https://www.um.edu.mt/library/oar/handle/123456789/47497 Sun, 19 Apr 2026 01:23:35 GMT 2026-04-19T01:23:35Z https://www.um.edu.mt/library/oar/handle/123456789/54795 Title: Sampling methods and techniques : a study of legionella isolated from freshwater habitats Abstract: In this study Legionella was studied by two different methods, the indirect culturing method and the direct fluorescent analysis (DFA). The indirect culturing method was used to isolate the legionellae from the sample while the DF A method to count the actual number of Legionella in the sample. Legionella was isolated from four different samples. The samples from which isolation occurred were called Legionella-positive samples. The most common habitats from which Legionella was isolated were cooling towers and water tanks. 20% of the water tanks/tap water and 60% of the cooling towers were Legionella-positive samples. The species, most commonly found in the isolates was Legionella pneumophila serogroup 1. Other factors that were found to affect the growth of Legionella were incubation and sedimentation. Description: DIP.ENV.HEALTH Wed, 01 Jan 1997 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/54795 1997-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/48709 Title: Recycling of plastic waste. Abstract: The majority of wastes both industrial and urban including plastic waste, goes to landfill sites. Waste disposal has now emerged as the priority public concern in most countries, not only because it is finally recognised that we are running out of landfill space but perhaps even more importantly because landfills represent an uncontrolled source of toxins and contaminants which have the potential to ruin our water and food supplies. The plastic proportion of waste volume is almost double the weight fraction, so it is the volume of plastics which fills landfills, and pick-up vehicles. Certainly improved compacting of plastics will help but it is not sufficient. Plastics represent the fast growing portion of municipal waste in most countries for example in United States the waste stream has increased by weight from 1% in 1960 to 2.7% in 1970, 7.2% by 1984 and it is predicted that plastics will account for almost 10% of the municipal waste stream by the year 2000. This rapid rise in the use of plastic reflects their unique advantages in term of physical and chemical properties especially for packaging. This situation is also present in Malta. The household waste fraction of Textiles, Plastics and Wood has increased from 6% in 1970 to 11% in 1986, to 14% in 1989 according to the Malta National Waste Study Interim Report (p 2.12 Table 2.6). This is estimated to increase in the near future as it is clear that plastic will continue to displace paper metal and glass in many applications. Thus it is necessary that viable recycling technologies and economically feasible commercial recycling businesses are developed and established. Other solutions include refurbishing degradability, design of plastic parts and energy recovery. However there is no simple solution to waste disposal as it is a complex problem. Most plastics are extremely resistant to biodegradation. This phenomenon starts to create significant economical and environmental problems when landfill sites starts to overflow, with plastic a visible part of the problem. Paper, wood and other remnants slowly decompose. Plastic however, may stay intact for a long time. There is still a problem, whether or not degradable plastics should be introduced as this may create problems in the recycling stream, because the quality and lifetime of plastic articles may be contaminated by degradable resin. There are two basic categories of degradable plastics which are : a) Biodegradable and b) Photodegradable plastics. Biodegradable plastic is decomposed by the action of micro-organisms while photodegradable plastic decomposes on exposure to ultra-violet radiation. However degradation is not a magic solution for the plastic waste disposal problem and degredation in certain conditions is not as fast as expected. At present however only a limited amount of degradable plastics can be found in the market place. Description: DIP.ENV.HEALTH Wed, 01 Jan 1997 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/48709 1997-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/48644 Title: Paper recycling. Abstract: The purpose of this dissertation is to provide a guide for the planning of a paper recycling plant, including details of the preliminary evaluations needed, and an examination of the environmental and economical impacts involved. Also, the equipment needed for implementation of such a project, the different type of paper used and their value for recycling are analysed. Accordingly, an assessment of the different wastepaper classifications and efficient way of collecting same was carried out to clearly specify the wastepaper categorisation requirements for Malta. Finally a conclusion is drawn regarding the importation of unprinted paper values and the acceptance of recycled paper by our society. Description: DIP.ENV.HEALTH Wed, 01 Jan 1997 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/48644 1997-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/48638 Title: Indicators of product quality and food safety. Abstract: There are various ways to assess quality and to grade the quality of a product. To assess quality in general there is no need of complicated methods. This is because it is either good for the purpose it is intended for, or not. For example the most common method that every person uses to indicate if the food (in this case) is good to eat or not we use our sense of smell and taste. According to their analysis we will eat or reject the food. This is a very simplistic idea of indication but it is the most commonly in use in our daily life. Naturally we cannot rely on this method to indicate to us if a sample of food has bacteria or a dangerous chemical in it. Therefore, nowadays, we use much more accurate analysis of food. To be successful these analysis must be tailored for the search of a specific target. In these cases they are called indicators. Indicators may be chemical, bacteriological or visual. All of the three indicators are used and accurate, as long as, they are used in their proper context, for they tend to be very specific and it is of the out most importance that whoever conducts the tests, has a very good background of what type of indicators there are available. This is because certain indicators are not used to assess if the product is good to eat or not, but to grade the quality of the product in respect of another competitor's product. In this dissertation there are various examples of chemical, bacteriological and visual indicators and there are as well some practical food safety tips which can help the reader to be more conscious about the hazards that can be hidden in an innocent looking small little food can. Description: DIP.ENV.HEALTH Wed, 01 Jan 1997 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/48638 1997-01-01T00:00:00Z