The Effect of Temperature on the Destruction of Salmonellas in Activated Sludge

The effect of temperature on the survival of salmonellas in activated sludge was examined. The results showed that the Salmonella destruction rates increased in line with increasing temperature of the mixed liquor from 5° to 25°C, whereas at 30°C the rate declined markedly. This is most probably due to inactivation of ciliate protozoa at the higher temperature resulting in increased survival of the pathogens. The slow reduction in the number of salmonellas at 30°C may be the result of nutrient starvation, in addition to other possible mechanisms such as the lytic action of bacterial viruses

The occurrence of antibiotic resistant Salmonellas in sewage and the effect of primary sedimentation on their numbers

The widespread use of antibiotics has led to the occurrence of resistant strains of bacteria in sewage and in the aquatic environment. This study has shown that there is no significant change in the proportion of antibiotic-resistant and antibiotic sensitive salmonellas during sedimentation of sewage and hence these organisms must have acquil·ed resistance during the initial use of the antibiotic and not during sewage treatment. Primary sedimentation alone can remove more than 80% of the total salmonellas present in raw sewage but negligible reductions will occur if the process is not optimised. The best way of controlling the release of antibiotic resistant salmonellas into the environment is to control the prescription and use of antibiotics

A Study of the Bacterial Population Fluctuations During Poultry Processing

The microbial assessment of skin-washed water samples taken from 39 poultry carcasses and the wash water from a poultry processing unit revealed cumulative increases z"n the number of microflora at each stage of processing. A comparison of the bacterial population densities on the skin at the' start and at the end of processing showed that the levels of E. coli and coli forms increased by 231.1% and 263.1% respectively whereas the Salmonella concentrations decreased by about 9%. A positive correlation was obtained between the occurrence of bacterz"a and parameters such as wash water pH and temperature, and suspended solids concentration. An examination of the storage tank effluent which was used to store the poultry carcasses pri"or to packaging showed that E. coli and Salmonella were able to thrive in the liquid. During the 4 h incubation period, the levels of both organisms decined rapidly during the initial half hour, but quickly became adapted and multipUed z"n the subsequent hours. The implications of both, the field and laboratory studies are discussed with a view of reducing the level of contamination during processing

A Study of the Problems Related to the Testing of Smoke Emission From Diesel Powered Vehicles in Malaysia

This study was carried out to examine the smoke emission level from diesel powered vehicles plying Malaysian roads and the problems related to the enforcement of the Motor Vehicles (Smoke and Gas Emission) Rules 1977. The results show that approximately 35% of the lorries examined had excessive smoke emission compared to 33% for taxis, 16% for buses and mini buses, and 13% for cars. Further examination£on of the data did not show any relationship between the degree of smoke emission and parameters such as age and maintainance of the vehicle, or duration since the last mandatory inspect£on by the RTD. A study of the past records of enforcement carnage out by the DOE showed that an average of only 52. 7% of the planned exercises were actually carnage out during 1979 to 1983. This was due to various reasons including manpower and budget problems, equipment, transportation, and weather. The selection of suitable sites for curb-side enforcement is nearly always hampered by the need to select locations which would not cause severe traffic problems and hence did not necessarily match the traffic flow. The main problem faced by the RTD is the lack of space to carry out inspection of the motor vehicles. The results also give a strong indication that some drivers of diesel vehicle may adopt underhand tactics such as tempenng with the engine parts or adding volatile additives into the fuel tanks to achieve short term reductions for smoke emission during the RTD tests

Managing potential health risks associated with drinking water supplies: some issues and approaches

More than 90% of Malaysia's water supplies are derived from surface water sources. Long-term monitoring programs and research data indicate that many river systems are moderately to grossly polluted by domestic and industrial wastes. Properly planned, long-term, interdisciplinary studies are needed to assess the health implications of the country's social and industrial development and the associated impacts on the quality of drinking water supplies. New areas of potential risks need to be properly evaluated and the multiple barrier concept in providing safe water supplies needs to be properly coordinated, instituted and continuously monitored

A Study of Some Community Water Supply Problems in Wilayah Persekutuan

This study was carried out to examine the various sources of water which are being used by residents in squatter settlements around Kuala Lumpur. The results showed that piped water from the public stand-pipes was used primarily Jar drinking and cooking purposes but water from other sources was also collected to augment their water supply jar use in washing, gardening, etc. An evaluation of the methods used Jar the collection and storage of water other than piped water, indicated that the system can be further improved to yield good quality water by adoption of appropriate technologies for household water treatment

A Study of the Air Quality in Underground Car Parks with Emphasis on Carbon Monoxide and Airborne Lead

The concentrations of carbon monoxide and airborne lead in three enclosed underground car parks in Kuala Lumpur were measured simultaneously with traffic flow for a period of three months. The measurements were taken at a height of 1. 5 m from the ground for a duration of8 - 13 hours. A large variation in the airborne lead levels was observed which ranged from 1.75 to 23.9 J1g/m 3 in relation to traffic flow. The mean carbon monoxide concentration ranged from 23.2 to 65.2 ppm. The mean concentration of both pollutants at all the three sites was found to exceed the proposed Malaysian Air Quality Standard of 0.7 J1g/m 3 for lead and 9 ppm (8 hours average) for carbon monoxide. A positive correlation was observed between traffic flow and carbon monoxide as well as lead at the locations studied

Degradation of cellulose by Aspergillus sp Trichoderma koninggii, and Myriococcum sp.

Culture filtrates obtained from Aspergillus sp, Trichoderma koningii and Myriococcum sp were shown to be active in degrading cotton wool and filter paper. The optimum temperature for growth for Aspergillus sp and T. Koningii occurred at 37° while that of Myriococcum at 45°-50°C. Optimum temperature for activity was recorded as 45° C for T. koningii and 40° C for Aspergillus sp and Myriococcum sp; the pH optima occurred at pH 5.0, 4.0 and 7.0 respectively. The action of these organisms on various cellulosic wastes was tested and pineapple waste was the most amenable to degradation. Synergistical studies using crude enzyme extracts indicated only a small increase in enzyme activity (40%)

Treatment of Palm Oil Mill Effluent by Mesophilic Anaerobic Digestion with Flocculant Addition

This paper presents research findings on the use of flocculants in the anaerobic digestion of palm oil mill ellluent (POME) under mesophilic conditions (37°C). Zetag 88N, a cationic polyacrylamide of high molecular density, was added to the digester at the beginning of the operation. The use of the flocculant enabled pelletization to occur in the digester within three months of start-up for the substrate which is difficult to granulate naturally. The effect of pelletization resulted in an increase in biomass concentration and produced a good solid-liquid separation within the digester, resulting in enhanced treatment performance and the ability to tolerate higher organic loads. Stable mesophilic anaerobic digestion can be operated up to a maximum organic loading rate of 19 kg chemical oxygen demand (COD) m-3 day-l (hydraulic retention time = 3.6 days

Decolorization of reactive orange 16 dye by copper oxide system

The decolorization of reactive orange 16 dye (RO16) from aqueous solution by CuO/H2O2 was investigated. The amount of dye removed was determined by measuring the concentration of the dye at its characteristic wavelengths by UV-Vis spectrophotometer. The effects of CuO dose, H2O2 concentration and UV light on the decolorization of the dye were investigated. It was found that the removal rate increased with increasing mass of CuO and increasing concentration of H2O2. The combination of CuO, H2O2 and UV light was the best system with dye removal of 100% after 6 h. The removal efficiency observed was in the order: CuO/ UV/H2O2 > CuO/H2O2 > CuO/UV= CuO > UV/H2O2> H2O2> UV