Background: The treatment plant is central and collects fats, oil and grease-enriched wastewater from across the country. The treatment process is follows: After a physico-chemical treatment of the vegetable oil wastewater (might also contain residues of mineral oil – up to 10% v/v), the pretreatment effluent enters a 60 cubic meter aerobic bioreactor (SBR - Sequence Batch Reactor). In order to increase the company’s capacity to treat wastewater without the need for significant infrastructure alteration (i.e., increase in tank volume), it was necessary to increase treatment yield and decrease the required hydraulic retention time. The biological process is performed in a 60 cubic meters bioreactor for several days (batch reactor). Use of the SBP technology was aimed to reduce the HRT (hydraulic retention time), enabling the company to increase its ability to receive additional volumes of wastewater for treatment.

Method: We established an introduction device encasing a perforated cage for SBP capsules implementation within the bioreactor. The perforated cage which held the SBP capsules was immobilized approximately 1-1.5 m below the water surface, above the air diffusers.

Findings: Prior to implementation of the SBP treatment, HRT values were as follows (control): under an organic load of 12,000 mg/L, the HRT for water disposal to sewage was 8.22 days (represented by an average of 6 batches). For a higher organic matter load (12,000-15,000 mg/L), the HRT for water disposal to sewage increased to 9.5 days. These values were used as a reference for our project.

After implementation of the SBP technology, the observed HRT of organic loads below 12,000 mg/L was 5.75 days. Batches of wastewater encasing an organic load of 12,000-15,000 mg/L presented a HRT of 6 days only! (represented by 4 batches).