Treatment plant’s two existing single-ring oxidation ditches were facing increased flows and a new tougher phosphorus limit of less than 2.3 kg (5 lb) of total phosphorus per day. In addition to a tight budget, the small amount of land available also hampered the city’s options. The consultant’s evaluation confirmed fine-bubble aeration “would ...

  • Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment

    The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother ...


    By IWA Publishing

  • pH/ORP Sensors for Metallurgical Applications

    Importance of pH Measurement Hydrometallurgical concentrating and refining applications require pH/ORP sensors to withstand aggressive environments while maintaining accurate measurement. Processes such as cyanide leaching (e.g gold) and solvent extraction (e.g. copper, nickel, zinc) require pH and ORP to be at very specific values to yield the desired chemical species. pH may need ...


    By IC Controls Ltd.

  • Microorganism growth control - Case Study

    KDF Process Media uses Oxidation Reduction Process for Scale and Bacteria Removal A plastic injection molding plant uses KDF media to control microorganisms and eliminate scale build-up in cooling towers-at 25% of the cost of chemical treatments. Photo courtesy of Marley Tooling Technologies, Inc. KDF process media are incorporated into carbon blocks and other matrices for bacteria removal and ...


    By KDF Fluid Treatment, Inc.

  • Inhibition of unwanted nitrification

    Respirometer The respirometer utilized in this study corresponds to the BM-Advance model, with the following main features: Compact analyzer, with very low maintenance and user friendly operation Direct oxygen measurements from a maintenance-free oxygen sensor No oxygenation restriction during test performance Full control and results by ...


    By SURCIS, S.L.

  • Optimization of VFAs and ethanol production with waste sludge used as the denitrification carbon source

    An acidification metabolite such as volatile fatty acids (VFAs) and ethanol could be used as denitrification carbon sources for solving the difficult problem of carbon source shortages and low nitrogen removal efficiency. A proper control of environmental factors could be essential for obtaining the optimal contents of VFAs and ethanol. In this study, suspended solids (SS), oxidation reduction ...


    By IWA Publishing

  • Effects of oxidation reduction potential in the bypass micro-aerobic sludge zone on sludge reduction for a modified oxic–settling–anaerobic process

    Batch experiments were conducted to determine the effect of oxidation reduction potential (ORP) on sludge reduction in a bypass micro-aerobic sludge reduction system. The system was composed of a modified oxic–settling–anaerobic process with a sludge holding tank in the sludge recycle loop. The ORPs in the micro-aerobic tanks were set at approximately +350, −90, ...


    By IWA Publishing

  • Control of trichloroethylene plume migration using a biobarrier system: a field-scale study

    The objective of this field-scale study was to evaluate the effectiveness of controlling trichloroethylene (TCE) plume migration using the polycolloid substrate (PS) biobarrier. The developed PS (containing soybean oil, lactate and surfactants) could release substrate to enhance the TCE dechlorination. In this study, a biobarrier comprising PS injection wells was installed. Injection wells were ...


    By IWA Publishing

  • Stop metal losses in processes with Sulphide, Cyanide, Ammonia and Pressure Fluctuations

    Abstract Losses of metal are often traced to incorrect pH/ORP signals in floatation, leaching, extraction, electrolysis, and precipitation processes, aggravated by pressure changes. IC Controls a Canadian mining sensor manufacturer developed a new superior pH/ORP sensor that stops metal losses, reduces environmental footprint and contributes to sustainability. The cause of incorrect pH/ORP ...


    By IC Controls Ltd.

  • Development of polymer lab-on-a-chip (LOC) for oxidation-reduction potential (ORP) measurement

    Reverse osmosis (RO) desalination has been recognized as a promising method to solve the water shortage problem. Nevertheless, since it is energy intensive and has many problems associated with biofouling/fouling of RO membranes in RO plants, its commercial acceptance is still slow. Especially, as high levels of oxidizing agents negatively affect RO membrane efficiency and life span. So, there is ...


    By IWA Publishing

  • Monitoring pH and ORP in a SHARON reactor

    This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been ...


    By IWA Publishing

  • The effect of nitrite on oxygen uptake in activated sludge as it relates to the redox potential

    The objective of this investigation was to show that the low nitrate bend in the redox potential curve is in fact the result of nitrite inhibition of oxygen uptake. The oxygen sensor used indicated traces of oxygen at the time of the observed low nitrate bend which supports the hypothesis. However, an oxygen sensor with a lower measuring range is needed in order to show conclusively that this ...


    By IWA Publishing

  • Biological nitrogen removal in a step-feed CAST with real-time control treating municipal wastewater

    The performance of a 18 L step-feed cyclic activated sludge technology (CAST) combined with real-time control treating real municipal wastewater was evaluated. The operation strategies employed pH and oxidation reduction potential (ORP) as on-line control parameters, which can control the durations of oxic and anoxic phases flexibly. The obtained results showed that the studied process had ...


    By IWA Publishing

  • Oxidizer operating cost reduction strategies

    The mainstream media today is full of allusions to energy awareness and conservation. Just as visible these days are media references to astronomical dollar figures that can boggle the mind. This article does not seek to break out of that mold, but rather to conform to it – as Oxidizer Stack Heat Recovery offers a tremendous opportunity for both energy conservation and energy cost reduction. ...

  • Selenium Removal

    The oil refinery was in search of a feasible solution for the removal of selenium. Discharge permit changes by the EPA require a reduction of 50% from current levels. Integrated Engineers, Inc. was given an opportunity to perform a feasibility test to determine a treatment process as well as estimated operational costs. The best process was to adjust the pH from 7.0 to 10.0 using caustic, ...


    By Integrated Engineers Inc.

  • Lead Plating

    A Midwest company is plating lead and etching the material with an HCl batch. The resultant wastewater had a lead concentration of 2,000-4,000 ppm. Traditional chemistry (pH adjustment to 9.8, coagulation/flocculation) could only decrease the concentration to 5.0 ppm. The facility was had to retreat the wastewater and only then could reach a lead level of 3.0 ppm.  With the use of the ...


    By Integrated Engineers Inc.

  • Continuous emission monitoring and control of packed tower odor control systems using the sycamore CEM

    ABSTRACT Packed-tower chemical scrubbers, with sodium hydroxide (caustic) and sodium hypochlorite (bleach), are commonly used to treat foul air from wastewater treatment processes. The available control mechanisms include a pH probe and controller for the sodium hydroxide feed, an oxidation reduction potential (ORP) probe with a controller toestablish the bleach feed, and proprietary ...

  • Optimizing Metals Removal

    Optimizing Wastewater Metals Removal Making Wastewater Metals Insoluble for Easy Removal To remove metals from wastewater, the metals need to be insoluble (not in solution). Many facilities, such as in the ...


    By Integrated Engineers Inc.

  • Improved Control for your Cooling Tower and Boiler

    The power of microprocessor based programming along with the ease of interfacing with standard Internet based controllers has enabled improved cooling tower and boiler control with just the click of a mouse. Many of these improvements can significantly enhance your chemical treatment program, and provide greater flexibility in your chemical treatment program. These new algorithms offer ...


    By Walchem, Iwaki America Inc.

  • Meat Packing Wastewater Disinfection Difficulties Leads to a State of the Art Control System and Consistent Regulatory Compliance

    ABSTRACTJohn Morrell & Co. is a meat packing plant located in Sioux Falls, South Dakota. The facility also maintains a tertiary wastewater treatment facility with a direct discharge following treatment. The treatment facility had good effluent compliance history until the spring of 2001, when sporadic elevated levels of fecal coliform and infrequent spikes in chlorine residual were ...

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