生物颗粒活性炭处理苯酚废水

研究了生物颗粒活性炭(BGAC)处理合成苯酚废水的效果和机理。结果表明,BGAC能够高效处理苯酚废水,处理效果优于活性污泥法和颗粒活性炭(GAC)吸附。BGAC、活性污泥和GAC分别对75 mg/L的苯酚废水连续处理,平均去除率分别为98%、60%和90%。通过苯酚出水pH值和反应器中溶解氧的变化情况分析,BGAC对苯酚废水的处理主要借助于活性炭的吸附和微生物降解的交替作用。     

粉末活牲炭回流技术去除原水中氨氮的研究

将含粉末活性炭(PAC)的沉淀池排泥水回流至原水进水处,延长PAC在系统中的停留时间,考察系统对氨氮、有机物和浊度的去除效果及去除氨氮的影响因素.结果表明,在温度为21～25℃,投炭量为50 mg/L条件下,系统第7～8天运行稳定,对氨氮、UV254和CODMn的去除率分别为40%、45%和60%左右,出水浊度在1 NTU左右,活性炭泥的生物量为130 nmolP/g左右.当活性炭泥回流比为6%,原水CODMn不超过10 mg/L,Ph为7～8,浊度不超过180 NTU时,对氨氮去除效果最好,为40%～50%,可应对原水氨氮浓度小于1 mg/L的情况.     

A pollutant removal prediction tool for stormwater derived diffuse pollution.

This report describes the development of a methodology to theoretically assess the effectiveness of structural BMPs with regard to their treatment of selected stormwater pollutants (metals, polyaromatic hydrocarbons and herbicides). The result is a prioritisation, in terms of pollutant removal efficiency, of 15 different BMPs which can inform stormwater managers and other stakeholders of the best available options for the treatment of urban runoff pollutants of particular environmental concern. Regardless of the selected pollutant, infiltration basins and sub-surface flow constructed wetlands are predicted to perform most efficiently with lagoons, porous asphalt and sedimentation tanks being the least effective systems for the removal of pollutants. The limitations of the approach in terms of the variabilities in BMP designs and applications are considered.     

Characterization of cobalt ferrite-supported activated carbon for removal of chromium and lead ions from tannery wastewater via adsorption equilibrium

In this experiment, cobalt ferrite-supported activated carbon (CF-AC) was developed and characterized via the wet impregnation method for the removal of Cr and Pb(II) ions from tannery wastewater. Batch adsorption was carried out to evaluate the effect of experimental operating conditions (pH of solution, contact time, adsorbent dose, and temperature), and the removal efficiencies of Cr and Pb(II) ions by the developed adsorbents were calculated and recorded for all experimental conditions. These variables were estimated and reported as removal efficiencies of 98.2% for Cr and 96.4% for Pb(II) ions at the optimal conditions of 5, 0.8 g, 80 min, and 333 K for pH, adsorbent dose, contact time, and temperature, respectively. The equilibrium for the sorption of Cr and Pb(II) ions was studied using four widely used isotherm models (the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models). It was found that the Freundlich isotherm model fit better with the coefficient of determination (R²) of 0.948 4 and a small sum of square error of 0.000 6. The maximum adsorption capacities (Q_m) of Pb(II) and Cr adsorbed onto CF-AC were determined to be 6.27 and 23.6 mg/g, respectively. The adsorption process conformed well to pseudo-second order kinetics as revealed by the high R² values obtained for both metals. The thermodynamic parameters showed that adsorption of Cr and Pb(II) ions onto CF-AC was spontaneous, feasible, and endothermic under the studied conditions. The mean adsorption energy (E) values revealed that the adsorption mechanism of Cr and Pb(II) by CF-AC is physical in nature. The results of the study showed that adsorbent developed from CF-AC can be efficiently used as an environmentally friendly alternative adsorbent, for removal of Cr and Pb(II) ions in tannery wastewater.     

Modification of granular activated carbon surface by chitosan coating for geosmin removal: sorption performances.

This study presents the results of the sorption performances for geosmin removal by sorption onto granular activated carbons (GAC) manufactured from different raw materials of coconut shell and bituminous coal. The surface of GAC was modified by chitosan coating. The 90% deacetylated chitosan flakes were used for coating on GAC with the GAC: chitosan ratio of 5:1. The surface of GAC was characterised by scanning electron microscope (SEM) analysis, Fourier transform infrared spectroscopy and measurement of the pH solution of GAC samples. The sorption of geosmin onto the chitosan for both uncoated and coated GACs could be described by the Freundlich adsorption model. Data revealed that the sequence of Freundlich constant (K(F)) was chitosan coated bitominous coal (CB) > uncoated bituminous coal (UB) > chitos approximately equal to an coated coconut shell (CC) approximately equal to uncoated coconut shell (UC). The bituminous coal based GAC with chitosan coating had a maximum capacity of 23.57 microg/g which was approximately two-fold of uncoated bituminous coal based GAC. Two simplified kinetic models, pseudo-first order and pseudo-second order, were tested to investigate the sorption mechanisms. It was found that the intraparticle diffusion was a rate controlling step for the sorption and followed the pseudo-second order equation.     

Contaminant removal and hydraulic conductivity of laboratory rain garden systems for stormwater treatment

In order to evaluate the influence of substrate composition on stormwater treatment and hydraulic effectiveness, mesocosm-scale (180 L, 0.17 m(2)) laboratory rain gardens were established. Saturated (constant head) hydraulic conductivity was determined before and after contaminant (Cu, Zn, Pb and nutrients) removal experiments on three rain garden systems with various proportions of organic topsoil. The system with only topsoil had the lowest saturated hydraulic conductivity (160-164 mm/h) and poorest metal removal efficiency (Cu ≤ 69.0% and Zn ≤ 71.4%). Systems with sand and a sand-topsoil mix demonstrated good metal removal (Cu up to 83.3%, Zn up to 94.5%, Pb up to 97.3%) with adequate hydraulic conductivity (sand: 800-805 mm/h, sand-topsoil: 290-302 mm/h). Total metal amounts in the effluent were <50% of influent amounts for all experiments, with the exception of Cu removal in the topsoil-only system, which was negligible due to high dissolved fraction. Metal removal was greater when effluent pH was elevated (up to 7.38) provided by the calcareous sand in two of the systems, whereas the topsoil-only system lacked an alkaline source. Organic topsoil, a typical component in rain garden systems, influenced pH, resulting in poorer treatment due to higher dissolved metal fractions.     

pH对粉末活性炭去除有机物的影响

粉末活性炭去除水中有机物的效果受水的pH影响较大。降低水的pH,可显著提高粉末活性炭去除有机物的效果。对于黄浦江水,当pH为5.5,粉末活性炭投加量为40mg/L时,DOC和UV_(254)的去除率分别达到43.8％和36.2％。     

Modification of granular activated carbon using low molecular weight polymer for enhanced removal of Cu(2+) from aqueous solution.

Palm shell activated carbon was modified via surface impregnation with polyethyleneimine (PEI) to enhance removal of Cu(2+) from aqueous solution in this study. The effect of PEI modification on batch adsorption of Cu(2+) as well as the equilibrium behavior of adsorption of metal ions on activated carbon were investigated. PEI modification clearly increased the Cu(2+) adsorption capacities by 68% and 75.86% for initial solution pH of 3 and 5 respectively. The adsorption data of Cu(2+) on both virgin and PEI-modified AC for both initial solution pH of 3 and 5 fitted the Langmuir and Redlich-Peterson isotherms considerably better than the Freundlich isotherm.     

Removal of dissolved nitrogen, phosphorus and carbon from stormwater by biofiltration mesocosms.

Biofiltration systems are becoming a popular stormwater treatment device in water sensitive urban design for the removal of fine particulate and dissolved pollutants from stormwater. However, there is limited published data on the effectiveness of these systems for nutrient removal. We constructed biofiltration mesocosms to assess nutrient removal (nitrogen, phosphorus and carbon) under experimental conditions. Different types of media were compared (gravel, sand, and sandy-loam) in vegetated and non-vegetated mesocosms (six treatments in total). Five plant species were used. Vegetated sand and vegetated sandy-loam provided the best overall treatment. Vegetated mesocosms were very effective in removing nitrogen (63-77% removal) and phosphorus (85-94% removal) from synthetic stormwater, and removed substantially more nutrients than the non-vegetated treatments. All treatments removed a substantial portion of the carbon from the stormwater (28-66%). When flushed with tap water, nitrogen and phosphorus were retained by the vegetated mesocosms, but leached from the non-vegetated mesocosms. Plant growth was most vigorous in the sandy-loam media, indicating that this is a good growth media, even without the addition of organic matter.     

负载纳米水合氧化铁活性炭去除水中铅的实验研究

通过共沉淀法制备一种负载纳米水合氧化铁活性炭,研究其对铅的吸附性能、负载前后活性炭的结构的影响,并进行TEM和XRD表征分析。利用动态小柱实验探究不同p H值、进水浓度和空床接触时间对铅吸附能力的影响,同时比较负载前后活性炭处理实际河道水中铅的吸附穿透曲线。结果表明:无定型的纳米水合氧化铁成功负载于活性炭上,负载后的活性炭显著提高了铅的吸附性能,其对铅的吸附容量随p H值、空床接触时间的增大而增加,进水浓度的变化基本不影响铅的吸附容量。以实际河道水为处理对象,得出负载前后的活性炭穿透点运行的床体积分别为1233和11004,显著提高了9倍,表明负载纳米水合氧化铁活性炭可以有效去除实际水体中的铅,具有良好的应用前景。     

Pollutant removal efficiency of alternative filtration media in stormwater treatment.

Sorption experiments were used to assess the ability of various materials (sand, compost, packing wood, ash, zeolite, recycled glass and Enviro-media) to remove heavy metal contaminants typically found in stormwater. Compost was found to have the best physicochemical properties for sorption of metal ions (Cu, Zn and Pb) compared with sand, packing wood, ash, zeolite and Enviro-media. The compost sorption of these metal ions conformed to the linear form of the Langmuir adsorption equation with the Langmuir constants (q,) for Zn(ll) being 11.2 mg/g at pH 5. However, compost was also found to leach a high concentration of dissolved organic carbon (DOC, 4.31 mg/g), compared with the other tested materials. Various combinations of sand, compost and other materials were observed to have excellent heavy metal removal (75-96% of Zn and 90-93% of Cu), with minimal DOC leaching (0.0013-2.43 mg/g). The sorption efficiency of the different Enviro-media mixes showed that a combination of traditional (sand) and alternative materials can be used as an effective medium for the treatment of dissolved metal contaminants commonly found in stormwater. The application of using recycled organic materials and other waste materials (such as recycled glass) also provides added value to the products life cycle.     

The removal of residual organic matter from biologically treated swine wastewater using membrane bioreactor process with powdered activated carbon.

The objective of this study was to characterize the mechanisms of the COD removal in the membrane bioreactor (MBR) process with powdered activated carbon (PAC) addition and to determine its optimal operation, for the removal of residual organic matters (ROM) from biologically treated swine wastewater. The MBR process with PAC showed higher removal efficiency of chemical oxygen demand (COD(Mn)) than that without PAC. When the average COD(Mn) concentration of the influent was 217 mg/L, the average COD(Mn) concentration of the permeate from the MBR with PAC was about 41.5 mg/L, indicating an approximate removal efficiency of 81%. On the other hand, the average COD(Mn) concentration of the permeate from the MBR without PAC was 172 mg/L. The PAC dosage estimated to obtain the above removal efficiency was about 0.74 g per litre of influent. Among the total residual organics removed by PAC-added MBR, 46.5% was removed by PAC adsorption, 20.8% by biodegradation, 4.4% by membrane separation, and 9.3% by enhanced microorganism activity. From these results, the MBR process with PAC was considered as a very useful treatment process for the reduction of COD(Mn) in biologically treated swine wastewater.     

Evaluating Escherichia coli removal performance in stormwater biofilters: a laboratory-scale study

Biofilters are common, low energy technologies used for the treatment of urban stormwater. While they have shown promising results for the removal of stormwater microorganisms, certain factors affect their performance. Hence, this study investigated the effects of particle-microbial interaction, inflow concentration, antecedent microbial levels and plant species on microbial removal capacity. A biofilter column study was set up to evaluate removal performance and a sequential filtration procedure was used to estimate microbial partitioning. The columns were dosed with different concentrations of free phase Escherichia coli only and E. coli mixed with stormwater sediment. Results indicate that the microbial removal is significantly affected by inflow concentration and antecedent microbial levels. Leaching was only observed when a relatively low inflow concentration event occurred within a short period after a very high inflow concentration event. Finally, Lomandra longifolia showed better removal compared with Carex appressa.     

Application of ionic liquids for the removal of heavy metals from wastewater and activated sludge

This paper presents the results of adsorption studies on the removal of heavy metals (Cr, Cu, Cd, Ni, Pb and Zn) from standard solutions, real wastewater samples and activated sewage sludge using a new technique of liquid-liquid extraction using quaternary ammonium and phosphonium ionic liquids (ILs). Batch sorption experiments were conducted using the ILs [PR4][TS], [PR4][MTBA], [A336][TS] and [A336][MTBA]. Removal of these heavy metals from standard solutions were not effective, however removal of heavy metals from the industrial effluents/wastewater treatment plants were satisfactory, indicating that the removal depends mainly on the composition of the wastewater and cannot be predicted with standard solutions. Removal of heavy metals from activated sludge proved to be more successful than conventional methods such as incineration, acid extraction, thermal treatment, etc. For the heavy metals Cu, Ni and Zn, ≥90% removal was achieved.     

粉末活性炭去除原水中阿特拉津突发污染的研究

利用中试装置研究了水源水阿特拉津突发污染的应急处理措施.试验结果表明:常规工艺不能有效去除原水中的阿特拉津,投加粉末活性炭(PAC)可有效去除阿特拉津,确保出水达到水质标准的要求;PAC投量为50 mg/L时,可使初始浓度为200 μg/L的阿特拉津降低到2 μg/L以下;KMnO4与PAC联用的去除效果比单独使用PAC略有改善但并不显著,预氯化则会降低PAC对阿特拉津和UV254的去除率.     

活性炭填充三维电极电解法处理氨氮废水研究

针对传统城市污水处理厂冬天出水存在氨氮浓度偏高的问题,采用间歇试验法对活性炭填充三维电极深度去除污水中的氨氮进行了研究。考察了氨氮初始浓度,电流密度,氯离子浓度,p H值等因素对氨氮去除效果的影响。结果表明:氨氮去除速率随着电流密度和氯离子浓度增加而增加,单位氨氮去除能耗随着电流增加而增加,随着氯离子浓度增加而减少。p H值在3.0~9.0范围内对三维电极除氨氮过程影响比较小。实际废水在经过2.5h电解后,氨氮浓度从28.0 mg/L下降至0.3 mg/L,去除率高达99%,可以满足国家污水排放标准一级A要求。     

Phenol adsorption by activated carbon produced from spent coffee grounds

The present work highlights the preparation of activated carbons (ACs) using spent coffee grounds, an agricultural residue, as carbon precursor and two different activating agents: water vapor (ACW) and K(2)CO(3) (ACK). These ACs presented the microporous nature and high surface area (620-950 m(2) g(-1)). The carbons, as well as a commercial activated carbon (CAC) used as reference, were evaluated as phenol adsorbent showing high adsorption capacity (≈150 mg g(-1)). The investigation of the pH solution in the phenol adsorption was also performed. The different activating agents led to AC with distinct morphological properties, surface area and chemical composition, although similar phenol adsorption capacity was verified for both prepared carbons. The production of activated carbons from spent coffee grounds resulted in promising adsorbents for phenol removal while giving a noble destination to the residue.     

Achieving multiple benefits from stormwater harvesting.

As the concept of integrated urban water management is incorporated into the practice of urban water servicing, new options, such as stormwater harvesting, which can have multiple benefits, are of increasing interest. The multi-functional benefits of stormwater harvesting include the potential to enhance urban stream health through improvements to the flow regime as well as providing a valuable water supply source. This paper synthesises a current research programme being undertaken to assess the viability of, and develop recommendations for, stormwater harvesting. The design of the collection, treatment, storage, flood protection, and distribution components of an integrated system are each discussed, along with the environmental flow consequences of urban stormwater harvesting. The incorporation of swales and biofilters into the collection system was not found to lead to significant exfiltration and evaporation losses in most circumstances and so can be employed as part of the treatment train. Further treatment can be provided by WSUD-type biophysical measures such as ponds, wetlands or novelly designed biofilters or physio-chemical treatment processes. Depending on the design, the stormwater storage component may or may not provide flood protection. In many circumstances, the storage capacity requirements are not considered to be a barrier to stormwater harvesting.     

纳米零价铁/活性炭复合材料去除水中六氯苯的影响因素研究

本文主要研究纳米零价铁/活性炭材料对水中六氯苯(HCB)的去除能力和影响因素。吸附等温研究结果表明该材料对六氯苯的去除符合Langmuir吸附即化学吸附机理。对水中六氯苯和脱氯产物的分析证明纳米零价铁/活性炭对六氯苯的去除包括吸附和脱氯。溶液p H,水中常见阴阳离子的存在等因素都会影响六氯苯去除。低p H对去除有利,这主要是由于低p H对纳米零价铁的氧化过程有利,导致脱氯反应加快。低浓度的HCO-3、Cl-和SO42-能促进六氯苯的去除。这些离子在低浓度时能加快零价铁的腐蚀,对六氯苯的去除有利。而高浓度时则由于铁氧化物沉积会产生抑制作用。NO-3则与六氯苯发生竞争反应,导致六氯苯的去除随硝酸盐的浓度增加而降低。常见的阳离子如Mg2+对六氯苯的去除没有影响。Cu2+和Fe2+的存在不仅改变了溶液的p H,还对纳米零价铁的氧化还原特性有影响。但总体而言,Cu2+和Fe2+的存在对六氯苯的去除是有利的。     

Arsenic removal by iron and manganese coated sand.

In this study, as a promising technique for the treatment of both As(III) and As(V) at the same time in a single reactor, a column reactor containing both manganese-coated sand (MCS) and iron-coated sand (ICS), at different configuration of MCS and ICS, was used to treat wastewater contaminated with As(III). Prior to column experiments, batch experiments for the adsorption of As(V) by ICS were performed with variation of solution pH, ionic strength and types of background ions to investigate the effect of these parameters on the As(V) adsorption behaviour. As(V) adsorption onto ICS was quite similar with the variation of ionic strength by using NaNO3 as a background ion as well as in the presence of different types of background ions except phosphate. The adsorption curves shifted to the lower pH region with the increase of the initial arsenic concentration due to the finite number of adsorption sites on the ICS. For model prediction on the adsorption of As(V) onto ICS, the MINEQL program employing an inner-sphere complexation and a diffuse layer model was used. Model predictions generally agreed well with experimental results. From the column test, column system packed with equal ratio of MCS and ICS was identified as the best system due to a promising oxidation efficiency of As(III) to As(V) by MCS and adsorption of As(V) by both MCS and ICS.