Ovivo Inc.

Enviroquip Inc.

The University of Akron

Eimco Water Technologies LLC

Hiren Trivedi

John Vorwaller

Tyson Beaman

David Stensel

Sophia Baker

Sergio Pino-Jelcic

James Porteous

Lu-Kwang Ju

Dennis Livingston

H David Stensel

Michael Snodgrass

Tyson Beamnan

A continuous flow granular/flocculent sludge wastewater process selects for granule biomass capable of nitrogen and phosphorus removal and controls granule size and concentration of granular and flocculent sludge for optimal nutrient, organic, and solids removal in a smaller footprint. A series of biological process zones lead to a secondary clarifier. Mixed liquor sludge, preferably from an aerobic zone, goes through a classifier or separator processing flow from the aerobic zone, to the secondary clarifier. In a sidestream process that can be included a portion of sludge preferably from an aerobic zone goes through a classifier or separator to selectively produce a granular-rich effluent, and the clarifier may also have a separator to further concentrate granular biomass, most of which is cycled back to an initial multi-stage anaerobic process zone. The anaerobic zone is structured and operated to encourage growth of granules in subsequent process zones.

Biomass selection and control for continuous flow granular/flocculent activated sludge processes

Combined Sewer Overflow (CSO) events require certain minimum treatment, before discharge, according to EPA regulations. However, these events are infrequent, and CSO treatment systems remain idle most of the time. Tertiary filtration is typically used to polish off the secondary treated water in order to remove suspended matter, phosphorous, etc. Tertiary systems are usually designed to handle design flows and remain active most of the time. These are two independent unit operations requiring major capital investment and operational expense. According to this invention an interchangeable system is able to switch a tertiary treatment reactor back and forth between two applications ensuring seamless operation, smooth transition and significant cost savings for treatment facilities.

Interchangeable system for overflow treatment and tertiary filtration for wastewater treatment facilities

A continuous flow granular/flocculent sludge wastewater process selects for granule biomass capable of nitrogen and phosphorus removal and controls granule size and concentration of granular and flocculent sludge for optimal nutrient, organic, and solids removal in a smaller footprint. It includes anaerobic, anoxic, and aerobic process zones, a high soluble biodegradable COD loaded first reactor in anaerobic or anoxic zones, a granular sludge classifier with recycle of underflow granular sludge to the first reactor, a secondary clarifier to settle flocculent sludge and particulates and recycle of flocculent sludge from the secondary clarifier underflow to an aerobic process zone. Wasting of sludge from the two separate recycle lines controls the bioprocess flocculent and granular sludge concentrations and SRTs. Bypass around and recycle flow to the classifier to maintain desired flow under various influent flow conditions aid control of granule size. On/off mixer operation of anaerobic and anoxic reactors may be used.

Phagotrophic algae are used in connection with aerobic or anaerobic digestion of solids, especially waste activated sludge (WAS), to more efficiently digest solids and to meet, over a shorter period of time, volatile solids standards and specific oxygen uptake rate requirements as well as pathogen reduction requirements.

Digestion of waste activated sludge with algae

In a wastewater treatment plant, the liquid side of the plant has preferably four stages for nitrification and/or denitrification, prior to further treatment such as a clarifier. Energy requirements are reduced by reducing aeration requirements. Four or more tanks/zones comprise serial anoxic and aerobic stages, but in the anoxic stages simultaneous nitrification/denitrification takes place in accordance with the known process of U.S. Pat. No. 5,906,746. By this arrangement the system can achieve a volume ratio of about 20% aerobic tankage to the total tankage volume, as compared to a much higher ratio in a typical prior art system of serial aerobic/anoxic stages, and greatly reducing aeration requirements.

Energy efficient wastewater treatment for nitrogen and phosphorus removal

A sewage treatment plant, on the liquid side, is operated so as to effect nitrification and denitrification within a single tank and simultaneously to remove water, without the need for separate clarification. An aerobic/anoxic zone is maintained in a single tank, wherein the SymBio process of U.S. Pat. No. 5,906,746 is maintained. This is combined with the advantages of an MBR process, by placing a series of membrane separators within the tank and continuously withdrawing nearly pure water. Supplemental process air provided in the MBR tank is controlled by the SymBio process to maintain simultaneous nitrification and denitrification in a single tank and thus reducing the additional process air requirements.

Sewage treatment process

In the liquid side of sewage treatment process, a combination aerobic/anoxic stage is closely monitored such that phosphorus can be removed as well as nitrogen. As in a known process, the aerobic/anoxic stage is monitored as to a coenzyme of the active bacteria. When the bacteria of flocs within this stage show a switch to anaerobic condition via such coenzyme, the low dissolved oxygen level in the stage is maintained for a preselected period of time or to a preselected extent of the anaerobic condition, before oxygen is added. This somewhat brief anaerobic condition within the flocs is sufficient to release significant amounts of phosphorus into the liquid. When aeration then is increased, enhanced biological phosphorus uptake is effected. A small aerobic stage is included after the aerobic/anoxic stage to ensure maximum phosphorus uptake, and in one embodiment this stage includes a membrane separator, allowing downstream secondary clarification to be eliminated.

Growing community of inventors

Cedar Park, TX, United States of America

Hiren Trivedi