Introduction:
The MBR WWTP receiving sanitary wastewater enriched with a local industrial wastewater that including high concentration of proteins, fats and oil from slaughterhouses, and seasonal (Mid-September to December) in?ows draining by olive mill wastewater (OMWW).
Treatment process:
The WWTP is having two MBR-bioreactors, each can treat 2400 cubic meters per day.
The in?ow drained into an anaerobic chamber flows then to an anoxic chamber. The incubation time in each chamber is 0.5–1 h. The incoming stream from the anoxic chamber is separated into two identical bioreactors (830 m3 each) (pond A and pond B). Both bioreactors are extensively aerated (dissolved oxygen >1 mg/L) and the mixed liquor within the bioreactor is ?ltrated by micro?ltration membranes (KOBOTA, Japan). The hydraulic retention time (HRT) within the bioreactors is approximately 8 h. Bioreactor and anoxic pond circulation of the mixed liquor is conducted to induce the de-nitri?cation process in order to reduce the total nitrogen concentration within the ef?uents. The observed organic load of the in?uents is considered high (average biochemical oxygen demand (BOD) of 507 mg/L and chemical oxygen demand (COD) of 1677 mg/L), and the BOD/ COD ratio is low (BOD/COD=0.3), indicating high concentrations of relatively recalcitrant organic matter. The MBRs contained a high concentration of MLSS (average values of 13,600 mg/L).
Treatment aim:
To stabilize the biological process to overcome of shock load stress episodes (reducing intensity and recovery time).
SBP technology treatment:
The MBR treatment plant has two identical bioreactors (pond A and pond B). Pond A was set as the control system (without SBP capsules implementation) and pond B was set to be the test system introducing encased SBP capsules (4 SBP introduction devices were used). In order to observe a similar starting point of both bioreactors, both systems were monitored prior to the introduction of the SBP capsules. This was done in order to evaluate the performance of each bioreactor prior to the experimental interval. It was found that both bioreactors presented a similar biodegradation rate performance (BOD ef?uents), and presented a stabilized biological process.
The SBP capsules encase a selective aerobic (obligate and facultative) biomass that aim to treat the fraction of fat and oils, especially the dissolved and the emulsi?ed fractions (NatiCapMunicipal). Additionally, we chose to use a supplemental culture to challenge against the antimicrobial agents within the mixed liquor named, NatiCapPetroleum. The bacterial culture encased in the NatiCapPetroleum capsules was used to facilitate the biodegradation of the short chains of hydrocarbons, solvents and phenol compounds expected to be present within the OMWW. This formulation provides some protection from cytotoxic agents. Therefore, the SBP technology treatment designed to reduce hard biodegradable fatty acids and detoxi?ed antimicrobial agents resulted positively in the protection of the activated sludge within the mixed liquor. The additive treatment of several types of exogenous bacterial cultures used in the SBP technology allowed us to achieve wider metabolic activity and therefore to present a better solution to increase the bioprocess ef?ciency.
Major findings:
According to the ef?uent’s chemical analysis results, we observed similar COD effluent values between the control and the test system. In order to evaluate the technology contribution to the biological process stabilization, we de?ned stress/risk events according to two parameters: intensity and the duration of the incidence until achieving full recovery. The ef?uent’s BOD values present and indicate three biological process stress events during the study period. These stress incidents resulted in signi?cant increases in BOD values of the ef?uents in both systems. Moreover, it seems that there is a correlation between a biological stress event and the mixed liquor (MLSS) reduction values. The supplementary SBP treatment induces effective process stabilization mainly during signi?cant biomass (MLSS) reduction events. Successful SBP treatment eliminates or reduces the frequency and the intensity of the biomass risk events, thus elevating the treatment effectiveness.
More details about this project and results can be found within the followed article:
Ofir Menashe and Eyal Kurzbaum, A Novel Bioaugmentation Treatment Approach using a Confined Microbial Environment: A Case Study in a MBR Wastewater Treatment Plant, Environmental Technology, (on-line publication, DOI: 10.1080/09593330.2015.1121293), Jan. 2016.
