Background
Sophisticated municipal wastewater treatment is already the norm in the developed world, and is becoming widespread in developing nations as well. However, two main problems pose a growing challenge to existing wastewater treatment plants:
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Rapid urbanization and growing populations worldwide often cause unforeseen growth in the quantities of wastewater to be treated by existing facilities
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Increasingly stringent effluent requirements require plants to remove pollutants (especially nutrients) which were not necessarily considered in the original plant design.
In many cases, existing treatment systems are either intrinsically unable to meet these two challenges (for example, extensive lagoon systems), or require addition of reactors and other process volumes which call for expensive civil works and space which may not be available in the existing plant location.
The Aqwise AGAR® process offers a simple, cost-effective solution for both of these problems, and allows municipal plants to both increase their treatment capacity and upgrade the effluent quality with minimal civil works and little or no added treatment volume. The AGAR® process can be installed within an existing intensive treatment process (such as the activated sludge process), added to an extensive pond or aerated lagoon system, or designed and constructed as a stand-alone wastewater treatment plant in a number of configurations, depending on local conditions and requirements.
Applications
The AGAR® process is a flexible process, which can be applied in a number of main plant configurations according to existing conditions and plant requirements. Once the desired process configuration has been decided upon and the required civil and electromechanical works completed, Aqwise Biomass Carriers are introduced into the tanks in a quantity calculated for the required loads. This offers one of the AGAR® process’ strongest advantages: Additional increases in treatment capacity can be achieved simply and economically simply by adding more plastic carriers to the process. The basic configurations applied in municipal wastewater treatment are:
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Moving Bed Bio Reactor (MBBR) configuration: In this configuration, the wastewater is treated only with Biomass carriers, or in other words, there is no suspended biomass (such as the activated sludge Mixed Liquor) involved. As a result, the process configuration can be extremely simple – from a once-through flow with no recycles, meant for carbonaceous BOD removal only, and followed by a solids removal mechanism (such as a clarifier, DAF unit, etc,) to a sophisticated process with internal recycles, designed for extensive nutrient removal. In both cases there is no need for RAS recycle from the clarifiers, and solids handling units can be much smaller and more economical.
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Fixed Film Activated Sludge Treatment (FFAST) configuration: In this configuration, a roughing filter (see previous paragraph) is added before a conventional activated sludge system. The roughing filter serves to greatly reduce dissolved pollutant (BOD) concentrations, thereby allowing a smaller downstream unit to achieve greater treatment goals.
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Integrated Fixed-film Activated Sludge (IFAS) configuration: In this process, biomass carriers are introduced into the activated sludge system, in locations determined during process design. This configuration is perfectly suited for enhanced nitrogen removal, as the fixed biomass, when competing with suspended biomass (MLSS), tends to develop very high concentrations of nitrifying populations, thereby dramatically improving nitrogen removal capabilities.
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The AGAR® Roughing Filter for Biological Nutrient Removal (RF-BNR) configuration offers a treatment process based on a bio-film which provides organic carbon removal, followed by nitrification and de-nitrification, without circulation of activated sludge. Denitrification occurs in both pre-denitrification reactor, and in an innovative, patent pending, fixed/moving bed reactor in which intensive endogenous denitrification occurs.
Benefits
Introducing the AGAR® process to your municipal wastewater treatment needs offers the following benefits:
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Minimal or no additional reactor volume required. In tight locations, where proximity to existing neighborhoods or other space limitations exist, the AGAR® process offers one of the only methods for increasing plant treatment capacity, as well as effluent quality upgrade.
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Minimal change to plant operations: Operation of the AGAR® process blends in with traditional activated sludge operation, as it fits into the existing plant configuration. Thought the plant process is significantly upgraded, the operator does not need to learn a completely new technology, and Operation and Maintenance activities are barely changed.
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Minimal interference during the upgrade: As retrofit changes in the physical layout of the plant are minimal, the process can be introduced into the plant with very little interference and upset to normal plant operations.
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Staged implementation: Once the (minimal) infrastructure changes required for the AGAR® process are completed, the only parameter defining treatment capacity is the volume of Biomass Carriers inside the basins. Carriers can be added on demand, and within hours, the plant capacity is expanded proportionally. This allows both timely adaptation to changing requirements (either increase in wastewater quantities or improved effluent requirements), and Just In Time expenditure, so that investment in the upgrade is done only when needed, not years ahead of time.
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Withstanding of Toxic or Shock loads of industrial wastewater: In configurations where the Biomass Carriers precede a conventional system, they serve as a buffer for extreme fluctuations in wastewater quality: If incoming wastewater includes a toxic spill, or a surge in organic load (both usually due to industrial wastewater), the fixed-film biomass can absorb and significantly attenuate the effects, thereby protecting downstream processes and allowing rapid return to normal process operation. Due to the nature of the fixed biomass and its acclimatization to fixed spatial conditions (unlike suspended biomass, fixed biomass constantly “feels” similar, usually highly loaded, process conditions), recovery after shocks is quicker and more complete than in the suspended biomass.
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| Monclova, Mexico |
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| Yavne, Israel |
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