Instrumentation, control and automation in wastewater--from London 1973 to Narbonne 2013

Key developments of instrumentation, control and automation (ICA) applications in wastewater systems during the past 40 years are highlighted in this paper. From the first ICA conference in 1973 through to today there has been a tremendous increase in the understanding of the processes, instrumentation, computer systems and control theory. However, many developments have not been addressed here, such as sewer control, drinking water treatment and water distribution control. It is hoped that this review can stimulate new attempts to more effectively apply control and automation in water systems in the coming years.

Recruitment of practices in primary care research: the long and the short of it

OBJECTIVE

To determine factors that facilitated or hindered recruitment of general practices into a large New Zealand primary care project that aimed to determine general practice characteristics of immunization coverage.

METHODS

The project had a multi-level recruitment strategy requiring recruitment of randomly selected practices before randomly selecting GPs, practice nurses and caregivers of children enrolled at those practices. Detailed quantitative and qualitative recruitment data were recorded on an access database. Post-recruitment, recruiters underwent semi-structured interviews. Analysis was mixed method, with triangulation of descriptive statistics of the number of calls and time course to recruitment and general inductive thematic analysis of qualitative data.

RESULTS

Identifying key decision makers and how individual practice processes work can save significant recruitment time. Factors identified as assisting practice recruitment included using a personal approach from doctor to doctor, getting buy-in from all practice staff, streamlining the research process to minimize disruption to the practice and flexibility to accommodate practices.

CONCLUSIONS

The task of recruiting should not be underestimated. Adequate time and resource need to be allocated from the onset. Long periods where practices have no added burdens such as audits, mass vaccination programmes or influenza season are unlikely, therefore there are always considerable challenges in recruiting practices for research. Remaining flexible to individual practice styles and influences and acknowledging the commitment of participants is important.

A comparative analysis of different approaches for integrated WWTP modelling

In this paper a comparative analysis of the most important approaches for integrated WWTP modelling is presented. After an introductory presentation of the most important drawbacks and challenges for plant wide modelling, the fundamentals of three different approaches to construct integrated models are presented: "Interfaces" "Standard Supermodel" and "Tailored Supermodel". Afterwards, a comparative analysis of these approaches from different points of view (difficulties for the model end user, characterization of the process in the plant, flexibility or adaptability for each case of study, simulation platform requirements and computational costs) is carried out. From this comparison, some important conclusions about the suitability of each alternative depending on the simulation case study are extracted.

Determining immunisation coverage rates in primary health care practices: A simple goal but a complex task

PURPOSE

To explore the quality of data recording by practices and identify issues to be considered and addressed before such data can be used as a continuous measure of immunisation delivery.

METHODS

One hundred and twenty-four randomly selected general practices visited to measure immunisation coverage using the various practice management systems (PMS) in use. To capture all target children it was necessary to build two queries: one generated a list of all children aged between 6 weeks and 2 years who had been to the practice, regardless of enrollment status; the other asked dates and nature of all immunisations given. Each different PMS required a unique query to extract the necessary information.

RESULTS

Variability encountered included different types and versions of PMS and operating systems; variable degree of staff technical competence with their PMS; proportion of enrolled children ranging from nearly 0 to 100%; lack of consistency of the nature and location of data entry and coding; and unreliability of dates relating to some vaccination events.

RECOMMENDATIONS

To improve recording of immunisation coverage we recommend a standard early age of registration and enrollment; standard definitions of the denominator and of immunisation delay; greater uniformity of PMS; improved staff training; intrinsic data quality checks; integration of PMS with changes in the immunisation schedule; incentives and interval electronic checks to improve data quality.

Towards a benchmark simulation model for plant-wide control strategy performance evaluation of WWTPs

The COST/IWA benchmark simulation model has been available for seven years. Its primary purpose has been to create a platform for control strategy benchmarking of activated sludge processes. The fact that the benchmark has resulted in more than 100 publications, not only in Europe but also worldwide, demonstrates the interest in such a tool within the research community In this paper, an extension of the benchmark simulation model no 1 (BSM1) is proposed. This extension aims at facilitating control strategy development and performance evaluation at a plant-wide level and, consequently, includes both pre-treatment of wastewater as well as the processes describing sludge treatment. The motivation for the extension is the increasing interest and need to operate and control wastewater treatment systems not only at an individual process level but also on a plant-wide basis. To facilitate the changes, the evaluation period has been extended to one year. A prolonged evaluation period allows for long-term control strategies to be assessed and enables the use of control handles that cannot be evaluated in a realistic fashion in the one-week BSM1 evaluation period. In the paper, the extended plant layout is proposed and the new suggested process models are described briefly. Models for influent file design, the benchmarking procedure and the evaluation criteria are also discussed. And finally, some important remaining topics, for which consensus is required, are identified.

Continuity-based interfacing of models for wastewater systems described by Petersen matrices

In this paper the Petersen and composition matrices that modellers are now familiar with are used as a basis to construct interfacing models between subsystems considered in wastewater treatment. Starting from continuity considerations and a set of transformation reactions between components used in the two models of the subsystems to be interfaced, a set of linear algebraic equations needs to be solved. The theoretical development is illustrated using a simplified integrated model of an activated sludge system coupled to an anaerobic digester. Continuity-guaranteed interfacing of subsystems will facilitate optimization studies of the within-the-fence process units of a wastewater treatment plant or of the integrated urban wastewater system.

The normal and abnormal distribution of the adrenomedullary imaging agent m-[I-131]iodobenzylguanidine (I-131 MIBG) in man: evaluation by scintigraphy

The scintigraphic distribution of m-[131I]iodobenzylguanidine (I-131 MIBG), an adrenal medullary imaging agent, was studied to determine the patterns of uptake of this agent in man. The normal distribution of I-131 MIBG includes clear portrayal of the salivary glands, liver, spleen, and urinary bladder. The heart, middle and lower lung zones, and colon were less frequently or less clearly seen. The upper lung zones and kidneys were seldom visualized. The thyroid appeared only in cases of inadequate thyroidal blockade. The "normal" adrenal glands were seldom seen and faintly imaged in 2% at 24 hr after injection and in 16% at 48 hr, in patients shown not to have pheochromocytomas, whereas intra-adrenal, extraadrenal, and malignant pheochromocytomas usually appeared as intense focal areas of I-131 MIBG uptake at 24 through 72 hr.

Value of bowel preparation in adrenocortical scintigraphy with NP-59

The use of radiolabeled cholesterol derivatives for functional imaging of the adrenal cortex may be rendered inaccurate or impossible because of the excretion of activity by the liver and its subsequent appearance in the colon. A simple bowel preparation (bisacodyl 5 or 10 mg nightly) significantly reduced bowel background activity during 6 beta-[I-131]iodomethyl-19-norcholesterol (NP-59) adrenal cortical scintigraphy. Activity interfering with image interpretability was present less frequently in patients taking bisacodyl: three days after injection 22% compared with 59%; five days after injection 23% compared with 35%. As bisacodyl acts only on the colon and does not disturb the enterohepatic circulation of cholesterol or bile acids, it is ideal for use with a tracer of cholesterol metabolism.

Effectiveness of coronary care units in small community hospitals

A prospective study was undertaken from 1969 to 1974 to evaluate a program establishing coronary care units in small community hospitals. Crude mortality rates from acute myocardial infarction in these small hospitals were 14.5%, slightly higher but not statistically different from concurrently collected data in three larger comparision hospitals (11.5%). Mutivariate discriminate analysis of clinical characteristics was used to calculate a risk score for each patient admitted. Observed deaths exceeded expected deaths (134 versus 119) (P greater than 0.30) in small hospitals but observed deaths were less than expected (55 versus 77)(P less than 0.05) in comparison hospitals. Mortality was significantly greater in those units admitting fewer than 60 patients with infarctions yearly (20.9%) than in those admitting more than 60 (10.7%) (P less than 0.001). These data suggest that coronary care units in small community hospitals can provide adequate coronary care, but their level of performance drops when fewer than 60 patients with infarctions are admitted yearly.