A process for producing PHA comprises obtaining biomass produced in the course of biologically treating a first wastewater source containing RBCOD. The biomass is to be exploited with a second wastewater source having a different RBCOD content from the first wastewater source in order to accumulate and thereby produce PHA. Before subjecting the biomass to a PHA accumulation process, the biomass PHA accumulation potential is enhanced via an acclimation process with the second wastewater source. During acclimation, the biomass is subjected to repeated feast-famine periods. During each feast period, the biomass is exposed to a fraction of the second wastewater source. The RBCOD uptake and/or biomass respiration rate is directly or indirectly measured during each feast period. The famine period is maintained for a period of time that is at least two times greater than the length of time of the proceeding feast period. After at least two feast-famine acclimation periods or after one or more measured parameters reveal an increased RBCOD relative uptake or respiration rate of the biomass during a subsequent feast period, the biomass is subjected to a PHA accumulation process using the second wastewater source.

The present disclosure discloses a method and device for removing Organic Micropollutants (OMPs) in water, and belongs to the technical field of wastewater treatment. The method includes the following steps: S1: aerating residual sludge under a starvation condition to enrich starved-state microorganisms; and S2: treating wastewater containing OMPs under an aeration condition with sludge containing the starved-state microorganisms obtained in step S1, and periodically updating the sludge containing the starved-state microorganisms. According to the present disclosure, aerobic starvation treatment is performed on the sludge to gradually reduce the abundance of microorganisms that may use degradable organic matters only and enrich microorganisms that may use complex organic matters in the sludge, and the enriched sludge may degrade various OMPs and be used to remove OMPs in wastewater. The process is easy to operate and low in cost and has relatively high practical application value.

A system and method for monitoring process water treated with a biocide is provided. The system includes a biocide feeding unit and a dissolved oxygen sensor. The dissolved oxygen sensor works in two modes, a biocide feeding mode and a background mode, and alerts an operator when the dissolved oxygen value indicates a fault in the system. A drop in dissolved oxygen during feeding can indicate faulty production of biocide or biocide degradation, both of which can lead to unwanted disinfection by-products.

A cost-effective system and method dissolves gas, such as oxygen, into water in a manner that prevents gas bubble carry over by using a bubble capture system (BCS). The system and method further eliminates or minimizes turbulence at the suction and discharge of a pump using an energy dissipation header (EDH). The BCS can create a top-down flow that permits bubbles to rise faster than the velocity of the downward flow of water. The EDH can use a pipe design, such as a slotted pipe design, that permits a maximum system water flow. The technology can be applied to water bodies to mitigate eutrophication and may also be applicable in other fields, such as wastewater lift stations, fish farms, oil and gas industry, tidal applications with low flushing rates, and winter under ice oxygenation to prevent fish kills.

The present disclosure provides an in-situ method for removing sulfates. The method comprises delivering at least one low molecular weight organic compound (LMWOC) to soil or groundwater to attain a concentration of the LMWOC of 750-3000 mg/L, such as 1000-2000 mg/L, or about 1500 mg/L, especially whereby sulfate is reduced to below 250 mg/L in the soil or groundwater. The method may further comprise contacting the soil or groundwater with an oxidizer, such as hydrogen peroxide, whereby the concentration of metals or metalloids is reduced in the soil or groundwater.

A method and system of treating a liquid stream is provided. The water is treated by utilizing a free radical scavenging system and a free radical removal system. The free radical scavenging system can utilize actinic radiation with a free radical precursor compound, such as ammonium persulfate. The free radical removal system can comprise use of a reducing agent. The water may be further treated by utilizing ion exchange media and degasification apparatus. A control system may be utilized to measure and regulate addition of the precursor compound, the intensity of the actinic radiation, and addition of the reducing agent to the water.

Systems and method for treating wastewater including a vessel having an inlet and an outlet, a pump in fluid communication with the outlet of the vessel, the pump configured to pump wastewater out of the vessel, a separator in fluid communication with the pump, the separator configured to separate grit from the wastewater, the separator having a first outlet for discharging a grit stream and a second outlet for discharging a wastewater stream, a grit washing system in fluid communication with a source of washing fluid and the first outlet of the separator, the grit washing system configured to wash and dewater grit from the grit stream, the grit washing system having an outlet for discharging a wash wastewater stream, and a return conduit configured to recycle the wastewater stream discharged from the separator to one of the inlet of the vessel and an inlet to the pump.

Provided is a water quality management apparatus for an aquaculture pond, the apparatus having a storage unit for storing water quality-related measured values measured at appropriate time intervals by external sensors set in the aquaculture pond, an assessment unit for calculating a predicted future value on the basis of fluctuations in the measured values and determining the time when the predicted value will exceed a reference value that indicates deterioration of water quality, and a display unit for displaying the time when the reference value will be exceeded. Said time is the time when exchange of pond water will be necessary.

A redox water treatment method comprises first determining the composition of water and whether water treatment requires either oxidation or reduction, or both to optimize nitrogen removal by a bioreactor. Sulfur dioxide (SO.sub.2) is injected into the water to be treated to provide H.sup.+, SO.sub.2, SO.sub.3.sup.=, HSO.sub.3.sup.−, dithionous acid (H.sub.2S.sub.2O.sub.4), and other sulfur intermediate reduction products forming a sulfur dioxide treated water, which behaves either as a reducing agent or an oxidizing agent depending on the strength of the acid concentration, which alters sulfurous acid from a reducing agent to a more powerful oxidizing agent.

There are provided processes for treating wastewater. The processes can comprise treating a mixture comprising the wastewater and an activated sludge, in a single reactor, with an electric current having a density of less than about 55 A/m.sup.2, by means of at least one anode and at least one cathode that define therebetween an electrical zone for treating the mixture; exposing the mixture to an intermittent ON/OFF electrical exposure mode to the electric current in which an OFF period of time is about 1 to about 10 times longer than an ON period of time; and maintaining an adequate oxidation-reduction potential in the single reactor. Such processes allow for substantial removal of carbon, nitrogen and phosphorus from the wastewater in the single reactor of various forms and for obtaining another mixture comprising a treated wastewater and solids.