For rock type of high filtration rate tricking filters, organic load assumed is 0.4-2.4 kg BOD/m³d. Intermediate rate filtration trickling filters would have different organic load. It is around 0.24-0.48 kg BOD/m³d.

The retention time is considered as 30 mins for flocculation zone. The volume is calculated by multiplying retention time and flow. The area is n calculated by dividing volume by height. From area diameter can be calculated.

For plastic type high filtration rate trickling filters, BOD removal efficiency is 60-90%. This is lower than rock type low filtration rate trickling filters. The BOD removal efficiency rate is highest only when low filtration rate type trickling filters are used.

A central energy-dissipating inlet (EDI) can be used, or Monroe Environmental will design a peripheral feed system that distributes influent around perimeter of tank, and aids in activated sludge secondary settling.

Facultative bacteria are used in trickling filters. Pseudomonas and Alcaligenes are some of strains used in se filters. Also, Flavobacterium and Achromobacter are also used in this type of treatment.

The filtering media is made by syntic fibre specially processed and has a high void ratio(95% and above), which enables trapping of debris and suspended solids in and out of media simultaneously.

Area= Flow rate/ Surface loading rate. This is represented as mm². Area = 1500/7 = 215 mm².

The porosity of such syntic media is around 88-90%. These media are highly porous. Hence this is highly efficient in removal of colloidal and suspended solids.

The penetration of suspended solids is deep through filter bed. The length of run is two days. Before starting operation again, pre-treatment of rapid sand filter beds is done by coagulation.

Tube settlers decrease vertical distance of settling. Hence floc particles settle faster. A floc particle must settle before agglomerating to form larger particles.