Sewer solids separation by sedimentation--the problem of modeling, validation and transferability.

Sedimentation of sewer solids in tanks, ponds and similar devices is the most relevant process for the treatment of stormwater and combined sewer overflows in urban collecting systems. In the past a lot of research work was done to develop deterministic models for the description of this separation process. But these modern models are not commonly accepted in Germany until today. Water Authorities are sceptical with regard to model validation and transferability. Within this paper it is checked whether this scepticism is reasonable. A framework-proposal for the validation of mathematical models with zero or one dimensional spatial resolution for particle separation processes for stormwater and combined sewer overflow treatment is presented. This proposal was applied to publications of repute on sewer solids separation by sedimentation. The result was that none of the investigated models described in literature passed the validation entirely. There is an urgent need for future research in sewer solids sedimentation and remobilization!

Sustainable and integrated water resources management for the coastal areas of Shandong Province, China.

Water scarcity and water pollution are severe problems in the Northern part of China, strongly affecting socio-economic development and standards of living and environment. The Shandong province is specifically plagued by water scarcity. In the coastal catchments of the Shandong province the water scarcity is even increased due to saltwater intrusion, reducing the usability of water resources available. The pressing water problems in the costal catchments in the Shandong province and resulting socio-economic troubles forced the Chinese authorities to implement a variety of measures to relieve water scarcity and abate saltwater intrusion. But not much has been achieved so far as the measures are not coordinated in their effects and cost-benefit relations have not been considered sufficiently. Such a situation calls for good, which means integrated, sustainable water management. The assessment of this situation in the project "Flood Control and Groundwater Recharge in Coastal Catchments" financed by the German Ministry of Research and Education is presented. Further objectives and first ideas for an IWRM-concept are explained. These ideas are based on concepts developed in Germany in the context of the fulfilment of the European Water Framework Directive.

Modelling of sedimentation and remobilization in in-line storage sewers for stormwater treatment.

A special arrangement of combined sewer overflow tanks is the in-line storage sewer with downstream discharge (ISS-down). This layout has the advantage that, besides the sewer system, no other structures are required for stormwater treatment. The verification of the efficiency with respect to the processes of sedimentation and remobilization of sediment within the in-line storage sewer with downstream discharge is carried out in a combination of a field and a pilot plant study. The model study was carried out using a pilot plant model scaled 1:13. The following is intended to present some results of the pilot plant study and the mathematical empirical modelling of the sedimentation and remobilization process.

Effective pollutant retention capacity of permeable pavements for infiltrated road runoffs determined by laboratory tests.

The infiltration of urban runoff always implies an entrance of pollutants into the soil and ground water. Due to legal regulations in many communes there is no longer any permission needed for stormwater infiltration, if administrative regulations and the requirements of standards are observed. The results of a research project carried out under the heading "Development of an assessment procedure for permeable pavements" show, that the pollutant retention capacity of permeable pavements varies considerably, depending on the material and the specific reactive surface. The objective of the study was to work out recommendations of suitable permeable pavements for different types of urban runoff. Selected data about the quality of urban runoff was compiled into a runoff matrix, which was used for defining characteristic dilutions. In batch tests, the material of the infiltration devices is penetrated with the dilutions. A test installation in large scale is used to calibrate the sorption coefficients derived from the batch experiment.

Monitoring in inline storage sewers for stormwater treatment to determine efficiencies.

A special structure of combined sewer overflow tanks is the inline storage sewer with downstream discharge (SKU). This layout has the advantage that besides the sewer system, no other structures are required for storm water treatment. Consequently only very little space is required and compared to combined sewer overflow tanks, there is an enormous potential in reducing costs during construction. To investigate the efficiency of an inline storage sewer, a monitoring station was established in Dortmund-Scharnhorst, Germany. The monitoring station was in operation for a period of 2.5 years. Within this period water samples were taken during a total of 20 discharge events. Besides the complete hydraulic data collection, seven water samplers took more than 5,000 water samples during dry and wet weather. This adds up to a total of more than 20,000 individual lab analyses. The average of the total efficiency for the SKU-West is 86%. 29% of this efficiency can be attributed to the throttle flow. The remaining 57% can be divided into a part of 48% that can be attributed to the process storage and 9% that can be attributed to sedimentation and erosion process.

A software monitor for intermittent bacteria contamination in urban rivers.

Norwegian receiving waters are of such high water quality that authorities consider opening them for bathing. The leading parameter to monitor the quality of bathing waters is fecal coliform bacteria (FC). For this parameter no rapid detection method is available. The main objective of this case study was to find a way to quickly predict bacteria contamination by observing different online parameters such as flow, conductivity or spectral absorption coefficient (SAC). In this study historical data from 1994 to 2000 was analyzed, and over a period of five weeks water samples were taken and analyzed for bacteria. The analysis of the historical data revealed fundamental sampling problems, which made the data useless for the purpose of this study. The analysis of the data collected for this study showed that exceeding the bathing water standard for bacteria can be predicted by evaluating the SAC with an acceptable accuracy. Furthermore a simple river quality model was implemented, including bacteria as a load fraction. With the help of rain data and discharge predictions expected bacteria numbers exceeding the bathing water standard could also be forecast.

Storm water management in an urban catchment: effects of source control and real-time management of sewer systems on receiving water quality.

For the examination of the effects of different storm water management strategies in an urban catchment area on receiving water quality, an integrated simulation of the sewer system, wastewater treatment plant and receiving water is carried out. In the sewer system real-time control measures are implemented. As examples of source control measures the reduction of wastewater and the reduction of the amount of impervious surfaces producing storm water discharges are examined. The surface runoff calculation and the simulation of the sewer system and the WWTP are based on a MATLAB/SIMULINK simulation environment. The impact of the measures on the receiving water is simulated using AQUASIM. It can be shown that the examined storm water management measures, especially the source control measures, can reduce the combined sewer overflow volume and the pollutant discharge load considerably. All examined measures also have positive effects on the receiving water quality. Moreover, the reduction of impervious surfaces avoids combined sewer overflow activities, and in consequence prevents pollutants from discharging into the receiving water after small rainfall events. However, the receiving water quality improvement may not be seen as important enough to avoid acute receiving water effects in general.

Integrated modelling as an analytical and optimisation tool for urban watershed management.

In recent years numerical modelling has become a standard procedure to optimise urban wastewater systems design and operation. Since the models were developed for the subsystems independently, they did not support an integrated view to the operation of the sewer system, the wastewater treatment plant (WWTP) and the receiving water. After pointing out the benefits of an integrated approach and the possible synergy effects that may arise from analysing the interactions across the interfaces, three examples of modelling case studies carried out in Germany are introduced. With these examples we intend to demonstrate the potential of integrated models, though their development cannot be considered completed. They are set up with different combinations of self-developed and commercially available software. The aim is to analyse fluxes through the total wastewater system or to integrate pollution-based control in the upstream direction, that is e.g. managing the combined water retention tanks as a function of state variables in the WWTP or the receiving water. Furthermore the interface between the sewer and the WWTP can be optimised by predictive simulations such that the combined water flow can be maximised according to the time- and dynamics-dependent state of the treatment processes.

Effects of real time control of sewer systems on treatment plant performance and receiving water quality.

Four individual mathematical submodels simulating different subsystems of urban drainage were intercoupled to an integral model. The submodels (for surface runoff, flow in sewer system, wastewater treatment plant and receiving water) were calibrated on the basis of field data measured in an existing urban catchment investigation. Three different strategies for controlling the discharge in the sewer network were defined and implemented in the integral model. The impact of these control measures was quantified by representative immission state-parameters of the receiving water. The results reveal that the effect of a control measure may be ambivalent, depending on the referred component of a complex drainage system. Furthermore, it is demonstrated that the drainage system in the catchment investigation can be considerably optimised towards environmental protection and operation efficiency if an appropriate real time control on the integral scale is applied.

Stepwise hapticity changes in sequential one-electron redox reactions of indenyl-molybdenum complexes: combined electrochemical, ESR, X-ray, and theoretical studies.

Reduction of the dication [(eta5-Ind)(Cp)Mo[P(OMe)3]2]2+ (1(2+)) and oxidation of the neutral complex (eta3-Ind)(Cp)Mo[P(OMe)3]2 (1) proceed through a one-electron intermediate, 1+. The structures of 1(2+) and 1 have been determined by X-ray diffraction studies, which show the slip-fold distortion angle, Omega, of the indenyl ring increasing from 4.1 degrees in 1(2+) to 21.7 degrees in 1. Cyclic voltammetry and bulk electrolysis were employed to define the thermodynamics and heterogeneous charge-transfer kinetics of reactions 1(2+) + e(-) <==> 1+ and 1+ + e(-) <==> 1: DeltaE1/2 = 113 mV in CH3CN and 219 mV in CH2Cl2/0.1 M [NBu4][PF6]; k(s) = 0.4 cm x s(-1) for 1(2+)/1+ couple, 1.0 cm x s(-1) for 1+/1 couple in CH3CN. ESR spectra of 1+ displayed a surprisingly large hyperfine splitting (7.4 x 10(-4) x cm(-1)) from a single 1H nucleus, and spectra of the partially deuterated indenyl analogue confirmed assignment of a(H) to the H2 proton of the indenyl ring. The related eta5 18-electron complexes [(eta5-Ind)(Cp)Mo(dppe)]2+ (2(2+)) (dppe = diphenylphosphinoethane) and (eta5-Ind)(Cp)Mo(CN)2 (3) may also be reduced in two successive one-electron steps; ESR spectra of the radicals 2+ and 3- showed a similarly large a(H2) (8.7 x 10(-4) and 6.4 x 10(-4) x cm(-1), respectively). Molecular orbital calculations (density functional theory, DFT, and extended Hückel, EH) predict metal-indenyl bonding in 1+ that is approximately midway between that of the eta5 and eta3 hapticities (e.g., Omega = 11.4 degrees ). DFT results show that the large value of a(H2) arises from polarization of the indenyl-H2 by both inner-sphere orbitals and the singly occupied molecular orbital (SOMO) of 1+. The measured ks values are consistent with only minor inner-sphere reorganizational energies being necessary for the electron-transfer reactions, showing that a full eta5/eta3 hapticity change may require only small inner-sphere reorganization energies when concomitant with a pair of stepwise one-electron-transfer processes. The indenyl ligand in 1+ is best described as donating approximately four pi-electrons to Mo by combining a traditional eta3 linkage with two "half-strength" Mo-C bonds.

Syntheses and structural and electrochemical characterizations of vanadatricarbadecaboranyl analogues of vanadocene and the structural characterization of the [Li(CH(3)CN)2+](6-CH(3)-nido-5,6,9-C(3)B(7)H(9-) tricarbadecaboranyl anion.

A single-crystal X-ray determination of the [Li(CH(3)CN)(2)(+)](6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-)) salt has shown that the 6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-) tricarbadecaboranyl anion has a nido-cage geometry based on an octadecahedron missing the unique six-coordinate vertex. The resulting six-membered open face is puckered, with two of the cage carbons (C6 and C9) occupying the low-coordinate cage positions above the plane of the four remaining atoms (C5, B7, B8, and B10). The Li(+) ion is centered over the open face and is solvated by two acetonitrile molecules. The reactions of the 6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-) anion with various vanadium halide salts, including VCl(4), VCl(3), and VBr(2), each resulted in the isolation of the same five paramagnetic products (2-6) of composition V(CH(3)-C(3)B(7)H(9))(2). X-ray crystallographic determinations of 2-5 showed that the complexes consist of two octadecahedral VC(3)B(7) fragments sharing a common vanadium vertex and established their structures as commo-V-(1-V-4'-CH(3)-2',3',4'-C(3)B(7)H(9))(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9)) (2), commo-V-(1-V-5'-CH(3)-2',3',5'-C(3)B(7)H(9))(1-V-4-CH(3)-2,3,4-C(3)B(7)H(9)) (3), commo-V-(1-V-5'-CH(3)-2',3',5'-C(3)B(7)H(9))(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9)) (4), and commo-V-(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9))(2) (5). These complexes can be considered as tricarbadecaboranyl analogues of vanadocene, (eta(5)-C(5)H(5))(2)V. However, unlike vanadocene, these complexes are air- and moisture-stable and have only one unpaired electron. The five complexes differ with respect to one another in that they either (1) contain different enantiomeric forms of the CH(3)-C(3)B(7)H(9) cages, (2) have a different twist orientation of the two cages, or (3) have the methyl group of the CH(3)-C(3)B(7)H(9) cage located in either the 2 or 4 position of the cage. Subsequent attempts to oxidize the compounds with reagents such as Br(2) and Ag(+) were unsuccessful, illustrating the ability of the tricarbadecaboranyl anion to stabilize metals in low oxidation states. Consistent with this, both the electrochemical oxidation and the reduction of 2 were much more positive than those of the same oxidation state changes in vanadocene. The one-electron reduction of 2 is a remarkable 2.9 V positive of that of Cp(2)V.

Studies on the binding of Urtica dioica agglutinin (UDA) and other lectins in an in vitro epidermal growth factor receptor test.

Urtica dioica agglutinin (UDA), a GlcN-Ac-specific lectin from the rhizomes of Urtica dioica, was found to inhibit the binding of (125)I-labelled epidermal growth factor (EGF) to its receptor (EGF-R) on A431 epidermoid cancer cells at concentrations of 500ng/ml to 100µg/ml. The effects of other lectins such as wheat germ agglutinin (WGA), which possesses the same sugar specificity, and the mannose-specific agglutinin from Canavalia ensiformis (Con A) were less pronounced. The inhibitory effect of UDA could be antagonized by the GlcN-Ac trimer (N,N',N″-triacetylchitotriose), suggesting hat UDA may be the major antiprostatic compound of Urtica dioica drug, acting by blocking the EGF-R in prostate tissues.

The structure and regulation of family practice residency laboratories.

BACKGROUND: Increasing regulation of physician office laboratories (POLs), increased complexity of outpatient care, and technological advances have increased the need to train family practice residents in POL management. There is little information on how residency laboratories are organized, how they are regulated, and how often quality controls and proficiency testing are done. METHODS: A questionnaire was sent to 385 ACGME-approved family practice residencies to determine the scope of testing, quality-assurance activities, and administrative structure of the residency laboratory. RESULTS: Two hundred and ninety-seven programs responded, for a response rate of 77%; 91.6% were performing routine office tests and 40.7% were performing automated testing. Of programs that performed automated tests, 71.2% were performing daily normal and abnormal quality-control specimens. Proficiency testing was only performed by 57.8% of programs. The program's parent hospital viewed the residency laboratory as a POL in 55.6% of cases and as a satellite of the hospital laboratory in 32.6%. CONCLUSIONS: Residency laboratories are more frequently organized as POLs than satellite laboratories of the parent hospitals. The POL model offers an excellent opportunity to teach residents about office laboratory management. Residency laboratories should be implementing proficiency testing for both patient safety and resident teaching. Many residency laboratories will need to increase the frequency of quality controls as the new CLIA '88 regulations are implemented. Accreditation by a private organization may be an attractive option for family practice office laboratories.

Implementing the US preventive services guidelines in a family practice residency.

BACKGROUND: Despite growing emphasis on preventive services, physicians still provide low levels of these services to their patients. Barriers to providing preventive services might be modified by more effective teaching models at the residency level. The purpose of this study was to evaluate a practice-based teaching model designed to increase resident compliance with the US Preventive Services Task Force Guidelines. METHODS: In Phase One of this study, physicians received didactic education about the US Preventive Services Task Force Guidelines. Subsequently, physicians' compliance with these recommendations was monitored. During Phase Two of the study, a comprehensive two-visit "Health Check" appointment was instituted. It incorporated a computerized health risk appraisal that was reviewed with patients. After the Health Check program was implemented, physicians' compliance with the guidelines was again audited. RESULTS: The chart audits revealed an overall increase in the level of preventive services provided by physicians from 31% in Phase One to 74% in Phase Two (P < .01). CONCLUSIONS: This type of teaching model can effectively increase the level of preventive services provided to patients in a family practice residency.

Wegener's granulomatosis.

Wegener's granulomatosis is a rare disease of unknown etiology. Until recently it was considered uniformly fatal. Family physicians should be aware of the variable presentations of this disease and keep the diagnosis in mind when faced with a puzzling, chronic, progressive multisystem process. New laboratory markers can lead to earlier diagnosis, and aggressive treatment can improve the prognosis.