Moringa oleifera seeds as a flocculant in waste sludge treatment

In this study the results of a laboratory based investigation to determine the effectiveness of Moringa oleifera seeds as a flocculant for activated sludge treatment are presented. Waste sludge samples are activated sludge from Taman Dr. Tun. Ismail Activated Sludge Wastewater Treatment plant, Kuala Lumpur, Malaysia. Moringa oleifera seed was applied as dry powder (shelled blended), solution (shelled blended), and solution (shelled blended oil extracted). Results of vacuum filtration studies showed that residual sludge volume of up to 11%, 20% and 45% for shelled blended oil extracted, shelled blended, and control (no Moringa applied), respectively, was achievable. Sludge volume reduction of up to 67% was achievable using gravity settling for shelled blended solution and 48% for shelled blended oil extracted respectively compared to the control. The shelled blended category applied in powder form performed the same as the solution of shelled blended but performed better than the shelled blended oil extracted category in gravity settling. The specific cake resistance of sludge treated with shelled blended Moringa oleifera averaged 2.5 x 10¹²m/kg at 4000mg/l dosage. Vegetable oil from the shelled Moringa oleifera of up to 30% was obtained as a by product.     

Floc settling characteristics of turbid water coagulated with moringa oleifera seeds

The results of studies into the particle aggregations and settling rates of flocs from turbid water (kaolin suspension) with turbidities varying from 50 to 550 NTU coagulated with Moringa oleifera seeds are presented. The results of the laboratory based study showed that the maximum value of the “apparent aggregation rate”, K _app,increased with increase in initial turbidity. K _app was found to be 0.000778 for low turbidity (50 NTU) and 0.00654 for high turbidity (550 NTU). The velocity gradient for rapid mix at the maximum K _app was found to be constant at 443/sec for all turbidities. Settling rate of floc coagulated with Moringa oleifera seed was dependent on the initial turbidity of the water sample. For water with initial turbidity of 50 NTU, 30% to 70% turbidity was removed between 60 and 210 minutes, while for high turbidity of 400 to 550 NTU, 80% to 95% turbidity removal occurred between 60 and 150 minutes.     

Coagulation of turbid water and softening of hardwater with Moringa oleifera seeds

In this study, the effects of 5 process variables on softening hardwater and coagulation of surface water with a M. oleifera seed extract were investigated. Multiple regression analysis showed a strong correlation (R² (adj.) = 0.99 between M. oleifera seed dosage and the initial hardness of synthetic hardwater. Since M. oleifera is known to be a polyelectrolyte, the softening mechanism is likely to be adsorption. An adsorption isotherm developed was approximately linear and conformed to the Langmuir type. For the coagulation studies, the water samples were from three rivers in Kano, Nigeria over a three month period during the rainy season (June‐August 1994). The turbidity of the water sample varied from 105–350 NTU. When used as primary coagulant, M. oleifera was able to achieve up to 99% turbidity removal for two of the water samples at the optimum dosage of 250 mg/l. For the third water sample, the optimum dosage was 450 mg/l which is assumed to be due the high value of the colour of the water. Saving in alum usage of up to 40% was achievable when M. oleifera was used in conjunction with alum.     

PDM复配PAC用于冬季低温低浊长江水降浊研究

该文报道了用有机阳离子高分子聚二甲基二烯丙基氯化铵（PDM）与聚合氯化铝（PAC）现场复配用于冬季低温低浊长江水的脱浊处理研究过程。通过混凝烧杯实验,考察了药剂投加量及PAC与PDM的复配配比对低温低浊长江水脱浊效果的影响。结果表明,对温度为8℃左右,浊度在50NTU以下的长江水,在与南京某水厂相近的混凝搅拌条件下,达到南京某水厂6NTU沉淀出水浊度标准时,PAC需1．28mg／L的投加量,而PDM特征粘度分别为0．48、1．46、2．56dL／g的复配药剂随PAC／PDM复配比例50：1,20：1,10：1的变化分别需1．15～1．00mg／L,1．24～1．14mg／L,1．20～1．10mg／L的投加量,相对于PAC单独处理分别能减少10．15％～21．87％、12．68％～19．72％、11．76％～19．12％。因此,PDM助凝效果明显,同时PAC与PDM的复配配比越低,复配混凝剂混凝脱浊效果越好,PDM特征粘度对复配混凝剂用于冬季长江水的处理的影响不大,但可使絮团明显增大,提高沉淀性能。采用PDM复配混凝剂处理低温低浊长江水,能提高出水水质,减少无机铝盐加量,增强了供水安全性,在长江流域冬季实际生产中具有较强的实用性。     

四段式生物接触氧化池预处理微污染珠江原水研究

利用广州市白鹤洞水厂闲置的一组回转式隔板絮凝池，通过加装填料和曝气设备构建了四段式生物接触氧化池，并采用其预处理微污染珠江原水。结果表明，该工艺对NH3-N、CODMn和浊度的去除效果良好，末段出水的NH3-N、CODMn和浊度平均值分别为0．41mg／L、3．41mg／L、16．5 NTU，相应的平均去除率分别为92．03％、47．85％和61．09％。该工艺对氨氮的去除较为高效，是处理高氨氮微污染原水的一种有效方法。     

The perils of foreign intervention: the Nile perch disaster for Lake Victoria

The present study involved the use of a pilot scale water treatment plant to treat turbid surface water from a stream using processed Moringa oleifera seed and alum as primary coagulants. At low initial turbidity of 21.5 to 49.3 NTU, residual turbidities of 2.7, 1.8 and 1.4 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For medium turbidities varying from 51.8 to 114 NTU, lowest residual turbidities of 2.9, 1.2 and 1.4 were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. For high turbidity varying from 163 to 494 NTU, minimum residuals of 1.4, 1.9 and 0.9 NTU were achieved after treatment using Moringa oleifera, alum, and alum with Moringa oleifera as coagulant‐aid, respectively. The proposed mechanism for turbidity removal by Moringa oleifera seed in this study is a combination of partial‐charge neutralization and micro‐bridging or an electrostatic patch mechanism based on the results of zeta potential measurements.     

呼延水厂低温低浊水的絮凝试验研究

针对太原市呼延水厂出水浊度不达标的问题进行了絮凝试验研究.结果表明:该厂原水属低温低浊水,有机胶体较多,絮凝效果差,其根本原因是絮凝剂投量不足.进一步的试验表明:以聚合氯化铝(PAC)为絮凝剂、以活化硅酸为助凝剂,除浊效果较好;活化硅酸的投加时间对絮凝效果有较大的影响,以快速混合用时1min、聚合氯化铝投量为15 mg/L、延迟30 s后投加0.5～1mg/L的活化硅酸(以SiO2,计)为最佳运行条件;滤池反冲洗排水回流至配水井有利于低温低浊水的处理,并可节省絮凝剂或助凝剂的投量.     

二次通用旋转组合设计下磁絮凝工艺处理河道水效果

在实验室运用二次通用旋转组合设计研究苏州河道水处理工艺,系统分析了磁絮凝工艺处理苏州河道水的四个影响因素(PAC投加量、PAM投加量、磁粉投加量、沉淀时间)对磁絮凝效果的影响效应。并运用方差分析、回归模型方程分析、单因子效应分析以及双因素交互效应分析,得出最佳工况为PAC投加量15 mg/L、PAM投加量0.58 mg/L、磁粉投加量2.7 mg/L、沉淀时间2.1 min,此时理论上浊度可达到0.73 NTU,浊度去除率为97.2%,用此参数进行试验,得到实际浊度为0.82 NTU,实际浊度去除率可达96.9%。     

强化活性炭滤池过滤性能的试验研究

采用在活性炭滤池前端投加不同药剂的方法深度净化某水厂沉淀池出水,考察了不同滤池形式、聚合氯化铝(PAC)投加量和阳离子型聚丙烯酰胺(PAM)投加量对沉后水浊度的去除效果。结果表明,在下向流滤池前端投加0.3 mg/L的PAC和0.03 mg/L的PAM可以明显强化活性炭滤池的过滤效果,使出水浊度小于0.1 NTU;与砂滤池出水相比,活性炭滤池对浊度的去除率提高了16.6%,CODMn去除率提高了56%;相应的滤池水头损失增加较快,但仍可以满足运行周期不小于24 h的设计要求;滤后水中铝和溴酸盐含量均满足《生活饮用水卫生标准》(GB 5749—2006)要求。     

杭州市南星水厂O3/BAC工艺的运行效果分析

杭州市南星水厂深度处理一期工程采用预臭氧、常规处理、后臭氧、生物活性炭工艺。结合生产性试验确定了预臭氧及后臭氧段的臭氧投量分别为0．30～0．60mg／L和1．50～1．70mg／L。工程投产后的运行结果表明：O、／BAC工艺对微污染源水的处理效果良好，对浊度、CODM。NH4^＋-N、NO2^--N的去除率分别为99．2％、（57％～77％）、（61％～99．7％）、（-25％～99．74％），出水浊度〈0．2NTU、色度〈3倍，CODMn、NH4^＋-N、NO2^-N分别为0．48～1．57mg／L及0．237、0．053mg／L以下；季节对O3／BAC工艺的净化效果影响较大，春、夏、秋季的除污效果较好，冬季的相对较差。深度处理工艺的制水成本为0．561元／m^3，较常规工艺的（0．447元／m^3）仅增加约0．114元／m^3。     

Isolation and characterization of coagulant extracted from Moringa oleifera seed by salt solution

It is known that M. oleifera contains a natural coagulant in the seeds. In our previous research, the method using salt water to extract the active coagulation component from M. oleifera seeds was developed and compared with the conventional method using water. In this research, the active coagulation component was purified from a NaCl solution crude extract of Moringa oleifera seeds. The active component was isolated and purified from the crude extract through a sequence of steps that included salting-out by dialysis, removal of lipids and carbohydrates by homogenization with acetone, and anion exchange. Specific coagulation activity of the active material increased up to 34 times more than the crude extract after the ion exchange. The active component was not the same as that of water extract. The molecular weight was about 3000 Da. The Lowry method and the phenol-sulfuric acid method indicated that the active component was neither protein nor polysaccharide. The optimum pH of the purified active component for coagulation of turbidity was pH 8 and above. Different from the conventional water extracts, the active component can be used for waters with low turbidity without increase in the dissolved organic carbon concentration.     

混凝沉淀/PAC吸附/超滤工艺处理引黄水库冬季原水

采用混凝沉淀/粉末活性炭吸附/超滤工艺(简称PAC-UF工艺)处理黄河下游引黄水库冬季原水,中试结果表明:当处理冬季低温低浊水时,聚合氯化铝的最佳投量为6 mg/L,粉末活性炭的最佳投量为20 mg/L;PAC-UF工艺可以将出水的浊度控制在0.1 NTU以下,去除率达98%以上;投加20 mg/L的粉末活性炭能使混凝沉淀/UF工艺对COD_(Mn)和UV_(254)的平均去除率分别提高12%和15%;同时,投加粉末活性炭还能够缓解超滤膜的不可逆污染,但缓解的程度有限.     

新型车载式除油装置在江汉油田的生产性试验

介绍了新型车载式除油装置的工作原理及在江汉油田的生产性试验情况。试验结果表明，该装置的除油、除浊效果明显，平均出水浊度〈1 NTU，油浓度〈5mg／L，含铁量〈0.5mg／L，达到了国家规定的回注水A1标准。     

丹江口水库水低温低浊期混凝剂优选

针对低温低浊时期丹江口水库水,通过混凝沉淀烧杯试验,对水厂普遍使用的3种混凝剂三氯化铁（FeCl3）、聚合氯化铝（PAC）和硫酸铝（AS）的投加量与沉淀时间进行优选.结果表明,在试验范围内,FeCl3和PAC投加量与余浊有很强的负相关性,在投加量为12 mg/L时余浊最小,分别为0.38和0.30 NTU,明显优于AS;混凝剂投加量与UV254去除效果高度正相关,混凝剂对UV254去除作用强弱关系为PAC＞AS＞FeCl3,投加量为12 mg/L时去除率最高,分别为59％,57％和52％;投加FeCl3和PAC所形成的絮体沉淀速度快,在20～ 30 min时即可完全沉淀,而投加AS形成的絮体所需沉淀时间在40 min以上.最后在中试系统对最优混凝剂PAC投加量与浊度和UV254之间的关系进行了适应性检验,结果表明适应性良好.     

臭氧/过滤/活性炭工艺深度处理污水厂二级出水

采用臭氧/过滤/活性炭工艺深度处理济南市水质净化二厂的二级出水.结果表明,在臭氧投加量为3 mg/L、滤床和炭床的滤速均为6～12 m/h、各工艺段的接触时间为13 min的务件下,组合工艺对浊度、CODMn、NH4+-N和NO2--N均有一定的去除效果,而对NO3--N基本无去除作用;当原水的平均浊度、CODMn、NH4+-N和NO2--N分别为0.87 NTU、1.24 mg/L、1.78 mg/L、0.13 mg/L时,组合工艺出水的平均浊度、CODMn、NH4+-N和NO2--N分别可降至0.25 NTU、0.79mg/L、1.29 mg/L、0.05 mg/L.     

二次微絮凝改善过滤效果的试验研究

为改善过滤效果,开展了沉后水的二次微絮凝过滤中试研究。结果表明,当聚合氯化铝(PAC)投量为 0. 2mg/L、微絮凝时间为 2~4min时,可确保滤后水浊度<0. 1NTU的目标值。二次微絮凝过滤不仅解决了初滤水浊度偏高的问题,而且提高了对有机物和藻类的去除率,同时滤后水的铝含量没有升高,过滤水头损失也没有明显的增加。     

高锰酸钾与粉末活性炭联用处理低温低浊水研究

考察了高锰酸钾与粉末活性炭联用对宁夏宁东水厂冬季低温低浊水的处理效果。结果表明,单独使用高锰酸钾做助凝剂,聚合氯化铝作为混凝剂时,随着高锰酸钾投加量的增加,浊度去除率呈现先增加后减小的趋势,当高锰酸钾投加量达到0．5mg／L时,浊度去除率最高,出水CODMn和UV254的去除率随高锰酸钾投加量的升高而上升;UV254的去除率随着粉末活性炭投加量的增加而升高,当粉末活性炭投加量大于30mg／L时,其对浊度的去除率无明显影响;高锰酸钾与粉末活性炭联用可以明显提高低温低浊水的浊度和UV254的去除率,在我国冬季北方低温低浊水处理中具有广泛的应用前景。     

高浊度原水处理投药条件的选择

在常规处理条件下,对西南地区突发性非多砂高浊度原水进行了加药条件优化试验.结果表明,采用单级絮凝、分级沉淀工艺,先投加PAC,60～120 s后投加PAM,对高浊度原水有良好的去除效果.原水浊度为15 000 NTU时,投加200 mg/L PAC、0.4～0.5 mg/L PAM,静沉30 min后.出水浊度为1.7...     

吸附架桥机理主导下APAM的多级絮凝效能

对吸附架桥机理主导下阴离子聚丙烯酰胺(APAM)的絮凝过程进行了研究,通过改变絮凝剂投加工况,对比分析常规絮凝与多级絮凝在污染物去除效果、絮体性能、絮体生长动力学与污泥调理能耗等方面的差异。结果表明,相同投药量下,两级絮凝的出水浊度低于三级絮凝和常规絮凝,两级絮凝在最少的APAM投加量(2 mg/L)下达到最低的出水浊度(19.53 NTU);与常规絮凝相比,两级絮凝的絮体成长速率、平均粒径和沉降速率分别增加12.67%、30μm、36.74%。两级絮凝在投加间隔为240 s、投配比为1∶1条件下絮凝效能最优,出水浊度为15.34 NTU,絮体沉降速率为1.1 NTU/s,絮体密度达到1.123 4 g/cm³。絮体破碎再絮凝过程中,两级絮凝与常规絮凝破碎后均能恢复至破碎前水平,但破碎后均出现不可逆的絮体结构破损,粒径在0~100μm的絮体颗粒增多,粒径>400μm的絮体减少,破碎后两级絮凝的絮体强度因子(68.15%)高于常规絮凝(41.63%),两级絮凝的絮体强度和抗破碎剪切能力更高。在剩余污泥调理方面,两级絮凝产生的污泥只需要投加40mg/L的APAM就可以达到最低的滤饼含水率(75.5%)。因此,两级絮凝可以显著提升除浊效能与絮体性能,是强化絮凝的发展方向。     

水平潜流人工湿地处理住宅灰水技术研究

以陶粒及天然沸石为基质,黄菖蒲为植物,构建新型水平潜流式人工湿地,研究其净化实际小区灰水的效果,进水流量50 L/d,水力停留时间2 d,进水COD、NH3-N、 TN、TP浊度为164、4.3、5.2、0.44 mg/L、82.4 NTU时,出水可分别降至70 、1.07 、2.07 、0.33 mg/L、7.27 NTU,去除率分别为57.32%、75.19%、60.26%、24.24%、91.18%,对实际灰水COD、NH3-N、TN、浊度有良好的去除效果。利用人工配水考察不同水力停留时间下湿地的去污效果。提高停留时间能有效提高湿地对COD、NH3-N的去除效果,停留时间为3 d时,该湿地的去污效果最好,COD、NH3-N、TN、TP浊度去除率分别为68.46%、81.75%、66.67%、34%、86.91%。