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BACKGROUND: Diagnostic echocardiography has poor access for patients with suspected heart failure. Pre-echocardiography screening with electrocardiograms (ECGs) is recommended as a means of targeting this scarce resource. There are data to support this policy when ECGs are interpreted by cardiologists but not by GPs. AIM: To assess the value of GP-reported ECGs as a pre-echocardiography screening test for left ventricular systolic dysfunction (LVSD). DESIGN OF STUDY: Cross-sectional study of GPs' ECG reporting skills. SETTING: General practice, NHS in Scotland. METHOD: A randomly selected, stratified sample of 123 Scottish GPs reviewed 180 ECGs (100 abnormal, 50 normal and 30 duplicate) from 150 patients with suspected heart failure. Forty-one patients had LVSD on echocardiography. GPs were required to categorise ECGs as normal or abnormal. RESULTS: Mean sensitivity was 0.94 (95% CI = 0.92 to 0.95). Mean specificity 0.58 (95% CI = 0.56 to 0.60). Mean positive predictive value (PPV) was 0.47 (95% CI = 0.46 to 0.48). Mean negative predictive value (NPV) was 0.96 (95% CI = 0.95 to 0.97). Mean likelihood ratio was 2.39 (95% CI = 2.28 to 2.50). Seventy of 123 (57%) GPs achieved sensitivity of 0.9 and specificity of 0.5 for the detection of LVSD. CONCLUSION: Most Scottish GPs have the skills to perform pre-echocardiography screening ECGs in patients with suspected LVSD. However, differences in ECG reporting performance between individual GPs will result in widely varying referral rates for echocardiography and differences in the detection rate of LVSD. The implications of these findings need to be considered when heart failure diagnostic services are being developed. [ABSTRACT FROM AUTHOR]

Numerous studies have demonstrated that anaerobic packed-bed reactors (APBRs) containing media such as clay chip, small stone, and porousplastic modules are effective for treating a variety of organic wastes. Most of these studies focused on the treatment capabilities of the processes, yet little work was done about the factors affecting their designs and performance. This paper presents the results of a study on a laboratory scale APBR system examining the significance of media factors such as media roughness, specific surface area, porosity and pore size on treatment performance. The results showed that media roughness and pore size were more important over surface area on the reactor performance. Within the same media porosity, pore size plays a more significant role than surface area in term of COD removal efficiency. The study indicates that the ability of a support medium to retain biomass either as suspended growth entrapped in the void space,or by attachment to the media surface is a significant considerationin an upflow APBR. A testing protocol for measuring methane gas produced by the suspended biomass using a batch serum bottle technique was developed and presented in this study. The method involved measurements of hourly methane production and instantaneous TOC concentrationfrom the suspended biological solids extracted from various reactor heights. The proportion of methane production associated with the suspended biomass was as high as 58% at organic loading rate of 16 g COD/L day. The results suggest that media pore size and porosity play a significant role in the performance of upflow APBRs. [ABSTRACT FROM AUTHOR]

Sludge dewatering is a process whereby water is removed from sludge so as to reduce its volume and alter its physical state from semisolid to damp solid. This physical change reduces the volume of sludge considerably and therefore the cost of disposal. The degree of reduction of sludge volume or dewatering is a function of the characteristicsof sludge and the type of dewatering device. Sludge characteristics such as specific resistance, capillary suction time(CST), filter yield and solid content can be determined in the laboratories. Knowledge of these. characteristics with different dosages of sludge conditioners helps in effective dewatering and sludge handling operations. Oil and grease have an affinity for suspended solids. Experiences show that the presence of oil in wastewater results in poor substrate utilization causing less aerobic treatment and subsequently hinder settlingand dewatering processes. Sludge samples with different oil contentsvarying from 1.8% to 8.0% by weight have been examined in the laboratory to find out their specific resistance, capillary suction time and filter yield. Alum was used as a conditioner. Different dosages of alum varying from 2% to 12% by weight were used to determine the optimum chemical dosage for varying oil contents. Buchner funnel apparatus, filter leaf apparatus and capillary suction time test apparatus were used to determine the dewatering characteristics specific resistance, filter yield and capillary suction time respectively. Addition ofalum decreases the specific resistances and capillary suction times of oily sludges rapidly up to 4% dosages. Alum dosages beyond 4% onlyincrease the solids content in the sludge cake and increase the sludge volume to be handled. The total suspended solids of filtrate decrease with alum dosage. The correlations between dewatering characteristics were studied. A correlation between CST and specific resistance to filtration was established. CST can be measured easily and quicklyin th [ABSTRACT FROM AUTHOR]

Photographic industry which is extensively used by the medical and film industries heavily depend on silver. The industry produce large quantities of wastewater containing high concentrations of silver compounds. Sliver in all forms is regarded as toxic heavy metal and prohibited from discharging into public sewers. Also silver is an expensive commodity and recovery of silver from these wastewaters and recycling improves production cost. Thus makes the process an environmentally friendly operation. This paper gives an insight of an improved silver extraction process developed at the building department of Ngee Ann Polytechnic to effectively recover silver from photographic wastes and to treat the waste water to standards acceptable for disposal, bythe Ministry of the Environment. [ABSTRACT FROM AUTHOR]