Biodisk Corporation
Additional Advantages
Additional advantages in comparison to typical municipal systems such as extended aeration and sequential batch reactors. The additional advantages include:
• Small foot-print allows for cost effective architectural design
• Totally enclosed system
• Safe - no open ponds or exposed tanks
• Blends easily with surrounding community
• Easily expandable with modular design
• Addresses today's needs today and easily accommodate future designs
• Low power consumption
• Huge biomass inventory
• Segregated biomass development
• Very low noise levels
• High Resale value
• Life-cycle costs of a BIODISK facility are substantially less than for comparable treatment processes
Architecture: The small footprint allows cost effective architectural design of a totally enclosed system. Land can be expensive. It is a fact that in some locations the smaller space required for an RBC will save the owner enough space to pay for the system.
In Jakarta Indonesia, the RBC is sited in the basement car parking area. On several projects the RBC was 27 car parking spaces smaller than the competition. At $27,000 per parking space the client's revenue increased by $729,000 US and more than paid for the complete system.
In most instances, just the savings in concrete or brickwork can be an advantage. A small structure is not as ominous and a small building blends in with the surrounding architecture easily. When it looks like a treatment plant, the Not In My Back Yard (NIMBY) process kicks in. When it looks like the New Horizons project in the Applications Section, it just adds elbow space to the neighbour's property. A covered treatment plant is also safer from a health perspective; there is no airborne bacteria or exposed wastewater.
Low Power Consumption: The BIODISK operates at one half to one eighth of the power requirements for other forms of aeration equipment. The largest drive on the biggest BIODISK is less than 10 hp. There are no high power requirements for the supporting equipment. Phosphorous is removed with a fractional hp chemical feed pump that is flow proportioned by a flow meter. Sludge is returned from the final tank by a small hp submersible pump. Filtration and disinfection power draws are consistent with other technologies.
The low power required not only affects the daily operation of the disk but it also reduces the size of the standby generator when required. The prospective owner of a BIODISK wastewater treatment plant needs to be aware of the total installed electrical draw of the plant as compared to other installations.
Biomass Inventory: The high biomass inventory is an inherent feature of the BIODISK process. The RBC is referred to as a fixed film system. The biomass is attached and cannot be washed out. Attached growth systems (fixed
film) have up to 10 times more bug population than other forms of wastewater treatment. This is important when considering the effects of shock loading. Shock loading can be biological and or hydraulic.
It is next to impossible to wash the biomass off the disks with a hydraulic surge. The biomass is like the seaweed that grows on the rocks on an ocean shoreline. The wave action cannot wash off the seaweed and hydraulic surges cannot
wash off the biomass. The final clarifier is designed for a peak hydraulic load of three times its design capacity and it can be washed out. What is important about the final clarifier of an RBC is that the influent is approximately 40 mg/L BOD and SS.
A suspended growth system for other forms of treatment has a final clarifier influent of about 2,250 mg/L. Wastewater strength of this magnitude can and does cause sever pollution in surface water during washout conditions. If the process discharges to a filter bed with a strength of 2,250 mg/L, it can overwhelm the filter bed. Even a normal operating suspended growth system will periodically discharge rags and debris that end up in the filter bed.
Mr. Farley Fry has tested the response time to hydraulic upset in the RBC at Virginia Polytechnic Institute. Mr. Fry has said the RBC will recover in 24 hours for BOD and five days for nitrification. An operator has commented on
how long it would take a suspended growth system to restart after a hydraulic upset and his answer was "Six to eight weeks as long as it was not in cold climate conditions". The RBC does not lose its biomass inventory with shock hydraulic loading.
Organic shock can also be accommodated in the BIODISK. With an inventory of 5 to 10 times more biomass the assimilation capacity is proportionally bigger. The microbes are like foragers that accumulate organic material in the
shell structure for later consumption.
Segregated biomass development: Allows for more efficient treatment. The BIODISK is a self-regulating process. The operator does not have to perform tests to balance the system. There are no mixed liquor suspended solids to
monitor. The process is not affected by sludge age. Dissolved oxygen is not a design parameter. The operator may have to have effluent samples tested to ensure compliance. The operator can tell if the system is operating correctly with some visual inspection of the colour and texture of the biomass, the quantity of floating materials and the odour within the process.
1. The biomass that matures on the disk is directly related to the food source. If there is 25% of the designed organics then the system will receive 25% of the food and just 25% of the disk surface area will be used. With 75% of design loading the disk will have 75% of the surface area covered by biomass.
2. The colour of the biomass indicates the system’s condition. Normal biomass will be dark brown in colour and cover the complete disk. It will then progress to a lighter brown on the succeeding stages. When the system is upset
by excessive amounts of fats, oils and grease the disks will start to have grey and black patches. If the external problem is not corrected, the first and then subsequent sections of the disks will also turn grey and the process efficiency will decrease.
3. When operation is normal the odour inside the system will have an organic scent like good garden earth. Unpleasant odours are associated with organic overload, high greases, detergents, some form of biological inhibitor, or a combination of these. This biomass is a living body, which can be killed by wax strippers, antibacterial soaps or excessive use of detergents. All forms of wastewater treatment, not just BIODISK, will be adversely affected by such harsh chemicals. In the BIODISK the adverse effect of chemicals is dampened by the use of a primary sedimentation tank.
4. It is normal to have the fats, oils and greases collect along the sides of the BIOZONE. This is called scum. The system design incorporates a primary tank where the floating material can be retained. The amount of floating solids is
related to the amount of biosolids that are retained on the bottom of the same primary tank. When the scum gets thick it is a visual indicator that the system needs to be cleaned out. Cleanout is required about once a year.
Noise Levels: Noise levels are very low eveninside the BIODISK. The only sound is the gentle rotation of the disk in the water. The mechanical components are limited to a shaftmounted reducer and the gentle hum of the electric motor can be heard. Resale Value: The BIODISK has resale value. Two of the school projects in the Applications section have benefited from the resale of a treatment works. It is often suggested that if the treatment works has a short life span, then use a full steel tank. Many steel tank systems have been moved from location to location successfully. Construction camps, for instance, are a good example of use and reuse of the BIODISK. If you cannot find a buyer for your system we will help. Used systems are in demand.
Life Cycle Costs: The lower power consumption is one of the biggest life cycle cost savings of the BIODISK. At 1/2 to 1/8 the power draw of comparable forms of treatment the electrical cost saving over the life of the works can more than cover the capital expenditure. The small RBC footprint reduces house-cleaning time. There is no requirement to have an onsite lab to monitor the process. In some jurisdictions a lower level of operator certification helps to reduce costs. If the process discharges to a tile field then the field will have an indefinite life. No rags or high strength wastes will be discharged to the bed. Control panels do not have any programmed logic control (PLC) requirements. Simple mechanical timers can easily be adjusted by the operator without the need for computers or associated programs. Sludge disposal can be labour intensive and expensive. There is less sludge to dispose of in the BIODISK process and the stored sludge does not have to be aerated or have any process requirements.
Source: http://www.biodisk.ca/pdf/additional_advantages.pdf
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