MS2 removal from high NOM content surface water by coagulation ‐ ceramic microfiltration,for potable water production

MS2 bacteriophages removal from surface water, characterized by high natural organic matter (NOM) content, was investigated by inline coagulation/flocculation pretreatment followed by ceramic microfiltration (MF). MS2 and DOC removal increased with lower pH and higher coagulant dose. Lowering the coagulant pH from 6.5 to 5.5 for polyaluminum chloride (PACl), and to 5.0 for iron chloride (FeCl), respectively, along with doubling of the coagulant dose from 2 to 4 mg Al/L, and from 4 to 8 mg Fe/L, respectively, maximized the virus removal, resulting in more than six log unit reductions up to complete virus retention. However, high residual metal concentrations were found under such conditions. Comparison of conventional two‐stage coagulation pretreatment with simple inline coagulation did not show any significant performance differences. Both investigated coagulants showed virus inactivation about two log units after 60 min contact time, which is equivalent to a virus inactivation of 99%. This inactivation was only reversible to a small extend by chemical or physical floc destruction. The investigated process combination can comply with modern hygienic barrier standards. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

不同混凝剂对马铃薯淀粉废水混凝效果的影响

用混凝剂Fe2(SO4)3、PAC、PFSS、PAFC处理马铃薯淀粉废水,研究了混凝剂的种类、投药量、废水pH值、助凝剂PAM的投加量以及沉降时间等对混凝效果的影响。结果表明,混凝沉淀法预处理马铃薯淀粉废水优选混凝条件为:pH为7,混凝剂PAFC为1 200 mg/L,助凝剂PAM为5 mg/L,沉降25 m in。在此条件下,废水的浊度、COD去除率分别达97.27%及40.55%。投药量明显减少,而沉积物产量较高,为后续生化处理提供了有利条件。     

Lab and pilot scale investigations on membrane fouling during the ultrafiltration of surface water

In the combined laboratory and pilot plant investigation powder activated carbon dosing and inline coagulation were investigated for surface water from river Spree. The aim was to understand the fouling behaviour of this raw water and to understand and to identify strategies to minimize the irreversible fouling in this application. Trials with activated carbon showed significant differences in the adsorption of biopolymers on different types of carbon. Whereas the TOC removal was in the same range for both types the coarse carbon type showed very small removal of biopolymers. The effect of different types of coagulants, dosage and pH was investigated in a laboratory filtration set up. Samples were investigated by LC-OCD measurements for fractionation of DOC for raw water, flocculated water and permeate. The removal of biopolymers was possible with iron and alumina salts, however the alumina salts tend to remove humic acids as well and this results in a higher overall DOC removal. In the pilot plant the inline coagulation was investigated under actual site conditions. Whereas the results for the effect of coagulation and DOC removal were confirmed it turned out that aluminium coagulants give a significantly higher increase in differential pressure. The use of ferric coagulants at slightly acidic pH was thus identified as a robust method to achieve a stable performance of the ultrafiltration system at this site.     

强化混凝中不同分子质量有机物的变化特点

采用三氯化铁作为混凝剂，通过变化投加量和pH，考察各个分子质量区间的DOC和UV254的变化情况，了解强化混凝去除有机物的效果和机理。增加混凝剂的投加量能有效地促进各分子质量区间的UV254的去除，但对DOC的去除效果较差。三氯化铁对小分子质量的有机物具有很好的去除效果，总去除率的至少50％为去除小分子质量有机物所贡献。降低pH能有效地促进各分子质量区间的DOC和UV254的去除，去除有机物的最佳pH为5．5。在最佳的pH下，小分子质量的有机物得到了最大限度的去除。     

聚硅酸铁钛絮凝剂制备及焦化废水混凝处理试验

制备无机-无机多元复合型絮凝剂聚硅酸铁钛,通过正交试验考察Fe:Ti、(Fe+Ti):Si以及碱化度对混凝能力的影响,将其应用于焦化废水生化出水的混凝处理,并研究其对焦化废水中有机物的特性去除以及混凝过程中絮体粒径变化趋势.研究结果表明:配比为Fe:Ti=7:1、(Fe+Ti):Si=6:1、碱化度=0.8的絮凝剂混凝...     

高分子絮凝剂处理高浓度化妆品原料生产废水研究

化妆品原料生产过程中产生的废水水质成分复杂、有机物含量高、难降解,利用混凝工艺处理该废水能够减缓生化处理单元的负担,提高污水处理效率。为揭示无机高分子混凝剂混凝过程中污染物的去除机制和污泥性质的变化,考察了不同的絮凝剂聚合氯化铝(PAC)、聚合硫酸铁(PFS)、聚合氯化铝铁(PAFC)和助凝剂聚丙烯酰胺(PAM)投加浓度对污染物去除率和污泥性质的影响。采用傅里叶变换红外光谱(FTIR)、X射线能谱(EDX)、扫描电镜(SEM)、热重分析仪(TGA)分析污泥絮体官能团、表面形貌、元素组成和热稳定性的变化,采用三维荧光光谱(3D-EEM)和超滤技术分析出水中有机物分子量的分布规律和有机物成分的变化,优化最佳混凝工艺运行条件。结果表明:进水中的天然有机物(NOM)荧光强度高,有机物分子量主要分布在>100×10³和<3×10³区间,其所占比例分别为22.89%和50.57%。当进水COD为6700～7500 mg/L时,在助凝剂PAM投加浓度为0.03 g/L,PAC、PFS和PAFC投加浓度分别为2.8 g/L、2.8 g/L和3.0...     

Olive Mill and Winery Wastewaters Pre-Treatment by Coagulation with Chitosan

The pre-treatment of both winery wastewater (WW) and olive mill wastewater (OMW) by coagulation, using a natural organic coagulant, was investigated as a possible alternative to conventional metal based coagulants, in order to produce a potentially reusable organic sludge. Chitosan was chosen as a model natural organic coagulant and the coagulation process was optimized investigating different coagulant doses and pH values. In spite of the notably lower polluting load for the WW compared to the OMW, the efficiency of the chitosan coagulation was found to be high in terms of total suspended solids (81% and 80% for OMW and WW respectively) and turbidity (94% and 92% for OMW and WW respectively) removal for both wastewaters, but a notable difference was observed in terms of organic matter removal (32% and 73% in terms of COD for OMW and WW respectively). Taking into account that the best performances of the coagulation process by chitosan were achieved at the actual pH for OMW as well as no significant differences were observed for WW as the pH was changed, no chemicals addition is required to adjust pH.     

最佳混凝投加量和pH去除水中有机物的研究

对强化混凝去除黄浦江水的有机物进行了试验研究。尽管增加混凝剂投加量和降低pH都能有效地提高去除有机物的效果，但降低pH去除有机物更有效。不同的pH，达到最佳有机物去除效果所需的混凝投加量是不同的，pH越低，所需的投加量就越少。就黄浦江水来说，达到最佳有机物去除效果的硫酸铝投加量为8mg/L（以Al计），pH在5．5，DOC和UV254的去除率可分别达到46％和57％，较常规处理方法，去除率可提高1倍。强化混凝也能有效地去除消毒副产物。     

Synthesis and characterization of polymeric inorganic coagulants for water treatment

This research explored the feasibility of preparing and utilizing preformed polymeric solution of Al(III) and Fe(III) as coagulants for water treatment. The differentiation and quantification of hydrolytic Al and Fe species in the coagulants were done by utilizing spectrophotometric method based on the interaction of Al or Fe with ferron as a complexing agent. In addition, 27A1-NMR, FT-IR, and powdered XRD were used to characterize the nature and structure of the hydrolytic species in these coagulants. The properties of the polyaluminum chloride (PAC1) and polymeric iron chloride (PIG) showed that the mass fractions of the maximum polymeric Al produced at r(OH/Al)=2.2 and Fe at r=1.5(OH/Fe) were 85% and 20% of the total aluminum and iron in solution, respectively. Coagulation tests were conducted under various coagulant dosages and pHs for each coagulant prepared. In case of PAC1 coagulants, a coagulation test on Nakdong river waters with three PACls (r=2.0, 2.2, 2.35) showed that the effectiveness of coagulation was in the order, r=2.2>2.0>2.35, corresponding to the order of polymeric aluminum contents. And, for the PIC1 coagulants, the PIC1 of r=1.5 was most effective for the removal of turbidity and TOC from the raw water. Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University.     

无机混凝剂影响因素及其混凝效果对比研究

以生活污水为研究对象,考察了3类无机混凝剂(铁盐、铝盐、钙盐)的影响因素,同时考察了投加量对出水pH值的影响,并进一步比较了在相同投加量及最佳pH值下,各混凝剂的混凝效果。结果表明:TP和CODCr的去除率随着混凝剂投加量的增加先快速升高而后趋于稳定;FeCl_3、Fe_2(SO_4)_3、FeSO_4、PFS以及AlCl_3、Al_2(SO_4)_3、PAC和CaO的最佳pH值分别为5、6、8、6、7、6、7、10;出水pH值随着混凝剂投加量的增加而降低,其中AlCl_3、CaO对pH值影响最为显著;在相同投加量及最佳pH值下,FeCl_3、PAC对TP和CODCr的去除效果最好,综合考虑2个指标,AlCl_3的去除效果最佳。     

Physico-chemical treatment of pulping effluent: Characterization of flocs and sludge generated after treatment

The present study deals with the treatment of simulated pulping effluent (pH = 11, and total organic carbon (TOC) = 1900 mg/L) by acid precipitation and coagulation-flocculation processes. The maximum TOC removal (= 4845 mg/g Al³⁺) from the effluent was found with Al₂(SO₄)₃ coagulant. Addition of sufloc (a flocculant) improved the sludge settling significantly. Hydrolyzed mono- and polynuclear species generated from Fe and Al coagulants could have resulted in TOC removal. Thermal analysis of sludge showed release of gases like CO, CO₂, HCHO, CH₃SH and SO₂ during combustion. Afterwards, the dissolved metal species in treated wastewater samples should be removed.     

Removal of disinfection by-products precursors by polyaluminum chloride coagulation coupled with chlorination

The effect of coagulation coupled with chlorination (i.e., pre-, inter-, and post-chlorination) on the formation of disinfection by-products (DBPs) and the removal efficiency of DBPs precursors were investigated. Compared with coagulation coupling with pre-chlorination, coagulation coupled with inter-chlorination could lead a higher removal efficiency of dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA) and chloroacetic acids formation potential (CAAsFP). The CAAsFP/DOC value of residual DOC showed that coagulation with inter-chlorination has a beneficial effect on CAAs precursors removal. More DBPs were produced during inter-chlorination than that of pre-chlorination at pH 7.5, while less DBPs were produced during inter-chlorination than that of pre-chlorination at pH 5.5. In addition, the precipitate of humic acid (HA) after coagulation was chlorinated to study the kinetics of chlorine decay. The results showed that coagulated-HA had a higher reactivity with chlorine than aqueous-HA at pH 7.5. Furthermore, the trends of zeta potential during coagulation process suggested that the distribution of chlorine species had significant influence on the removing of DBPs precursors by coagulation coupled with chlorination.     

新型无机高分子混凝剂处理含氟废水的实验研究

含氟工业废水危害大,处理困难,采用新型无机高分子混凝剂能有效降低废水中的氟。本文在实验条件下制备了不同金属离子的聚硅酸氯化物,考察了pH值,混凝剂用量,碱化度B和Fe(Al)／A物质的量比对除氟率的影响,并利用红外光谱和透射电镜对混凝机理进行探讨。     

Development of a novel method to prepare Fe- and Al-doped TiO2 from wastewater

A simple and novel method to synthesize iron and aluminium-doped titanium dioxide (TiO₂) was investigated. Titanium tetrachloride (TiCl₄) was used as a coagulant to remove organic matter from wastewater. The settled floc (sludge) was dewatered and incinerated at 600 °C after TiCl₄ flocculation. The resultant by-product from the waste sludge was valuable TiO₂. TiCl₄ coagulant was added with FeCl₃ and Al₂(SO₄)₃ coagulants to dope iron and aluminium on TiO₂ in a flocculation process. The effect of iron and aluminium on TiO₂ was investigated in terms of scanning electron microscopy/energy dispersive X-ray (SEM/EDX), X-ray diffraction (XRD), optical absorbance and photocatalytic activity. The majority of Fe/TiO₂ and Al/TiO₂ particles were found to be less than 1 μm size formed by 0.1 μm agglomerates using SEM analysis. Fe/TiO₂ included Ti, O, C, P and Fe elements and Al/TiO₂ consisted of Ti, O, C, P and Al elements as confirmed by EDX results. Remaining organic carbon from the settled organic matter was the source of C atom in TiO₂ whereas the P atom in TiO₂ came from phosphorus nutrient present in wastewater. The majority of acetaldehyde with Fe/TiO₂ and Al/TiO₂ was significantly removed under UV irradiation within 60 min. However, at higher iron concentration, acetaldehyde removal decreased by almost 50%. Under visible light irradiation, the photo-decomposition of acetaldehyde using the Fe/TiO₂ and Al/TiO₂ was marginal.     

Polyacrylamide-induced coagulation process removing suspended solids from palm oil mill effluent

Palm oil mill effluent (POME) is a colloidal suspension with 2–4% suspended solids. About 50% of the suspended solids are cellulosic compounds, which are not degraded in the typical biological treatment systems. Chemical (polymer-induced coagulation) and physical (settling) pretreatment methods were examined to remove the suspended solids in this study. A novel physicochemical treatment with high water recovery and sludge compressibility including three cationic polyacrylamides (C-PAM; as coagulant) and three anionic polyacrylamides (A-PAM; as flocculant) with different molecular weights and charge densities was used. The coagulants used were biodegradable. The combination of a C-PAM (Chemfloc1515C) with medium molecular weight and charge density and an A-PAM (Chemfloc 430A) with high molecular weight and charge density at doses of 300 and 50 mg/dm³ showed the best total suspended solids (TSS) and chemical oxygen demand (COD) removal (96.4 and 70.9%, respectively). The optimal condition was found at pH 5, rapid mixing at 150 rpm for 1 min, and slow mixing at 40 rpm for 30 s. As a conclusion, the physiochemical pretreatment using biodegradable coagulants was a promising alternative to effectively separate TSS (96.4%) with high water recovery (76%).     

Effect of potassium permanganate dosing position on the performance of coagulation/ultrafiltration combined process

The effects of potassium permanganate(KMnO_4)dosing position on the natural organic matter(NOM)removal as well as membrane fouling were investigated in the coagulation/ultrafiltration combined process.KMnO_4 oxidation altered the NOM characteristics in terms of hydrophobicity and molecular weight,and destroyed humic substances originated from terraneous organisms in raw water.The optimal KMnO_4 dosage was 0.5 mg·L~(-1) in the peroxidation enhanced coagulation process with respect to the dissolved organic carbon(DOC)removal.When KMnO_4 was dosed into both upstream and downstream of coagulation,namely in the proposed twoposition dosing mode,coagulation and KMnO_4 oxidation worked individually on the apparent DOC removal.However,compared to the KMnO_4 addition prior to or after coagulation,the two-position dosing mode dramatically alleviated membrane fouling and reduced fouling irreversibility.This was attributed to the change of NOM characteristics as a result of KMnO_4 addition prior to coagulation and the presence of MnO_2 on membrane surface as a result of KMnO_4 addition prior to ultrafiltration.This work may provide useful information for the application of KMnO_4 oxidation in the coagulation/ultrafiltration combined system.     

磁性离子交换树脂在饮用水预处理中的应用

磁性离子交换树脂(MIEX Resin)是水处理领域新开发的一种新型树脂,由于其在给水预处理中的良好效果,成为研究的热点。文章对MIEX Resin的基本工作原理、MIEX DOC工艺的组成和效果、MIEX DOC工艺与其它水处理工艺的联合应用情况作了简要综述。MIEXR树脂的珠粒粒径和磁性,是MIEXR树脂有别于传统树脂的最大特点,并且这两个特点使此种树脂在给水预处理中得以有效应用。MIEX DOC工艺对相对分子质量中等和小的有机物有较高的去除率,与混凝在去除有机物方面具有互补作用,磁性离子交换树脂能极大改善后续工艺的处理效果。     

Interaction of ozone and organic matter in coagulation with inorganic polymer flocculant-PACl: Role of organic components

In this study, two model waters were used to evaluate the ozone effect on aquatic organic matter (AOM) removal by coagulation with inorganic polymer flocculant (IPF)-polyaluminum chloride (PACl). Flocs formation during coagulation processes were detected by using PDA (Photometric Dispersion Analyzer). Apparent molecular weight distribution (AMWD) and resin fractionation (RF) were also performed to characterize the change of AOM as a result of pre-ozonation. The experimental results show that the dosage of O₃, characteristics and composition of AOM are the most important factors on the behavior of coagulation. Great differences have been found between the two model waters. Coagulation in model water 1 (MW1) (composed of humic acids) is impaired markedly by pre-ozonation, as more DOC (Dissolved Organic Carbon) is produced with increasing O₃ dosage. Floc formation, as exhibited from decreasing of the slopes of FI (Flocculation Index), is retarded gradually during coagulation process. Although residual turbidity is reduced with 1.15 mg/L O₃, removals of DOC and UV₂₅₄ all decreased. As for model water 2 (MW2) (composed of salicylic acid), FI is retarded also, but turbidity and DOC removals of coagulation after pre-ozonation are improved to a certain extent. Coagulation performance judged from removal of DOC is improved distinctly by pre-ozonation. Fractionation results show that molecular weight of organic matter (OM) of MW1 is converted from higher to lower; and OM becomes from more hydrophobic to more hydrophilic, which might be one of the mechanisms involved in the impairment of ozonation on coagulation effect. OM in MW2 is oxidized and mineralized to a greater extent, thus its impairment on coagulation is released. Finally, according to water properties, some proposed applications were provided for application of ozone in water treatment process.     

染料废水脱色混凝剂PSDC-Ⅵ的开发及工程应用

采用从杭州钢铁厂采集来的钢渣(水渣),经过粉碎、碱浸、酸溶、聚合(加入不同量的Fe3+和Al3+)和过滤等方法制得脱色混凝剂PSDC-Ⅵ系列3种。研究了它们对染料废水的脱色效果,考察了影响PSDC-Ⅵ系列混凝剂混凝及脱色效果的因素,并与PAC进行比较。试验表明,PSDC-Ⅵ系列混凝剂在pH≤7和pH≥10时,对试验的染料废水脱色效果较差,在pH=8时,达到最佳脱色效果点。同时在杭州市某印染厂染料废水工程中应用,改进了原有染料废水处理工艺流程,取得了良好的处理效果。PSDC-Ⅵ系列混凝剂处理该厂染料废水的混凝和脱色效果比用PAC时的效果好。     

磁性助凝剂资源化制备及强化污染物沉淀分离

通过高温碳化处理,研发并优化磁性助凝剂的资源化制备,并回用于混凝过程强化污染物的沉淀分离。采用磁化曲线、扫描电镜等表征手段,对不同高温制备得到的磁性助剂进行结构及形貌的表征。进一步对混凝过程中絮体的粒度粒型分析得知,磁性助剂有利于污染物的沉淀分离,加入700℃碳化后的磁性助剂(PFS:RW700=1:1.43)使污染物的沉淀分离效率提高至99.45%。磁性助剂带有的磁性使助剂易被絮体包裹,从而加速沉降;磁性助剂中含大量的碳且表面带有羧基等官能团,具有一定的吸附能力;经高温碳化结晶度增加且颗粒大小均一,有利于成核加快絮体增长。通过优化磁性助剂与聚合硫酸铁(PFS)的投加比,仍保持较高的污染物去除率,与活性炭相比,水处理成本降低了2 RMB/t,为解决混凝污泥资源化途径提供技术支撑。