QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse.

Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as individual risks but also related to the endemic situation in the general population. The highest individual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.     

The large PAO cells in full-scale EBPR biomass samples are not yeast spores but possibly novel members of the beta-Proteobacteria.

Large, homogenous clusters of coccobacilli were found to be abundant in the biomasses from a conventional plant at Rosebud, Victoria, Australia. The identity and the in situ physiology of these dominant microorganisms were investigated in this study. These large clustered cells were revealed to be neither Gram positive nor Gram negative bacteria and contain polyP granules. Cells with similar features were also observed in some enhanced biological phosphate removal (EBPR) systems and reported as yeast spores and Rhodocyclus-related polyphosphate accumulating organisms (PAOs). In this study, fluorescent in situ hybridization (FISH) probing showed these cells were prokaryotic and members of the beta-Proteobacteria. However, these large clustered cells did not respond to the PAO mix FISH probes. The in situ physiology of these large cells was studied with FISH in combination with microautoradiography (MAR) in order to understand their substrate assimilation abilities under different conditions as well as their phosphate uptake ability. These cells were able to take up acetate, glutamate and aspartate, but not glucose under both aerobic and anaerobic conditions. Nile Blue A staining in combination with MAR showed that cells incubated under anaerobic conditions contained polyhydroxyalkanoates (PHA) granules. In addition, MAR showed aerobic 33Pi assimilation with all these substrates, consistent with them supporting an EBPR capacity in these large cells. As well as raising doubts about a role for yeasts in EBPR, this study suggests that much still needs to be learned about the identity and level of biodiversity of the PAO in EBPR systems, and emphasizes the benefits of using techniques like FISH/MAR and PHA staining/MAR to resolve the in situ physiology of the populations of interest there.     

Application of a bio-electrochemical reactor process to direct treatment of metal pickling wastewater containing heavy metals and high strength nitrate.

The fundamental performance of a bio-electrochemical reactor for the direct treatment of metal pickling wastewater was investigated experimentally. In the reactor, carbon anode and cathode were installed. On the cathode, denitrifying microorganisms were immobilized. Continuous experiments were carried out by feeding a synthetic wastewater containing nitrate and binary heavy metal ions, copper and lead, under different operating conditions. Acetate as well as the electric current was supplied at the minimum amount for stoichiometry of the dissimilatory denitrification reaction. The results indicated that the dissolved copper and lead removal, denitrification and neutralization could be achieved simultaneously in a single bio-electrochemical reactor. The dissolved heavy metals were removed by electrochemical deposition on cathode and by the other phenomena such as the formation of insoluble suspensions and the sorption on suspended bacterial sludge. Denitrification proceeded effectively with the utilization of both added acetate and hydrogen gas generated by electrolysis of water. The pH value increased up to around neutral due to the occurrence of denitrification in the reactor, although the influent pH was less than 3. The removal efficiencies of heavy metals and nitrate increased with increasing the current density. The applied electric current was indispensable for sustaining the stable treatment in the reactor.     

让援助更为明智

为全世界儿童提供初等学校教育将是一项漫长而且耗费甚大的工程。幸好，自1990年以来，主要的捐助者极大地增加了他们对于总体教育，特别是初等教育的官方发展援助（ODA）。2003年对所有教育目标的捐赠承诺额达到了67亿美元，是6年前承诺额真实数量的两倍以上。对于初等教育的承诺额增加得甚至更快，在1990—2003年间增长了四倍，达到19亿美元。对于初等教育的援助比总体ODA增长的更快，其在承诺额中的份额从1990年的0．4％增长到2003年的1．9％（见图1和图2）。     

Major issues in Indonesia's urban land development

This article addresses issues of urban land development in Indonesia, including urban land use; ownership and transfers; land taxation; and land information systems. Until very recently, urban land-use planning in Indonesia was largely top-down in character and neglected to include the public as a stakeholder. This article argues that the role of government in urban land-use development needs to change at all levels and that the capacity of local government in land-use management needs to be strengthened. The presence of private developers in urban development should be encouraged. Land development permits—as a means of urban development control—while they may still be necessary should be granted primarily in relation to urban land-use plans (RUTR). Land taxation instruments have not been effectively applied to control land utilisation in the cities. Data and information on land affairs are lacking.     

Organic and detergent degradation in combined O3/UF for domestic laundry wastewater reclamation.

This paper focuses on the evaluation of organic and detergent degradation in a combined Ozone/UF system for domestic laundry wastewater reclamation. Formation of by-product was investigated by GC/MS for the reclaimed water. Ozone was injected into the raw wastewater in a 10 L contact tank and the wastewater was circulated through the membrane module for inner pressurized cross-flow filtration. The concentrate was returned back to the contact tank. The membrane used in this experiment was hollow fiber polysulfone UF membrane with MWCO 10,000. It has an effective filtration area of 0.06 m2. The experiment was carried out with intermittent ozone injection, 5 min injection and 10 min idling. Ozone was dosed at the concentration of 1.5 mg/L. The flux of the UF could be maintained at 0.24 m/d under filtration pressure 40-45 kPa and water temperature, 20-22 degrees C. The organic removal efficiency by the system was 90% in terms of COD. Ozone was considerably effective to degrade organics in the wastewater. Molecular weight of organics in the raw waste was mostly greater than 10,000 (72% of 950 mgCOD/L). However 86% of effluent COD (94-100 mg/L) was composed of organics smaller than MWCO 500 by ozone injection. No harmful by-products by ozone contact were detected from the analysis of treated water using GC/MS. It was identified that residual organics in the treated water were 1,1'-Oxybisbenzene, Octadecanoic acid, Squalene and Benzenmethanol, etc., which were additives contained originally in the detergent. Consequently the reclaimed water quality could be estimated safe enough to recycle for the rinsing cycle in a washing machine.     

The FTC in the 1980s

This paper reviews the antitrust activities of Federal Trade Commission during the 1980s with special emphasis on the role of economics and economists. We contrast the FTC during the 1980s to its record in the 1970s and conclude that the agency was more active during the 1980s than is popularly believed. Perhaps more significant than changes in the level of enforcement activity was the agency's move to a more economics-oriented approach to antitrust enforcement and an increased role for Commission economists. The paper also comments on what FTC economists learned about American industry during the 1980s.     

The Effects of Delays on the Stability and Rate of Convergence to Equilibrium of Oligopolies*

The stability of oligopolies is investigated using the Cournot strategy and a general output adjustment procedure. Information delays are incorporated in the adjustment procedure and their specific effects upon the dynamic stability of oligopolies is investigated. The stability of equilibrium for discrete models is unaffected by information delays and remoteness of planning horizons; however the rate of convergence to equilibrium may be slowed. For continuous models with delays, some restraints are required for stability.     

Living with the Curse of Dimensionality: Closed-Loop Optimization in a Large-Scale Fisheries Simulation Model

Facilitated by remarkable increases in computational speed, simulation models are becoming more and more complex and are being increasingly used in applied economic analysis. However, computational limitations remain a major barrier to the study of dynamically optimal policies. We study the problem of carrying out dynamic optimization in conjunction with large simulation models and propose a method for working around the computational difficulties that arise in such problems. Our methods are applied to a model of the Gulf of Mexico's red snapper fishery to study the dynamically optimal total allowable catch.     

The Bundesbank's Communications Strategy and Policy Conflicts with the Federal Government

In this paper we provide an estimate of the likelihood of conflict between the federal government and the Bundesbank for the 1989-1998 period. We rely on a novel proxy for the impact of public communication by Bundesbank officials on the probability of conflict, in addition to interest rate, exchange rate, money supply behavior, as well as electoral influences. The empirical evidence is consistent with the view that speeches by the Bundesbank president dealing with inflation and economic policy are a positive source of conflict in a probabilistic sense. Conflict was not a constant but flared up at times of economic stress and could be exacerbated by the “talking” of Bundesbank officials.