Biological wastewater treatment typically requires the use of bacteria for degradation of carbonaceous and nitrogenous compounds present in wastewater. The high lipid containing biomass can be used to extract oil and the contents can be termed as bio-oil (or biodiesel or myco-diesel after transesterification). The separate experiments were conducted on actual wastewater samples with 5% v/v inoculum of Mucor circinelloides MTCC1297 and Trichoderma reesei NCIM992 strains. The observed reductions in chemical oxygen demand (COD) were 88.72% and 86.75% in 96 hrs and the observed substrate based biomass yields were 0.21 mg VSS/mg COD and 0.22 mg VSS/mg COD for M. circinelloides reactor and for T. reesei reactor, respectively. The resulted bio-oil production from wastewater treatment by M. circinelloides and T. reesei reactors was 142.2 mg/L and 74.1 mg/L, whereas biomass containing bio-oil contents (%w/w) were 22.11% and 9.82%, respectively. In this experiment, the fungal wastewater treatment was also compared with conventional bacterial process with respect to specific growth rate, biomass production, and oil content. This study suggests that wastewater can be used as a potential feedstock for bio-oil production with the use of oleaginous fungal strains and which could be a possible route of waste to energy.
The aim of this work was to optimize the biodegradation of polyvinyl alcohol (PVA) containing actual textile wastewater for a sustainable treatment solution. The isolated microbial consortia of effective PVA degrader namely Candida Sp. and Pseudomonas Sp., which were responsible for symbiotic degradation of chemical oxidation demand (COD) and PVA from desizing wastewater. In the process optimization, the maximum aeration was essential to achieve a high degradation rate, where as stirring enhances further degradation and foam control. Batch experiments concluded with the need of 16 lpm/l and 150 rpm of air and stirring speed respectively for high rate of COD and PVA degradation. Optimized process leads to 2 days of hydraulic retention time (HRT) with 85–90% PVA degradation. Continuous study also confirmed above treatment process optimization with 85.02% of COD and 90.3% of PVA degradation of effluent with 2 days HRT. This study gives environment friendly and cost effective solution for PVA containing textile wastewater treatment.
Fluidization of carrier media for biofilm support and growth defines the moving bed biofilm reactor (MBBR) process. Major MBBR facilities apply virgin polyethylene (PE)-based circular plastic carrier media. Various carriers were studied to replace these conventional carriers, but polyurethane (PU) foam-based carrier media has not been much explored. This study evaluates the potential of PU foam carrier media in aerobic MBBR process for simultaneous nitri-denitrification (SND). Two parallel reactors loaded with conventional PE plastic (circular) and PU foam (cubical) carriers compared for their removal efficiencies of chemical oxygen demand (COD) and nitrogen contaminants from wastewater. Results indicate that average COD removal in MBBR containing PE plastic carrier media was 81%, compared to 83% in MBBR containing PU foam. Average ammonical and total nitrogen reduction was 71% and 59% for PU foam-based MBBR, compared to 60% and 42% for PE plastic-based MBBR. SND-based nitrogen removal capacity was doubled in aerobic MBBR filled with PU foam carrier media (27%), than MBBR containing PE plastic carrier media (13%). Cost economics also governs the commercial advantage for the application of PU foam-based carrier media in the MBBR process.
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