An embodiment provides a method for measuring dissolved oxygen of an aqueous sample, including: introducing an aqueous sample into a measurement device comprising at least two dissolved oxygen sensors, wherein at least one of the at least two dissolved sensors comprises a trend sensor and at least another of the at least two dissolved sensors comprises a reference sensor; measuring a first value of dissolved oxygen using the trend sensor, wherein the trend sensor samples at a trend frequency; measuring a second value of dissolved oxygen from a reference sensor, wherein the reference sensor samples at a reference frequency, the reference frequency being less than the trend frequency; and correcting the first value of dissolved oxygen based upon the second value of dissolved oxygen. Other aspects are described and claimed.

Bioelectrochemical Systems (BES) for use as Biological Oxygen Demand (BOD) sensors, systems incorporating BES sensors for measuring BOD, and methods of using the sensors and systems for measuring BOD. The disclosed sensors are inexpensive to construct, long-lasting, have a fast response, and a large dynamic range. The invention includes biological oxygen demand (BOD) sensors which incorporate at least three working electrodes, at least one counter electrode, a reservoir for dilution fluid, and a sensor for measuring an electric current or a voltage which flows from the working electrodes to the counter electrode. The BOD sensors will typically also include at least one electrically active microbe disposed in proximity to the working electrode.

The present invention provides a method of determining chemical oxygen demand (COD) for a sample with a high concentration of chloride. The method includes obtaining the sample, determining a concentration of chloride in the sample to obtain a known concentration of chloride in the sample, dosing an amount of the sample, an acid and an oxidizing agent into a container to obtain an analyte, heating the container containing the analyte, photometrically determining a preliminary chemical oxygen demand (COD) of the analyte in an analytic device, and correcting for the high concentration of chloride using a chloride correction to obtain the chemical oxygen demand (COD).

A computer-implemented method includes controlling an instrument to measure a fluorescence emission spectrum of a sample including a first peak emission wavelength and at least a second peak emission wavelength, emitted in response to an excitation wavelength and controlling the instrument to measure an absorbance obtained at the excitation wavelength of the sample. The method may include determining, using the computer, a ratio of the measurements at either the second peak emission wavelength, or a sum of measurements at a plurality of peak emission wavelengths including at least the first peak emission wavelength and the second peak emission wavelength, to the first peak emission wavelength, and calculating, using the computer, a value for a quality parameter based on a combination of at least the ratio and the absorbance measurement. The method may include controlling an associated process based on the quality parameter.

A microbial sensor, system and method that can be used to determine the chemical environment and/or substrate concentrations in saturated and unsaturated natural and environments, such as soils, aquifers and sediments are disclosed. The system may be used for monitoring municipal and industrial treatment facilities and sites where chemicals or contaminants were released to natural environments. The electrochemical microbial sensor system can be referenced using either a cathode exposed to oxygen or a reference cell (silver/silver chloride or calomel) for monitoring natural or man-made environments.

Method and system for detection and quantification of oxidizable organics in water. The method involves the partial electrolytic decomposition of the oxidizable organics in a short time frame, preferably less than five seconds, and does not involve the use of toxic reagents. The system includes an electrochemical sensor probe that, in turn, includes a boron-doped diamond microelectrode array. The system additionally includes an electronic transducer and a computing device. The system utilizes an analysis technique to convert sensor signal to a result that can be correlated with COD or BOD values obtained by standard methods. The method and system are particularly suitable for, but not limited to, use in monitoring of water quality at wastewater treatment plants. By employing the method before and after adding aerobic microorganisms to the sample, the method may be used to distinguish biologically oxidizable organics from total oxidizable organics.

A method for determining a parameter includes forming a reaction mixture by adding a volume of a solution to a sample. The solution contains a substance acting as a reaction partner for the analyte, where the reaction partner enters into a chemical reaction with the analyte, forming a reaction product of the analyte. The volume of the solution is adjusted, based on measured values of a physical or chemical measurand which are detected during the addition of the solution in the reaction mixture and whose value depends on the concentration of the analyte or of the substance in the reaction mixture. A titration of the solution to be titrated is subsequently performed from which a quantity of the substance present in the reaction mixture after addition of the volume of the solution is determinable, and a value of the parameter is ascertained using the titration.

A computer-implemented method includes controlling an instrument to measure a fluorescence emission spectrum of a sample including a first peak emission wavelength and at least a second peak emission wavelength, emitted in response to an excitation wavelength and controlling the instrument to measure an absorbance obtained at the excitation wavelength of the sample. The method may include determining, using the computer, a ratio of the measurements at either the second peak emission wavelength, or a sum of measurements at a plurality of peak emission wavelengths including at least the first peak emission wavelength and the second peak emission wavelength, to the first peak emission wavelength, and calculating, using the computer, a value for a quality parameter based on a combination of at least the ratio and the absorbance measurement. The method may include controlling an associated process based on the quality parameter.

An embodiment provides a method for measuring at least one characteristic of an aqueous sample, including: introducing an aqueous sample into a measurement device comprising one or more electrodes; oxidizing a transition metal to produce a higher valent metal by applying an electrical potential between an anode and a cathode of the measurement device; oxidizing, using the higher valent metal as a catalyst, a material within the aqueous sample; measuring a characteristic of the aqueous sample based upon the oxidized material, using a measurement device selected from the group consisting of: an electrochemical measurement device and an optical measurement device; and optimizing the electrical potential and at least one reagent delivered to the measurement device based on the measurement of the characteristic. Other aspects are described and claimed.

The invention simulation device and method for studying the influence of wetland plant litter decomposition on water quality, belongs to the ecological engineering field. The simulation device comprises a distributing reservoir, a planting pool and a discharge bay, and the three are connected successively through a first-level pipeline; the distributing reservoir is used to supply water to the planting pool; the discharge bay is used to collect wastewater discharged from the planting pool; the planting pool comprises a plurality of planting units; the planting unit is a container-like structure and used to hold the planting substrate and plant wetland plants on the planting substrate. By using the simulation device and/or simulation method of the invention, the whole process of the influence of plant litters especially wetland plants litters on water quality under natural state can be highly simulated and restored.