US 5,240,600 A · Water and wastewater treatment system

Abstract

A biological treatment system involving the use of a gas dissolving pressure vessel, a pressurized water release assembly, a pretreatment chamber, a bioreactor, an open vessel, a post-treatment unit, a sludge removal unit, and a removable gas collection and purification unit for both wastewater treatment and air emission control is described. Gases are dissolved efficiently in a water inside the pressure vessel under controlled high pressure and high rotating velocity. Chemicals, or microorganisms, or both arm dosed to an influent water producing a pretreated water containing chemical flocs and biological flocs. The bioreactor comprising a hanging biological contactor is adopted when biochemical reaction is intended. A pressurized water containing supersaturated gases is produced in the pressure vessel and than depressurized through the pressurized water release assembly becoming a depressurized water containing micro bubbles. The pretreated water containing chemical flocs or biological flocs, or both are gently mixed and held together with the depressurized water containing micro bubbles in the open vessel for separation of chemical/biological flocs to the water surface, producing a purified effluent and a waste gas. A portion of the purified effluent is recycled for gas dissolution and micro bubbles production. When necessary, the waste gas is collected, purified and recycled to the pressure vessel or the bioreactor, or both for reuse.

An apparatus for dissolving a plurality of gases into a recycled liquid stream by pressurization, releasing the pressurized recycled liquid stream containing said dissolved gases to a reduced pressure, generating micro gas bubbles in a depressurized liquid stream, purifying gases escaping from said depressurized liquid stream, concentrating microorganisms as a floating scum on the surface of said depressurized liquid stream, recycling a portion of said concentrated microorganisms in the floating scum to an influent liquid stream for treating said influent liquid stream, and discharging a clarified effluent liquid stream comprising:

(a) an influent pipe means and a a liquid flow measuring means connected to the influent pipe means for measuring the flow of said influent liquid stream;
(b) a pretreatment chamber means directly or indirectly connected to said influent pipe means comprising feeder means for feeding chemicals and/or microorganisms into said influent liquid stream, separation modules means located in said pretreatment chamber means for removing oil and suspended solids from said influent liquid stream, and a first discharge means for discharging a pretreated effluent liquid stream;
(c) a bioreactor means connected to said pretreatment chamber means for receiving and treating said pretreated effluent liquid stream in the presence of microorganism, organisms and dissolved gas and producing a bioreactor effluent liquid stream and a waste gas stream;
said bioreactor means further comprising means for delivering at least one gas to said bioreactor means;
(d) said means for delivering at least one gas comprises a bubbles distribution means positioned near bottom of said bioreactor means for generating coarse gas bubbles with diameter greater than 90 microns;
(e) means positioned inside said bioreactor means for holding microorganisms or organisms to be attached;
(f) means connected to said bioreactor means for discharging said bioreactor effluent liquid stream;
(g) means connected to said bioreactor means for receiving the recycled floating scum or settled sludges or both containing microorganisms;
(h) an inlet pipe means connected to a nozzle assembly means for feeding said recycled liquid stream, another liquid flow measuring means connected to the inlet pipe means for measuring the flow of said recycled liquid stream, gas injector means connected to said inlet pipe means for feeding a first gas into said recycled liquid stream, pump means connected to said inlet pipe means for forcing said recycled liquid stream through said gas injector means, said another liquid flow measuring means, and said nozzle assembly means;
(i) an enclosed cylindrical pressure vessel means having a tangentially disposed liquid stream vessel inlet means connected to said inlet pipe means for delivering said recycled liquid stream into said cylindrical pressure vessel means;
said pump means, said nozzle assembly means and said inlet pipe means cooperating to feed the recycled liquid stream under conditions to yield a rotating liquid stream inside said pressure vessel means which rotates at over 2500 rpm;
and said pressure vessel means further comprising a pressure gauge, a safety valve, gas bleed off valve means, plural gas inlet means for feeding at least a second and third gases into said pressure vessel means, gas flow meter means and regulator means connected to the plural gas inlet means for regulating the pressure in said pressure vessel means to 2-7 atmospheres, and a vessel outlet means;
(j) at least one pressurized meter release assembly means connected to the vessel outlet means of said pressure vessel means and positioned inside an open vessel means;
said pressurized water release assembly means further comprising a pressure reduction valve for allowing said recycled liquid stream to be depressurized in stages under laminar flow conditions for generation of micro gas bubbles with diameter less than 80 microns in the depressurized liquid stream inside said open vessel means;
(k) said open vessel means connected directly or indirectly to said bioreactor means for receiving both the bioreactor effluent liquid stream from the bioreactor means and the depressurized liquid stream from the pressurized water release assembly means and for holding the depressurized liquid stream containing said micro gas bubbles sufficiently long so that a floating scum layer forms on the free surface of the liquid and a subnatant forms below the floating scum;
a second discharge means to discharge said subnatant as said clarified effluent liquid stream;
means, including said inlet pipe means, for recycling a portion of said effluent from the second discharge means to the pressure vessel means and defining said recycled liquid stream;
sludge removal means for collecting of said floating scum on the liquid surface of said open vessel means and collection of settled sludges near bottom of said open vessel means;
a removable gas collection and purification means positioned over the top of the open vessel means and bioreactor means to receive and purify waste gas stream escaping from said open vessel means and bioreactor means, and to recycle a purified gas stream to said pressure vessel means and said bioreactor means, said gas collection and purification means further comprising a gas mover, a gas purifier, gas by-pass lines, and an enclosure over said open vessel means and bioreactor means, said gas purifier, further comprising a demister and an adsorber;
(l) means including said sludge removal means connected to said open vessel means for recycling a portion of said floating scum and/or settled sludge containing microorganisms to said bioreactor means;
(m) post-treatment means connected to said open vessel means for further treating said clarified effluent liquid stream and producing a post-treated effluent liquid stream;
and
(n) a third discharge means to discharge said post-treated effluent liquid stream.

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Water and wastewater treatment system

Life of this patent

Water and wastewater treatment system

Life of this patent

Abstract

Claims23