Lagoon nitrification systems offered commercially include:
• ATLAS-IS™ — Internal clarifier system by Environmental Dynamics, Inc.
• CLEAR™ process — SBR variant by Environmental Dynamics, Inc.
• Ashbrook SBR — SBR system by Ashbrook Corporation
• AquaMat® process — Plastic biomass carrier ribbons by Nelson Environmental, Inc.
• MBBR™ process — Plastic biomass carrier elements by Kaldnes North America, Inc.
• Zenon membrane process
Environmental Dynamics, Inc. (EDI; Columbia, MO) offers their Advanced Technology Lagoon Aeration System with Internal Separator (ATLAS-IS™), which is designed to provide a high level of treatment with minimal operation and maintenance requirements. The process consists of a fine-bubble, floating, lateral aeration system that contains a series of internal clarifiers or settlers. The settlers are constructed of a plastic material and may contain lamella baffles. The units are installed within a complete-mix zone of the aerated pond system. Mixed liquor enters the settling chamber through the bottom. A slight concentration of the MLSS takes place in the settler as the mixed liquor rises and spills over a weir into an effluent pipe. No return-activated sludge (RAS) or waste-activated sludge (WAS) is required. Over time the MLSS will build up to a level adequate to grow nitrifying microorganisms. Some solids are carried downstream so no separate sludge wasting is necessary. The ATLAS-IS™ system has been tested at Ashland, Missouri, and has been successful in building up MLSS and in achieving nitrification. A layout of the system is shown in Figure 4.32.
Environmental Dynamics, Inc., also offers an SBR variant known as the Cyclical Lagoon Extended Aeration Reactor (CLEAR™ ). A completely mixed aerated
lagoon cell is partitioned into three zones using floating baffle curtains. Influent is fed to each of the three zones sequentially. Aeration is applied to the zone receiving influent wastewater and, for part of this cycle, one of the other two zones. While the inflowing zone is aerated, the other two zones cycle between settling and decanting. WAS is removed using airlift pumps, either to downstream facultative ponds for storage or to further processing and disposal. A control system is provided to operate the motorized wastewater influent valves and decanters. Currently, no full-scale installations of the CLEAR™ process are in operation, but it appears the process should function as claimed. A depiction of the process is shown in Figure 4.33.
The Ashbrook Corporation (Houston, TX) SBR system consists of decanters, motorized valves, and a control system. A facility has been installed in a lagoon system in Quincy, Washington, where the aerated lagoon has been portioned into sections and air is provided for complete mixing in two or more SBR cells. Operation is similar to a conventional SBR process, and the system in Quincy has been working well. The facility is shown in Figure 4.34, and effluent data are provided in Table 4.24.
184.108.40.206.4 AquaMat® Process
The biomass carrier system AquaMat® is marketed by Nelson Environmental, Inc. (Winnipeg, Manitoba). Plastic ribbons slightly more dense than water are connected to a plastic float; these ribbons extend into the waste stream 3 feet or more and provide additional surface area for bacteria to grow. When used with lagoon systems, the application is referred to as the Advanced Microbial Treatment System (AMTS). Year-round nitrification has been achieved in an aerated
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