64 results about "Mixed liquor suspended solids" patented technology

Methods and apparatus for treating wastewater are described, one method embodiment including the steps of flowing a mixed liquor suspended solids to a high rate clarification stage, forming a clarifier effluent, a first waste activated sludge stream, and a return waste activated sludge stream. The high rate clarifier effluent stream then flows to a membrane stage that includes a membrane media, producing a membrane reject (retentate) stream and a treated effluent (permeate) stream. Optionally, the methods include routing a screened raw wastewater to an anaerobic and / or aerated anoxic stage and introducing a gas comprising oxygen to the wastewater during the aerated anoxic stage, and optionally allowing the product of this stage to flow to an aeration stage prior to the high rate clarification stage.

A system for enhancing an activated sludge process that includes at least one aeration tank subsystem for receiving a flow a wastewater and for introducing dissolved oxygen to a population of microorganisms to promote growth of biological flocs in a mixed liquor defined by a concentration of mixed liquor suspended solids. A weighting agent impregnation subsystem includes an impregnation tank for mixing the mixed liquor, virgin weighting agent, and recycled weighting agent to impregnate the weighting agent into biological flocs suspended in the mixed liquor to form weighted biological flocs. A flocculant injection port located downstream from at least one aeration tank for introducing a flocculant to the mixed liquor for enhancing settling and thickening of the weighted biological flocs and for providing agglomeration of non-impregnated biological flocs and / or partially impregnated biological flocs with weighted biological flocs. At least one clarifier separates and collects the weighted biological flocs from the mixed liquor to provide a secondary effluent and a settled sludge. A return activated sludge subsystem recycles the majority of the settled sludge to the at least one aeration tank. A weighting agent recovery subsystem removes and shears the remaining settled sludge and recovers the weighting agent therefrom and reintroduces the weighting agent to the at least one aeration tank. A wasting subsystem wastes the remaining sludge of the weight agent recovery subsystem to control the population of the microorganisms in the mixed liquor.

A process for producing a biomass for use in the treatment of Fischer-Tropsch (FT) reaction water includes introducing a nutrient component comprising Carbon (C), Nitrogen (N) and Phosphorus (P), and water into an aerobic reaction zone containing a sewage sludge, and maintaining, in the aerobic reaction zone and under aerobic conditions, a F / M ratio of 0.25-2 kg COD / kg MLSS, where F / M=Food to Microorganism Ratio; COD=Chemical Oxygen Demand, expressed as mg oxygen / B of liquid in the aerobic reaction zone; and MLSS=Mixed Liquor Suspended Solids, expressed as mg solids in the aerobic reaction zone / B of liquid in the aerobic reaction zone. The F / M ratio is maintained for a period of time, to produce a biomass suitable for use in the treatment of FT reaction water.

A method and system for controlling dissolved oxygen levels in a secondary treatment system of a wastewater treatment facility that can employ a membrane bioreactor in which oxygen introduction into mixed liquor is controlled to prevent bulking and minimize generation of extra cellular polymeric substances. The control is exercised by insuring that dissolved oxygen levels within the mixed liquor do not fall below a minimum system level at which microorganism stress would occur. This is done by setting a minimum dissolved oxygen level control point equal to a sum of the minimum system level and an adjustment factor determined on the basis of oxygen uptake rate and time delays inherent in sensing oxygen levels and changes thereof within the mixed liquor. The minimum system dissolved oxygen level can be continually calculated on the basis of an inferred food to mass ratio that would vary with sensed mixed liquor suspended solids.

The invention provides a method for rapidly culturing autotrophic nitrogen removal granule sludge under conditions of low substrate concentration and high ascending velocity and belongs to the technical field of biological sewage treatment. The method provided by the invention comprises the following steps of: crushing a small amount of anaerobic ammonia oxidation granule sludge, uniformly mixing the crushed anaerobic ammonia oxidation granule sludge with common anaerobic fermentation sludge and aerobic activated sludge and charging the obtained mixture into an upflow anaerobic sludge blanket (UASB) reactor. Artificially synthesized low-ammonia-nitrogen wastewater (total nitrogen is 30-50mg / L) is taken as inflow of the UASB, a continuous flow operation mode is adopted, the ascending velocity of the UASB is 4-7m / h constantly, and culturing is carried out for 50-80 days, so that the high-efficiency autotrophic nitrogen removal granule sludge is obtained. The granule sludge prepared by adopting the method is higher in content of anaerobic ammonia oxidation bacteria, is applicable to treatment of low-ammonia-nitrogen wastewater and is a wastewater biological treatment product with a wide market prospect, wherein the content of anaerobic ammonia oxidation bacteria in the granule sludge is 1.36*10<8>copy / g-MLSS (mixed liquor suspended solids); and when the granule sludge is added into an autotrophic nitrogen removal reactor, the total nitrogen removal rate of the reactor and operation stability of the reactor can be effectively improved, and the problems that urban sewage quantity is high and the autotrophic nitrogen removal granule sludge is easy to run off are solved.

The invention discloses a method for improving treatment efficiency of a sewage plant by utilizing a bypass sludge activity enhancing technology. The method comprises the following steps of: enabling sewage after primary pretreatment to pass through a main biological tank for secondary treatment and then flow into a secondary sedimentation tank, performing sludge-water separation in the secondary sedimentation tank, discharging supernatant fluid of the secondary sedimentation tank or enabling the supernatant fluid to be subjected to follow-up advanced treatment, conveying activated sludge concentrated by the secondary sedimentation tank to a bypass biological tank through a sludge reflux pump and a pipeline, and enabling the activated sludge to reflux to the water inlet end of the main biological tank after aerobic, anoxic and anaerobic biochemical process treatment in the bypass biological tank. According to the method disclosed by the invention, the total amount of the activated sludge in the sewage plant can be greatly improved by simply transforming (combined building) the existing biological tank or only newly building a small-volume bypass biological tank (separate building), and the total retention quantity of MLSS (mixed liquor suspended solids) of the biological system disclosed by the invention can be improved by 18%-100% in comparison with the process in the prior art. The method disclosed by the invention is suitable for not only new building of sewage plants, but also upgrade and standard-raising transformation of the existing sewage plants; and the method disclosed by the invention has the advantages of high efficiency, low consumption and low investment.

A magnetic activated sludge reactor and a method for realizing short-cut denitrification belong to the field of wastewater treatment. The reactor is provided with a water inlet pipe, a water outlet pipe, a dredge pipe, and a stirring device which is used for fully mixing wastewater and magnetic activated sludge, the bottom of the reactor is provided with a microporous aeration disc, and a gas flowmeter is arranged between the microporous aeration disc and an air blower; dissolved oxygen DO, an oxidation-reduction potential ORP and a pH electrode are installed on the inner wall of the reactor, and a display controller, a PID (proportion integration differentiation) controller and a computer are installed on the outer side of the reactor. The method for realizing short-cut nitrification comprises the following steps that: under the condition that MLSS (mixed liquor suspended solids) is equal to 13,000mg / L, an aeration control strategy is based on the PH value; and the online control runs automatically. The reactor and the method provided by the invention are applicable to municipal wastewater treatment plants and other wastewater treatments of breeding wastewater, monosodium glutamate wastewater, coking wastewater and the other nitrogen-containing organic industrial wastewater treatment, aim at energy and consumption reduction, and have the advantages that the operation management is simple, manpower and material resources can be saved, the denitrification rate is high, reaction volume is smaller, sludge production is lower and the cost on sludge treatment and disposition can be effectively reduced, and the like.