Comparison of different combined treatment processes to address the source water with high concentration of natural organic matter during snowmelt period

The source water in one forest region of the Northeast China had very high natural organic matter(NOM) concentration and heavy color during snowmelt period. The efficiency of five combined treatment processes was compared to address the high concentration of NOM and the mechanisms were also analyzed. Conventional treatment can hardly remove dissolved organic carbon(DOC) in the source water. KMn O4pre-oxidization could improve the DOC removal to 22.0%. Post activated carbon adsorption improved the DOC removal of conventional treatment to 28.8%. The non-sufficient NOM removal could be attributed to the dominance of large molecular weight organic matters in raw water, which cannot be adsorbed by the micropore upon activated carbon. O3+ activated carbon treatment are another available technology for eliminating the color and UV254 in water. However, its performance of DOC removal was only 36.4%, which could not satisfy the requirement for organic matter. The limited ozone dosage is not sufficient to mineralize the high concentration of NOM. Magnetic ion-exchange resin combined with conventional treatment could remove 96.2%of color, 96.0% of UV254 and 87.1% of DOC, enabling effluents to meet the drinking water quality standard. The high removal efficiency could be explained by the negative charge on the surface of NOM which benefits the static adsorption of NOM on the anion exchange resin. The results indicated that magnetic ion-exchange resin combined with conventional treatment is the best available technology to remove high concentration of NOM.     

生物活性炭流化床净化采油废水的效能及特性

为了解决采油废水生化处理难度大、处理效率低等问题,采用颗粒活性炭为载体的内循环流化床反应器工艺在好氧条件下净化采油废水.利用果壳粒状活性炭为载体,投配率为15%时效果较好;最优化水力停留时间为5h.借助有机物的表征参数COD、UV₂₅₄、UV₄₁₀、有机酸以及GC/MS分析方法对该工艺净化采油废水中的有机物的能力进行了研究,结果表明,COD去除率在25%～45%之间波动,UV₂₅₄、UV₄₁₀和有机酸的平均去除率分别为85.9%、73.6%和51.5%,含油量去除率可达100%,但很难去除长链烷烃.研究还发现,由于采油废水中含有某些高浓度的无机离子,如Ca²⁺、Cl^-,占据了活性炭吸附活性中心,从而对活性炭吸附和降解有机物的性能产生不利影响;采油废水温度较高也是影响生物活性炭处理效果的一个因素.     

混凝-吸附处理黄河水及对氯消毒中氯衰减的影响

选用2种无机高分子混凝剂聚合氯化铁(PFC)和聚合氯化铝(PAC)处理黄河水,考察了混凝剂的投加量对浊度、UV254、DOC和高锰酸盐指数的去除效果,并结合混凝出水的Zeta电位分析其混凝机制.选择粉末活性炭与混凝联用,研究了混凝剂和吸附剂投加量以及二者的投加顺序对有机物去除效果的影响,并对混凝吸附后出水进行加氯消毒,考察水中残余氯随时间的变化.结果表明,2种混凝剂均有较高的浊度去除率(﹥90%).PAC对UV254、高锰酸盐指数和DOC的去除率分别为29.2%、26.1%和27.9%;PFC对三者的去除率分别为32.3%、23.3%和32.9%.PAC在混凝过程中,电中和作用占主导地位;PFC在混凝过程中,吸附架桥和电中和同时发挥作用.混凝-吸附联用处理黄河水样时,有机物的去除率随混凝剂和吸附剂投加量的增加而升高.先混凝后吸附工艺对UV254和DOC的去除效果优于先吸附后混凝工艺.先使用PAC混凝后吸附对UV254和DOC的去除率分别为95.2%和99.9%;对于PFC,先混凝后吸附对UV254和DOC的去除率分别为90.1%和99.9%.但是先投加粉末活性炭能提高矾花的沉降性能,且处理出水在保持持续消毒效果方面优于前者.     

长江原水臭氧-生物活性炭挂膜中试研究

为了探究面向长江水源的臭氧-生物活性炭深度处理工艺的挂膜技术,进行了长江原水常州段的臭氧-生物活性炭挂膜中试研究.结果表明,在挂膜前期,由于炭柱的物理吸附作用逐渐饱和,炭柱对DOC(溶解性有机碳)、UV_(254)和COD_(Mn)(高锰酸盐指数)的去除率逐渐降低,对氨氮几乎没有去除,在挂膜中后期,由于活性炭上生物膜逐渐成熟,生物降解起主导作用,有机物和氨氮去除率升高并趋于稳定.90 d后,炭柱对DOC、UV_(254)和COD_(Mn)这3个有机物指标的去除率分别稳定在30.64%、57.50%和30.00%以上,氨氮去除率稳定在88.93%左右,认为挂膜成功.扫描电镜图显示活性炭表面出现丰富的菌胶团,同时高通量测序也验证了活性炭中丰富多样的微生物群落结构.     

南水北调丹江口水库原水有机物分子组成规律及其强化混凝处理的效能对比

以取自南水北调中线工程的丹江口水库原水作为研究对象,考察了丹江口水库原水中有机物的分子量大小和亲疏水性分子组成规律,并确定了其所适用的强化混凝工艺条件.分离试验表明,丹江口原水中有机物主要以小分子量形式存在.其中,1 000组分的溶解性有机碳(DOC)和UV254所占比例最大,分别为39.98%和39.10%,且此区间还具有最高的三卤甲烷生成潜能(THMFP)和含氮消毒副产物生成潜能(N-DBPFP).亲疏水性方面,原水中弱疏水性组分含量最高,疏水性有机物的比例用DOC表征时超过80%.强疏水性组分含量最低但是强疏水性组分的THMFP最大,占总量的57.31%,而各组分的NDBPFP则相差不大.混凝试验表明,当采用聚合硫酸铁(PFS,4 mg·L-1)和聚丙烯酰胺(PAM,0.4 mg·L-1)处理丹江口原水时,强化混凝效果最好,可实现较为有效的去除浊度(76.33%)、DOC(25.57%)、UV254(37.78%)及THMFP(23.16%).本研究成果可为南水北调河南受水区既有水厂升级改造与工艺的优化运行提供有效的理论和技术支持.     

铁氮共掺杂生物炭对二级水溶解性有机物的吸附特性与长效性评价

为经济高效地去除污水厂二级水中溶解性有机物(DOM),采用铁氮共掺杂生物炭材料(Fe-N-C)作为新型吸附剂,系统分析了该新型碳材料对于二级水DOM的吸附性能、动力学过程、选择性和作用机制.此外,通过固定床吸附装置深入考察了该吸附材料的长效性和重复利用性.结果表明,Fe-N-C对于二级水DOM具有突出的吸附性能,投加量...     

混凝和活性炭吸附去除微污染水源水中DON的研究

溶解性有机氮(dissolved organic nitrogen,DON)作为饮用水中新兴氮消毒副产物(nitrogenous disinfection by-products,N-DBPs)的前体物逐渐受到国内外学者的关注.为探讨混凝和活性炭吸附对微污染水源水中DON的去除机制,首先测定原水中DON、溶解性有机炭(dissolved organic carbon,DOC)、NH4+-N、UV254、pH和溶解氧(dissolved oxygen,DO)等指标和DON、DOC分子量分布;接着通过混凝和活性炭吸附试验来考察原水中DON、DOC和UV254变化,并应用三维荧光光谱对原水中DON变化进行表征.结果表明,微污染水源水中DON、DOC和UV254分别为1.28 mg.L-1、8.56 mg.L-1和0.16 cm-1,DOC与DON比值(DOC/DON)为6.69 mg.mg-1,SUVA为1.87 m-1.(mg.L-1)-1;小分子量(<6 000)DON占较高比例约为68%,大分子量(>20 000)DON占的比例为22%;当混凝剂投加量为10 mg.L-1,DON的去除率大约为20%,DOC和UV254去除率约26%、70%;当活性炭投加量为1.0 g,DON、DOC和UV254的去除率大约为60%、35%、100%;混凝和活性炭吸附组合试验时,对DON、DOC的去除率大约为82%和64%;三维荧光光谱证实,原水中DON变化与3个主要峰有关,分别代表物质为色氨酸类蛋白质、芳香族类蛋白质和富里酸类物质.     

磁性离子交换树脂对原水中有机物去除效能的研究

采用磁性离子交换树脂(MIEX)预处理原水中有机物的中试试验结果表明,MIEX技术可有效地去除原水中的有机物,对UV254,DOC和CODMn的去除率分别稳定在82%、66%和50%,MIEX预处理可以有效强化混凝沉淀对有机物、藻细胞和浊度的去除.与常规工艺相比,在混凝剂聚合氯化铝投加量降低56%时,该工艺对UV254和CODMn的去除率分别为90%和71%,对藻细胞数和浊度的去除率分别为99%和95%.对溶解性有机物分级和分子量分布的测定表明,MIEX预处理主要去除混凝沉淀无法有效去除的小分子区间的亲水性和疏水性有机物,可以有效控制消毒副产物的产生,MIEX预处理与混凝沉淀联用工艺出水的三卤甲烷生成势(THMFP)和卤乙酸生成势(HAAFP)比原水降低了88%和87%.     

水源水消毒副产物生成势与UV254/DOC的相关性研究

使用XAD-4和XAD-8树脂对宜兴3个水源原水中DOM进行亲疏水性分类,采用优化方法测定分类水样的DBPFP,并进行DBPFP与DOM量化指标之间的相关性分析,以确定实际生产过程DBPs生成量的主要影响因素.由三维荧光光谱图得到3个水源原水DOM组成差异较大,水质区别明显.由亲疏水性分类分析发现原水中疏水性和亲水性DOM含量较高,疏水性DOM水样的DBPFP大于原水,得到水样的DBPFP主要取决于DOM与消毒剂反应产生DBPs的效率,而不是DOM的量.引入UV_(254)/DOC这个指标,发现不同分类水样UV_(254)/DOC的差异情况与其DBPFP相吻合,对两者进行回归分析,发现水样THMFP和DHAAFP与UV_(254)/DOC之间存在明显的线性关系,线性可决系数R2分别为0.89和0.85.因此研究减小原水UV_(254)/DOC的技术工艺对于控制给水中DBPs浓度具有重要意义.     

MIEX中试实验对二级出水中有机物去除的3DEEM解析

利用三维荧光光谱研究了磁性离子交换树脂（magnetic ion exchange resin,MIEX）对污水厂二级出水中有机物的去除特征.结果表明,磁性树脂处理二级出水过程中,两级反应过程和进水流量对DOC和UV254有较显著的去除效果,去除率分别达到25.5%～53.5%和27.6%～52.2%,其中50 L.h-1流量条件下,出水中DOC和UV254浓度分别为3.29 mg.L-1和0.057cm-1.水中芳香族蛋白质或酚类物质和类腐殖酸物质荧光强度较高,磁性树脂使二级出水中色氨酸类芳香族蛋白质、芳香族蛋白质、腐殖酸类荧光强度分别下降38.2%、85.8%和85.7%,腐殖酸和富里酸峰消失,并露出溶解性微生物代谢产物荧光峰.不同进水流量条件下,色氨酸类芳香族蛋白质荧光强度下降率和芳香族蛋白质或酚类物质荧光强度下降率与进水流量的负相关性最好,50～100 L.h-1流量条件对各类荧光物质的去除率影响最大.磁性树脂与二级出水中色氨酸类芳香族蛋白质和芳香族蛋白质或酚类物质有更好的线性置换关系（R2=0.834 8）,磁性树脂对二级出水中芳香族蛋白质或酚类物质的置换作用则最显著（a=850.2）.     

Removal of fluorescence and ultraviolet absorbance of dissolved organic matter in reclaimed water by solar light

Storing reclaimed water in lakes is a widely used method of accommodating changes in the consumption of reclaimed water during wastewater reclamation and reuse. Solar light serves as an important function in degrading pollutants during storage, and its effect on dissolved organic matter(DOM) was investigated in this study. Solar light significantly decreased the UV_(254) absorbance and fluorescence(FLU) intensity of reclaimed water.However, its effect on the dissolved organic carbon(DOC) value of reclaimed water was very limited. The decrease in the UV_(254) absorbance intensity and FLU excitation–emission matrix regional integration volume(FLU volume) of reclaimed water during solar light irradiation was fit with pseudo-first order reaction kinetics. The decrease of UV_(254) absorbance was much slower than that of the FLU volume. Ultraviolet light in solar light had a key role in decreasing the UV_(254) absorbance and FLU intensity during solar light irradiation. The light fluence-based removal kinetic constants of the UV_(254) and FLU intensity were independent of light intensity. The peaks of the UV_(254) absorbance and FLU intensity with an apparent molecular weight(AMW) of 100 Da to 2000 Da decreased after solar irradiation, whereas the DOC value of the major peaks did not significantly change.     

Effect of different molecular weight organic components on the increase of microbial growth potential of secondary effluent by ozonation

Ozonation has been widely applied in advanced wastewater treatment. In this study, the effect of ozonation on assimilable organic carbon （AOC） levels in secondary effluents was investigated, and AOC variation of different molecular weight （MW） organic components was analyzed. Although the removal efflciencies were 47%-76% and 94%-100% for UV2s4 and color at ozone dosage of 10 mg/L, dissolved organic carbon （DOC） in secondary effluents was hardly removed by ozonation. The AOC levels increased by 70%-780% at an ozone dosage range of 1-10 mg/L. AOC increased significantly in the instantaneous ozone demand phase, and the increase in AOC was correlated to the decrease in UV254 during ozonation. The results of MW distribution showed that, ozonation led to the transformation of larger molecules into smaller ones, but the increase in low MW （〈1 kDa） fraction did not contribute much to AOC production. The change of high MW （〉100 kDa and 10-100 kDa） fractions itself during ozonation was the main reason for the increase of AOC levels. Furthermore, the oxidation of organic matters with high MWs （〉 100 kDa and 10-100 kDa） resulted in more AOC production than those with low MWs （1-10 kDa and 〈1 kDa）. The results indicated that removing large molecules in secondary effluents could limit the increase of AOC during ozonation.     

微污染水源中溶解性有机氮组成规律及其水处理特性

以上海市黄浦江和青草沙长江原水为对象,研究了两大水源水中溶解性有机氮(DON)的含量变化、分子组成特征及其在常规净水工艺中的去除效果,并对DON与常规水处理指标间的相关性进行了分析.结果表明:两种原水以DOC、DON和UV254表征的有机物含量均以小分子量(<5kDa)和亲水性有机物为主;微污染黄浦江原水中同时存在外源性及内源性污染,而青草沙长江原水中内源性污染占主导地位;饮用水常规净水处理工艺对黄浦江原水中DON的去除率为40%,优于长江原水DON的去除率16.7%;黄浦江和长江原水DON浓度与DOC和UV254相关性良好,其相关系数分别为0.59,0.52和0.74,0.51;鉴于常规处理对DON去除效果有限,而DON是导致强三致特性含氮消毒副产物(N-DBPs)的总前体物,因此水厂应通过强化常规、深度处理等手段改善DON在净水工艺中的去除效果.     

Evaluation of drinking water treatment combined filter backwash water recycling technology based on comet and micronucleus assay

Based on the fact that recycling of combined filter backwash water（CFBW）directly to drinking water treatment plants（WTP）is considered to be a feasible method to enhance pollutant removal efficiency,we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems,one with recycling of combined backwash water,the other one with a conventional process.An integrated approach of the comet and micronucleus（MN）assays was used with zebrafish（Danio rerio）to investigate the water genotoxicity in this study.The total organic carbon（TOC）,dissolved organic carbon（DOC）,and trihalomethane formation potential（THMFP）,of the recycling process were lower than that of the conventional process.All the results showed that there was no statistically significant difference（P>0.05）between the conventional and recycling processes,and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial.It was worth noting that there was correlation between the concentrations of TOC,DOC,UV₂₅₄,and THMFPs in water and the DNA damage score,with corresponding R² values of 0.68,0.63,0.28,and 0.64.Nevertheless,both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units,which meant that the disinfection by-products（DBPs）formed by disinfection could increase the DNA damage.Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk,compared to the traditional process.     

Effect of algal flocculation on dissolved organic matters using cationic starch modified soils

Modified soils(MSs) are being increasingly used as geo-engineering materials for the sedimentation removal of cyanobacterial blooms. Cationic starch(CS) has been tested as an effective soil modifier, but little is known about its potential impacts on the treated water.This study investigated dissolved organic matters in the bloom water after algal removal using cationic starch modified soils(CS-MSs). Results showed that the dissolved organic carbon(DOC) could be decreased by CS-MS flocculation and the use of higher charge density CS yielded a greater DOC reduction. When CS with the charge density of 0.052, 0.102 and0.293 meq/g were used, DOC was decreased from 3.4 to 3.0, 2.3 and 1.7 mg/L, respectively.The excitation–emission matrix fluorescence spectroscopy and UV254 analysis indicated that CS-MS exhibits an ability to remove some soluble organics, which contributed to the DOC reduction. However, the use of low charge density CS posed a potential risk of DOC increase due to the high CS loading for effective algal removal. When CS with the charge density of 0.044 meq/g was used, DOC was increased from 3.4 to 3.9 mg/L. This study suggested, when CS-MS is used for cyanobacterial bloom removal, the content of dissolved organic matters in the treated water can be controlled by optimizing the charge density of CS. For the settled organic matters, other measures(e.g., capping treatments using oxygen loaded materials) should be jointly applied after algal flocculation.     

某微污染水源自来水厂的纳滤深度处理效果研究

采用一级四段纳滤组合工艺处理南方某微污染水源自来水厂的传统净水工艺段出水,考察了纳滤膜工艺对出水水质的提升效果.结果表明,纳滤对常规水质指标与微量有机物有较好的去除效果,对混凝沉淀池出水中TOC和UV_(254)的去除率在95%以上(出水TOC≤0.3 mg·L~(-1),UV254≤0.005 cm~(-1));对卤乙酸、三卤甲烷前体物、多环芳烃和有机氯农药的截留率分别在62%、85%、50%和95%左右,使用UMU-SOS测试的出水遗传毒性低于检出限,不同段纳滤膜对相对分子质量较大的消毒副产物前体物与有机氯农药的去除率未呈现明显差异,但对相对分子质量较小的多环芳烃去除效果呈现明显差异,表明纳滤主要依靠物理截留去除水中相对分子质量较大的有机物,对相对分子质量较小的有机物则存在较大的局限性.与之相比,水厂目前使用的双级臭氧-生物活性炭深度处理工艺对传统净水工艺出水中多环芳烃、有机氯农药、遗传毒性的去除截留率分别仅为17%、62%、80%左右,显示纳滤对微量有机物的去除效果更为理想.     

Removal of microcystin-LR from drinking water using a bamboo-based charcoal adsorbent modified with chitosan

The bamboo charcoal adsorbent modified with chitosan can effectively remove microcystin-LR from drinking water.     

Removal natural organic matter in typical south-China source water during enhanced coagulation of a with IPF-PACl

Systematic investigation on enhancing removal of natural organic matter （NOM） using inorganic polymer flocculant （IPF）, polyaluminum chloride（PACI） and polyacrylamide（PAM） was performed in a typical south-China source water. Enhanced coagulation and applying polymer flocculant-aid were compared through jar tests and pilot tests. Raw water and settled water were characterized and fractionated by resin adsorption. The results show that DOC composes major part of TOC. The DOC distribution keeps relatively stable all around the year with typical high amounts of the hydrophilic matter around 50%. The distribution between HoB, HoA and HoN varies and undergoes fluctuation with the year round. During the summer season, the HoN becomes gradually the major part in hydrophobic parts. PACI with the species being tailor-made shows little pH effect during coagulation. The enhanced coagulation dosage for PACI could be 4.5 mg/L for the typical source water. The highest TOC removal achieved 31%. To be economically, 3 mg/L dose is the optimum dosage. Although hydrophilic fractions of NOM of both treatment strategies are removed about 30%, NOM causing UV254 absorbance were well removed（about 90%）. Hydrophobic bases and acids fractions are much more removed under enhanced conditions. The hydrophilic fraction could be better removed using PAM, the polymer coagulant aid.     

Dissolved organic matter removal using magnetic anion exchange resin treatment on biological effluent of textile dyeing wastewater

This study investigated the removal of dissolved organic matter（DOM） from real dyeing bio-treatment effluents（DBEs） with the use of a novel magnetic anion exchange resin（NDMP）.DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight（MW）（〈3 kDa） DOM fractions constituted a major portion（〉50%） of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254absorbance（SUVA254）,and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon（DOC） removal via NDMP treatment was performed by comparing it with that of particle active carbon（PAC）. Results indicated that the removal of DOC from DBEs via NDMP was 60%,whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC,NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants,with selected concentrations of 10% NaCl（m/m）/1%NaOH（m/m）,could improve desorption efficiency.     

Drinking water production by ultrafiltration of Songhuajiang River with PAC adsorption

In recent years, membrane ultrafiltration （UF） of surface water for drinking water treatment has become a more attractive technology worldwide as a possible alternative treatment to conventional clarification. To evaluate the performance of ultrafiltration membranes for treatment of surface water in North China, a 48-m^2 low pressure hollow fiber membrane ultrafiltration pilot plant was constructed. Ultrafiltration was operated in cross-flow and with powdered activated carbon （PAC） adsorption. Turbidity was almost completely removed to less than 0.2 NTU （below Chinese standard 1 NTU）. It was found that PAC addition enhanced organic matter removal. The combined process of PAC/UF allowed to 41% removal of CODMn, 46% removal of DOC and 57% decrease in UV254 absorbance. The elimination of particles, from average 12000/ml in the raw water to approximately 15/ml in the permeated, was observed. When PAC concentration was below 30 mg/L, backwashing could recovery the membrane flux with backwash interval/backwashing duration of 1/30.