Sulphur transformation and deposition in the rhizosphere of Juncus effusus in a laboratory-scale constructed wetland

Sulphur cycling and its correlation to removal processes under dynamic redox conditions in the rhizosphere of helophytes in treatment wetlands are poorly understood. Therefore, long-term experiments were performed in laboratory-scale constructed wetlands treating artificial domestic wastewater in order to investigate the dynamics of sulphur compounds, the responses of plants and nitrifying microorganisms under carbon surplus conditions, and the generation of methane. For carbon surplus conditions (carbon:sulphate of 2.8:1) sulphate reduction happened but was repressed, in contrast to unplanted filters mentioned in literature. Doubling the carbon load caused stable and efficient sulphate reduction, rising of pH, increasing enrichment of S(2-) and S(0) in pore water, and finally plant death and inhibition of nitrification by sulphide toxicity. The data show a clear correlation of the occurrence of reduced S-species with decreasing C and N removal performance and plant viability in the experimental constructed wetlands.     

Growth Inhibition by Nitrocompounds of Selected Uric Acid-Utilizing Microorganisms Isolated from Poultry Manure

The overall objective of this study was to evaluate the potential ability of nitrocompounds to reduce ammonia volatilization by inhibiting uric acid–utilizing microorganisms. Experiment I was conducted to evaluate the effects of nitrocompounds on the growth of uric acid–utilizing microorganisms isolated from poultry manure during six-hour incubation. There were five treatments: (1) control, (2) 50 mM nitroethane, (3) 50 mM nitroethanol, (4) 50 mM nitropropanol, and (5) 50 mM nitropropionic acid. Optical density values of nitrocompounds were significantly lower than that of control at two, four, and six hours. Plate counts of uric acid–utilizing microorganisms after six-hour incubation exhibited that nitrocompounds greatly reduced the growth of these microorganisms except for the nitroethane (P < 0.05). The nitropropanol and nitropropionic acid treatments showed significantly higher inhibitory effects compared to the nitroethanol. Experiments II and III were conducted to evaluate inhibitory effects of nitrocompounds on growth of uric acid–utilizing microorganisms compared to non-nitrocompounds such as ethanol, propanol, and propionic acid. Experiments II and III consisted of seven treatments: (1) control, (2) nitroethanol, (3) nitropropanol, (4) nitropropionic acid, (5) ethanol, (6) propanol, and (7) propionic acid. The incubation times of Experiments II and III were 6 and 24 h, respectively. The nitrocompounds were significantly more successful in inhibiting growth of uric acid–utilizing microorganisms compared to those non-nitrocompounds. These results suggest that nitrocompounds exhibit potential to reduce ammonia volatilization in poultry manure by inhibiting growth of uric acid–utilizing microorganisms.     

The Effects of Magnesium and Ammonium Additions on Phosphate Recovery from Greenhouse Wastewater

Phosphorus recovery from greenhouse wastewater, using precipitation-crystallization, was conducted under three levels of calcium concentration, 304 mg/L (7.6 mmol/L), 384 mg/L (9.6 mmol/L), and 480 mg/L (12 mmol/L), and also with additions of ammonium and magnesium into the wastewater. Jar test results confirmed high phosphate removal, with more than 90% of the removal achieved with a pH as low as 7.7. Under the low calcium concentration, ammonium addition affected the chemical reactions at pH lower than 8.0, where struvite was produced; when the pH was raised to 8.8, other calcium compounds dominated the precipitation. Under the medium calcium concentration, ammonium and magnesium addition helped struvite precipitation in the low pH range. Hydroxyapatite (HAP) was the main product. Under the high calcium concentration, ammonium addition showed no effects on the precipitation.     

工业烟气氨排放特征及其对颗粒物污染形成影响

氮氧化物（NO_X）超低排放控制背景下,工业烟气氨（NH₃）逃逸问题被广泛关注。为探究重点行业NH₃逃逸现状及其对空气质量的影响,本研究于2022年3—6月针对江苏省7个重点行业烟气NH₃排放进行了监测,并针对NH₃逃逸严重的4条生产线测试其可凝结颗粒物（CPM）的排放特征。研究结果显示,68家企业的NH₃排放质量浓度为0.7～65.4 mg/m³,热电、日用玻璃行业的NH₃逃逸问题突出,其NH₃平均质量浓度分别为37.4,39.2 mg/m³。采用选择性非催化还原（SNCR）脱硝设施的工业烟气NH₃排放质量浓度分别是采用选择性催化还原（SCR）和SNCR+SCR联合技术的2.36,1.42倍;NH₃逃逸现象严重的生产线的排气筒出口处CPM质量浓度达到717～1 322 mg/m³,抵消了脱硫、脱硝和除尘带来的减排效果,对细颗粒物（PM_2.5）污染有直接贡献。研究结果可对我国二次颗粒物来源与治理方向提供支撑。     

氨精制产品质量影响因素及改进措施

阐述了浓氨水循环洗涤法脱硫工艺原理，原则流程，开工、运行过程中存在的问题及解决方案，影响液氨产品质量因素及采取的措施，以及对原林源石化公司含硫法水汽提-氨精制系统不足提出的改进建议。     

折光率法和电导率法测定稀土废水中氯化铵

阐述了折光率法与电导率法测定稀土废水中高浓度氯化铵的原理和方法.在恒温和低悬浮物浓度条件下,折光率与氯化铵质量浓度线性关系良好;当保持外界条件不变时,氯化铵质量浓度在5 000 mg/L～60 000 mg/L与电导率显著相关.经t检验,两种方法与银量法差异均不显著,且操作简单,准确快速,适用于水处理过程中的现场实时监测.     

博物馆室内微环境中碱性气体的被动采样方法研究

针对博物馆微环境中的碱性污染气体-氨气,采用自行研制的被动采样器,建立了一套适合博物馆馆藏文物保存环境中氨气含量分析的被动采样-离子色谱检测方法,应用于博物馆的实地采样分析,通过与主动法采样对照,获得了被动采样器在博物馆微环境中氨的吸收系数,从而获得采样点空气中氨气的浓度,为博物馆文物保存环境监测提供了可行方法。