Industrial Wastewater Treatment
Anaerobic Advance Digesters (AAD)
World Technologies delivers Anaerobic Advance Digesters (AAD) solutions, equipment and lifecycle support for reliable industrial water and wastewater operations in Singapore and the region.
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Anaerobic Advance Digesters (AAD)
Anaerobic digestion is a series of biological processes in which microorganisms break down biodegradable material in the absence of oxygen which bring several benefits:
- High COD Load
- High COD / BOD Reduction
- No Chemical Consumption
- Low Opersating Cost
- Biogas Generation
One of the end products is biogas, which is combusted to generate electricity and heat, or can be processed into renewable natural gas and transportation fuels.
Inside the digester. Anaerobic digestion is the simple, natural breakdown of organic matter into carbon dioxide, methane and water, by two groups of microorganisms, bacteria and archaea. Since many of these are intolerant to oxygen, this process is known as anaerobic
Advantage of Anaerobic Digester
- Higher BOD / COD reduction
- More biogas storage at the top of the digester & no need of separate biogas holder
- Can operate over a wide temperature (25 °C – 40 °C)
- Better Process Stability to Handle Shock Loads due to Long HRT & Large Biomass Inventory
- Ability to Handle High Strength
- Wastewater without Pre-dilution
- Lower Sludge Generation and thereby Reduced Sludge Disposal Problem
- Minimal Energy requirements
- Greater and uniform gas production
- No Running Chemicals Or Dilution Water Required
- In-built clarifier in the digester & therefore low suspended solids at the digester outlet
- Simple operation & minimum instrumentation
- Ability to remain dormant for weeks at a time but ready for quick start-ups
Anaerobic Advance Reactor vs UASB
- Perfect Design for operation philosophy and convenient
- Efficient Reactor solids separation
- Capacity to Resist Shock Loading
- Smaller Foot Print and save lot of space
- Floating roof with Geo Membrane with all safety
- Higher BOD, COD reduction compare to all other processes
- More Biogas Generation to generate electricity
- Work well with 25- 38 C temp
- Low operating cost compare to all other processes
- Less Execution time and quick installation
- Unique design for flushing arrangement
COD Reduction and Biogas Generation
Managed Alkalinity
Anaerobic Digesters generate alkalinity via the decomposition of Organic Nitrogen and hence there is no need for Caustic addition or Alkalinity Control. The pH neutral effluent after our anaerobic treatment can be discharged safely for further treatment or be used in agricultural fields for its fertiliser value. It will not require any further pH adjustment. Other technologies with a lower HRT or otherwise will require pH adjustment and daily continuous addition of chemicals which will add maintenance cost for daily operations, since the conversion of Organic Nitrogen to Ammonia and Bicarbonate will not be complete.
Flexible Digester Cover
World Technologies digesters have a polymeric reinforced membrane cover which is good for tough Anaerobic and corrosive environments. The polymeric membrane floats on the liquid surface and is attached to the side walls of the digester tank. Thus, the load of the membrane cover is taken up by the water and not the side walls of the tank. The polymeric membranes are resistant to corrosion and can be easily fixed during operation if required. Other digesters use steel covers and the weight of steel is transferred to the digester walls and hence the walls are thicker and incur a higher cost. Further, the steel will corrode due to the H2S in the biogas.
No Chemicals for Operation
Our digesters during initial start up will require some seed sludge either from local domestic sewage plant or animal waste for the anaerobic bacteria to be added to the digesters. Some alkalinity addition may be required. This is only one time during start up and commissioning.
Other technologies require routine and continuous addition of chemicals such as lime dosing because of the smaller HRT of the digesters. This results in annual increase in O&M costs. Their technology requires a lime solution tank and feed equipment capital investment.
Consistency of Operation
Due to the high HRT, our digesters provide consistent performance and can take peak loadings without any problems. Other technologies have lower HRTs and higher loading rates. This may lead to sludge washouts and the operation of the overall digester system becomes very delicate which results in partial treatment, and hence will be difficult to control. Once out of control, and if the Anaerobic Bacteria is washed out, it will take another few months for it to destabilise, which would require experienced manpower.
Unique Mixing Technology
We uses a slow speed lamella mixing technology which is a submerged mixer with a mast to lift the mixer for service and repair. This high volume low power mixer is designed to provide complete mixing of digester contents. Other technologies require multiple mixers and use top entry mixers. With multiple mixers connected power is high and hence yearly Operation & Maintenance cost will be high.
Seed Sludge/ Wastewater out
Our designs do not have this problem, other technologies such as UASB and low HRT digesters require and rely on the development of dense sludge particles which settle at the bottom part of the digester. With increased 100% feed loading, these sludge washes out from the digester and hence this technology requires dilution of the waste and cannot feed 100% of the waste
Clarifiers to Prevent Sludge Washout
Our technology does not require any clarifiers on top of the digesters to hold off the washout of sludge. Some other technologies require their special patented such clarifiers at the top of the digesters that would prevent the sludge to washout from the digesters.
COD Reduction and Biogas Generation
World Technologies can offer COD reductions in the range of 75% – 80% our technology typically is seen to provide around 44% more biogas than competing technologies.
Frequently Asked Questions
What is Anaerobic Advance Digesters (AAD) and how does it work?
Anaerobic Advance Digesters (AAD) is an engineered water or wastewater treatment process selected to achieve a defined quality, recovery or discharge objective. Its operating principle and treatment stages depend on the application.
What contaminants or water-quality problems can Anaerobic Advance Digesters (AAD) address?
Performance depends on the selected configuration. Water analysis is used to identify suspended solids, dissolved salts, hardness, oil, organics, nutrients, metals or other parameters that the treatment train must control.
How is a Anaerobic Advance Digesters (AAD) system designed and sized?
Design uses flow and load profiles, laboratory analysis, target outlet quality, recovery, operating hours, redundancy, footprint, utilities, sludge or concentrate handling and lifecycle cost.
How much does Anaerobic Advance Digesters (AAD) cost in Singapore?
Cost depends on capacity, feed quality, materials, automation, civil and installation scope, performance requirements and ongoing consumables. A site-specific assessment is needed for a reliable budget.
Can World Technologies upgrade or maintain Anaerobic Advance Digesters (AAD)?
Yes. World Technologies can review existing performance and support suitable upgrades, equipment replacement, commissioning, troubleshooting, consumables and preventive maintenance.