Effects of solids retention time on the performance of bioreactors bioaugmented with a 17β-estradiol-utilizing bacterium, Sphingomonas strain KC8

This study investigated the performance of lab-scale sequencing batch reactors (SBRs) that were inoculated with nitrifying activated sludge and bioaugmented with a Sphingomonas strain KC8 (a 17β-estradiol-degrading bacterium). The bioaugmented SBRs were supplied with synthetic wastewater (average initial total organic carbon (TOC) = 175 mg L⁻¹ and average initial ammonia-N = 25 mg L⁻¹) and daily dose of 17β-estradiol (1 mg L⁻¹) and operated under three solid retention times (SRTs) of 5, 10, and 20 d. After three times periods of the operating SRTs, the overall removal of TOC (>87%) and ammonia (>91%) was similar in all the SBRs. Higher 17β-estradiol removals (>99%) were observed for the SBRs. Neither estrogens nor estrogenic activity was detected in the treated water, except some samples from the SBR operating under 5 d of SRT. The ratios of known estrogen degraders (Sphingomonas strain KC8 and ammonia-oxidizing bacteria) and amoA gene to the total bacterial population decreased as SRT increased, suggesting the presence of unknown estrogen-degraders in SBRs operating at SRT = 10 and 20 d. Real-time-terminal-restriction fragment length polymorphism analysis showed that the evenness of microbial community structures was not affected by the SRT; while, the diversity indices suggest that longer SRTs might lead to more diverse microbial community structure. Overall, the results suggested that bioaugmented bioreactors operating at long SRTs (10 and 20 d) were effective in removing 17β-estradiol to the non-estrogenic treatment endpoint.     

Minimal pesticide-primed soil inoculum density to secure maximum pesticide degradation efficiency in on-farm biopurification systems

Addition of pesticide-primed soil containing adapted pesticide degrading bacteria to the biofilter matrix of on farm biopurification systems (BPS) which treat pesticide contaminated wastewater, has been recommended, in order to ensure rapid establishment of a pesticide degrading microbial community in BPS. However, uncertainties exist about the minimal soil inoculum density needed for successful bioaugmentation of BPS. Therefore, in this study, BPS microcosm experiments were initiated with different linuron primed soil inoculum densities ranging from 0.5 to 50 vol.% and the evolution of the linuron mineralization capacity in the microcosms was monitored during feeding with linuron. Successful establishment of a linuron mineralization community in the BPS microcosms was achieved with all inoculum densities including the 0.5 vol.% density with only minor differences in the time needed to acquire maximum degradation capacity. Moreover, once established, the robustness of the linuron degrading microbial community towards expected stress situations proved to be independent of the initial inoculum density. This study shows that pesticide-primed soil inoculum densities as low as 0.5 vol.% can be used for bioaugmentation of a BPS matrix and further supports the use of BPS for treatment of pesticide-contaminated wastewater at farmyards.     

Restoring the plant productivity of heavy metal-contaminated soil using phosphate sludge, marble waste, and beneficial microorganisms

Assisted natural remediation (ANR) has been highlighted as a promising, less expensive, and environmentally friendly solution to remediate soil contaminated with heavy metals. We tested the effects of three amendments (10% compost, C; 5 or 15% phosphate sludge, PS5 and PS15; and 5 or 15% marble waste, MW5 and MW15) in combination with microorganism inoculation (rhizobacteria consortium alone, mycorrhizae alone, and the two in-combination) on alfalfa in contaminated soil. Plant concentrations of Zn, Cu, and Pb were measured, along with proline and malondialdehyde production. The microbiological and physicochemical properties of the mining soil were evaluated. Application of the amendments allowed germination and promoted growth. Inoculation with the rhizobacteria consortium and/or mycorrhizae stimulated plant growth. PS and MW stimulated the production of proline. Inoculation of alfalfa with the rhizobacteria-mycorrhizae mixture and the application of MW allowed the safe cultivation of the legume, as shown by the low concentrations of metals in plant shoots. Zn and Pb concentrations were below the limits recommended for animal grazing and accumulated essentially in roots. Soil analyses showed the positive effect of the amendments on the soil physicochemical properties. All treatments increased soil pH (around 7), total organic carbon, and assimilable phosphorus content. Notably, an important decrease in soluble heavy metals concentrations was observed. Overall, our findings revealed that the applied treatments reduced the risk of metal-polluted soils limiting plant growth. The ANR has great potential for success in the restoration of polymetallic and acidic mining soils using the interaction between alfalfa, microorganisms, and organo-mineral amendments.     

生化黄腐酸对污染水体生物修复的强化作用

研究了生化黄腐酸（BFA）对污染水体生物修复的强化作用。生化黄腐酸能提高水体中微生物活性,加快微生物对目标污染物的降解。在污染水体生物修复强化作用的试验中,投加生化黄腐酸,CODCr、NH3-N、TP和浊度的去除率分别增加了29．47％、20．61％、35％和19．86％,同时有利于水体DO的提升。     

垃圾压缩站污水的生物强化处理

垃圾压缩站污水是一种具有高COD、高NH3-N特点的有机污水.以厌氧/好氧组合工艺为基础,通过投加高效菌株对活性污泥系统进行生物强化.实验结果表明,与空白相比,厌氧出水COD去除率提高约30%,好氧出水NH3-N去除率提高约20%.最终出水COD《120 mg/L, NH3-N《25 mg/L,均达到《污水综合排放标准》(GB 8978-1996)二级排放标准.     

The biodegradation of cable oil components: impact of oil concentration, nutrient addition and bioaugmentation

The effect of cable oil concentration, nutrient amendment and bioaugmentation on cable oil component biodegradation in a pristine agricultural soil was investigated. Biodegradation potential was evaluated over 21 d by measuring cumulative CO₂ respiration on a Micro-Oxymax respirometer and ¹⁴C-phenyldodecane mineralisation using a ¹⁴C-respirometric assay. Cable oil concentration had a significant effect upon oil biodegradation. Microbial respiratory activity increased with increasing cable oil concentration, whereas ¹⁴C-phenydodecane mineralisation decreased. Bioaugmentation achieved the best cable oil biodegradation performance, resulting in increases in cumulative CO₂ respiration, and maximum rates and extents of ¹⁴C-phenyldodecane mineralisation. Generally, nutrient amendment also enhanced cable oil biodegradation, but not to the extent that degrader amendment did. Cable oil biodegradation was a function of (i) cable oil concentration and (ii) catabolic ability of microbial populations. Bioaugmentation may enhance cable oil biodegradation, and is dependent upon composition, cell number and application of catabolic inocula to soil.     

Performance and microbial community analysis of bioaugmented activated sludge for nitrogen-containing organic pollutants removal

Nitrogen-containing organic pollutants (quinoline, pyridine and indole) are widely distributed in coking wastewater, and bioaugmentation with specific microorganisms may enhance the removal of these recalcitrant pollutants. The bioaugmented system (group B) was constructed through inoculation of two aromatics-degrading bacteria, Comamonas sp. Z1 (quinoline degrader) and Acinetobacter sp. JW (indole degrader), into the activated sludge for treatment of quinoline, indole and pyridine, and the non-bioaugmented activated sludge was used as the control (group C). Both groups maintained high efficiencies (> 94%) for removal of nitrogen-containing organic pollutants and chemical oxygen demand (COD) during the long-term operation, and group B was highly effective at the starting period and the operation stage fed with raw wastewater. High-throughput sequencing analysis indicated that nitrogen-containing organic pollutants could shape the microbial community structure, and communities of bioaugmented group B were clearly separated from those of non-bioaugmented group C as observed in non-metric multidimensional scaling (NMDS) plot. Although the inoculants did not remain their dominance in group B, bioaugmentation could induce the formation of effective microbial community, and the indigenous microbes might play the key role in removal of nitrogen-containing organic pollutants, including Dokdonella, Comamonas and Pseudoxanthomonas. Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis suggested that bioaugmentation could facilitate the enrichment of functional genes related to xenobiotics biodegradation and metabolism, probably leading to the improved performance in group B. This study indicated that bioaugmentation could promote the removal of nitrogen-containing organic pollutants, which should be an effective strategy for wastewater treatment.     

耐盐复合菌剂生物强化处理高盐高硫废水

从实验室处理高盐废水的生物反应池中筛选到1株耐盐脱氮硫杆菌XSH7.为提高系统在高盐条件下的处理效果,将该硫杆菌和本实验室保藏的高效硝化菌SW32混合制成复合菌投加到SBR反应池中进行生物强化.比较了强化系统(BS)与非强化系统(NBS)的处理效果,研究了复合菌对系统去除COD、NH3-N和硫代硫酸盐(THS)的影响,并对投菌量与周期作了考察.结果表明,投加复合菌能加快COD降解速度,增强耐负荷冲击能力,提高COD、NH3-N和THS的去除率.10%(质量分数)投菌量的系统24 h即可达到稳定出水,COD、NH3-N和THS去除率最高可达到93%、92%、92%,最大耐受负荷分别为1.128 0,0.C74 5、1.053 0 kg/(m3·d).     

A syntrophic propionate-oxidizing microflora and its bioaugmentation on anaerobic wastewater treatment for enhancing methane production and COD removal

Methane fermentation process can be restricted and even destroyed by the accumulation of propionate because it is the most difficult to be anaerobically oxidized among the volatile fatty acids produced by acetogenesis. To enhance anaerobic wastewater treatment process for methane production and COD removal, a syntrophic propionate-oxidizing microflora B83 was obtained from an anaerobic activated sludge by enrichment with propionate. The inoculation of microflora B83, with a 1:9 ratio of bacteria number to that of the activated sludge, could enhance the methane production from glucose by 2.5 times. With the same inoculation dosage of the microflora B83, COD removal in organic wastewater treatment process was improved from 75.6% to 86.6%, while the specific methane production by COD removal was increased by 2.7 times. Hydrogen-producing acetogenesis appeared to be a rate-limiting step in methane fermentation, and the enhancement of hydrogen-producing acetogens in the anaerobic wastewater treatment process had improved not only the hydrogen-producing acetogenesis but also the acidogenesis and methanogenesis.

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生物强化技术及其在废水治理中的应用

介绍了生物强化技术在废水治理中的应用现状,评价了生物强化作用的效果,并对生物强化机理、生物强化剂的优化选择、反应动力学、系统的优化设计等方面进行了讨论。生物强化技术是一种生物治理废水的高效技术,在废水治理中具有广阔的应用前景。