Nitrogen Removal in Wastewater Irrigation Systems and Its Influence on Groundwater Pollution

The experiment included ten soil columns and field investigation in 1 - 2 year duration. Data on the columns continuously flooded with waste water indicated that when total input of NH4-N reached to above 70% of the NH4-N adsorption capacity in soil the breakthrough would appear in the output . Adequate removal of nitrogen from the waste water would require at least 170 cm deep groundwater table . Fine textured soil would promote denitrification . The columns simulating discontinuous waste water irrigation indicated that denitrification existed only in the partial microenvironment of reduction .Groundwater table depth had no strong influence on nitrogen removal . The investigation in field revealed that the groundwater recharged with waste water was not polluted by nitrogen when the aeration profile was in finer textures owing to the combined contribution of nitrification and denitrification .

Occurrences of Glucocorticoids in Aquatic Environment and Their Removal during Wastewater Treatment

Glucocorticoids(GCs) are a group of endocrine-disrupting compounds(EDCs) frequently prescribed against various medical conditions.Recently,GCs have been shown to be effective in managing septic shock in patients infected with the 2019 novel coronavirus(COVID-19).Due to colossal consumption and potential risks to aquatic organisms,GCs have immensely attracted the focus of the scientific research community as a water pollutant.Therefore,the aim of this paper is to review the current knowledge on the occurrence of various GCs in the aquatic environment and their removal during wastewater treatment.A variety of GCs are ubiquitous in surface water,hospital wastewater,and sewage water worldwide.And the minimum concentration in volume is below 0.01 ng/L,and the maximum one is 10 000 ng/L,and enter the environment through hospital and urban wastewater discharging.Compared with natural GCs,higher risks to aquatic environments could be induced by synthetic GCs.The current activated sludge processes used in wastewater treatment plants(WWTPs) are not fully effective in eliminating GCs,some of which may further increase the risk of GC in the environment.In comparison with the aerobic process in WWTPs,the anaerobic and anoxic processes were found to be more efficient for GC degradation.Of the studied GCs,fluticasone propionate,clobetasol propionate,fluocinolone acetonide,and triamcinolone acetonide need more attention due to their low removal efficiencies and strong toxicity.Among the advanced treatment processes,reverse osmosis,ultraviolet irradiation,CaO_(2),and plasma could achieve significant GC activity removal while micro/ultra-filtration,chlorination,and ozonation were less efficient.

焦化废水中痕量苯并(a)芘的固相萃取和GC-MS检测方法

为了解决焦化废水中痕量苯并(a)芘含量过高的问题,需要对苯并(a)芘含量进行高精度检测,基于此,本文利用固相萃取对苯并(a)芘进行提取,利用气相色谱/质谱方法,建立了一套分析流程。首先将1%的有机改性剂羟甲烷加入苯并(a)芘的水样中,然后用固相萃取纯化,再用CH2Cl2洗脱。最后,采用氮气吹入浓度法和定容法进行了GC-MS分析。该方法具有较高的准确度和精密度,可用于焦化废水中痕量苯并(a)芘的定量检测,以期为相关人员提供参考。

Petrochemical wastewater treatment with a pilot-scale bioaugmented biological treatment system

In solving the deterioration of biological treatment system treating petrochemical wastewater under low temperatures, bioaugmentation technology was adopted by delivering engineering bacteria into a pilot-scale two-stage anoxic-oxic (A/O) process based on previous lab-scale study. Experimental results showed that when the concentrations of COD and NH4+-N of the influent were 370~910 mg/L and 10~70 mg/L, the corresponding average concentrations of those of effluent were about 80 mg/L and 8 mg/L respectively, which was better than the Level I criteria of the Integrated Wastewater Discharge Standard (GB8978-1996). According to GC-MS analysis of the effluents from both the wastewater treatment plant (WWTP) and the pilot system, there were 68 kinds of persistent organic pollutants in the WWTP effluent, while there were only 32 in that of the pilot system. In addition, the amount of the organics in the effluent of the pilot system reduced by almost 50% compared to that of the WWTP. As a whole, after bioaugmentation, the organic removal efficiency of the wastewater treatment system obviously in- creased.

Treatment of pharmaceutical wastewater containing recalcitrant compounds in a Fenton-coagulation process

The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.

Rgwo performances of submerged membrane bioreactor treating brewery wastewater: A laboratory study

Performances of submerged membrane bioreactor (SMBR) treating brewery wastewater were investigated in this study. With little variation of COD:TN:TP ratio (100:5:1) in influent, SMBR showed high removal efficiency (>90%) for both COD and NH4^+-N, and it also showed a strong resistive ability for shock organics loading rate, evidenced by no obvious fluctuation for COD in the effluent when the organics loading rate suddenly increased from 0.27 g/(gMLSS·d) to 0.54 g/(gMLSS·d). Comparatively different with the COD removal, TN and TP removal showed a strong correlation with the growth stage of the sludge in SMBR. When the sludge was in the multiplication stage, about 45% of TN was removed and an average removal efficiency of 30% for TP was also observed. However, when the activated sludge was in the steady stage, the removal efficiency for TN decreased to about 30%, whereas, the removal efficiency for TP was very low, and sometimes even below zero. The results of GC/MS indicated that the residual organic matters in the effluent were mainly alkyl hydrocarbon with high molecular weight, and coupling with the results of electroscopic scanning, it is speculated that biomass formed at external and internal membrane fibers played an important role for the removal of small organics.

Advanced Treatment of Biologically Treated Chemical Comprehensive Wastewater by Nano-TiO2 Photocatalytic Oxidation

Nano-TiO2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.

生物流化床A/O^2工艺处理焦化废水过程中有机组分的GC/MS分析

在自行设计的2000m·3d-1规模的生物流化床A/O2工艺中,以实际焦化废水为研究对象,采用GC/MS法分析各单元工艺的有机物组分,解析了污染物的降解规律.结果发现,焦化废水中酚类物质占有机物总量的90%以上;厌氧阶段对废水COD的去除率为10%~15%,主要为大分子复杂有机物分解为有机酸、有机醇类,此过程使废水BOD/COD值由0.30提高到0.45;一级好氧阶段可去除大部分的酚、胺、喹啉、吡啶、呋喃、吲哚、萘等组分,COD的去除率达到65%~70%;二级好氧阶段的COD去除率为40%~50%.间甲苯酚、哌嗪、哌啶、长链烃类、苯类等在生物处理出水中可被检出,属于难降解成分,有必要对其进行深度处理.采用TTC脱氢酶法测试了不同工艺段废水对酶活的影响,在相同的TOC浓度时,厌氧出水和一级好氧出水的酶活达26~29μg·h-1,滤池出水的酶活为几个工艺段水质的最低值7.02μg·h-1,显示其中可被微生物利用的有机物急剧减少.

抗生素废水的GC-MS分析与显色物质的初步确定

为确定抗生素废水中有机污染物构成和显色物质,以二氯甲烷为萃取剂,萃取废水中的有机物,经过浓缩纯化后,利用气相色谱质谱联用(GC-MS)技术对制药废水中的有机成分进行了分析鉴定,结合计算机质谱图库,定性确定了废水中60种有机污染物。其中,脂类为主要污染物成分,经对脱色后的废水进一步GC-MS分析后,初步确定油酸甲酯为此类抗生素废水的主要显色有机物。

GC-MS分析印染废水处理中有机污染物的降解特性

印染废水水量大、成分复杂、污染物浓度高,属于难处理的工业废水之一.以浙江某污水处理厂各处理单元废水为研究对象,应用气相色谱-质谱联用仪(GC-MS)分析了印染废水处理中有机物的降解过程.结果表明,初沉池、二沉池、终沉池水样中分别含有50、40、30种有机物,其中三氯甲烷、1,2-二氯乙烷、1,1,2-三氯乙烷等8种有机物属于环境优先控制污染物;筛选出苯乙酮、三氯甲烷、2-氯-2-甲基丁烷等5种物质作为印染废水的特征污染物.该结果对印染废水的处理与回用具有重要的意义.

GC-MS法同时测定壬基酚聚氧乙烯醚短链生物降解产物

采用固相萃取-气相色谱-质谱联用法，研究了污水中壬基酚聚氧乙烯醚短链生物降解产物NP、NP、EO、NP2EO同时定量检测的方法；优化了相关色谱条件和选择定量离子。结果表明，当进样量为4μL，进样口温度为320℃时，可获得较高的色谱响应值，改善了方法的检测灵敏度；选用多个质谱特征离子进行定量分析，各种降解产物的选择离子色谱图响应值占总离子流色谱图响应值的70％左右，较准确地反映了各产物不同同分异构体的组成。该方法的相对标准偏差小于5％，NP2EO加标回收率在98．34％-101．40％之间；采用该方法对实际污水样品进行了分析，结果表明重现性较好，精密度和准确度均满足痕量分析的要求。

肝素提取废水的GC-MS分析和处理研究

肝素钠废水含有高浓度无机盐和大量有机污染物,对环境具有潜在的毒性且难以处理,已经受到环境工作者的关注。为了了解废水的主要成分和处理此类废水,本实验用GC-MS对废水进行了分析,并且利用芬顿试剂对其进行了处理,结果发现废水中有机物有26种,其中脂肪酸和芳香衍生物占有较大比例,处理后,有机成分只有3种;讨论了影响处理效果的因素和最佳的工艺条件,发现当pH值为6.66,硫酸亚铁和过氧化氢的量分别为2.5 g/L和2.8‰(v/v),搅拌速度为2000 r/min,搅拌时间为15 min时,COD的去除率可达到94.50%。

用GC／MS联用分析焦化厂蒸氨废水中的有机物组成

本文对焦化厂蒸氨废水进行了ＧＣ和ＧＣ／ＭＳ联用分析，共鉴定了１４种有机物，其中主要有机物是酚类、吲哚和喹啉，分别占有机物总量的３９５％、２３９％和１７８％。

吹扫捕集—GC—MS测定废水中的硝基氯苯

建立了吹扫捕集-GC—MS测定水样中硝基氯苯类化合物的方法。考察了吹扫温度、吹扫时间等对吹扫捕集效率和方法检出限的影响。在室温下，当吹扫时间为30min时，该方法的最低检出限可达0．002mg／L，工作曲线的线性范围为2×10^-3～2mg／L，相对标准偏差在2％～6％，加标回收率在97．0％～110．0％。与国家标准方法相比，该法具有操作简便、灵敏度高、线性范围宽且无须使用有毒有机溶剂等优点，可满足工业废水和地表水中硝基氯苯的测定要求。

化纤厂棉浆粕废水中有机污染物的GC-MS分析

化纤厂棉浆粕废水在酸性条件下经乙醚萃取———Kuderna-Danish(K-D)浓缩器浓缩,采用气相色谱-质谱(GC/MS)联用仪对其有机污染物进行了分析研究。结果表明,在该废水中检测出14种有机物,主要污染物为有机酸类,占有机物总量的35.19%。其次为酯类和酮类,分别占有机物总量的30.03%和19.68%。此外,浆粕废水中还检测出二苯胺和环境优先污染物苯酚,分别占有机物总量的7.85%和5.42%。

GC-MS用于测定造纸废水中的多环芳烃

研究了不同前处理手段和测试条件对气相色谱质谱联用仪(GC-MS)测定造纸废水中多环芳烃(PAHs)持久性有机污染物的影响。经对比,最优测试条件为选用DB-5作为GC-MS毛细管色谱柱,选用二氯甲烷作为萃取剂,萃取时间30 min,同时加入1.0 g NaCl作为盐析剂,机械振荡20 min。

顶空-GC/MS法同时测定废水中16种挥发性酮、醇、酯、腈类化合物

为了准确分析挥发性酮、醇、酯、腈类化合物在废水中的残留情况,建立了顶空-气相色谱-质谱法测定废水中16种挥发性酮、醇、酯、腈类化合物的方法,选用DB-624(30m×0.32mm×1.8μm)毛细管柱,在柱流速1.5mL/min条件下,采用电子轰击电离源,全扫描定性,选择离子进行外标法定量。结果表明16种化合物线性良好,相关系数r>0.995。当废水取样量为10.0L时,方法检出限为0.04～0.95mg/L,在3个不同加标水平下,实际废水样品中16种化合物的相对标准偏差为0.32%～7.61%,加标平均回收率为89.2%～118%。本方法可快速、准确测定废水样品中的16种挥发性酮、醇、酯、腈类化合物。