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Notes: Sewage treatment using the activated-sludge process evolved from the fill-and-draw system which was developed by Ardern and Lockett in 1914; the sequencing batch reactor is a modern development of this system. Its success is due to modern technology, particularly the programmable logic controller which controls operational sequences. The process has a single rectangular reaction tank where the various sequences of wastewater fill and aeration, activated-sludge settlement and effluent decanting are carried out.This paper reviews the sequencing batch reactor compared with conventional activated sludge, and explains (a) the similarities and differences, (b) the circumstances in which the system is likely to be cost competitive, and (c) modifications that could increase the effectiveness of sequencing batch- reactor systems in the future.

Notes: Objective To determine whether maternal influenza virus infection in the second and third trimesters of pregnancy results in transplacental transmission of infection, maternal auto-antibody production or an increase in complications of pregnancy.Design Case-control cohort study.Population Study and control cohorts were derived from 3975 women who were consecutively delivered at two Nottingham teaching hospitals between May 1993 and July 1994. A complete set of three sera was available for 1659 women.Methods Paired maternal ante- and postnatal sera were screened for a rise in anti-influenza virus antibody titre by single radial haemolysis and haemagglutination inhibition. Routine obstetric data collected during and after pregnancy were retrieved from the Nottingham obstetric database. Cord samples were tested for the presence of IgM anti-influenza antibodies, and postnatal infant sera were tested for the persistence of influenza-virus specific IgG. Paired antenatal and postnatal sera were tested against a standard range of auto-antigens by immunofluorescence.Main outcome measures Classification of women as having definite serological evidence of an influenza virus infection in pregnancy (cases) or as controls.Results Intercurrent influenza virus infections were identified in 182/1659 (11.0%) pregnancies. None of 138 cord sera from maternal influenza cases was positive for influenza A virus specific IgM. IgG anti-influenza antibodies did not persist in any of 12 infant sera taken at age 6–12 months. Six of 172 postnatal maternal sera from cases of influenza were positive for auto-antibodies. In all cases the corresponding antenatal serum was also positive for the same auto-antibody. There were no significant differences in pregnancy outcome measures between cases and controls. Overall, there were significantly more complications of pregnancy in the cases versus the controls, but no single type of complication achieved statistical significance.Influenza infection in the second and third trimesters of pregnancy is a relatively common event. We found no evidence for transplacental transmission of influenza virus or auto-antibody production in pregnancies complicated by influenza infections. There was an increase in the complications of pregnancy in our influenza cohort.

Notes: Patients attending the ear, nose and throat (ENT) department at St James's University Hospital, Leeds, UK, for evaluation of palpable head and neck lesions have a fine needle cytology (FNC) specimen taken and receive the result at the same out-patient visit. This study was designed to discover if there is a significant difference in the efficiency of the methods with and without suction. The method was chosen randomly on each occasion and the adequacy or otherwise of the specimen was determined taking into account the site and nature of the lesion and the total cellularity of the sample. The level of blood contamination was also compared by each method. When benign and malignant lesions from all sites were analysed together the method with suction produced a significantly higher number of adequate samples than the method without suction. The exception was in the case of samples from lymph node lesions measuring 〈 1 cm, where adequate specimens were only obtained without suction. The non-suction technique was particularly poor at sampling salivary gland lesions in the 1–1.5 cm category. There was no significant difference in the level of blood contamination between the two methods at any site. These results are at variance with most other similar studies and possible reasons for this are discussed.

Notes: In vitro studies have demonstrated positive effects of bioactive compounds on several functions of the immune system. In the present study, 25 of such compounds were tested for their immune modulating properties on influenza virus specific human B- and T-cell responses in vitro. One of these compounds, N-acetyl-l-cysteine was shown to increase influenza virus specific lymphocyte proliferation and interferon(IFN)-γ production at a concentration of 1.0 mmol/l. Furthermore, N-acetyl-l-cysteine was found to enhance a specific activity of two influenza specific CD8+ cytotoxic T-lymphocyte clones directed towards HLA-A*0201 and HLA-B*2705 restricted epitopes. A second compound, chlorogenic acid, was shown to enhance antigen specific proliferation of lymphocytes in three out of four donors, at concentrations of 10–50 µmol/l. Neither of the two compounds exhibited a positive effect on the production of influenza virus specific antibodies by human peripheral blood mononuclear cells in vitro.

Notes: Several methods are available to remove hydrogen sulphide and volatile organic sulphides from ventilated air at sewage-treatment works. Some methods use alkaline and oxidative chemical scrubbers which may have high capital and operational costs. Other methods, such as bio-scrubbers and bio-filters, are used to biochemically oxidize sulphides. Biological scrubbers have the advantage of low operating costs, but their performance may be adversely affected by a high concentration of sulphide (〉 100 ml/m3).This paper describes the development of a novel, compact and low-cost ‘rusty-iron’ chemical filter which catalyzes the oxidation of hydrogen sulphide and organic sulphides to colloidal sulphur and water. Operating costs are relatively low, with no need for routine maintenance. Full-scale demonstration of the effectiveness of such filters was carried out over two years at several treatment works, the results of which are described and discussed together with details of capital costs. The overall percentage removal of hydrogen sulphide by compact multistage filters was found to exceed 95%, irrespective of inlet sulphide concentrations which varied from 34 to 500 ml/m3 (ppm).

Notes: During the last thirty years, attempts have been made to increase the rate of treatment of wastewater in compact activated-sludge systems whilst ensuring (a) an adequate supply of dissolved oxygen, (b) good settleability of activated sludge, and (c) consistently high-quality effluents.This paper describes two successful systems, i.e. oxygenated activated sludge and the deep-shaft process, which are used to intensify the rate of treatment in relatively compact aeration tanks. Data are presented of full-scale oxygen activated-sludge systems, including Vitox and Unox, together with information on the operation and performance of the deep-shaft process.

Notes: The biological filtration of sewage remains the process which is most commonly used for small works in rural areas throughout the UK. In many cases, the need to produce an effluent of high quality with full nitrification is essential in order to comply with the standards set by the Environment Agency. Traditionally, design loading rates of biological filters have been based on historical experience of performance, and on relatively short-term statistical evaluation of the performance of a large number of treatment works, using average and maximum values for flow and loading rates. Many works which were designed on such information have failed to nitrify consistently, particularly during the winter and spring months.This paper describes the detailed evaluation of six full-scale, biological-filtration sewage-treatment works over a period of two years, in which there were significant changes in sewage flow rate, composition and temperature, from summer to winter. The key parameters which influence the production of high-quality nitrified effluents were determined. The conclusions are used to provide a detailed guide on the design of conventional-media biological filters to produce, consistently, fully-nitrified effluents.

Notes: This paper reviews research and development on the causes, consequences and methods of controlling septicity in sewers. It draws on information given in 55 published papers on the subject. Explanations are given on the deviation of equations used to predict critical conditions in sewers and rising mains. The consequences of septicity, including toxicity, corrosion and odour nuisance, are described and discussed. Prevention is always recommended over cure, but where this cannot be achieved the methods of controlling septicity generally rely on maintaining an adequate supply of oxygen (dissolved or chemically available) to oxidize previously-formed sulphide. Other options to cure the effects of septicity include minimizing the emission of hydrogen sulphide into the atmosphere, deodorizing vented air, and the use of protective coatings or corrosion-resistant pipes.

Notes: Eleven of 12 cases with erosive pustular dermatosis of the scalp gave a history of antecedent physical or infective trauma. We propose that this clinical disorder may be a non-specific inflammatory response to injury of ageing and sun-damaged scalps.