联合生物法处理炼油厂含油污泥的研究

大港石化公司采用联合生物法处理含油污泥,对使用好氧、厌氧工艺处理含油污泥的结果进行了探讨。实验结果表明:先进行好氧处理然后脱水再进行厌氧堆肥工艺处理含油污泥,除油率达到97.6%,除磷、钾的指标低于《城镇垃圾农用控制标准》(GB8172-87)的要求外,其他指标均符合该标准要求,且避免了二次污染。     

NaCl和KCl对厌氧污泥抑制的动力学研究

在厌氧颗粒污泥和厌氧絮状污泥系统中,进行盐质量浓度(NaCl或KCl质量浓度,下同)对厌氧污泥抑制动力学的研究,得到不同拟合的COD降解动力学方程及参数.实验结果表明:当盐质量浓度为10～30 g/L时,KCl对厌氧污泥的COD比降解速率的抑制程度大于NaCl;当盐质量浓度由0 g/L增至10 g/L时,半速率常数逐渐增加;当盐质量浓度由10 g/L增至30 g/L时,半速率常数逐渐减小;在厌氧污泥系统中,NaCl抑制作用下的盐抑制常数高于KCl,且颗粒污泥的盐抑制常数高于絮状污泥.     

零价铁-反硝化菌在地下水硝酸盐污染修复中的应用

综述了应用零价铁-反硝化菌复合体系去除地下水中硝酸盐氮污染的研究进展.脱氮技术主要包括物理化学法、化学还原法和生物反硝化法,但单独使用任何一种方法都无法得到令人满意的处理效果.以零价铁在水中厌氧腐蚀所释放的氯气供给微生物进行反硝化,可以同时解决这两种技术单独使用时所存在的弊端.在此复合体系中,主要反应包括产氨、析氢和反硝化,降低脱氮产物中的氨氮比例就要减少产氨反应的发生几率.此外,使用纳米铁代替零价铁和反硝化细菌复合,可以大大提高脱氮反应速率.然而,该技术的研究在国内外尚处于起步阶段,在反应机理、产物控制、条件优化等方面都存在不足,还需要深入研究.     

The response of soil Arthrobacter agilis lush13 to changing conditions: Transition between vegetative and dormant state

This work was aimed at studying the response of soil non-spore-forming actinobacterial strain Arthrobacter agilis Lush 13 to changing natural conditions, such as nutrient availability and the presence of degradable and recalcitrant aliphatic and aromatic substrates. The A. agilis strain Lush13 was able to degrade octane, nonane, hexadecane, benzoate, phenol, and 2,3-, 2,4-, 2,5-, 2,6-dichlorophenols, but not grew on 3,4-dichlorophenol, 2,3,4-, 2,4,5-, 2,4,6-trichlorophenol (TCP), pentachlorophenol (PCP), 2-chlorobenzoate, 3-chlorobenzoate, 3,5-dichlorobenzoate, 2,4-dichlorobenzoate. Under growth-arresting conditions due to nitrogen- or multiple starvation or recalcitrant (non-utilizable) carbon source, the studied strain preserved viability for prolonged periods (4–24 months) due to transition to dormancy in the form of conglomerated small and ultrasmall cyst-like dormant cells (CLC). Dormant cells were shown to germinate rapidly (30 min or later) after removal of starvation stress, and this process was followed by breakdown of conglomerates with the eliberation and further division of small multiple actively growing daughter cells. Results of this study shed some light to adaptive capabilities of soil arthrobacters in pure and polluted environments.     

Impact of redox conditions on metolachlor and metribuzin degradation in mississippi flood plain soils

Abstract

The effect of soil redox conditions on the degradation of metolachlor and metribuzin in two Mississippi soils (Forrestdale silty clay loam and Loring silt loam) were examined in the laboratory. Herbicides were added to soil in microcosms and incubated either under oxidized (aerobic) or reduced (anaerobic) conditions. Metolachlor and metribuzin degradation under aerobic condition in the Forrestdale soil proceeded at rates of 8.83 ngd^‐1 and 25 ngd^‐1, respectively. Anaerobic degradation rates for the two herbicides in the Forestdale soil were 8.44 ngd^‐1 and 32.5 ngd^‐1, respectively. Degradation rates for the Loring soil under aerobic condition were 24.8 ngd^‐1 and 12.0 ngd^‐1 for metolachlor and metribuzin, respectively. Metolachlor and metribuzin degradation rates under anaerobic conditions in the Loring soil were 20.9 ngd^‐1 and 5.35 ngd^‐1. Metribuzin degraded faster (12.0 ngd^‐1) in the Loring soil under aerobic conditions as compared to anaerobic conditions (5.35 ngd^‐1).     

A novel use of anaerobically digested liquid swine manure to potentially control soybean cyst nematode

Experiments were carried out in two steps to determine the effect of anaerobically digested swine manure on soybean cyst nematode (SCN) egg control. In the first step, liquid swine manure underwent anaerobic digestion to search for the best digestion time for both volatile fatty acids (VFA) and ammonium nitrogen (NH₄ ⁺) enrichment. The results showed that about 17 and 28 days of incubation were needed, respectively, to reach the maximal levels of VFA and NH₄ ⁺ in the manure. In the second step, raw, VFA-enriched, and NH₄ ⁺-enriched manure were applied separately, at four different rates (25, 50, 100, and 200 mL/pot), to soil pots inoculated with nematode eggs in a greenhouse environment. Soil samples were collected 35 and 61 days after inoculation to determine the effect of such treated manure on SCN egg productivity. The data indicated that the SCN egg counts were inversely related to the manure application rates in a linear manner with correlation coefficients of 0.998, 0.967, and 0.900 for raw, NH₄ ⁺-enriched, and VFA-enriched manure for the 35-day samples. While no such relationships were found for the 61-day samples, implying that none of the treatments were still effective 61 days after application. At the four application rates, the VFA-enriched manure performed best in reducing SCN egg counts (by 18.1, 19.5, 34.3, and 18.6%) as compared to the raw manure treatment. In contrast, the NH₄ ⁺-enriched manure achieved mostly negative reductions. To achieve the best control of SCN egg growth, the VFA-enriched manure should be used and applied to soybean fields every 35 days.     

The effects of residual tetracycline on soil enzymatic activities and plant growth

A pot trial was carried out to investigate the adverse effects of tetracycline (TC) on soil microbial communities, microbial activities, and the growth of ryegrass (Lolium perenne L). The results showed that the presence of TC significantly disturbed the structure of microbial communities and inhibited soil microbial activities in terms of urease, acid phosphatase and dehydrogenase (p < 0.05). Plant biomass was adversely influenced by TC, especially the roots with a reduction of 40% when compared with the control. Furthermore, TC decreased the assimilation of phosphorus by the plant although the concentration of phosphorus was increased by 20% due to decreased plant biomass. TC seemed to increase the concentration of dissolved organic carbon (by 20%) in soil. The findings implied that the agricultural use of animal manure or fishpond sediment containing considerable amounts of antibiotics may give rise to ecological risks.     

膜生物反应器中生物膜的生长特性

实验采用经甲苯培养驯化而成的单一假单胞菌菌种,通过分析平板式生物膜反应器内,不同阶段假单胞细菌生物膜干重、厚度、活性生物量和生物种群分布的变化,研究生物膜特性与降解效率之间的关系。实验结果表明,在挂膜初期生物膜迅速生长,生物量以及生物膜干重增长很快,有利于甲苯及营养物质的传输,降解效率也快速提升。随着生物膜的生长,生物量及干重也逐步增加,厚度逐渐增加使传质阻力不断增大,生物膜上层微生物的有机底物供应不足,使生物膜上层结构稀疏,最终维持一个甲苯的总传输量与生化降解量的平衡,生物量的生长与衰亡也达到动态平衡,形成了一个较高且稳定的降解效率。     

油田水反硝化技术抑制硫酸还原菌

利用反硝化技术对江苏油田5个联合站的采出水,进行了添加不同抑制剂的浓度、种类、不同配比和接种DNB菌对SRB、DNB的菌落数量、硫化氢的产生量和氧化还原电位的影响的静态实验。研究结果表明:投加一定浓度的硝酸盐、亚硝酸盐和钼酸盐,对油田采出水SRB的生长都有不同程度的抑制作用,而同等浓度的抑制效果表现为亚硝酸盐>硝酸盐>钼酸盐,同时投加DNB和0.3～0.5 g/L(比例为1∶1)的亚硝酸盐/硝酸盐可较好地抑制油田采出水中的SRB和硫化氢的产生,其中0.5 g/L抑制效果最明显,可抑制硫化氢的产生10 d以上,SRB和硫化氢抑制率分别可达87%和98%。以不同药剂的常压静态腐蚀实验结果表明,抑制剂的腐蚀速率比杀菌剂和缓蚀剂略高,但低于石油天然气行业中标准规定的0.0076 mm/a,也远低于对照样的0.152 mm/a。     

微氧环境下无色硫细菌和硫酸盐还原菌脱硫

通过间歇曝气形成微氧环境让SRB和CSB实现共生,使含硫酸盐有机废水中硫酸根最终转化成单质硫达到脱硫目的.研究考察了曝气量对SRB还原和CSB氧化的影响,确定了合适的曝气强度和水力停留时间,使得单质硫占系统内总硫比值最大.实验结果显示,在进水COD/SO42-=2000/1500 mg/L、曝气开关时间为2 s/2 min、生化时间为10 h时,单质硫产率最大,为89.53％,SO42-浓度降至最低值72.7 mg/L,还原率达95.1％,此时脱硫效果较好.