DAT-IAT工艺冬季、夏季有机物去除比较

对天津经济技术开发区污水处理厂采用先进的DAT-IAT工艺进行冬季和夏季的实际运行效果比较,并就DAT池和IAT池在运行中的作用进行分析。研究发现:污水处理厂对BOD的平均去除率在96%以上,对COD的平均去除率在75%左右,均能保证出水达标,对于BOD和COD的去除效果冬季和夏季无明显差别,对SS的去除效果冬季略优于夏季,DAT-IAT工艺系统的抗冲击负荷能力较强,污水处理厂DAT池过高的BOD去除率对后续的脱氮除磷效果会产生不利影响。影响处理效果的原因主要为污水处理厂进水量不充足,水质水量变化大,且ρ(BOD)/ρ(COD)值偏低,不利于生化处理。此外,DAT池的非限制性曝气工艺不仅使BOD在DAT池中过度消耗,影响后续处理,而且浪费能源,建议减少DAT池曝气时间或调整DAT池运行参数。     

Assessing the removal potential of soil-aquifer treatment systems for bulk organic matter.

The fate of effluent organic matter (EfOM) during groundwater recharge was investigated by studying the removal behavior of four bulk organic carbon fractions isolated from a secondary effluent: Hydrophilic organic matter (HPI), hydrophobic acids (HPO-A), colloidal organic matter (OM), and soluble microbial products (SMPs). Short-term removal of the bulk organic fractions during soil infiltration was simulated in biologically active soil columns. Results revealed that the four organic fractions showed a significantly different behavior with respect to biological removal. HPI and colloidal OM were prone to biological removal during initial soil infiltration (0-30 cm) and supported soil microbial biomass growth in the infiltrative surface. Additionally, colloidal OM was partly removed by physical adsorption or filtration. HPO-A and SMPs reacted recalcitrant towards biological degradation as indicated by low soil biomass activity responses. Adsorbability assessment of the biologically refractory portions of the fractions onto powered activated carbon (PAC) indicated that physical removal is not likely to play a significantly role in further diminishing recalcitrant HPO-A, HPI and SMPs during longer travel times in the subsurface.     

Fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration.

Understanding the fate of effluent organic matter (EfOM) and natural organic matter (NOM) through riverbank filtration is essential to assess the impact of wastewater effluent on the post treatment requirements of riverbank filtrates. Furthermore, their fate during drinking water treatment can significantly determine the process design. The objective of this study was to characterise bulk organic matter which consists of EfOM and NOM during riverbank filtration using a suite of innovative analytical tools. Wastewater effluent-derived surface water and surface water were used as source waters in experiments with soil columns. Results showed the preferential removal of non-humic substances (i.e. biopolymers) from wastewater effluent-derived surface water. The bulk organic matter characteristics of wastewater effluent-derived surface water and surface water were similar after 5 m soil passage in laboratory column experiment. Humic-like organic matter in surface water and wastewater effluent-derived surface water persisted through the soil passage. More than 50% of total dissolved organic carbon (DOC) removal with significant reduction of dissolved oxygen (DO) was observed in the top 50 cm of the soil columns for both surface water and wastewater effluent-derived surface water. This was due to biodegradation by soil biomass which was determined by adenosine triphosphate (ATP) concentrations and heterotrophic plate counts. High concentrations of ATP in the first few centimeters of infiltration surface reflect the highest microbial activity which correlates with the extent of DOC reduction. Good correlation of DOC removal with DO and biomass development was observed in the soil columns.     

Membrane-flocculation-adsorption hybrid system in wastewater treatment: micro and nano size organic matter removal .

Cross flow microfiltration with in-line flocculation reduces the fouling of membranes thus leading to high quality product water. A detailed experimental study conducted with an artificial suspension (particle size distribution similar to that of surface water) revealed that the filtration rate can be increased by several times by adopting in-line flocculation. In-line flocculation-microfiltration is therefore an attractive technique to reduce internal clogging while improving the permeate flux significantly. A detailed ultrafiltration (UF) study was conducted with biologically treated sewage effluent with pretreatment by flocculation and powdered activated carbon adsorption. The TOC removal by the NTR 7410 UF membrane alone was 43.6%. The TOC removal increased significantly by the use of pretreatment: 69.3% by flocculation and 91% by flocculation followed by adsorption. The organic colloidal portion (between 3,500 dalton and 0.45 microm) in the biologically treated effluent was removed up to more than 65% by the pretreatment of flocculation. The molecular weight of the biologically treated effluent ranged from 250 to about 3,573 dalton with the highest fraction in the range of 250-845 dalton. By the incorporation of pretreatment, the majority of both large and small molecular weight organic matter was removed. This hybrid system led to practically no filtration flux decline in membrane filtration.     

Recent advances in structure and reactivity of dissolved organic matter: radiation chemistry of non-isolated natural organic matter and selected model compounds

The importance of natural organic matter (NOM) as a source of carbon in natural waters, as the source of reactive oxygen species, or for the complications its presence causes in treatment of natural waters, is undeniable. Recent studies have also pointed to the major photochemical role of triplet excited state of natural organic matter in the environmental fate of pharmaceutical and personal care products (PPCPs) in waters. However, the characterization of NOM is problematic due to its complex molecular structure. One approach to better understand NOM chemistry is the use of model compounds. As the condensation of a plant's phenolic compounds leads to humification and the formation of NOM, a structurally broad group of nine phenolic compounds were selected as model compounds for this study. With methods used in the discipline of radiation chemistry, the oxidative chemistry and transient spectra of these phenols were studied. In addition, the oxidative chemistry and transient spectra of a sample of NOM from the Black River, North Carolina, USA, was characterized. This natural water sample was used as received and represents the first studies of non-isolated NOM by pulsed radiolysis. The results of the transient spectra of the NOM revealed that the radical intermediates were very long lived. This phenomenon was not captured using the nine model compounds suggesting that more complex compounds are needed to further our understanding of the oxidation chemistry of NOM.     

Differentiation of wastewater effluent organic matter (EfOM) from natural organic matter (NOM) using multiple analytical techniques.

Using three analytical techniques of size exclusion chromatography (SEC), fluorescence excitation-emission matrix (EEM), and dissolved organic nitrogen (DON) measurement, differentiating characteristics of effluent organic matter (EfOM) from natural organic matter (NOM) have been investigated. SEC reveals a wide range of molecular weight (MW) for EfOM and high amount of high MW polysaccharides, and low MW organic acids compared to NOM. Clear protein-like peaks using fluorescence EEM were a major feature of EfOM distinguishing it from NOM. Fluorescence index (FI), an indicator to distinguish autochthonous origin from allochthonous origin, differentiated EfOM from NOM by exhibiting higher values, indicating a microbial origin. In EfOM samples, DON present in higher amounts than NOM.     

AOPs with ozone and UV radiation in drinking water: contaminants removal and effects on disinfection byproducts formation.

In this study, the advanced oxidation with ozone and UV radiation (with two low pressure UV lamps, at 254 and 185 nm wavelength) were experimented on a surface water in order to study the removal of two odorous compounds (geosmin and 2-methylisoborneol) and a pesticide (metolachlor), the influence on organic compounds (UV absorbance and THM precursors) and bromate formation. Different batch tests were performed with ozone concentration up to 10 mg/L, UV dose up to 14,000 J/m2 and a maximum contact time of 10 minutes. The main results show that metolachlor can be efficiently removed with ozone alone while for geosmin and MIB a complete removal can be obtained with the advanced oxidation of ozone (with concentration of 1.5-3 mg/L and contact time of 2-3 minutes) with UV radiation (with doses of 5,000-6,000 J/m2). As concerns the influence on the organic precursors, all the experimented processes show a medium removal of about 20-40% for UV absorbance and 15-30% for THMFP (trihalomethanes formation potential). As concerns bromate formation, the advanced oxidation of ozone/UV 254 nm shows a bromate formation that is about 40% lower with respect to conventional oxidation with ozone.     

Three dimensional fluorescent spectroscopy analysis for the evaluation of organic matter removal from industrial estate wastewater by stabilization ponds.

The fluorescent excitation emission matrix (FEEM) was utilized to evaluate the removal of organic matter by stabilization ponds, which consist of aeration, facultative, and oxidation ponds of a central wastewater treatment plant of an industrial estate in northern Thailand. The result shows that six fluorescent peaks of influent wastewater and effluent water after aeration, facultative, and oxidation ponds were detected from the FEEMs at 230 nmEx/295 nmEm (A), 275 nmEx/300 nmEm (B), 240 nmEx/355 nmEm (C), 280 nmEx/355 nmEm (D), 275 nmEx/410 nmEm (E) and 330 nmEx/410 nmEm (F). The putative origins of peaks A and B, C and D, and E and F were tyrosine-like, tryptophan-like, and humic and fulvic acid-like substances, respectively. The aeration pond was the main course of action used to reduce the tyrosine-like substances at peaks A and B by 88 and 52%, respectively, and tryptophan-like substances at peaks C and D by 43 and 39%, respectively. There was only a 20 per cent decrease of humic and fulvic acid-like substances at peak E and an 18 per cent decrease at peak F through the use of aeration ponds. Total per cent reductions of total fluorescent organic matter after aeration ponds; facultative ponds; and oxidation ponds were 46, 51 and 54%, respectively. These values were notably similar to the total percent reduction of DOC by the same respective processes at 54, 53, and 55%.     

细骨料中有机质对混凝土性能的影响

本文就细骨料中有机质对水泥砂荣和混凝土性能的影响程度进行了试验分析,论证了有机质超标的细骨料在水工混凝土中应用的可行性.     

The role of plant uptake on the removal of organic matter and nutrients in subsurface flow constructed wetlands: a simulation study.

Plants in constructed wetlands have several functions related to the treatment processes. It is generally agreed that nutrient uptake is a minor factor in constructed wetlands treating wastewater compared to the loadings applied. For low loaded systems plant uptake can contribute a significant amount to nutrient removal. The contribution of plant uptake is simulated for different qualities of water to be treated using the multi-component reactive transport module CW2D. CW2D is able to describe the biochemical elimination and transformation processes for organic matter, nitrogen and phosphorus in subsurface flow constructed wetlands. The model for plant uptake implemented describes nutrient uptake coupled to water uptake. Literature values are used to calculate potential water and nutrient uptake rates. For a constructed wetland treating municipal wastewater a potential nutrient uptake of about 1.9% of the influent nitrogen and phosphorus load can be expected. For lower loaded systems the potential uptake is significantly higher, e.g. 46% of the nitrogen load for treatment of greywater. The potential uptake rates could only be simulated for high loaded systems i.e. constructed wetlands treating wastewater. For low loaded systems the nutrient concentrations in the liquid phase were too low to simulate the potential uptake rates using the implemented model for plant uptake.     

Wastewater dissolved organic matter: characteristics and sorptive capabilities.

An evaluation of the mobility of organic pollutants with wastewater dissolved organic matter (DOM) is essential to better understanding their fate and toxicity to the environment. In this study, DOM from two wastewater treatment plants (in Lachish and Netanya, Israel) were fractionated to hydrophobic-acid (HoA) and hydrophobic-neutral (HoN) fractions. The fractions were characterised and their sorptive capabilities for s-triazine herbicides and polycyclic aromatic hydrocarbons (PAHs) were studied. For all sorbates, binding to the HoN fractions was much higher than to HoA fractions. The high binding coefficients obtained for the studied triazines by the HoN fractions suggested that their sorption is governed by hydrophobic-like interactions rather than H-bonding. The binding coefficients of PAHs measured for the HoN fractions were within the range reported for humic acids and much higher than for the HoA fraction, suggesting that the HoN fraction plays an important role in the overall sorption of these compounds by DOM. Higher sorption coefficients were measured for the Netanya DOM sample containing a higher level of hydrophobic fractions (HoA + HoN) than the Lachish DOM, suggesting that the sorption of hydrophobic organic compounds by DOM is governed by the relative content of these structural substances.     

核晶凝聚诱导造粒法同步去除硬度和有机物的研究

针对石油废水中无机离子与有机物共存的特点,构建了一体化核晶凝聚诱导造粒装置,探究了该体系对石油废水中总硬度和溶解性有机物的去除效果和去除原理.研究结果表明:当氢氧化钠投加量为250 mg/L时,总硬度、钙离子和COD的去除率分别为88.35％、90％和52.92％.结合SEM和XRD表征结果发现钙离子主要以碳酸钙形式附...     

Effect of recirculation on organic matter removal in a hybrid constructed wetland system

This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems caused by small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 years in order to show applicability of these systems. The present study involves removal of organic matter and suspended solids in serially operated horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands. The pilot-scale wetland was constructed downstream of anaerobic reactors at the campus of TUBITAK-MRC. Anaerobically pretreated wastewater was introduced into this hybrid two-stage sub-surface flow wetland system (TSCW). Wastewater was first introduced into the horizontal sub-surface flow system and then the vertical flow system before being discharged. Recirculation of the effluent was tested in the system. When the recirculation ratio was 100%, average removal efficiencies for TSCW were 91 +/- 4% for COD, 83 +/- 10% for BOD and 96 +/- 3% for suspended solids with average effluent concentrations of 9 +/- 5 mg/L COD, 6 +/- 3 mg/L BOD and 1 mg/L for suspended solids. Comparing non-recirculation and recirculation periods, the lowest effluent concentrations were obtained with a 100% recirculation ratio. The effluent concentrations met the Turkish regulations for discharge limits of COD, BOD and TSS in each case. The study showed that a hybrid constructed wetland system with recirculation is a very effective method of obtaining very low effluent organic matter and suspended solids concentrations downstream of anaerobic pretreatment of domestic wastewaters in small communities.     

阳澄湖原水中溶解性有机物去除规律研究

考察原水—预臭氧—混凝沉淀—砂滤—后臭氧—生物活性炭—氯消毒工艺对阳澄湖原水中溶解性有机物(Dissolved organic matter,DOM)的去除规律,结果表明阳澄湖原水溶解性有机碳(Dissolved organic carbon,DOC)与紫外吸光度UV254总体呈现夏季高、冬季低的特征,随着原水DOC与UV254的降低,各工艺单元对DOC与UV254的去除率也逐渐降低,去除率分别在29.2％?44.3％与55.4％?66.5％.对UV254的去除优于DOC,常规处理工艺优于深度处理工艺,对大分子的去除优于小分子.平行因子分析法(Parallel factor analysis,PARAFAC)分析三维荧光光谱确定阳澄湖水样DOM由4组分构成,类蛋白类色氨酸C1、类酪氨酸C2、氨基酸或蛋白质C4,以及类腐殖质紫外区类富里酸C3.该工艺流程对C2、C3、C4去除率总体呈现上升趋势,达到30.1％、70.7％和43.4％.     

Effect of external organic matter on nutrient removal and growth of Phragmites australis in a laboratory-scale subsurface-flow treatment wetland.

Coconut dust, which is used intensively in horticultural applications, was tested as an external organic additive in a series of laboratory-scale subsurface-flow constructed wetlands planted with Phragmites australis. The systems were fed with a mixture of NO3(-)-N, NH4+-N, and SRP in tap water to simulate high nutrient loads. In the absence of plants, TN removal efficiency was 66%, and the efficiency increased to > 80% in the microcosm wetlands. TN and NO3- removal efficiencies were marginally increased by coconut-dust treatment in comparison with sand-bed microcosms. Analysis by ANOVA showed that the TN removal from a coconut dust-supplemented sand-bed microcosm was significantly different from a sand-bed microcosm (0.0437 < p < 0.05). All the systems showed an equal capacity to treat NH4+ nitrogen under low influent concentration levels. Phosphorus removal efficiencies were > 98% in all three systems, and a difference between planted and unplanted systems was not observed. Shoot height and shoot densities of P. australis grown in the coconut dust-supplemented medium were significantly higher than those grown in the sand-bed medium. The difference in P. australis growth in response to the coconut dust addition revealed that the added material has the potential to create favourable conditions for plant growth.     

Comparing the effluent organic matter removal of direct NF and powdered activated carbon/NF as high quality pretreatment options for artificial groundwater recharge.

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization.     

Sterols: a tracer of organic matter in combined sewers.

The important organic pollution of combined wet weather flows (WWF), its acute impact on receiving waters have been widely demonstrated. The main three possibly origins for this organic pollution are: runoff water (streets and roofs), wastewater and erosion of sewer sediments in combined sewer system. This work, for tracing the origin of organic particles bound in combined sewer system, has been focused on the innovative use of sterols. So, eight sterols have been selected and analysed for each kind of sample. Results are represented in contents of sterols (microg g(-1)) and in sterol profiles (%).The comparison of contents and profiles leads the separation between two groups: runoff water, characterized by the total absence of coprostanol, epicoprostanol and coprostanone, and the group of sewer deposits (gross bed sediment (GBS), organic layer (OL), biofilms) and wastewater. Moreover, sewer deposits and wastewater can be distinguished by their sterol contents and profiles. To evaluate their contribution to WWF a comparison between sterol signatures is done which shows that these effluents have a strong similarity in profiles and in contents of sterols to the organic layer.     

常规处理工艺对可同化有机碳去除特性的研究

对镇江市金西水厂常规处理工艺去除饮用水中可同化有机碳的特性进行了研究。试验结果表明原水与出厂水中AOC浓度波动较大,分别为41~178μg/L和47~198μg/L,均属于饮用水生物稳定性临界区间;因氯氧化、混凝沉淀和砂滤等共同作用,常规处理工艺对总AOC、AOC-P17、AOC-NOX的去除率分别为-13%、17.1%与-83.3%,且受水温影响明显;常规处理工艺改变了水中AOC的组成比例,出厂水中AOC-NOX所占比例由30%升至49%。     

Identification of humic acid-like and fulvic acid-like natural organic matter in river water using fluorescence spectroscopy

Identifying the extent of humic acid (HA)-like and fulvic acid (FA)-like natural organic matter (NOM) present in natural water is important to assess disinfection by-product formation and fouling potential during drinking water treatment applications. However, the unique fluorescence properties related to HA-like NOM is masked by the fluorescence signals of the more abundant FA-like NOM. For this reason, it is not possible to accurately characterize HA-like and FA-like NOM components in a single water sample using direct fluorescence EEM analysis. A relatively simple approach is described here that demonstrates the feasibility of using a fluorescence excitation-emission matrix (EEM) approach for identifying HA-like and FA-like NOM fractions in water when used in combination with a series of pH adjustments and filtration steps. It is demonstrated that the fluorescence EEMS of HA-like and FA-like NOM fractions from the river water sample possessed different spectral properties. Fractionation of HA-like and FA-like NOM prior to fluorescence analysis is therefore proposed as a more reasonable approach.     

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.