A method and apparatus for treating wastewater using a sequencing batch reactor wherein the biological solids are densified through hydraulic and organic selection pressures. Wastewater is introduced to the reactor near the end of the treatment cycle under anaerobic conditions following the effluent withdrawal step and prior to the start of next treatment cycle. A floating sludge withdrawal apparatus is used in conjunction with a floating surface mixer to selectively remove lighter flocculant solids and retain denser solids by temporarily reducing the mixing energy during the wasting process.

A recirculating aquaculture system (RAS) is disclosed, which includes a main tank, in which fish or shellfish are farmed; a first reactor fluidically connected to the main tank, wherein the first reactor is a batch reactor that operates under anoxic conditions; a second reactor fluidically connected to the main tank, wherein the second reactor is a moving bed biofilm reactor (MBBR); a feed stream fluidically connected to the main tank; and a data-driven controller operably connected to the first reactor, the second reactor, and the feed stream, wherein the data-driven controller is configured to bring and maintain the system (RAS) at a desired state.

A process for enriching phosphorus and recovering vivianite by a biofilm method includes the following steps: 1) an aerobic phosphorus absorption stage; 2) an anaerobic phosphorus release stage; 3) a cyclic enrichment stage; 4) a seed crystal forming stage; and 5) a crystal forming stage. Phosphorus is enriched by the biofilm method and recovered with vivianite as a recovery product, which solves the problem of phosphorus removal from municipal sewage and improves the economic value; by preparing high dissolved oxygen at the aerobic stage, a high-concentration phosphorus recovery solution can be obtained with a relatively low carbon-phosphorus ratio and relatively high enrichment times, and the consumption of carbon sources can be reduced; since the oxidation-reduction potential is controlled to be less than 100 mv by the biofilm method at the anaerobic phosphorus release stage, the oxidation-reduction potential does not need to be adjusted again during the recovery of vivianite.

Provided is a method for enhancing self-enrichment of anammox bacteria by nitrate-dependent denitrifying bacteria symbiotic metabolism, belonging to the field of biological wastewater disposal. Excess sludge from a municipal wastewater treatment plant is inoculated into an enhanced anammox bacteria self-enrichment system (a closed SBR (Sequencing Batch Reactor)). The method includes the following steps: taking sodium acetate as a carbon source, enriching nitrate-dependent denitrifying bacteria at first, and transforming nitrate into nitrite to provide a sufficient substrate for the growth of anammox bacteria; in turn, the enriched anammox bacteria provide nitrate for the nitrate-dependent denitrifying bacteria to grow.

A process for treating an aqueous fluid comprising a biodegradable organic substance the process comprising a bioreactor unit batch feeding stage, wherein the aqueous fluid that is to be treated is fed into a bioreactor unit; a batch reaction stage, wherein the aqueous fluid is microbiologically treated and biogas is produced in the bioreactor unit; a degassing unit feeding stage, wherein an aqueous suspension comprising microbiologically treated aqueous fluid and biomass is withdrawn from the bioreactor unit and fed batch-wise into a degassing unit; and a semi-continuous biomass separator unit feeding stage, wherein the degassed aqueous suspension is withdrawn from the batch degassing unit and fed into a biomass separator.