The influence of supply chain collaboration on collaborative advantage and port performance in maritime logistics

Although many academics and practitioners in the maritime industry have recognised the importance of supply chain collaboration (SCC) between ports and port users, there is still a lack of empirical work on this issue. This work empirically investigates the association between SCC, collaborative advantage and port performance in a maritime logistics context. Data were collected via a web-based questionnaire survey which engaged 178 responses from maritime logistics firms in South Korea. Hypotheses were tested by using structural equation modelling, following a hierarchical analysis process. The results confirm that SCC has positive impacts on collaborative advantage, which in turn helps to improve port performance. The finding indicates that collaborative advantage has a full mediation effect on the link SCC-port performance. This work invites managers to recognise the positive outcomes of inter-organisational SCC practices in enhancing collaborative advantage and port performance within port supply chain.     

Application of medium class land cover maps to AVSWAT2000 for the prediction of inflow, CBOD, TN and TP for Yongdam Lake, Korea.

This study tests the efficacy of using medium class land cover maps vs. the large class maps produced by the Korean Ministry of Environment for prediction of flow and CBOD, TN and TP concentrations. AVSWAT2000 was chosen as a model to process information for a sample site, Yongdam Lake watershed area, Korea. The watershed was divided into 11 sub-watersheds, as was done for implementation of the Total Waste Load Management Act by the Korean government. Calibration of AVSWAT2000 was performed using a trial-and-error method, by comparing the root mean square errors of the observed data and calculated results. This study suggests that AVSWAT2000 can be successfully applied in estimating pollutant load considering hydrologic and site-specific conditions of watersheds. With further study, this approach may be applied to improve watershed-scale water quality management strategies, especially for TMDL developments.     

The fouling characterization and control in the high concentration PAC membrane bioreactor HCPAC-MBR.

This study focuses on the experimental investigation to identify the effect of PAC at high concentrations on the fouling of membranes. A pilot-scale experimental apparatus was installed at a water treatment plant located downstream of Nakdong river basin, Korea. Effluent of rapid sand filter was used as influent of the system, which consists of PAC bio-reactor, submerged membrane module (hollow fiber with pore size 0.1 m) and air supply facility. PAC was dosed at 40 g/L initially and it was not replaced during the operation period. Suction type filtration was carried out at intervals of 12 min. suction and 3 min. idling. At the initial flux 0.36 m/d, the system could be operated stably for around 90 days at target trans-membrane pressure (TMP) of 40 kPa. Among total resistance of membrane filtration, cake and gel layer resistance, Rc+Rg, was the dominant fraction (more than 90% of the total) to increase the filtration pressure, which means that the filtration resistance could be controlled by the PAC cake layer and then irreversible membrane fouling could be prevented. Three minutes air backwashing every 3 days could extend the operation period to 127 days. Organics were analyzed in terms of molecular weight structure. The influent of the system consists of 15.0% and 74.4% of hydrophobic and hydrophilic natural organic matter (NOM), respectively. Hydrophobic and hydrophilic (electrostatic) interaction was the main factor on fouling of the membrane in the reactor. Hydrophobic fraction decreased slightly in the effluent, which means hydrophobic NOM removal in the reactor by adsorption. Organics accumulated in the membrane were extracted for analysis after a certain period of operation. The fraction of hydrophobic and hydrophilic organics was 41.4% and 38.9%, respectively. On the basis of the experimental results, the hydrophobic organics were the major materials causing the fouling of the membrane, which should be changed to other types of material.     

INFLUENCE OF LARGE-SCALE VORTICAL STRUCTURES ON THE PARTICLE DISPERSION IN A PLANE MIXING LAYER

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Domestic wastewater reclamation by submerged membrane bioreactor with high concentration powdered activated carbon for stream restoration.

This study focuses on the practical application of high concentration powdered activated carbon coupled membrane bio-reactor to domestic wastewater reclamation. The study was conducted in three parts, such as analysis of secondary domestic wastewater effluent, design and operation parameter evaluation and reclaimed water quality estimation for stream restoration. The organic concentration was 25.2-80.2 mgCOD(Cr)/L for the effluent of three domestic wastewater treatment plants. Around 50-75% of the COD was low molecular substances less than 1,000 which were quite biodegradable. The sawdust PAC was estimated to be proper adsorbent for the organics in the secondary effluents. Its Freundlich constant, K value was 5.847 and 1/n, 0.36. Using a system consists of single reactor with high concentration PAC (80 g/L) and submerged hollow fiber MF membrane module with nominal pore size of 0.1 microm, design and operation parameters were obtained, such as HRT of the bioreactor (2.5 hr), PAC concentration (80 g/L), the initial flux (less than 0.5 m/day) and intermittent suction cycle (12 min. suction and 3 min. idling). Organic removal by the system was high enough to produce reclaimed water for urban stream restoration The effluent organic concentration was at the level of 2 mg/L in terms of TOC (around 5 mg/L as COD(Cr)). Substances with molecular weight cut off < 1,000 were removed mostly by adsorption and biodegradation. Those above 1,000 were rejected at PAC cake layer on the membrane and gradually degraded by microorganisms during extended contact.     

Status analysis and strategic framework for sanitation management in Asia and Africa.

Following rapid population increase and industrial development, the ever increasing environmental pollution and the associated sanitation-related problem are no longer regional or local but have become an issue requiring global-dimensional concern and the provision of problem-solving alternatives. Especially, since most problems result from inappropriate sewerage and the lack of sewage treatment system are in a serious state occurring in economically underdeveloped regions, and as such, their significance is enormous. The United Nations Environment Programme (UNEP) has been making efforts to establish the technology selection methodology applicable in developing countries, through the accurate status, investigation and analysis of the wastewater management state in Asian and African regions, and the sanitation management guideline utilisable by political leaders or decision-makers. As part of this effort, the Korea Institute of Water Environment (KIWE), together with the UNEP, selected China and Vietnam (in Asia) and Kenya and Ethiopia (in Africa) as subject countries to investigate and perform on-site sanitation management investigations and analysis in this research. Results obtained from the on-site investigation were analysed, and in order to be helpful in establishing a strategy for sanitation management in underdeveloped countries, the strategic framework (SF) has been made based on characterised results.     

Fungal biodegradation of carbofuran and carbofuran phenol by the fungus Mucor ramannianus: identification of metabolites.

The fungus Mucor ramannianus was tested to elucidate the biological fate of a class of N-methyl carbamate pesticide carbofuran and its hydrolysed form carbofuran phenol. The elution profile obtained from analysis by high-pressure liquid chromatography equipped with a reverse-phase C-18 column showed that two peaks occurred after incubation of M. ramannianus with which 1 mM carbofuran was combined as a final concentration. In culture of M. ramannianus with 1 mM carbofuran phenol, it produced two other metabolites compared to metabolites of carbofuran. LC/MS analysis suggested that two of the metabolites produced from carbofuran phenol were most likely to be 2-hydoxy-3-(3-methylpropan-2-ol)phenol or 7a-(hydroxymethyl)-2,2-dimethylhexahydro-6H-furo[2,3-b]pyran-6-one and 3-hydroxycarbofuran-7-phenol.     

Factors determining residents’ preparedness for floods in modern megalopolises: the case of the Tokai flood disaster in Japan

This study examines how flood risk perception and home ownership affect residents’ preparedness for floods, focusing specifically on the case of the Tokai flood disaster in Nagoya City, one of Japan’s biggest metropolises, in 2000. The greatest rainfall ever recorded in Nagoya City (566.5 mm) occurred on 11–12 September 2000; as a result, a local river burst its banks and flooded the city. A survey was conducted of residents of the affected area in Nagoya City and its adjacent region. The respondents were asked to rate the extent of their experience with, anticipation of, and preparedness for floods before and after the Tokai disaster in terms of taking special measures against floods. The results showed that the degree of preparedness for floods was determined by the level of fear of floods and the amount of damage sustained during the Tokai flood, especially for homeowners. However, the residents’ preparedness did not depend on their anticipation of floods. These findings show that preparedness for floods depends on ownership of a home, fear of flooding, and the amount of damage from previous floods rather than on previous experience with and anticipation of floods.     

The effects of starvation on physical characteristics of flocs in SBR for treating saline wastewater.

This study focused on the effects of starvation on physical characteristics of flocs in SBR for treating saline wastewater. Feeding was stopped for 5 and 15 days. A time response of the floc to these starvation periods was monitored as well as the removal efficiencies of pollutants. Correlation between the physical characteristics of flocs and settling of sludge was conducted. As the starvation periods were increased, there was a shift in the floc size distribution from a high proportion of large flocs to the development of small size flocs. The fractal dimension of flocs also decreased, as starvation periods were increased. From the results, the effect of starvation on SBR treating saline wastewater can be ordered as follows: COD Mn removal < floc size and fractal dimension < T-N removal < T-P removal.     

Effects of addition sequence and rapid mixing conditions on use of dual coagulants.

The performance of dual coagulants in clay suspension was investigated in this study using aluminium chloride and the cationic polymer as coagulants. According to the study results, the performance of dual coagulants was affected by dosage of aluminium chloride. Beneficial effect by use of dual coagulants were only noted when aluminium chloride was underdosed. The addition sequence of coagulants was important for the performance of dual coagulants. Simultaneous addition resulted in the best performance, while addition of the polymer first resulted in the worst performance. Addition of aluminium chloride first resulted in the similar performance as single use of aluminium chloride. Although sulphate ion improved the floc characteristics, similar results were obtained. The effectiveness of rapid mixing depended on dosage of aluminium chloride. Extending rapid mixing (6 min) was beneficial when aluminium chloride was underdosed so that coagulation occurred at the combination region. However, such benefit was not observed at the optimum condition, which belonged to the sweep coagulation region. Different floc formation caused the difference. Extended rapid mixing would be beneficial when collision between clay particles and Al(III) was necessary. However, such benefit would disappear at the optimum condition because rapid mixing could break up the floc already formed.