Combined chemical and biological oxidation of penicillin formulation effluent

Antibiotic formulation effluent is well known for its important contribution to environmental pollution due to its fluctuating and recalcitrant nature. In the present study, the chemical treatability of penicillin formulation effluent (average filtered COD(o)=830 mg/l; average soluble COD(o)=615 mg/l; pH(o)=6.9) bearing the active substances penicillin Amoxicillin Trihydrate (C(16)H(19)N(3)O(5)S.3H(2)O) and the beta-lactamase inhibitor Potassium Clavulanate (C(8)H(8)KNO(5)) has been investigated. For this purpose, the penicillin formulation effluent was subjected to ozonation (applied ozone dose=2500 mg/(lxh)) at varying pH (2.5-12.0) and O(3)+H(2)O(2) (perozonation) at different initial H(2)O(2) concentrations (=2-40 mM) and pH 10.5. According to the experimental results, the overall Chemical Oxygen Demand (COD) removal efficiency varied between 10 and 56% for ozonation and 30% (no H(2)O(2)) and 83% (20 mM H(2)O(2)) for the O(3)+H(2)O(2) process. The addition of H(2)O(2) improved the COD removal rates considerably even at the lowest studied H(2)O(2) concentration. An optimum H(2)O(2) concentration of 20 mM existed at which the highest COD removal efficiency and abatement kinetics were obtained. The ozone absorption rate ranged between 53% (ozonation) and 68% (perozonation). An ozone input of 800 mg/l in 20 min was sufficient to achieve the highest BOD(5)/COD (biodegradability) ratio (=0.45) and BOD(5) value (109 mg/l) for the pre-treated penicillin formulation effluent. After the establishment of optimum ozonation and perozonation conditions, mixtures of synthetic domestic wastewater+raw, ozonated and perozonated penicillin formulation effluent were subjected to biological activated sludge treatment at a food-to-microorganisms (F/M) ratio of 0.23 mg COD/(mg MLSSxd), using a consortium of acclimated microorganisms. COD removal efficiencies of the activated sludge process were 71, 81 and 72% for pharmaceutical wastewater containing synthetic domestic wastewater mixed with either raw, ozonated or perozonated formulation effluent, respectively. The ultimate COD value obtained after 24-h biotreatment of the synthetic domestic wastewater+pre-ozonated formulation effluent mixture was around 100 mg/l instead of 180 mg/l which was the final COD obtained for the wastewater mixture containing raw formulation effluent, indicating that pre-ozonation at least partially removed the non-biodegradable COD fraction of the formulation effluent.     

Merits of ozonation and catalytic ozonation pre-treatment in the algal treatment of pulp and paper mill effluents

Since the performance of algal treatment for pulp mill effluent decreases with increasing color intensity and AOX content, which mainly originate from the chlorine bleaching of Kraft pulp, the separated CEH bleaching effluent was pre-treated by both the conventional and the heterogeneous catalytic ozonation processes. An increase in the BOD(5)/COD ratio from 0.11 to 0.28 and 87% color abatement in terms of Pt-Co were achieved by catalytic ozonation, which had the best treatment performance. Biodegradability enhancement of the CEH effluent correlated well with a decrease in toxicity, high-molecular-weight-compound content, and AOX abatement. By the pre-treatment of the CEH bleaching effluent, the overall efficiencies of algal treatment of the combined pulp mill effluent in terms of the fractional removal of COD and color were increased from 76% and 53% to 86-90% and 96-99%, respectively. Effects of both the conventional and the catalytic ozonation pre-treatments on subsequent biological treatment were close to each other and they reduced the filling period of the Sequential Batch Reactor (SBR) cycle from 8 to 5 days.     

Fenton法处理垃圾渗滤液技术的研究及应用

Fenton法是一种非常有效的高级氧化技术,已经逐渐应用于含有难降解有机物废水处理领域中。本文论述了Fenton法、Photo-Fenton法、电-Fenton以及类Fenton技术处理垃圾渗滤液的研究进展;分析了不同技术产生羟基自由基的原理、技术的主要影响因素以及技术的研究方向,并指出了这些技术在工程化应用方面的关键技术要点,旨在为该技术的工程化应用提供实践支持。     

Comparison of Diuron degradation by direct UV photolysis and advanced oxidation processes

The rates of Diuron elimination by some advanced oxidation processes (AOPs) such as Fe(III)/UV, Ferrioxalate/UV, Fe(III)/H(2)O(2)/UV, Ferrioxalate/UV/H(2)O(2) and Fe(III)/H(2)O(2) have been compared. Experiments have been conducted at pH=2.3+/-0.1 with a batch reactor equipped with a low-pressure mercury lamp emitting mainly at 253.7nm. Data obtained under the following experimental conditions ([H(2)O(2)](0)=10(-3)M, [Diuron](0)=5x10(-5)M and [Fe(III)](0)=10(-3)M) have shown that rates of Diuron oxidation were higher with the systems Fe(III)/H(2)O(2)/UV and Ferrioxalate/UV/H(2)O(2) than with Fe(III)/UV and Fe(III)/H(2)O(2). On the other hand, Fe(III)/UV was found to be very efficient in mineralization of Diuron solution in comparison to direct UV photolysis. The experimental results showed that radical ()OH is the major pathway in the process of Diuron degradation.     

Dissolved organic carbon dynamics in a riparian aquifer: effects of hydrology and nitrate enrichment

The capacity of riparian soils to remove nitrate (NO3) from ground water is well established, but the effects of ground water NO3(-)-enrichment on C dynamics are not well studied. We incubated horizontal cores of aquifer material extracted from beneath moderately well-drained (MWD) and poorly drained (PD) soils in a riparian forest in Rhode Island, USA for 132 d, and dosed (flow rate, 170 mL d(-1); dissolved O2, 2 in PD and 5 mg L(-1) in MWD cores) with ground water amended with either Br-, Br(-)+ NO3- (10 mg N L(-1)), or Br(-) + NO3(-) + DOC (20 mg C L(-1)). The DOC was extracted from forest floor material and added during the first 56 d of the experiment. Addition of NO3- had limited effect on CO2 production while DOC amendment had a significant effect in the PD but not in the MWD mesocosms. Total CO2 production (mg CO2-C kg(-1) soil) was 6.3, 7.0, and 10.1 in the PD and 3.6, 4.0, and 4.5 in the MWD cores amended with Br-, Br(-) + NO3-, and Br(-) + NO3(-) + DOC, respectively. Carbon balance (C(bal) = DOC(in) - (DOC(out) + CO2-C) showed a net C retention of 8.0 mg C kg(-1) soil in the DOC-amended MWD cores (equivalent to 50% of the DOC added), and a net C loss of 8.3 mg C kg(-1) soil in similarly treated PD cores. The lack of C retention in the PD cores was ascribed to reductive dissolution of minerals implicated in DOC sorption. These findings underscore that there is marked variation in C dynamics in riparian aquifers that has the potential to influence the fate of NO3- and DOC in the landscape.     

油田含油污水高级氧化技术研究

以气浮—过滤预处理后的污水为处理对象,通过臭氧氧化与Fenton氧化两种方法处理油田含油污水。经实验验证:Fenton在pH为4,H2O2初始浓度为0.08mol/L,Fe2+与H2O2的摩尔比为1:10,H2O2与CODCr的质量比为1:1,反应时间为60min的条件下,去除率达54.3%(CODCr100mg/L),可达到GB8978-1996《污水综合排放标准》二级标准。     

H2O2／Fe^2＋氧化偶合混凝法处理干膜废水的研究

本文研究了H2O2／Fe^2＋氧化偶合混凝法处理印刷电路板厂干膜废水。讨论了包括过氧化氢浓度、亚铁离子浓度、pH值、时间和混凝pH值等影响因素,试验结果表明,当过氧化氢浓度为457.0mg/L、铁离子浓度为400mg/L、氧化pH值4.0、反温度为40℃、反应时间180min时,COD去除率达84.7%,出水的水质达到排放标准。     

Dissolved organic carbon in runoff and tile-drain water under corn and forage fertilized with hog manure

Dissolved organic carbon (DOC) export from soils can play a significant role in soil C cycling and in nutrient and pollutant transport. However, information about DOC losses from agricultural soils as influenced by management practices is scarce. We compared the effects of mineral fertilizer (MF) and liquid hog manure (LHM) applications on the concentration and molecular size of DOC released in runoff and tile-drain water under corn (Zea mays L.) and forage cropping systems. Runoff and tile-drain water samples were collected during a 2-mo period (October to December 1998) and DOC concentration was measured. Characterization of DOC was performed by tangential ultrafiltration with nominal cut-offs at 3 and 100 kDa. Mean concentration of DOC in runoff water (12.7 mg DOC L(-1)) was higher than in tile-drain water (6.5 mg DOC L(-1)). Incorporation of corn residues increased the DOC concentration by 6- to 17-fold in surface runoff, but this effect was short-lived. In runoff water, the relative size of the DOC molecules increased when corn residues and LHM were applied probably due to partial microbial breakdown of these organic materials and to a faster decomposition or preferential adsorption of the small molecules. The DOC concentration in tile-drain water was slightly higher under forage (7.5 mg DOC L(-1)) than under corn (5.4 mg DOC L(-1)) even though the application rates of LHM were higher in corn plots. We suggest that preferential flow facilitated the migration of DOC to tile drains in forage plots. In conclusion, incorporation of corn residues and LHM increased the concentration of DOC and the relative size of the molecules in surface runoff water, whereas DOC in tile-drain water was mostly influenced by the cropping system with relatively more DOC and larger molecules under forage than corn.     

光助氧化技术在水处理中应用

对UV／H2O2技术、UV／O3技术、UV／O3／H2O2技术、photo—Fenton技术以及UV／TiO2技术进行了总结,对不同技术的原理、研究进展及应用进行了评述,并对今后光助氧化技术的研究方向提出了一些建议。     

Costs of the electrochemical oxidation of wastewaters: a comparison with ozonation and Fenton oxidation processes

In the work described here the technical and economic feasibilities of three Advanced Oxidation Processes (AOPs) have been studied: Conductive-Diamond Electrochemical Oxidation (CDEO), Ozonation and Fenton oxidation. The comparison was made by assessing the three technologies with synthetic wastewaters polluted with different types of organic compounds and also with actual wastes (from olive oil mills and from a fine-chemical manufacturing plant). All three technologies were able to treat the wastes, but very different results were obtained in terms of efficiency and mineralization. Only CDEO could achieve complete mineralization of the pollutants for all the wastes. However, the efficiencies were found to depend on the concentration of pollutant (mass transfer control of the oxidation rate). Results obtained in the oxidation with ozone (at pH 12) or by Fenton's reagent were found to depend on the nature of the pollutants, and significant concentrations of oxidation-refractory compounds were usually accumulated during the treatment. Within the discharge limits that all of the technologies can reach, the economic analysis shows that the operating cost of Fenton oxidation is lower than either CDEO or ozonation, although CD\EO can compete satisfactorily with the Fenton process in the treatment of several kinds of wastes. Likewise, the investment cost for the ozonation process seems to be higher than either CDEO or Fenton oxidation, regardless of the pollutant treated.     

Fenton试剂处理六氯苯废水的试验研究

研究了采用Fenton法处理六氯苯模拟废水的方法以及Fenton法处理六氯苯的影响因素。研究结果显示:在H2O2(30%)投加量为500mg/L,Fe2 投加量为1000mg/L,pH=2.5的条件下,经过4h的反应,废水中HCB去除率可达51.65%。     

Advanced oxidation treatment of pulp mill effluent for TOC and toxicity removals

Pulp mill effluent was treated by different advanced oxidation processes (AOPs) consisting of UV, UV/H2O2, TiO2-assisted photo-catalysis (UV/TiO2) and UV/H2O2/TiO2 in lab-scale reactors for total organic carbon (TOC) and toxicity removals. Effects of some operating parameters such as the initial pH, oxidant and catalyst concentrations on TOC and toxicity removals were investigated. Almost every method resulted in some degree of TOC and toxicity removal from the pulp mill effluent. However, the TiO2-assisted photo-catalysis (UV/TiO2) resulted in the highest TOC and toxicity removals under alkaline conditions when compared with the other AOPs tested. Approximately, 79.6% TOC and 94% toxicity removals were obtained by the TiO2-assisted photo-catalysis (UV/TiO2) with a titanium dioxide concentration of 0.75gl(-1) at pH 11 within 60min.     

Treatment of E. coli HB101 and the tetM gene by Fenton’s reagent and ozone in cow manure

The destruction of antibiotic-resistant microorganisms at the source of contamination is necessary due to their adverse effects and to their increasingly widespread occurrence in the environment. To address this problem, Fenton and ozone oxidation processes were applied to synthetically contaminated cow manure to remove the tetM gene and its host, Escherichia coli HB101. The efficiency of the processes was evaluated by enumeration of E. coli HB101 and by PCR amplification of the tetM gene. The results of this study show that 56.60% bacterial inactivation (corresponding to a 0.36 log reduction) was achieved by a Fenton reagent dose of 50 mM H₂O₂ and 5 mM Fe²⁺ without acidifying the manure. Despite the high organic content of cow manure, 98.50% bacterial inactivation (corresponding to a 1.83 log reduction) was obtained by the ozonation process with an applied dose of 3.125 mg ozone/g manure slurry. The PCR study revealed that the band intensity of the tetM gene gradually decreased by increasing the Fenton reagent and the applied ozone dose. However, significantly high doses of oxidants would be required to completely eliminate bacterial pollution in manure.     

Upflow column reactor design for dechlorination of chlorinated pulping wastes by Penicillium camemberti

A Penicillium camemberti strain isolated in our laboratory has been studied for its ability to degrade chlorinated pulping wastes, presumably containing a variety of chlorinated polyphenols. In batch tests, the highest removals (76% AOX, 61% color and 65% TOC) were obtained with 0.2 g/l feed acetate concentration. The tendency of the fungus to dechlorinate bleachery effluents better under non-shaking conditions and to attach onto surfaces suggested the use of immobilized cells rather than freely suspended ones in further exploitation of the process. An upflow glass wool packed column reactor established with this fungus could be operated for nearly two years in the laboratory. At best around 70% AOX could be removed from chlorinated pulping wastes in 7.3 h of contact with no aeration and with a minimal amount of carbon supplement (0.2 g/l). Finally, an asymptotic mathematical formula for determining Michaelis-Menten kinetic rates has been derived. The kinetic rates K(m) (the Michaelis constant or saturation constant for the substrate) and V(m) (the product of maximum rate for the enzymatic reaction and biomass concentration) were then calculated as 126.386 mg/l and 2.83017 mg/lh, respectively.     

Spatial and Seasonal Variation of Dissolved Organic Carbon (DOC) Concentrations in Irish Streams: Importance of Soil and Topography Characteristics

Dissolved organic carbon (DOC) concentrations have increased in many sites in Europe and North America in recent decades. High DOC concentrations can damage the structure and functions of aquatic ecosystems by influencing water chemistry. This study investigated the spatial and seasonal variation of DOC concentrations in Irish streams across 55 sites at seven time occasions over 1 year (2006/2007). The DOC concentrations ranged from 0.9 to 25.9 mg/L with a mean value of 6.8 and a median value of 5.7 mg/L and varied significantly over the course of the year. The DOC concentrations from late winter (February: 5.2 ± 3.0 mg/L across 55 sites) and early spring (April: 4.5 ± 3.5 mg/L) had significantly lower DOC concentrations than autumn (October: mean 8.3 ± 5.6 mg/L) and early winter (December: 8.3 ± 5.1 mg/L). The DOC production sources (e.g., litterfall) or the accumulation of DOC over dry periods might be the driving factor of seasonal change in Irish stream DOC concentrations. Analysis of data using stepwise multiple linear regression techniques identified the topographic index (TI, an indication of saturation-excess runoff potential) and soil conditions (organic carbon content and soil drainage characteristics) as key factors in controlling DOC spatial variation in different seasons. The TI and soil carbon content (e.g., soil organic carbon; peat occurrence) are positively related to DOC concentrations, while well-drained soils are negatively related to DOC concentrations. The knowledge of spatial and seasonal variation of DOC concentrations in streams and their drivers are essential for optimum riverine water resources management.     

Sorption and fractionation of dissolved organic matter and associated phosphorus in agricultural soil

Mobility of dissolved organic matter (DOM) strongly affects the export of nitrogen (N) and phosphorus (P) from soils to surface waters. To study the sorption and mobility of dissolved organic C and P (DOC, DOP) in soil, the pH-dependent sorption of DOM to samples from Ap, EB, and Bt horizons from a Danish agricultural Humic Hapludult was investigated and a kinetic model applicable in field-scale models tested. Sorption experiments of 1 to 72 h duration were conducted at two pH levels (pH 5.0 and 7.0) and six initial DOC concentrations (0-4.7 mmol L(-1)). Most sorption/desorption occurred during the first few hours. Dissolved organic carbon and DOP sorption decreased strongly with increased pH and desorption dominated at pH 7, especially for DOC. Due to fractionation during DOM sorption/desorption at DOC concentrations up to 2 mmol L(-1), the solution fraction of DOM was enriched in P indicating preferred leaching of DOP. The kinetics of sorption was expressed as a function of how far the solution DOC or DOP concentrations deviate from "equilibrium." The model was able to simulate the kinetics of DOC and DOP sorption/desorption at all concentrations investigated and at both pH levels making it useful for incorporation in field-scale models for quantifying DOC and DOP dynamics.     

Effects of TiO2 based photocatalytic paint on concentrations and emissions of pollutants and on animal performance in a swine weaning unit

The beneficial effect of a TiO2-based photocatalytic treatment on the indoor air purification of a swine farm has been evaluated in a trial performed in two identical mechanically ventilated traditional weaning units, with 391 animals lodged in each of them. One unit was used as reference, whereas the walls of the second unit (260 m2) were coated with ca. 70 g m(-2) of TiO2 and irradiated with ten UV-A lamps. The environmental parameters (i.e. the ventilation rate, the internal and external temperature and relative humidity), together with NH3, CH4, CO2 and N2O concentrations in the exhaust ducts and PM10 emissions, were monitored in the two units throughout all of the production cycle (75 days). Significant decreases in CH4 concentration (ca. 27%, P < 0.05) and PM10 emission (ca. 17%, P < 0.01) were observed, together with an increase of the piglets' productive performance in the treated unit with respect to the reference one. Indeed, the ADG (Average Daily Gain of piglets) was 424 g vs. 414 g for the piglets lodged in the two units, respectively, with a significantly better feed conversion ratio (FCR, ratio between the food ingested by the animals and their weight gain) of 2.18 vs. 2.44 (P < 0.001). Therefore, the photocatalytic treatment with TiO2 coating had positive effects not only on methane concentration and particulate matter concentration and emission, but also significantly improved the feed conversion ratio of growing piglets, very likely due to the increased quality of indoor air, with positive economic repercussions for the farmer. Internal photocatalytic treatment in swine husbandry could thus be considered as a potential Best Available Technology (BAT).     

Dissolved organic carbon fluxes under bare soil

The flux of dissolved organic carbon (DOC) in soil facilitates transport of nutrients and contaminants in soil. There is little information on DOC fluxes and the relationship between DOC concentration and water flux in agricultural soils. The DOC fluxes and concentrations were measured during 2.5 yr using 30 automatic equilibrium tension plate lysimeters (AETPLs) at 0.4 m and 30 AETPLs at 1.20-m depth in a bare luvisol, previously used as an arable soil. Average annual DOC fluxes of the 30 AETPLS were 4.9 g C m(-2) y(-1) at 0.4 m and 2.4 g C m(-2) y(-1) at 1.2 m depth. The average leachate DOC concentrations were 17 mg C L(-1) (0.4 m) and 9 mg C L(-1) (1.2 m). The DOC concentrations were unrelated to soil moisture content or average temperature and rarely dropped below 9 mg C L(-1) (0.4 m) and 5 mg C L(-1) (1.2 m). The variability in cumulative DOC fluxes among the plates was positively related to leachate volume and not to average DOC concentrations at both depths. This suggests that water fluxes are the main determinants of spatial variability in DOC fluxes. However, the largest DOC concentrations were inversely proportional to the mean water velocity between succeeding sampling periods, suggesting that the maximal net DOC mobilization rate in the topsoil is limited. Elevated DOC concentrations, up to 90 mg C L(-1), were only observed at low water velocities, reducing the risks of DOC-facilitated transport of contaminants to groundwater. The study emphasizes that water flux and velocity are important parameters for DOC fluxes and concentrations.     

Persistent elevated nitrate in a riparian zone aquifer

Streamside vegetated buffer strips (riparian zones) are often assumed to be zones of ground water nitrate (NO3(-)) attenuation. At a site in southwestern Ontario (Zorra site), detailed monitoring revealed that elevated NO3(-) -N (4-93 mg L(-1)) persisted throughout a 100-m-wide riparian floodplain. Typical of riparian zones, the site has a soil zone of recent river alluvium that is organic carbon (OC) rich (36 +/- 16 g kg(-1)). This material is underlain by an older glacial outwash aquifer with a much lower OC content (2.3 +/- 2.5 g kg(-1). Examination of NO3(-), Cl(-), SO4(2-), and dissolved organic carbon (DOC) concentrations; N/Cl ratios; and NO3(-) isotopic composition (delta15N and delta18O) provides evidence of four distinct NO3(-) source zones within the riparian environment. Denitrification occurs but is incomplete and is restricted to a narrow interval located within ~0.5 m of the alluvium-aquifer contact and to one zone (poultry manure compost zone) where elevated DOC persists from the source. In older ground water close to the river discharge point, denitrification remains insufficient to substantially deplete NO3(-). Overall, denitrification related specifically to the riparian environment is limited at this site. The persistence of NO3(-) in the aquifer at this site is a consequence of its Pleistocene age and resulting low OC content, in contrast to recent fluvial sediments in modern agricultural terrain, which, even if permeable, usually have zones enriched in labile OC. Thus, sediment age and origin are additional factors that should be considered when assessing the potential for riparian zone denitrification.     

UV/Fenton光解处理含三唑磷废水的研究

采用类UV／Fenton法对模拟三唑磷废水进行处理。在模拟废水中人工投加H2O2和Fe^3＋试剂能产生类Fenton试剂，类Fenton试剂在光照条件过程中可以产生大量活性羟基．OH，能够很好地氧化降解废水中的有机化合物。本方法可以有效的处理低浓度的含三唑磷的废水，提供三唑磷农药水样的UV／Fenton催化氧化过程的一级动力学方程。