Wastewater treatment
AssigneeThe Commonwealth Industrial Gases Limited
InventorsDenys A. Wickens, Brian J. Johnson, Mervyn R. Ogston
Life of this patent
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Abstract
A method for efficiently treating wastewater by aerobic digestion whereby on-site oxygen generating equipment continually provides a predetermined quantity of dissolved oxygen to the wastewater, the dissolved oxygen content being maintained at a predetermined level during peak flows by air being dissolved into the wastewater. The method being used for upgrading the capacity of an existing plant to treat wastewater; increasing the scope of an existing plant to allow removal of biological nitrogen and/or phosphorus; and designing new wastewater treatment plants. Further efficiency is introduced by using methane produced, during subsequent anaerobic digestion of the wastewater, to fuel compressors or the like which provide the air to the wastewater.
Claims17
A method for treating wastewater water by aerobic digestion, said method comprising:
- introducing into said wastewater contained within an uncovered aeration chamber a first fluid including an oxygen content of at least 50% to provide dissolved oxygen in accordance with a selected base load aerobic digestion capacity wherein said first fluid is produced on-site in conjunction with said wastewater treatment;
- and
- substantially simultaneously selectively introducing into said wastewater within the same aeration chamber in response to a reduction in the dissolved oxygen content of the wastewater, a second fluid to provide an additional variable load aerobic digestion capacity, wherein said base load and said variable load capacity in total provide a selected total aerobic digestion capacity.
A method for treating sludge derived from wastewater treatment including the steps of:
- operating first and second valve means for respectively admitting and releasing said sludge to and from an uncovered aerobic digestion chamber;
- introduced into said released sludge in said uncovered aerobic digestion chamber via compression means both a first fluid including an oxygen content of at least 50% to provide a selected base load aerobic digestion capacity and a second fluid to provide an additional variable load aerobic digestion capacity, wherein said base load and said variable load capacity in total provide a selected total aerobic digestion capacity;
- introducing said released sludge into an anaerobic digestion tank whereby methane is extracted from said anaerobic digestion tank and forwarding said methane to power said compression means;
- controlling the operation of said first and second valve means from a central processing unit to maintain said treatment substantially in a dynamic equilibrium during variations in the wastewater conditions including one or a combination to be treated;
- (1) quantity of wastewater to be treated;
- (2) compositions of wastewater to be treated;
- (3) the dissolved oxygen content, temperature, biological oxygen demand, pH and relevant flows of the wastewater being treated;
- and
- (4) previously obtained data relating to the expected lead time between respective process steps and the relationship between these leads times and the current trend.
Dependencies are inferred from the claim text.