Zenon Environmental Inc.

Other

Fernando A Tonelli

Henry Behmann

Robert W Langerak

Paul B Koehler

Hidayat Husain

R Philip Canning

Radu Apostolache

Ming Gang Liu

A method and system for treating wastewater in an onboard ship sewage treatment system having controlled suspended solids, the method comprising the steps of collecting wastewater in a collection tank and transferring the wastewater to a bioreactor to oxidize organic material contained in the wastewater by adding oxygen-containing gas thereto. The bioreactor is operated to provide a mixed liquor having a solids concentration of at least 5 g/l and the solids concentration is continuously increased in the mixed liquor in the bioreactor to not greater than 30 g/l. When the solids concentration in the mixed liquor reaches at least 15 g/l, a portion of the mixed liquor is removed from the bioreactor. Thereafter, wastewater is added to the bioreactor to decrease the solids concentration of remaining or residual mixed liquor to not less than 5 g/l. The bioreactor is further operated to increase the solids content again. A hollow fiber membrane is used to remove water from the mixed liquor to provide treated effluent.

Shipboard wastewater treatment system

A wastewater feed containing an ultimate BOD/COD ratio &gt;0.6 is well-suited for especially acclimated thermophilic and/or caldo-active living micro-organisms ('hot cells') which thrive in an autothermal aerobic (ATA) reaction zone having an ATA bioreactor ('ATAB') operating at substantially ambient atmospheric pressure in combination with a MF or UF membrane filtration device from which a solids-free permeate may be withdrawn. This combination, of ATAB and membrane device is a 'membrane bioreactor' (ATA MBR), which operates autothermally with a feed containing biodegradable organic materials having a BOD of at least 5,000 mg/L, preferably at least 10,000 mg/L (10 g/L) with a minor portion of 'municipal' wastewater or domestic sewage. Operation of the ATAB, preferably in the thermophilic range from 45.degree. C.-75.degree. C., with constant HRT from 1 to 12 days, is contingent upon maintaining a stable population of live hot cells. Such cells enhance the biokinetics of degradation and allow operation of the ATAB at higher COD loading and a lower concentration of TSS, than would be possible at a lower temperature. A surprisingly high membrane productivity allows production of much less sludge to be disposed of outside the system, than would have to be disposed of with a conventional mesophilic reactor in normal operation with a HRT of less than 24 hr. A combination of an MP MBR with an ATA MBR is highly effective when the MPB produces high BOD concentration mixed liquor for destruction by the ATAB.

Aerated hot membrane bioreactor process for treating recalcitrant

A system is provided to treat wastewater from a metal-working facility, such as an automotive manufacturing plant in a bioreactor using live microorganisms. Such wastewater contains waste fluids which are a mixture of relatively easily biodegradable fats and oils, much less easily biodegradable synthetic fluids, oils and greases, and nonbiodegradable material including inorganic finely divided solids such as metal and silicon carbide particles. Such waste fluids require a hydraulic retention time (HRT) and a solids retention time (SRT) which is 10 times greater than for sewage. High quality water is separated from suspended solids which are removed from the reactor at an essentially constant rate and fed to an ultrafiltration membrane. Concentrate is recycled to the reactor, except for a bleed stream to remove solids periodically. The membranes acquire a long and effective life despite large variations in membrane flux, because of a permeate recycle which permits operation of the bioreactor at constant volume; permits flow of feed wastewater to the reactor at constant flow rate; and allows operation of the membrane modules at a relatively low pressure in a narrow range which does not damage the membranes. Such operation of the bioreactor allows one to use a reactor which is one-half the size (volume) than one which would be required with a system without a permeate recycle. Effective and long-lived operation of the membranes is obtained by filtering out (through a 140 mesh screen) all solids greater in diameter than about 106 .mu.m. Pilot plant tests conducted with wastewater from automobile manufacturing plants over a period of more than a year provide evidence of the surprising effectiveness of the system over a prolonged period.

Membrane bioreactor system for treating synthetic metal-working fluids

A tubular membrane module for example for use in ultrafiltration has a tubular shell made of standard PVC pipe provided with moulded PVC end fittings that are secured to the pipe by epoxy resin adhesive. A membrane tube within the shell extends between the end fittings and is secured by a similar adhesive in respective sockets within the end fittings. Each socket has a blind end that receives the end portion of the membrane tube so that the tube is protected from shear effects due to fluid entering the tube under pressure in use.

Tubular membrane module

A system to treat wastewater from a metal-working facility, such as an automotive manufacturing plant in a bioreactor using live microorganisms. Such wastewater contains waste fluids which are a mixture of relatively easily biodegradable fats and oils, much less easily biodegradable synthetic fluids, oils and greases, and non-biodegradable material including inorganic finely divided solids such as metal and silicon carbide particles. Such waste fluids require a hydraulic retention time (HRT) and a solids retention time (SRT) which is 10 times greater than for sewage. High quality water is separated from suspended solids which are removed from the reactor at an essentially constant rate and fed to an ultrafiltration membrane. Concentrate is recycled to the reactor, except for a bleed stream to remove solids periodically. The membranes acquire a long and effective life despite large variations in membrane flux, because of a permeate recycle which permits operation of the bioreactor at constant volume; permits flow of feed wastewater to the reactor at constant flow rate; and allows operation of the membrane modules at a relatively low pressure in a narrow range which does not damage the membranes. Such operation of the bioreactor allows one to use a reactor which is one-half the size (volume) than one which would be required with a system without a permeate recycle. Effective and long-lived operation of the membranes is obtained by filtering out (through a 140 mesh screen) all solids greater in diameter than about 106 .mu.m. Pilot plant tests conducted with wastewater from automobile manufacturing plants over a period of more than a year provide evidence of the surprising effectiveness of the system over a prolonged period.

A tubular membrane module for use in ultrafiltration or microfiltration has a bundle of membrane tubes that extend between inlet and return headers. The inlet header is fixed to one end of a tubular housing having a permeate outlet while the return header is free to float longitudinally of the housing to accomodate dimensional changes in the tubes with respect to the housing. The tubes are sealed at their ends in sockets in respective potting collars but are mechanically secured and sealed to the headers. The sockets are undercut to protect the membranes from stripping due to fluid shear.

Growing community of inventors

Dundas, Canada

Fernando A Tonelli