Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, that generate from a first pair and a second pair of images of livestock that are within an enclosure and that are taken at different times using a stereoscopic camera, at least two distance distributions of the aquatic livestock within the enclosure. The distance distributions can be used to determine a measure associated with an optical property of the water within the enclosure. A signal associated with the measure can be provided.

A passive sampling device is provided that is comprised of a member having a first surface and a second surface opposite the first surface and a hole through the member extending from the first surface to the second surface. An adsorbent material is positioned between two mesh members. The adsorbent material allows for efficient and selective removal of organic molecules, such as, for example, perfluoroalkyl substances.

A sensing platform for continuous water resource monitoring by electrochemical detection and solution parameter correction is provided. The sensing platform employs a solid-state electrolyte three-electrode cell, creating a high ionic strength environment within the solid-state electrolyte membrane, which is in ion exchange equilibria with the sampled solution. This device may be used as a standalone sensor in environments where the water parameters (pH temperature, and ionic strength) are controlled, or in concert with compensation sensors where water parameters are not controlled.

A method for evaluating bioavailability of organic nitrogen in sewage through machine learning, includes: collecting the molecular composition information and bioavailability data of organic nitrogen in a sewage sample; establishing a model for predicting bioavailability of organic nitrogen in sewage through machine learning; measuring the molecular composition information of organic nitrogen in sewage from a target sewage plant; and predicting, according to the model, the bioavailability of the organic nitrogen in the sewage from the target sewage plant.

A method for evaluating bioavailability of organic nitrogen in sewage through machine learning, includes: collecting the molecular composition information and bioavailability data of organic nitrogen in a sewage sample; establishing a model for predicting bioavailability of organic nitrogen in sewage through machine learning; measuring the molecular composition information of organic nitrogen in sewage from a target sewage plant; and predicting, according to the model, the bioavailability of the organic nitrogen in the sewage from the target sewage plant.

A system and method for measuring concentration of oxidation ions in a solution includes a conduit that contains the solution at least temporarily, a pH sensor associated with the conduit and configured to provide a pH signal indicative of a pH of the solution, an oxidation reduction probe (ORP) associated with the conduit and configured to provide an ORP signal indicative of an oxidation reduction of the solution, and a controller configured to receive and process the pH signal and the ORP signal, wherein the controller calculates a concentration of oxidation ions in the solution based on the pH and ORP signals.

Methods, systems, and apparatuses are provided for detecting and determining conditions of and conditions within a fluid conduit.

Methods, systems, and apparatuses are provided for detecting and determining conditions of and conditions within a fluid conduit.

Measurement devices can be used for identifying concentration of arsenic species in water samples. The measurement devices can take the form of test strips including a substrate with at least one testing region that includes an amount of a testing medium. The silver reagent includes a polymer framework and a silver component that is stabilized by the framework, yet remains reactive enough to function as a colorimetric sensor for arsenic, e.g., ((Ag(H.sub.2btc))(Ag.sub.2(Hbtc))).sub.n. The initially substantially colorless testing medium exhibits a color change response when exposed to arsenic species, e.g., arsine, generated from samples including as little as 5 ppb arsenic, with an increasingly dark color as the concentration of arsenic is increased. Test strips fabricated with the silver coordination polymer display robust stability towards both light and water, allowing for an alternative to mercury-based field test kits in real-world field tests under direct sunlight and high humidity conditions.

One embodiment provides a system, including: at least two water analyzers, wherein at least one of the at least two water analyzers is positioned upstream of a purification apparatus and wherein at least another of the at least two water analyzers is positioned downstream of the purification apparatus; at least one processor; and a memory device that stores instructions executable by the processor to: receive water analysis data from the at least two water analyzers, wherein the water analysis data comprises information related to membrane integrity; identify an algorithm for calculating membrane integrity based upon received data corresponding to system attributes; and calculate, using the identified algorithm, the membrane integrity based upon the received water analysis data. Other aspects are described and claimed.