Use of Fused Laterite and Shredded PET bottles for Wastewater Treatment


Piles of shredded Plastics and fused laterite as filter media

The use of Biomedia in the treatment of wastewater has been incorporated into the pilot Tamale project as part of the innovative processes and low-cost but effective technology options of the intervention. The filter material (granite-19mm, 50mm and 100mm sizes) originally used in the trickling filter at the treatment plant has been replaced with piles of fused laterite (30mm, 50mm and 100mm sizes) as base structure and shredded flattened PET bottles (40mmx50mm Sizes). These materials have been used to increase digestion of unwanted organic compounds in wastewater by aerobic process.
As “fused laterite” are known for their iron and aluminum rich properties have potency for the removing substantially, high levels of phosphorous and heavy metals in the treatment process. By the treatment arrangement of the project, this process takes place in the final treatment process.

The treatment process passes through three stages from the in-let manhole into air-tight septic tank where suspended solids settles] for pre-treatment as first stage. The second stage of the process takes place in the Anaerobic Baffled Reactor (ABR) with effluent from the septic tank going through the baffles for treatment. These two stages are designed to go through anaerobic processes with the intention of recovering biogas (testing biogas potential will be done when plant starts work). The third stage consist of the trickling filter which works aerobically.
The biomedia is packed into the trickling filter where the effluent from the ABR is channeled for filtering. We do not expect that initial settling of fine particles of the biomedia in the bottom of the trickling filter would stall treatment at this stage because of their size
We used this media combination bearing in mind that plastics could take many years to break down and therefore would not be able to stall operational process of the trickling filter. The treated wastewater can be used as irrigation water for agriculture production without having to go through additional process of removing plastic particles.

Cheryl Van Kempen's picture

Hi Nash, 

This is a very interesting use of PET waste. Have you seen this application elsewhere or did you think of it yourself/ is your project the first to try it?

What is the exact role of the plastic in the process?