TRICKLING FILTERS with rock packing have been a common simple and low energy process used for secondary treatment since early 1900s. The concept of a trickling filter grew from the use of contact filters in England in the late 1890s. Biological growth on the media surface converts the organic waste material in to stable by-products such as CO2, H2O using microorganisms mainly the bacteria. The old plants used mainly Rock as the surface for the attached growth biological systems. This media had disadvantages due to heavy weight, elaborate supporting structure, water tight peripheral walls designed to take lateral thrust, low voltage, potentials for plugging, fly nuisance, poor wetting characteristics, etc. Even though the problems with rock media were leading with increased use of suspended growth biological systems, the advantageous of the process as such prevented the systems from going in to oblivion.
We have made some prominent improvements in the Conventional Bio-Tower Technology with the use of plastic media and our patented process named “Improved Bio-Tower Technology”.
All treatment technologies have similar primary treatment, after primary treatment raw sewage is taken to Improved BIO-TOWER, where sewage is evenly spread on packed bed of Plastic/PVC medium where fixed film of microorganism is formed over media. Biological degradation of organic matter present in sewage occurs as trickling sewage comes in contact with biological film formed over plastic media. This method is based on empirical data collected over the years, design curves have been developed for various organic loading and different temperature ranges. About 50 % organic load is removed without use of power.
Advantages
Attached growth systems are more suitable to take shock loads in terms of hydraulic and organic disturbances as compared to suspended growth systems.
Very high capacity to take organic load.
Trouble free operations even under difficult conditions.
Reliable and consistent nitrification, both in summer & winter operations.
Very low skilled operation, control and maintenance requirements and thus low operation and maintenance costs.
Low sludge production and easily drainable sludge.
Much smaller secondary settling tanks due to higher settling rates of the sludge produced.
Lower residual suspended solids concentration in treated wastewater.
Cost effective combinations with other treatment methods.
Improved plastic media design have significantly reduced tower sizes and costs and enhanced their capacities and efficiencies.
Installation depths up to 6.0 m require no intermediate supports. Higher installation depths with intermediate supports can be provided. This combined with efficient geometry can offer a very compact plant.
Long life of over 30 years - UV stabilized material.
Large specific surface areas to accommodate large microbial growth.
Very large voids from 90 to 97%.
Weight easy to handle and simpler for supporting structure.
Large depth - say 6 to 8 m., allows considerable saving of land.
The distribution pattern provides utilization of the complete surface area.
Due to cross flow configuration. The liquid has about 4 times higher retention time.
It has very low resistance to airflow leading to maximum contact of air, waste water & bio mass.
Low resistances to airflow and the mixing caused at the cross over points in the fill lead to optimum aeration.
Good wetting, continuous air movement and thinner biological growths eliminate fly nuisance.
Due to continuous redistribution of water flow, plastic media has a very high resistance to plugging.
Settled effluents TSS is much lower with Improved Bio-Tower.
No elaborate peripheral walls required because modules are self-supporting, only cladding suffices.
Requires no elaborate under drain system.
Skilled staff is not required for operation & maintenance.
Land required is less as compared to other technologies.
Power consumption is reduced because of ventilation and about 50% reduction in BOD in Imp. Bio-Towers.
Advantages