Questions and Answers
What is one reason algae are important for water quality?
What component makes up the structure of a virus?
Why are viruses considered host-specific?
In what way do viruses differ from other microorganisms?
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What role does algae play in the oxygen balance of water?
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What occurs when a virus reproduces within a host cell?
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What can happen when pathogens are present in the water supply?
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What is a common characteristic of viruses that use bacteria as hosts?
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What are the two types of hardness in water?
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Which ions are primarily responsible for water hardness?
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What is carbonate hardness associated with?
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What is the impact of hardness on soap usage?
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At what pH does HCO3 begin to convert to less soluble carbonates?
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What unit of measurement is commonly used for water hardness?
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Which category indicates very hard water based on hardness measurement?
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What defines alkalinity in water?
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What is the primary component of organic matter in wastewater by weight?
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Which parameter is NOT typically used to quantify organic matter in wastewater?
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When can the theoretical oxygen demand (ThOD) be used?
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What does the chemical oxygen demand (COD) measure?
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Which of the following compounds are typically neglected in ThOD calculations?
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What percentage of organic matter in wastewater do fats typically represent?
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What is one adverse effect of algae on water supply?
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How do aquatic weeds adversely affect water supply systems?
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What happens to sulphate under anaerobic conditions?
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What is a key hazard associated with oil and grease in water bodies?
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How does oil and grease affect the natural re-aeration of water bodies?
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What recent controversy surrounds fluoride?
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What is a consequence of the presence of oil and grease in the water?
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What is a consequence of having aquatic weeds in waterways?
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What is the abbreviation for Total Kjeldahl nitrogen?
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Which of the following forms of nitrogen is an ion?
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At which pH level is ammonia favored over ammonium ions?
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What is the consequence of high nitrate levels in drinking water?
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Which bacteria are involved in nitrification?
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What does the Total inorganic nitrogen (TIN) measure?
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Which test quantifies total nitrogen in raw municipal sewage?
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What is the chemical formula for ammonia gas?
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Which form of nitrogen is created from bacterial decomposition?
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What causes blue baby syndrome?
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Study Notes
Algae and Water Quality
- Algae contribute significantly to water quality, influencing taste, odor, and toxicity.
- Affect the oxygen balance in aquatic environments, potentially causing supersaturation or anaerobic conditions.
- Play a role in organic matter content and turbidity, impacting water filtration.
Viruses
- A virus consists of nucleic acid (DNA or RNA) and a protein coat (capsid), forming a nucleocapsid.
- Viruses can be naked or enveloped; examples include influenza and herpes viruses.
- Highly host-specific and may target specific tissues or cells within the host.
- Viruses do not reproduce outside living cells and typically lead to host cell death after replication.
- Bacteriophages utilize bacteria as hosts and are about 100 nm in size.
Pathogens in Water
- Waterborne pathogens can compromise human health, posing direct risks or being associated with aquatic insects.
- Microorganisms can survive in water for extended periods, impacting overall water quality.
Water Hardness
- Two types of hardness in water: carbonate (temporary) and non-carbonate (permanent).
- Primary contributors to hardness are calcium (Ca) and magnesium (Mg), with minor contributions from iron (Fe), manganese (Mn), strontium (Sr), and aluminum (Al).
- Carbonate hardness (easily removed by heating) relates to carbonates and bicarbonates, while non-carbonate hardness comes from other anions like sulfates and chlorides.
- Hardness affects soap efficiency and creates precipitates that can stain surfaces.
pH and Hardness Impact
- pH changes can lead to precipitate formation using bicarbonates, especially above pH 9.
- Hardness is measured in mg/L as CaCO3, categorized as soft (<50 mg/L), moderately hard (50-150 mg/L), hard (150-300 mg/L), and very hard (>300 mg/L).
Alkalinity
- Alkalinity measures water's capacity to neutralize acids, critical for maintaining pH stability.
Organic Matter in Wastewater
- Wastewater contains substantial organic matter, categorized into carbohydrates (30-50%), fats (10%), and proteins (40-60%).
- Various oxygen demand parameters measure organic matter, including ThOD, COD, BOD, and TOC.
Oxygen Demand Types
- ThOD: Theoretical oxygen demand based on known chemical equations; phosphorus and sulfur often overlooked in calculations.
- COD: Amount of oxygen needed to chemically oxidize organic matter in wastewater using potassium dichromate.
Nitrogen Compounds
- Common forms: organic nitrogen, ammonia (NH4+/NH3), nitrite (NO2-), nitrate (NO3-), and gaseous nitrogen.
- Ammoniacal nitrogen distribution varies with pH; NH4+ is favored at lower pH, while NH3 is favored at higher pH.
Nitrogen Measurements
- Total forms include total ammonia nitrogen (TAN), total inorganic nitrogen (TIN), total Kjeldahl nitrogen (TKN), and total nitrogen (TN).
- High nitrate levels in drinking water can lead to serious health issues like blue baby syndrome (methemoglobinemia).
Algal Effects on Water Supply
- Algae increase the demand for coagulants, clog filters, and promote bacteria aftergrowth.
- Aquatic weeds obstruct water supply screens, increase evapo-transpiration, and affect fish populations.
Sulfate in Water
- Present naturally in water and wastewater, essential for protein synthesis.
- Under anaerobic conditions, sulfate reduces to sulfide and can react with hydrogen to form hydrogen sulfide (H2S).
Oil and Grease in Water
- Interfere with natural re-aeration, are toxic to aquatic species, and pose fire hazards.
- Deteriorate water reuse potential, impart undesirable tastes and odors, and diminish recreational water quality.
Fluoride
- An inorganic anion associated with dental health benefits, though recent studies question its efficacy.
- WHO reports conflicting outcomes regarding cavity rates in children with and without fluoride exposure, raising skepticism over its supposed benefits.
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Description
This quiz explores the critical roles of algae, viruses, and pathogens in influencing water quality. It covers the effects of these microorganisms on oxygen balance, turbidity, and human health. Test your understanding of their characteristics and impacts in aquatic environments.