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Recently, the exploration of new alternatives to common organic solvents in combination with non-conventional energy sources is a subject of intense research and development as tools for green extraction of plant-derived natural products. This paper deals with the use of low frequency ultrasound (100 W, 32 kHz) and pulsed electrical fields (0.86 kV cm-1, 13 Hz) to raise the efficiency of the extraction of selected plant species rich in valuable phenolic compounds.Four types of natural deep eutectic solvents were applied for the ultrasound-assisted extraction of silymarin from milk thistle among which a choline-chloride-based mixture with glycerol was proved to be the most promising one. Additionally, the usage of high ultrasound power significantly increased the concentration of sylimarin as compared to traditional ethanol extraction, generating rapidly for 10 min considerable temperature rise as a side effect under non-cooling conditions. The application of PEF as a pre-treatment for 0.8 s to the extraction allowed reducing the ethanol percentage in the ethanol/water mixtures giving comparable phenolic yields, without any, or very little, increase in temperature. As such, optimized power intensity in conjunction with appropriate solvent system provides a potential to improve the release of thermally unstable bioactive compounds under mild processing conditions.

Anaerobic digestion of piggery wastewater mediated with biochar was investigated by COD removal rate, methane yield, process stability and microbial community analysis. The results showed that biochar could effectively improve the COD removal rate and methane yield. Compared with blank group, COD removal rate was increased by 2.3%-9.4% for 300BC and by 37.5%-44.0% for 500BC. The maximum methane yield was obtained in 1g 300BC and 500BC, which was increased by 43.20% and 89.52% respectively. Meanwhile, the final H2S concentration was also obviously decreased by BC. Microbial community analysis showed that the addition of BC could increase the abundance of methanogens compared with the blank group. 500BC had a higher positive effect on anaerobic digestion of methanogenic bacteria than 300BC.Meanwhile, the relative abundances of hydrotrophic methanogens in 500BC groups were significantly higher than that of acetoclastic methanogens in 300BC.

In the presence of nitrogen oxides, nitrate-reducing bacteria (NRB) may use nitrate as an electron acceptor, reduce nitrate to nitrite, and finally convert nitrite to nitrogen or ammonium (NO and N2O). Studies have shown that BCX (Bio-Competitive Exclusion) is a viable , ecologically benign, and low-cost technique for regulating NRB in its first phases of study and application. More precisely, Pseudomonas sp. to isolate nitrate-reducing bacteria from oil-field wastewater using 16S rDNA sequencing and selection (NRB). Including NO3 and NO2 as bio-activators has helped researchers get a deeper understanding of the processes that govern NRB activation. The potential for molybdate and NRB to inhibit Sulfate-Reducing Bacteria (SRB) was also investigated. The results showed that NO2 was more effective than NO3. The effect was greatest at a 1:4 ratio of NO3 to NO2. NRB activation synergized with low molybdic acid solution concentrations (5%). Static corrosion model experiments demonstrated the importance of SRB in the corroding process. Biological inhibitors were shown to have the lowest corrosion rates, proving their effectiveness. Scanning electron microscopy was used to examine the corroded steel sheet's surface morphology. In addition, there was almost no surface corrosion or pitting on the steel sheet.

With the rising interest for sustainable power source and ecological security, anaerobic digestion of biogas technology has attracted considerable attention within the scientific researchers. This paper proposes a new research achievement on biogas production from Rice Mill Wastewater (RMW) with the utilization of anaerobic digester. An anaerobic digester is maintained with RMW and distillery anaerobic sludge at mesophilic temperature condition for 15 days as stabilization mode. After attaining stabilization stage, studies continued to examine the effect of Organic Loading Rate (OLR) and Hydraulic Retention Time (HRT) on the mesophilic anaerobic digestion of RMW. The OLR of the anaerobic reactor increased stepwise from 0.25 to 3.91 Kg COD/m3/dayand HRT ranged from 1 to 32.0 days. The total chemical oxygen demand (TCOD) utilized was higher than 75% and the CH4 percentage of the biogas was 62.00-63.00% for the OLRs studied. The efficient working volume of the digester is preserved as 25% of distillery anaerobic sludge and 75% of rice mill wastewater, loaded at Mesophilic temperature conditions for study purpose. By changing the conditions of OLR and HRT, biogas production, methane yield and percentage of COD reduction is examined. An anaerobic sludge is utilized as a seeding material to biodegrade the organic pollutants present in the wastewater. It will enhance the biological treatment of effluent with anaerobic sludge in a continuous mode of activity.The result showed that the proposed analysis obtains more biogas production with reduced COD when compared with existing approaches.