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green Which of the following are true of the role of biofilms in water treatment? none false The use of biofilms to treat wastewater followed recent developments in the understanding of the role of biofilms in the environment. No. English engineers developed the first sand-filter treatment method (which uses biofilms) in the 1860s. false Drinking water treated with biofilms has higher disinfection demand than water filtered by other treatment systems. No. Biofilm-treated water tends to require lower levels of disinfectants because the water treated with biofilms tends to have higher biological stability. true Drinking water treated with biofilms has higher biological stability than water filtered by other treatment systems. Yes. Biofilm treatment systems tend to leave treated water more biologically stable. Thus, the water tends to require lower levels of disinfectants. true Biofilms used in water treatment systems can cause problems for drinking water. Yes. Measures must be undertaken to ensure that chunks of biofilm do not detach from the biofilm colony and make it through the system. false Biofilm treatment tends to lead to safe but undesirable effects in drinking water—for example, unsavory taste. No. Since biofilm-treated water is more biologically stable it has lower disinfection demand. Thus, the water is less likely to have unsavory taste resulting from disinfection byproducts. Which of the following are problems in industry that biofilms can cause? none true equipment damage Yes. Biofilms can cause equipment damage such as accumulating on cooling tower fill material. true biofouling Yes. Biofilms can cause biofouling, or biological fouling, which is the undesirable accumulation of living organisms. false bioremediation No. Bioremediation is a term that refers to beneficial processes in which living organisms counteract the effects of contaminants in the environment. true biocorrosion Yes. Biofilms can cause corrosion of pipes for example. true product contamination Yes. Biofilms can form on the surfaces of pipes that carry liquids, causing the liquids to become contaminated. Which of the following are true of infectious diseases? none false are the third leading cause of death worldwide No. Infectious diseases are the leading cause of deaths worldwide. Infectious diseases are the third leading cause of deaths in the US. true are still broadly endemic Yes. Endemic means that there is a large supply of agents that cause infectious diseases—and the diseases never really go away. false increased by about 25% between 1980 and 1992 No. Between 1980 and 1992, infectious disease increased by much more than 25% (58%, or 39% after age adjustment). false are attributable to over half of all the physician visits in the US No. Infectious diseases are attributable to about 25% of the physician visits in the US. true biofilms are reservoirs for the microorganism that cause infectious diseases Yes. Research shows that biofilms are reservoirs for pathogenic organisms and sources of disease outbreaks. Biofilms have been implicated in which of the following diseases? none true otitis media Yes. Biofilms are implicated in otitis media, which is the most common ear infection in US children. true cystic fibrosis Yes. Biofilms play a role in cystic fibrosis (a chronic disorder resulting in increased susceptibility to serious lung infection). false malaria No. Malaria is caused by protozoan parasites, not biofilms. true bacterial endocarditis Yes. Biofilms play a role in bacterial endocarditis—an infection of the inner surface of the heart and its valves. false HIV/AIDS No. AIDS is a result of damage to the human immune system by the human immunodeficiency virus (HIV). Which of the following lead to increased incidence of illnesses associated with pathogenic organisms in the household? none false biofilm colonization of oven surfaces No. It is unlikely biofilms would colonize oven surfaces due to extremely hot, dry conditions. true biofilm colonization of cutting boards Yes. Cutting boards can produce ideal conditions for biofilm colonization. true poor disinfection practices Yes. Since biofilms avidly colonize many household surfaces, it is important to clean such surfaces properly to help prevent the spread of infectious diseases. true ineffective cleaning products Yes. Cleaning products that are ineffective at removing harmful biofilms can cause increased incidence of infectious diseases. false microbial leaching No. Microbial leaching is a process that uses biofilms to help refine precious metals (for example, copper). Which of the following statements are true for biofilms in the environment? none true help recycle elements vital to life Yes. Biological activity of microorganisms (including microorganisms that live in biofilms) play a major role in the basic chemistry of the earth’s surface. false most biofilms produce harmful effects No. Most biofilms are harmless or even beneficial. true can decontaminate areas affected by oil spills Yes. Some naturally occurring bacteria in soil can be used for cleaning up contaminated areas (bioremediation). true are more effective at cleaning up contaminated sites under certain environmental conditions Yes. Scientists and engineers can make bioremediation more effective by providing the right conditions for biofilms to thrive. false can refine copper and other precious metals by concentrating the soluble metals inside the microorganisms within the biofilm No. Bacteria used in microbial leaching do not store the metals within their cells, but release the water soluble form of the metal into their surroundings. The metal is then recovered from the resulting liquid.