Enhancing the removal of hazardous pollutants from coke making wastewater by dosing activated carbon to a pilot‐scale activated sludge process

Powdered activated carbon (PAC) was investigated for its ability to remove 6 polycyclic aromatic hydrocarbons (Σ6PAHs) (fluoranthene, benzo[b + J]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, benzo[g,h,i]perylene), trace metals and colour from coke making wastewater when dosed to a pilot-plant activated sludge process (ASP). The ASP had a volume of 0.68 m3 and was operated to simulate the full-scale ASP treating coke wastewater from a steel works. Operational conditions included a flow rate of 0.78 m3/day, a hydraulic retention time of 21 hours, a sludge retention time of 38 days and a temperature of 27°C. The ASP was operated for a control period before PAC was dosed directly into the aeration cell at a dose of 400 mg/L. Powdered activated carbon addition resulted in a 20% increase in removal efficiency of the Σ6PAHs. Removal efficiency of trace metals was variable, but increased for nickel, chromium and cadmium by 22.6%, 20.5% and 12.4%, respectively. Improvement in colour removal efficiency was marginal at 5%. PAC addition allowed the improvement of treatment efficiencies in the ASP process at relatively low capital and operational costs, which may assist in reaching tighter effluent emission limits set for the industry

Use and Development of Diffusive Samplers to Analyse the Fate of Polycyclic Aromatic Compounds, Polychlorinated Biphenyls and Pharmaceuticals in Wastewater Treatment Processes

The efficiency of wastewater treatment systems is commonly measured by the reductions of parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) and/or reductions in levels of selected macro compounds (e.g. long-chained hydrocarbons and inorganic compounds). Less attention has generally been paid to micropollutants with high potential toxic effects, such as polycyclic aromatic compounds (PACs), including unsubstituted and alkylated polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes, polychlorinated biphenyls (PCBs), human pharmaceuticals and by-products formed during the treatment process. These organic micropollutants occur in wastewaters at trace and ultra-trace levels, therefore their detection requires advanced, costly analyses and large sample volumes. Furthermore, concentrations of micropollutants can fluctuate widely both diurnally and between days. Thus, in order to understand the fate of micropollutants in wastewaters there is a need to develop sampling techniques that allow representative samples to be readily collected. In the work underlying this thesis two types of diffusive passive samplers, semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCISs), were used to monitor non-polar and polar organic micropollutants in wastewaters subjected to various treatment processes. The pollutants sequestered in these samplers represent micropollutants in the dissolved phase that are available for aquatic organisms. Further, since they collect pollutants in an integrative manner, i.e. they sample continuously during the selected exposure time (usually approx. one to ca. three weeks), the results provide time-weighted average (TWA) concentrations. In addition, the effects of various environmental factors on the uptake of analyzed micropollutants in POCISs and SPMDs were investigated using laboratory calibration and in situ calibration with performance reference compounds (PRCs). The results confirm that SPMDs are good sampling tools for investigating the efficacy of wastewater treatment processes for removing non-polar PACs and PCBs, and the effects of varying the process settings. In addition, analyses of process streams in municipal sewage treatment plants demonstrated that conventional sewage treatment processes are not optimized for removing dissolved four-ringed PAHs, some of the five-ringed PAHs, and tri- to hexa-chlorinated biphenyls. The removal of bioavailable PACs was enhanced by adding sorbents with high sorption capacities to the sludge used in the activated sludge treatment step, and a biologically activated carbon system was designed that robustly removed bioavailable PACs, with removal efficiencies of 96.9-99.7 percent across the tested ranges of five varied process parameters. In situ SPMD calibration data acquired show that uptake of PACs, described by SPMD sampling rates (Rs), were four to eight times higher than published laboratory calibrated Rs values, mainly due to strong (bio)fouling and turbulence effects. In addition, the laboratory calibration study demonstrated that temperature affects the POCIS uptake of pharmaceuticals. The uptake of four pharmaceuticals was higher, by 10-56 percent, at 18 °C compared to 5 °C. For two of the pharmaceuticals our data indicate that the uptake was lower by 18-25 percent at 18 °C. Our results also indicate that uptake of the studied pharmaceuticals was in the linear phase throughout the 35 day exposure period at both temperatures. Finally, calibration studies enabled aqueous concentrations of micropollutants to be more accurately estimated from amounts collected in the passive samplers

Lithuanian market research and guidelines for marketing

Experienced international companies would agree that successful performance in the home country or in the particular market doesn’t guarantee a success in a new one. For that reason, Finnish company Cubicasa Ltd., that desires to grow internationally, is interested to gather information of new markets. Accordingly the aim of the thesis research is to evaluate the reasonability to the company to enter Lithuanian market by providing relevant information and precise data of the new market. In order to provide good and precise information for the case company, qualitative approach and case study method was chosen. For the theory part the books written by authors P.Kotler, B. Rosenbloom, G. Johnson, K.Keller were used. For the empirical part the primary data was collected by interviewing potential customers from Lithuania. Secondary data was gathered by using electronic research as relevant information is delivered on the web pages of institutions, organizations and companies. In order to answer to the research questions, the first part of the thesis was divided into two parts for macro and micro environments analysis. PESTEL and Porter’s five forces frameworks were used. Second part of the thesis was concentrated on marketing strategy. Potential customers were classified by segmentation, targeting and positioning analysis. Finally, marketing mix as the main tool to answer research questions was used. The background knowledge for this thesis was gathered during the lectures at Oulu University of Applied Science such as international business, marketing, intercultural skills. The research work implemented under the guidance of the lecturer Outi Sutinen. The subject for thesis was provided by the Cubicasa Ltd company during the meeting at the TUNNI event. Further discussions were held with founder of the company Mikko Perälä and head of product development Jarmo Lumpus. Lastly, in case if Cubicasa decides that Lithuanian market is attractive and worth to enter, it is advisable to apply given information and recommendations for the successful entry in the Lithuanian market

Estimation of Water Sampling Rates and Concentrations of PAHs in a Municipal Sewage Treatment Plant Using SPMDs with Performance Reference Compounds

Semipermeable membrane devices (SPMDs) were exposed at ten sampling points, each representing a different stage in the treatment process, in a municipal sewage treatment plant. Differences in SPMD uptake kinetics of polycyclic aromatic hydrocarbons (PAHs) due to variations in conditions at the sampling sites were evaluated by using five performance reference compounds (PRCs) with log Kow values of 4.20 to 6.34. PRC release rate constants (ke,PRC values) were calculated for PRCs for which 50−98% of the initial amounts were lost during the sampling period. The ke,PRC values were high, ranging from 0.08 to 0.11 day-1 for the studied PRCs, at sampling site W1 (raw sewage), the only sampling site where significant amounts of the PRCs with log Kow values >5 were released from the SPMDs. At the other sampling sites, only PRCs with log Kow values between 4.20 and 4.50 were released in significant amounts. The release rates at these sites were lowest (0.04 day-1) at sampling site W9 (the secondary clarifier) and highest (0.18 day-1) at W8 (the active sludge aeration basin). Differences between sampling rates (Rs) obtained using published laboratory-calibrated data and PRC-corrected Rs values were visualized by principal component analysis (PCA). The water concentrations of 24 studied PAHs fell substantially during the course of the sewage treatment process. However, low molecular weight PAHs were more effectively removed than high molecular weight PAHs. Significant deviations between actual and estimated water concentrations may arise unless PRC-corrected Rs values are applied

Methods of monitoring of waste water treatment efficiency

One major result of implementing the Water Frame Directive (WFD) for the water industry is the likelihood of more stringent requirements for the efficiency of removal of the pollutants included in the list of WFD priority substances. During the last decade, an ongoing debate on the technical aspects of water treatment and on the fate and effects of its constituents after discharge are taking place. Due to the recent development of analytical techniques, the knowledge about the chemistry and toxicology of the waste water has increased considerable. Characterization of the oil treatment efficiency by total petroleum hydrocarbon concentration (TPH) is not sufficient any more. Waste water before and after treatment should be characterized by toxicity and amounts of the individual compounds and mixtures which trigger the toxicity. In the situations where more efficient oil removal from waste water is required to meet the requirements, there are a number of treatment options available, including some tertiary ("polishing") treatment systems. New generation tertiary wastewater treatment system for removal or reducing of the oil compounds, including dissolved polycyclic aromatic hydrocarbons, bearing along most toxic potential, was developed under a Eureka funded project. The new waste water treatment system involves novel monitoring device to verify that the dissolved and bioavailable fraction of the contaminants are degraded, and that the final effluent is cleaner also from a toxicity point of view. Previous studies showed that more toxic compounds might be produced during the treatment process due to the transformation of the original chemicals. The monitoring device consists of a membrane-based diffusive, time integrative (2-30 days) sampler. The newly developed fast analytical method for the analysis of membrane extracts enable to give us information on the dissolved concentrations for more than 80 oil related compounds in the effluents as well as the toxicity results, by using standard bio-assay tests. Moreover the monitoring system is capable to accurately sample most of the WFD priority substances in waste water treatment effluent waters. lt was found that some of the compounds were effectively removed in waste water treatment plant (WWTP), but other compounds remained in the dissolved phase at the same concentrations. Furthermore, volatilization of low molecular weight PAHs during the treatment process was studied by means of the new monitoring system, resulting in the identification of significant release of WFD pollutants to the air. The changes in time-integrative toxicity during the treatment process were evaluated by standard ecotoxicity analysis using the same membrane extracts. The three bio-assays used were Daphnia magna, Microtox and Algal but also other organism- or cell test systems will be tested further. Our developed monitoring device is the state-of-art method for screening for environmental toxicity by integrating biologically and chemically based techniques for early warning and ecosystem health assessment purposes. It can provide invaluable information in highly polluted environments where bioindicator organisms would not survive or behave normally.</jats:p

Search for unidentified PCB sources in Swedish stream using semi permeable membrane devices

During the summer 2003 the stream Tvärån was sampled using passive, integrative technique for one period of 5 weeks. The investigation was performed with sampling sites upstream the industrial area in the city of Umeå, Sweden. When passing the industrial area, several storm water effluents was located and sampling was performed downstream several of these pipe effluents. The final site was located downstream in a dam with elevated concentration of PCB in the sediment. Three different sources were identified due to its separate congener pattern. One station had strong octachloro biphenyl pattern. The other two sites were dominated by trichloro- and pentachloro biphenyl pattern, respectively. These identified effluents will now be compared with possible industrial activities. In order to perform profile comparison between sampling sites and industrial activities we analyzed 79 individual PCB-congeners with HRGC/MS-MS. The congener group profile gave more information regarding the sources than the congener pattern itself. </p

Multivariate analysis of a biologically activated carbon (BAC) system and its efficiency for removing PAHs and aliphatic hydrocarbons from wastewater polluted with petroleum products

The efficiency of a biologically activated carbon system for treating wastewater polluted with petroleum products was examined and the effects of process parameters on its efficacy were evaluated. In each experiment 17 alkylated and 19 non-alkylated polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs, C10-C40) were extracted using semipermeable membrane devices from wastewater before and after treatment. The acquired data during experiments were analyzed using principal component analysis (PCA). The treatment system robustly removed dissolved PAHs across the studied ranges of the process parameters, providing overall removal efficiencies of 96.9-99.7% for the sum of 36 PAHs. However, the major contributor to their removal was sorption rather than biodegradation, and despite the general efficiency of the process there was up to a 9-fold range in the sums of quantified PAHs in the effluents between experiments. Combinations of long process contact time (24 h) with high temperature (24 degrees C) and moderate oxygen concentration (6-7mg O2 L-1) resulted in good removal of bioavailable PAHs. The removal of TPHs was more dependent on biological activities during the wastewater treatment, and consequently more dependent on the process parameters. In addition, small but significant proportions of PAHs were volatilized and released during the wastewater treatment.</p