Solid phase extraction and HPLC determination of veterinary pharmaceuticals in wastewater

This work focuses on the application of SPE-HPLC analysis of important veterinary pharmaceuticals from different classes in highly complex wastewater matrix. The pharmaceutical investigated included three sulfonamides (sulfamethazine, sulfadiazine and sulfaguanidine), a sulfonamide synergist (trimethoprim), a tetracycline (oxytetracycline), a fluoroquinolone (enrofloxacine) and a β-lactame (penicillin G/procaine). The method involves pre-concentration and clean-up by solid phase extraction (SPE) using Oasis HLB extraction catridges. Final analysis of the selected pharmaceutical compounds was carried out by high-performance liquid chromatography (HPLC) coupled with diode array detector (DAD). Recoveries were ranged from 68.3 to 97.9% with relative standard deviation below 8.4%. Only for sulfaguanidine low recovery was obtained. Limits of quantification were in the range 1.5-100 μg/L depending on pharmaceutical. The described method was applied to the determination of pharmaceuticals in wastewater samples from pharmaceutical industry.     

Development and characterisation of disposable gold electrodes, and their use for lead(II) analysis

There is an increasing need to assess the harmful effects of heavy-metal-ion pollution on the environment. The ability to detect and measure toxic contaminants on site using simple, cost effective, and field-portable sensors is an important aspect of environmental protection and facilitating rapid decision making. A screen-printed gold sensor in a three-electrode configuration has been developed for analysis of lead(II) by square-wave stripping voltammetry (SWSV). The working electrode was fabricated with gold ink deposited by use of thick-film technology. Conditions affecting the lead stripping response were characterised and optimized. Experimental data indicated that chloride ions are important in lead deposition and subsequent analysis with this type of sensor. A linear concentration range of 10–50 μg L⁻¹ and 25–300 μg L⁻¹ with detection limits of 2 μg L⁻¹ and 5.8 μg L⁻¹ were obtained for lead(II) for measurement times of four and two minutes, respectively. The electrodes can be reused up to 20 times after cleaning with 0.5 mol L⁻¹ sulfuric acid. Interference of other metals with the response to lead were also examined to optimize the sensor response for analysis of environmental samples. The analytical utility of the sensor was demonstrated by applying the system to a variety of wastewater and soil sample extracts from polluted sites. The results are sufficient evidence of the feasibility of using these screen-printed gold electrodes for the determination of lead(II) in wastewater and soil extracts. For comparison purposes a mercury-film electrode and ICP–MS were used for validation.     

Trace analysis and occurrence of anhydroerythromycin and tylosin in influent and effluent wastewater by liquid chromatography combined with electrospray tandem mass spectrometry

Two wastewater treatment plants (WWTPs) of northern Colorado were monitored for anhydroerythromycin and tylosin. An analytical method has been developed and validated for the trace determination and confirmation of these compounds in the raw influent and final effluent water matrices. This method was used to evaluate the occurrence and fate of these compounds in WWTPs. The method uses solid-phase extraction and liquid chromatography–tandem mass spectrometry with positive electrospray ionization. Detection and quantification was performed using selected reaction monitoring, and a method detection limit of between 0.01 and 0.06 μg/L was obtained. Unequivocal confirmation analysis of analyte identity according to the criteria (based on the use of identification points) of the 2002/657/EC European Commission Decision was possible with satisfactory results. Average recoveries for the two compounds ranged from 89.2±9.7% for raw influent to 93.7±6.9% for effluent wastewaters. The within-run precision of the assay was found to be always less than 14.1% for the two analytes. The overall precision was always less than 13.7%. The relative uncertainty of the present assay was also evaluated and the combined relative uncertainty ranged from 6.4 to 15.5% over three days of the validation study. These compounds were partially removed in the WWTPs with a removal efficiency of >50%. The measured concentrations in raw influents and effluents ranged from 0.09–0.35 and 0.04–0.12 μg/L for anhydroerythromycin to 0.06–0.18 and ND–0.06 μg/L for tylosin, respectively. The results indicate that WWTP effluents are relevant point sources for residues of these compounds in the aquatic environment. These occurrence results were compared with those in WWTP wastewaters of other countries.     

Analytical approaches for Hg determination in wastewater samples by means of total reflection X-ray fluorescence spectrometry

At present, there is a considerable interest in Hg monitoring in wastewater samples due to its widespread occurrence and the high toxicity of most of its compounds. Hg determination in water samples by means of total reflection X-ray fluorescence spectrometry (TXRF) entails some difficulties due to the high vapor pressure and low boiling point of this element that produce evaporation and loss of Hg from the surface of the reflector during the drying process, commonly used for sample preparation in TXRF analysis.The main goal of the present research was to develop a fast and simple chemical strategy to avoid Hg volatilization during the analysis of wastewater samples by TXRF spectrometry. Three different analytical procedures were tested for this purpose: (i) increasing the viscosity of the wastewater sample by adding a non-ionic surfactant (Triton^® X-114), (ii) Hg immobilization on the quartz reflectors using the extractant tri-isobutylphosphine (Cyanex 471X) and (iii) formation of a stable and non-volatile Hg complex into the wastewater sample. The best analytical strategy was found to be the formation of a Hg complex with thiourea (pH = 10) before the deposition of 10 μL of sample on the reflector for following TXRF analysis. Analytical figures of merit such as linearity, limits of detection, accuracy and precision were carefully evaluated. Finally, the developed methodology was applied for the determination of Hg in different types of wastewater samples (industrial effluents, municipal effluents from conventional systems and municipal effluents from constructed wetlands).     

Whole cell immobilised biosensors for toxicity assessment of a wastewater treatment plant treating phenolics-containing waste

Wastewater treatment plants dealing with industrial wastes are often susceptible to overload of toxic influent that can partially or completely destroy treatment for extended periods. An obvious candidate for monitoring toxicity in such wastewater systems is bioluminescent bacteria. However, the natural bioluminescent bacteria can be particularly sensitive to some industrial wastes and therefore their response to normal operational conditions does not reflect the status of the microbial community responsible for treatment. Moreover, the salt dependence of the marine bioluminescent bacteria, and the temperature sensitivity of some strains, further complicate their use. Here we describe the construction of whole cell genetically modified bioluminescent biosensors and their immobilisation for use in monitoring the toxicity of a complex industrial wastewater containing phenolic materials. A hand-held luminometer was designed for laboratory or field use, and the immobilisation system designed with several things in mind: the geometry of the instrument; the need for containment of GM bacteria; the maximisation of the bioavailability of the wastewater to the biosensor. The performance of a candidate GM sensor was compared with Vibrio fischeri in liquid culture and after immobilisation in thin films of poly(vinyl alcohol) (PVA) cryogels. The biosensors were tested against pure phenol and 3-chlorophenol as a reference toxic chemical known to be much more toxic to bacteria than phenol. The biosensors were then tested with the phenolics-containing industrial wastewater. The immobilisation system proved to operate predictably with pure toxicants, and was able to discriminate toxicity of various zones within the wastewater treatment plant.     

Indirect Electrochemical Oxidation of 4-Amino-dimethyl-aniline Hydrochloride

Introduction4Amino dimethyl anilinehydrochlorideisoneof themaincomponentsofthewastewaterresultedfrom vanillinproduction[1]whichinhibitsthenormalactivity ofthemicroorganismsofmicrobialpopulation,thereby affectingthebiologicaltreatmentprocessofvanillin.Comm…     

Entrapment of Lentinus sajor-caju into Ca-alginate gel beads for removal of Cd(II) ions from aqueous solution: preparation and biosorption kinetics analysis

A white rot fungus species Lentinus sajor-caju biomass was entrapped into alginate gel via a liquid curing method in the presence of Ca(II) ions. The biosorption of cadmium(II) by the entrapped live and dead fungal biomass has been studied in a batch system. The heat-treatment process enhanced the biosorption capacity of the immobilized fungal biomass. The effect of initial cadmium concentration, pH and temperature on cadmium removal has been investigated. The maximum experimental biosorption capacities for entrapped live and dead fungal mycelia of L. sajur-caju were found to be 104.8±2.7 mg Cd(II) g⁻¹ and 123.5±4.3 mg Cd(II) g⁻¹, respectively. The kinetics of cadmium biosorption was fast, approximately 85% of biosorption taking place within 30 min. The biosorption equilibrium was well described by Langmuir and Freundlich adsorption isotherms. The change in the biosorption capacity with time is found to fit pseudo-second-order equations. Cadmium binding properties of entrapped fungal preparations have been determined applying the Ruzic equations. Since the biosorption capacities are relatively high for both entrapped live and dead forms, they could be considered as suitable biosorbents for the removal of cadmium in wastewater treatment systems. The biosorbents were reused in three consecutive adsorption/desorption cycles without significant loss in the biosorption capacity.     

黄孢展齿革菌对镉离子的吸附

选用黄孢展齿革菌进行生物吸附镉离子的研究。比较多种处理方法发现采用甲醛交联-碱处理能显著提高吸附效果。当溶液pH为4.5,吸附温度为25-35℃,菌丝球粒径在1.5-2.0mm范围内,吸附时间为12h,吸附效果最佳。此时,镉离子浓度从10mg/L下降至0.04mg/L,达到国家污水综合排放标准。此外,该生物吸附过程是由快速吸附和缓慢吸附两个阶段所组成的。     

TREATMENT AND RESOURCE REUSE OF WASTEWATER FROM NAPHTHOL AS—E PRODUCTION PROCESS

The wastewalter from naphthol As-E production process was treated with macroporous polymeric adsorbent DNDA-222,Naphthol As-E and 2,3-acid in the wastewater could be removed completely and the Total Organic Carbon(TOC) of the wastewater was decreased more than 98% from 1655mg/L to less than 30mg/L.The adsorbates could be desorbed completely with NaOH aqueous solution.