Processes and system are provided for digesting biosolids in a multistage digestion system. The processes and system are well suited for producing Class A biosolids and biogas containing a high content of methane. Methods and systems are also provided for recovery of phosphorus from wastewater and biosolids.

A water treatment and recirculation system includes means to transport water flows at required pressures, a mechanical filter of approximately 100 microns to capture coarse particles, oxygen production means, autonomous electricity generation means, and variable control means using a PLC that administers parameters such as pressure, oxygen and CO.sub.2 levels, flows, pH, etc. The system also includes means to ultrafilter and remove particles of up to 0.02 microns, the purpose being removing organic material macromolecules, disinfecting bacteria and viruses with mechanical removal, and eliminate harmful contaminants such as ammonia, degasifying means to eliminate CO.sub.2 with a multitubular exchanger with membranes made of hydrophobic materials and micro perforations to take CO.sub.2 away to an extraction gas in atmospheric or vacuum conditions; and means to oxygenate water with a multitubular exchanger having membranes constituted by hydrophobic materials and microperforations that inject O.sub.2 into water of a gas under atmospheric conditions.

The invention provides methods and compositions for treating wash water from concrete production with carbon dioxide. The treated wash water can be reused as mix water in fresh batches of concrete.

A water treatment and recirculation system includes means to transport water flows at required pressures, a mechanical filter of approximately 100 microns to capture coarse particles, oxygen production means, autonomous electricity generation means, and variable control means using a PLC that administers parameters such as pressure, oxygen and CO.sub.2 levels, flows, pH, etc. The system also includes means to ultrafilter and remove particles of up to 0.02 microns, the purpose being removing organic material macromolecules, disinfecting bacteria and viruses with mechanical removal, and eliminate harmful contaminants such as ammonia, degasifying means to eliminate CO.sub.2 with a multitubular exchanger with membranes made of hydrophobic materials and micro perforations to take CO.sub.2 away to an extraction gas in atmospheric or vacuum conditions; and means to oxygenate water with a multitubular exchanger having membranes constituted by hydrophobic materials and microperforations that inject O.sub.2 into water of a gas under atmospheric conditions.

Described herein is a system to provide continuously measurements of an analyte present in a fluid sample, particularly dissolved oxygen in wastewater. The system comprises a sample chamber absent of ambient light to contain the sample and in many embodiments employs a non-invasive method of measuring the analyte and determining the change over time in the concentration of the analyte. It is also an aspect of the invention to deliver analyte measurements in real-time and provides the operator with feedback in substantially less time after sample collection than previously accomplished in the field. It is another aspect of the invention to simultaneously or at least in a substantially short period of time thereafter measure temperature to remove initial error encountered at the start of analyte measurement at least until the sample chamber reaches thermal equilibrium.

Disclosed herein are methods, systems, and devices for generating electricity from an effluent source. In the presence of electrogenic bacteria and substrate electrodes, an electroactive biofilm is produced which possesses bioconductive capacity for efficiently producing an electric current while treating an effluent source such as, e.g., wastewater. This disclosure relates generally to the production of electricity from a biological source. In particular, this disclosure relates to microbial fuel cells (MFCs) and other bioelectrochemical systems (BES) that exploit an exogenous fuel source.

The present disclosure relates, in part, to enhanced weathering systems and/or apparatuses and methods of use thereof. In one aspect, the present disclosure provides a method of at least partially sequestering CO.sub.2 from an influent aqueous solution comprising aqueous and/or gaseous CO.sub.2. In another aspect, the present disclosure provides a method of at least partially sequestering CO.sub.2 from a gaseous CO.sub.2 source. In another aspect, the present disclosure provides systems and/or apparatuses suitable for use in the methods described herein. In another aspect, the present disclosure provides a method of optimizing the design and operation of a system for at least partial sequestration of CO.sub.2 from a water source.

A method including directing an aqueous solution having dissolved carbon dioxide and dissolved ozone into a vessel, removing an amount of the dissolved carbon dioxide and irradiating the effluent with ultraviolet light to decompose an amount of the dissolved ozone is disclosed. The method may include removing the dissolved carbon dioxide by controlling pH. The method may include removing the dissolved carbon dioxide by contact with a membrane degasifier. A system including a channel fluidly connectable to a source of an aqueous solution having dissolved carbon dioxide and dissolved ozone, a dissolved carbon dioxide removal subsystem, and a source of ultraviolet irradiation is also disclosed. The dissolved carbon dioxide removal subsystem may include a source of a pH adjuster. The dissolved carbon dioxide removal subsystem may include a membrane degasifier.

A recirculating aquaculture system for producing aquatic species suitable for human consumption includes: a culture tank providing habitat for a selected aquatic species; a plurality of subsystems in communication with the culture tank and configured to recirculate and treat water within the system, the plurality of subsystems comprising: a solids control subsystem for removing particulates in the water, a recirculating pump subsystem for recirculating water within the system, an aeration/stripping subsystem for contacting air and water to strip carbon dioxide out of the water and into the air, a pH control subsystem to maintain the alkalinity of the water, an oxygenation subsystem for providing oxygen to the water, and an optional ozonation subsystem for providing ozone to the water; and wherein the water comprises iron cations at a concentration of at least about 0.1 ppm. Methods of maintaining the recirculating aquaculture system are also described.

An apparatus and a method for treating saltwater and removing chlorine in water to make a variety of sodium-based byproducts and chlorine gas is disclosed. The apparatus comprises a feed tank for receiving water. The feed tank is coupled to a plurality of Radio frequency (RF) chambers. Each of the RF chambers comprises an inlet and an outlet. The outlet is coupled to a treated water effluent manifold. Further, each RF chamber is coupled to a vacuum manifold. Each RF chamber comprises a recirculation pipe to pump water back into the feed tank. The RF chamber comprises a RF system used for bombarding RF energy at predefined frequencies on the water in order to liberate chlorine isotope. Additionally, the RF system bombards RF energy to stretch hydrogen bond in the saltwater to a point of breaking a molecule by applying low pressure. The hydrogen bond captures chlorine. Subsequently, the water is sent through the outlet to the treated water effluent manifold.