Product Profile

Trickling Filter Technology

Trickling Filter solutions for the 21st Century

Trickling filters have provided valuable service in treating wastewater for many years. They have proven to be simple to run, reliable, energy efficient and have met the treatment levels required.

Today Trickling Filters are a modern and highly attractive process due to the development of different kinds of plastic media, especially such as 2H Water Technologies provides.

  •  Full carbonaceous treatment
  •  Nitrification to very low concentrations
  •  Denitrification
  •  High rate applications

Although many equations and design rules for the trickling filter process have been published – it needs a lot of know-how and experience to find the best solution. This know-how has been gathered together by 2H specialists during 25 years of filter design and operational experience. 2H makes it available for you to ensure your project provides:

  •  Reliable compliance with effluent standards
  •  Maximum economic benefit for customers
  •  Optimum operation reliability
  •  Accurate hydraulic parameters for rotary distributors

Process Engineering

Secondary Treatment Filters


This treatment process reduces the levels of BOD and Ammonia within the waste water to levels that can be discharged into watercourses without compromising the condition of the receiving waters. The loading rates applied to 2H BIOdek secondary filters are typically between 0.2 KgBOD/ m³/d to 1.0 KgBOD/m³/d – depending on the required effluent quality.


With appropriate topographic layout 2H BIOdek filters can operate in gravity feed mode without the supply of additional energy. No other aerobic water treatment process offers this advantage.

Tertiary Nitrification Filters


This type of filter is installed following an existing process to enable the works to meet tighter ammonia discharge consents. The nature and type of biomass that establishes itself within tertiary nitrification filters produces negligible amounts of solids. Provided the works is within its suspended solids consent, no additional capital expenditure is required for post filter settlement.


2H BIOdek is particularly effective for this application due to its long retention times, crossflow structure and high specific surface area which all combine to produce a very high specific nitrification rate producing very low ammonia concentrations in the effluent.

High Rate Filters


Extremely high treatment rates can be achieved by using high rate filters thus minimising the site footprint. High rate filters are loaded at rates of 1.0 kg BOD/m³/d up to 5.0kg BOD/m³/d. They are normally designed to reduce the BOD loads by between 50% to 70%. The energy input is less than 0,2 Kwh per kg reduction in BOD. Particularly when dealing with an easily treatable waste, a strong biomass growth will be created. 2H BIOdek vertical flow media structure has the optimal structure to steadily expel the excess sludge.



Research through the past decade has proven that anoxic trickling filters are a reliable process for denitrification. Based on our research, 2H Water Technologies has patented a process solution, which even enables shallow filters to efficiently denitrify. By a simple method the filter media is sealed against atmospheric oxygen, forcing the biomass to use nitrate within the effluent stream for the supply of oxygen.

Typical Applications




Trickling filters with 2H media can be designed to meet stringent standards of new works. They are also utilised as a cost effective add on stage either to decrease the load as pre-treatment where the capacity of an existing works has to be increased or as a special treatment stage to meet new standards dictated by legislation.

The versatility of the 2H media range enables existing assets and treatment systems to be upgraded to meet future needs with minimum costs and disruptions to the treatment capacity.




When a company is faced with tighter discharge consents or higher industrial effluent charges, the 2H high rate filter media offers an economic, simple and reliable option to meet these demands. For the higher BOD/COD concentrations that can be experienced in industrial applications, 2H uses a combination of Cross Flow Media and Vertical Flow Media. Plus it’s really simple to operate and requires not special skills as well as being energy efficient.


Upgrading Existing Filters


One cost effective solution to increase the treatment capacity of an existing filter works is to replace the existing rock media or random media with 2H media. Due to the more open structure and high effective surface area, around 3 times the organic load, and up to 10 times the hydraulic flow, can be applied to 2H media than to rock media.

Trickling Filter – Approach

Modern Trickling Filters can be adopted at each stage of wastewater treatment. With the correct design application Trickling Filters can be used to replace or compliment existing equipment at any stage.

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