Application of organic polymeric flocculants in centrifugal dewa-tering of oil refinery sludge

In order to evaluate the applicability of the organic polymeric flocculants(OPF) in the treatment of oil refinery sludge, experiments were conducted to show that OPF have better performance of flocculation than inorganic flocculants. Both the anionic and cationic OPF have satisfactory flocculation efficiency in oil sludge treatment, but the latter are more cost efficient. Among the over 20 types of flocculants tested, 2 OPF(CPAM 2 and HPAM 2) were selected as the treatment agents, based on their good treatment performances, oil resistance and economic feasibility. It was demonstrated in the industrial scale centrifugal dewatering experiments that the application of either CPAM 2 or HPAM 2 could achieve high treatment efficiency of the oil sludge dewatering and reduce the COD of centrifugal liquid to less than 1000 mg/L.

Treatment of Oily Wastewater Using Composite Flocculant of Polysilicate Ferro-Aluminum Sulfate – Rectorite

In this study, a novel flocculant was prepared by an inorganic polymetric flocculant (IPF) - polysilicate ferro- aluminum sulfate (PSFA) and rectorite (REC). The structure of the PSFA-REC composite was characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD), in order to determine the optimal temperature. The flocculation test was made at 25℃, 45℃ and 65℃, the results indicated that when the temperature was 65℃, the removal efficiency of the oil and COD was the best, which was 87.2% and 92.6% respectively. Then by comparisons among rectorite (REC), PSFA and the composite PSFA-REC at the temperature of 65℃ and the optimal dosage of 11 mg/L, the composite PSFA-REC showed better flocculation performance than flocculant REC and PSFA alone.

Study on Application of Novel Flocculating Agent in Treating Refinery Wastewater with High Concentration of Pollutants

After conducting a lot of screening experiments the appropriate flocculating formulations for treating high-concentration wastewater discharged from a certain refinery were selected. The oil removal rate and COD removal achieved by these flocculating formulations were better than that achieved by the conventional compound formulation consisting of polyaluminium chloride(PAC) and polyacrylamide(PAA) . Addition of an oil/water separating agent to the formulation could improve its oil removal performance to facilitate the oil/water separation of the oil-in-water emulsion in the high-concentration wastewater along with improved adaptability of the formulation to the wastewater containing high concentration of pollutants. This flocculating agent has promising prospects for commercial application.

OKRA (HIBISCUS ESCULENTUS) AND FENUGREEK (TRIGONELLA FOENUM GRACEUM) MUCILAGE:CHARACTERIZATION AND APPLICATION AS FLOCCULANTS FOR TEXTILE EFFLUENT TREATMENTS

The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides were used for removal of solids (suspended solids (SS) and total dissolved solids (TDS)) and dyes from real textile effluents and aqueous solutions of different class of synthetic dyes.Influences of varying polysaccharide concentration,contact time and pH on removal of pollutant from the textile...

Synthesis and evaluation of cationic flocculant P(DAC-PAPTAC-AM) for flocculation of coal chemical wastewater

In this study,a high-efficiency cationic flocculant,P(DAC-MAPTAC-AM),was successfully prepared using UV-induced polymerization technology.The monomer Acrylamide(AM):Acryloxyethyl Trimethyl ammonium chloride(DAC):methacrylamido propyl trimethyl ammonium chloride(MAPTAC)ratio,monomer concentration,photoinitiator concentration,urea content,and cationic monomer DAC:MAPTAC ratio,light time,and power of highpressure mercury lamp were studied.The characteristic groups,characteristic diffraction peaks,and characteristic proton peaks of P(DAC-MAPTAC-AM)were confirmed by fourier transform infrared spectroscopy(FTIR),X-Ray diffraction(XRD),1H nuclear magnetic resonance spectrometer(1H NMR),and scanning electron microscopy(SEM).The effects of dosage,pH value,and velocity gradient(G)value on the removal efficiencies of turbidity,COD,ammonia nitrogen,and total phenol by poly aluminum ferric chloride(PAFC),P(DACMAPTAC-AM),and PAFC/P(DAC-MAPTAC-AM)in the flocculation treatment of coal chemical wastewater were investigated.Results showed that the optimal conditions for the flocculation of coal chemical wastewater using P(DAC-MAPTAC-AM)alone are as follows:dosage of 8-12 mg/L,G value of 100-250 s^-1,and pH value of 4-8.The optimal dosage of PAFC is 90-150 mg/L with a pH of 2-12.The optimal dosage for PAFC/P(DAC-MAPTAC-AM)is as follows:PAFC dosage of 90-150 mg/L,P(DAC-MAPTAC-AM)dosage of 8-12 mg/L,and pH range of 2-6.When P(DAC-MAPTAC-AM)was used alone,the optimal removal efficiencies of turbidity,COD,ammonia nitrogen,and total phenol were 81.0%,35.0%,75.0%,and 80.3%,respectively.PAFC has good tolerance to wastewater pH and good pH buffering.Thus,the flocculation treatment of coal chemical wastewater using the PAFC/P(DAC-MAPTAC-AM)compound also exhibits excellent resistance and buffering capacity.

Flocculation behaviors of a novel papermaking sludge-based flocculant in practical printing and dyeing wastewater treatment

In our previous studies,several papermaking sludge-based flocculants(PSBFs)were synthesized from wood pulp papermaking sludge.The structure-activity relationships of the PSBFs have been investigated in simulated dye wastewater treatment,but their efficiencies in practical printing and dyeing wastewater(PPDW)treatment are unknown.Herein,an PSBF was prepared,and its performance is discussed in comparison to polyaluminium chloride(PAC)and polyacrylamide(PAM)in PPDW treatment.The PSBF was used in three ways:as an independent flocculant,as a PAC aid,or used to treat the effluent of the PAC system.The results indicated that adding PSBF alone produced similar color and chemical oxygen demand(COD_(Cr))removals as the PAC system alone,but PSBF performed better than PAC when the pH of PPDW was higher than 7.0.Adding PSBF as a PAC aid improved the color,COD_(Cr)and turbidity removals,but the elimination efficiencies were slightly lower than those of the PAC+PAM system.However,when PSBF was used as a flocculant to treat the effluent of the PAC system(PAC→PSBF),the effluent qualities were enhanced.Compared with the PAC system,the color and COD_(Cr)removals of PAC→PSBF system increased by 16.21%and 13.26%,respectively.The excitation and emission matrix fluorescence results indicated that PSBF removed tryptophan-like pollutants more efficiently than PAC.Considering the pH requirements of the subsequent bioreactor treatment in practice,the PAC→PSBF system were also investigated at the PPDW pH level of 7.0.Its maximum removal efficiencies of color,COD_(Cr)and turbidity were 90.17%,32.60%and 82.50%,respectively.

Microwave assisted synthesis of poly（2-hydroxyethylmethacrylate） grafted agar （Ag-g-P（HEMA）） and its application as a flocculant for wastewater treatment

Poly（2-hydroxyethylmethacrylate） chains were grafted onto the backbone of agar using a microwave assisted method involving a combination of microwave irradiation and ceric ammonium nitrate to initiate the grafting reaction. The synthesized graft copolymers were characterized by intrinsic viscosity measurements, Fourier transform infrared spectroscopy, elemental analysis （C, H, N, O and S） and scanning electron microscopy. Ag-g-P （HEMA）-2 showed a much higher flocculation efficacy than agar. The optimized dosage of flocculation for Ag-g-P （HEMA）-2 in the wastewater was found to be 0.75 ppm. Compared to agar, Ag-g-P（HEMA）-2 was found to considerably reduce the pollutant load in the wastewater.

Iron and lead ion adsorption by microbial flocculants in synthetic wastewater and their related carbonate formation

Although microbial treatments of heavy metal ions in wastewater have been studied, the removal of these metals through incorporation into carbonate minerals has rarely been reported. To investigate the removal of Fe^3＋ and Pb^2＋, two representative metals in wastewater, through the precipitation of carbonate minerals by a microbial flocculant （MBF） produced by Bacillus mucilaginosus. MBF was added to synthetic wastewater containing different Fe^3＋ and Pb^2＋ concentrations, and the extent of flocculation was analyzed. CO2 was bubbled into the mixture of MBF and Fe^3＋/Pb^2＋ to initiate the reaction. The solid substrates were analyzed via X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy. The results showed that the removal efficiency decreased and the MBF adsorption capacity for metals increased with increasing heavy metal concentration. In the system containing MBF, metals （Fe^3＋ and Pb^2＋）, and CO2, the concentrated metals adsorbed onto the MBF combined with the dissolved CO2, resulting in oversaturation of metal carbonate minerals to form iron carbonate and lead carbonates. These results may be used in designing a method in which microbes can be utilized to combine CO2 with wastewater heavy metals to form carbonates, with the aim of mitigating environmental problems.

PAC-P(AM-BA)杂化高分子絮凝剂制备及絮凝效能评价

针对油田化学驱污水难处理问题,采用水溶液自由基胶束聚合法,以聚合氯化铝(PAC)为无机组分,丙烯酰胺(AM)、丙烯酸丁酯(BA)为有机单体,合成一种新型无机-有机杂化高分子絮凝剂(PAC-P(AM-BA))。利用傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA)、扫描电子显微镜(SEM)和比表面积分析仪(BET)对絮凝剂进行表征。结果表明,BA以化学键连接在聚丙烯酰胺(PAM)长链中,无机组分与有机组分之间以离子键连接。PAC-P(AM-BA)热分解温度为233.93℃,比表面积为30.351m^(2)·g^(-1)。絮凝实验结果表明,PAC-P(AM-BA)最佳投加量为20 mg·L^(-1),沉降时间为10 h,其絮体分形维数为1.733。在絮凝效能对比实验中,PAC-P(AM-BA)的平均除油率为90.3%,较阳离子聚丙烯酰胺(CPAM)和复配型絮凝剂(PAC+PAM)分别高出16.4%和29.0%。

杭锦旗地区钻井废水回用技术研究

为满足杭锦旗地区严格的环保要求,降低钻井成本,提高勘探与开发效益,对该区块钻井废水进行了分析,明确了废水不能回用原因。根据离子化学沉淀和颗粒絮凝机理,制定“提高pH值-氧化-离子捕捉-絮凝”废水处理方案,据此进行了废水回用实验研究。实验表明,处理后的废水回用到钻井液后,对钻井液性能影响不大。该技术在现场进行了应用,废水处理后回用效果好,达到了降本增效的良好效果。

聚合硫酸铁絮凝剂对好氧颗粒污泥处理含油废水的影响

为了明确絮凝剂PFS对好氧颗粒污泥颗粒化及运行效能的影响,以PFS和含油废水为探究对象,研究了PFS浓度对AGS处理含油废水的影响并揭示相关机制。结果表明,PFS存在利于AGS颗粒化,提高ASG内污泥浓度及大粒径污泥占比。AGS稳定性分析表明PFS提高了胞外聚合物含量,并促进了蛋白质和多糖含量,提高了Zeta电位。PFS促进了AGS处理含油废水过程内污染物、营养盐和油脂的去除,且PFS的最佳含量为50 mg/L。PFS作为骨架结构为微生物增殖提供便利条件。此外,PFS具有一定吸附能力从而提高了污染物、营养盐及油脂的去除。研究结果为AGS处理含油废水过程内快速颗粒化提供一定的数据支撑和理论依据。

化学絮凝-活性炭吸附法在处理含重金属废水中的应用

含重金属元素的废水是一种难以处理且对环境污染程度较高的工业废水。以含有Fe、Co、Mn、Ag等重金属离子的模拟废水为研究对象,采用先添加絮凝剂化学絮凝,再通过活性炭过滤的方法进行处理,并研究了活性炭种类、pH、硼酸含量对模拟废水中重金属元素去除效率的影响。实验结果表明活性炭颗粒越细、碘值越低对重金属的去除效果越好;该絮凝剂可以在较宽pH范围内和较高浓度硼酸存在下使用。化学絮凝+活性炭吸附过滤法对于含重金属元素工业废水的处理是一种既经济又高效的方法。

电絮凝协同集成膜处理电镀废水技术研究

以东方航空机械加工厂电镀废水为研究对象,开发了电絮凝-集成膜处理工艺。实验表明:电絮凝过程pH=7,电流密度5 A/dm^(2),电极板间距2.5 cm,电解时间35 min,集成膜进水pH=11,工作压力3.5 MPa, COD可降低至56.43 mg/L,悬浮物可降低至35.43 mg/L,两者去除率分别达到了97.42%和98.91%,出水中重金属含量均低于《电镀污染物排放标准》中污染物排放浓度限值。集成膜的再生使用碱液和次氯酸钠溶液清洗2.5 min,再使用盐酸清洗2.5min,膜通量可达到92.5%~98.2%之间。

自重及加载条件下絮凝剂调理废弃泥浆的脱水效果

群桩基础、地下连续墙等施工会带来巨量的废弃泥浆,城市地下空间开发利用及盾构掘进过程会产生大量高含水率泥浆状的渣土,常规的堆场处理受限于成本和环境问题,需要对废弃泥浆进行高效脱水处理,减少废弃泥浆量。为研究絮凝剂调理废弃泥浆的脱水效果,提升泥浆脱水效率,采用单一、复合絮凝剂调理废弃泥浆,通过室内量筒沉积和小型堆载预压试验,对比研究絮凝剂类型和掺量配比对泥浆泥水分离效果的影响,并为脱水效果提供判断依据。结果表明:有机絮凝剂能够改善泥浆的脱水性能,提高泥水分离程度,且存在最优掺量;复合絮凝剂能够发挥有机、无机絮凝剂的协同作用,更进一步提升泥浆脱水程度,其中PAM类复合絮凝剂脱水性能优异,PAM与CaO复合絮凝剂组合处理泥浆时,其沉积层含水率降低程度能够达到82.75%。研究成果可为废弃泥浆的合理处置和资源化利用提供参考。

不同絮凝剂对钻井泥浆的处理效果及絮凝机理

为研究不同絮凝剂对钻井泥浆的絮凝效果,采用破胶絮凝的方法对含水率高、成分复杂的山西某煤层气废弃钻井泥浆进行处理,研究不同破胶絮凝剂和助凝剂种类及投加量等因素对废弃钻井泥浆处理效果的影响,并利用扫描电子显微镜(SEM)探究了破胶助凝的机理。结果表明:2000 mg/L的硫酸铝破胶絮凝效果最优,10 mg/L的非离子聚丙烯酰胺(NPAM)与其协同处理效果最佳,处理后的液相色度、COD_(Cr)、悬浮物含量和泥饼含水率分别为20倍、61.98、32.50 mg/L、78.64%;硫酸铝的电中和作用可以和NPAM桥联网捕作用产生良好的协同效果,能够显著加快泥浆中颗粒物的絮凝沉降,增大絮体体积和疏松程度,从而降低液相污染物含量和泥饼含水率。研究结果可为废钻井泥浆的絮凝处理提供一定的参考和理论依据。

絮凝-电化学氧化协同工艺处理兰炭废水

采用絮凝-电化学氧化协同工艺处理兰炭废水,探究了反应过程中絮凝剂投加量、反应时间、初始pH值、外加电压以及NaCl添加量对化学需氧量(COD)和氨氮(NH_(3)-N)去除的影响及絮凝-电化学氧化协同作用机制.结果表明,随着絮凝剂聚合氯化铝铁(PAFC)投加量和外加电压的增加,兰炭废水中COD和NH_(3)-N的去除率逐渐升高.当PAFC投加量为50g/L、电压6V、反应时间4h,初始pH=9,NaCl添加量30g/L时,COD和NH_(3)-N去除率分别为82.37%和100%,更换极板进行二次电解COD去除率可达100%.兰炭废水中有机污染物主要是苯酚类､醇类和酰胺类物质,处理后酚类物质含量大幅减少,酮类、醇类和酸类物质相对占比有所增加.絮凝-电化学氧化过程中,PAFC既是絮凝剂又是Cl^(-)的提供者,其水解产生的Cl^(-)与NaCl引入的Cl^(-)在电场作用下向阳极定向迁移.阳极表面发生氧化反应产生的有效氯(Cl_(2)/ClO^(-))将兰炭废水中有机污染物氧化成中间产物氯酚,与絮凝剂中Al^(3+)的水解产物Al(OH)^(2+)、Al(OH)^(+)_(2)及Al(OH)_(3)通过静电和吸附作用结合形成絮凝体被去除.废水中剩余少量的氯酚及酰胺、环己二醇等有机污染物及NH_(3)-N则在ClO^(-)的间接氧化作用下转化为N_(2)、CO_(2)和H_(2)O得以去除.

复配絮凝处理高浓度含盐原油罐切水的研究

采用不同类型絮凝剂聚合[聚合氯化铝(PAC)、聚合硫酸铁(PFS)和聚丙烯酰胺(PAM)]处理高浓度含盐原油罐切水,探索絮凝剂投量浓度、搅拌速度、p H值和投加时间间隔对絮凝效果的影响。结果表明:复配使用絮凝剂聚合氯化铝与阳离子型聚丙烯酰胺(CPAM)处理高浓度含盐原油罐切水的絮凝效果更佳。絮凝剂的投量浓度、絮凝搅拌速度、p H值和投加间隔时间均影响絮凝的效果,其中絮凝剂的用量影响最大。较为适宜的絮凝条件:p H值为6~11,PAC投量浓度为400 mg/L且混合搅拌速度为200 r/min,CPAM投量浓度为1.0 mg/L且混合搅拌速度为100 r/min,2种絮凝剂的投加间隔为60 min。絮凝对浊度的去除率高达98.7%,固体悬浮物(SS)的去除率高达96.5%,废水中的石油类含量从0.339 mg/L降到0.115 mg/L,废水的氨氮、化学需氧量(COD)以及254 nm波长紫外光下的吸光度(UV_(254))的去除率分别达到55.0%,36.6%和20.4%,最终絮凝出水的总铁含量从41.85 mg/L降到5.42 mg/L。

新型有机絮凝剂处理磷酸铁母液试验研究

针对加氨水后的磷酸铁生产母液在处理过程中生成沉淀颗粒小且长时间难以沉淀的问题,采用絮凝沉淀法提高沉淀效率。通过对PFS+APAM和GFL49+GFA98共2种絮凝剂组合进行对比,选出最优组合,并在最优药剂组合条件下确定絮凝剂投加量、搅拌转速和搅拌时间。结果表明:GFL49+GFA98为最优絮凝剂组合,GFL49和GFA98的最佳投加量分别为280、2.2mg/L。当水温25℃、搅拌转速100r/min、搅拌时间90s、沉淀1min后母液上清液浊度为2.1NTU,浊度去除率为99.475%。实验证明:相较于传统絮凝剂PFS+APAM,GFL49+GFA98具有生成絮体更大、投加量小、产生污泥量少的优点。