Water Quality Control Engineering Practice Flashcards

Comprehensive Question and Answer flashcard set covering all topics, concepts, formulas, EPA methods, standards, and definitions from the Water Quality Control Engineering lecture notes.

What is Water Quality Control Engineering?

The application of engineering principles, scientific knowledge, design methods, monitoring techniques, and management strategies to prevent, reduce, treat, and control water pollution.

What is the primary goal of Water Quality Control Engineering?

To maintain or restore water quality so that water can safely support its intended uses while protecting public health, agricultural productivity, infrastructure, and aquatic ecosystems.

What are the three major groups of water quality parameters?

Physical parameters, chemical parameters, and biological parameters.

How is water quality defined?

Water quality describes the physical, chemical, and biological condition of water relative to a specific use.

What is the key concept behind water quality being "fit-for-use"?

A single water sample may be acceptable for one use but unsuitable for another, as quality requirements depend entirely on the intended application.

What are the water quality requirements for drinking water?

Very high microbiological and chemical safety requirements.

What key water quality parameters matter most for irrigation?

Salinity, sodicity, toxic ions, pathogens, and crop sensitivity.

What key water quality parameters are critical for aquaculture?

Dissolved oxygen (DO), temperature, pH, ammonia, and toxicity.

What factors determine water quality requirements for industrial use?

Industrial requirements depend on specific process needs, corrosion potential, scaling potential, and product quality standards.

What is the definition of contamination according to Republic Act No. 9275?

The production or introduction of substances not found in the natural composition of water that make the water less desirable or unfit for intended use.

What is the definition of water pollution according to Republic Act No. 9275?

Any alteration of the physical, chemical, or biological properties of a water body by the introduction of any substance that adversely affects its use or potential use.

What is the key distinction between water contamination and water pollution?

All pollution involves degradation of water quality or harm, whereas contamination refers to the presence of unwanted substances without necessarily causing measurable harm.

What is a point source of water pollution?

Pollution that enters water from an identifiable and discrete conveyance or location.

What are four examples of point sources of water pollution?

Wastewater discharge pipes, industrial outfalls, drainage channels, and effluent from processing facilities.

What is a non-point source of water pollution?

Pollution originating from diffuse areas that is commonly transported by rainfall, runoff, erosion, or leaching.

What are four examples of non-point sources of water pollution?

Fertilizer runoff, pesticide movement, sediment from fields, and urban stormwater.

What are the major pollutants associated with agricultural human sources?

Fertilizers, pesticides, sediment, manure, and irrigation return flow.

What are the main pollutants present in domestic wastewater sources?

Sewage, detergents, nutrients, pathogens, and household chemicals.

What major pollutants are generated by industrial sources?

Organic wastes, chemicals, heavy metals, heat, oils, and process wastewater.

What pollutants are typically found in urban runoff?

Stormwater, litter, oils, road contaminants, and construction sediment.

What are the primary impacts of sediment and suspended solids pollution?

Increased turbidity and habitat smothering.

What causes nutrient pollution and what is its main environmental impact?

Nutrient pollution is caused by excess nitrogen and phosphorus, leading to eutrophication and algal blooms.

What causes organic pollution and what are its environmental impacts?

Organic pollution originates from sewage, manure, and food-processing wastes, causing dissolved oxygen depletion and odor.

What is the main source and public health risk of pathogen pollution?

Pathogen pollution stems from fecal contamination and increases the risk of waterborne diseases.

What causes toxic chemical pollution and what is its primary impact?

It is caused by pesticides, heavy metals, and solvents, leading to acute and chronic toxicity in aquatic life and humans.

What causes thermal pollution and how does it impact water ecosystems?

Heated discharges cause thermal pollution, which lowers dissolved oxygen levels and induces ecosystem stress.

What sequence describes agricultural pollution pathways from farm to water bodies?

$$\text{FIELD / FARM} \rightarrow \text{POLLUTANTS} \rightarrow \text{PATHWAYS} \rightarrow \text{WATER BODY}$$

What four pathways transport agricultural pollutants from farms?

Runoff, leaching, erosion, and drainage.

What four receiving water bodies are affected by agricultural pollution pathways?

Rivers, lakes, groundwater, and coastal waters.

What step-by-step chain of events occurs during eutrophication?

Excess Nitrogen and Phosphorus cause algal growth, algae die, decomposition occurs, Dissolved Oxygen declines, and fish stress or fish kills result.

How does poor water quality affect crop health and yield?

Contaminated water with high salts, heavy metals, or pathogens can inhibit seed germination, reduce crop yields, and cause plant toxicity or disease.

What three negative effects does poor water quality have on soil integrity?

Soil salinization (causing infertility), soil structure degradation (reducing infiltration and root penetration), and nutrient imbalances.

How does poor water quality impact animal health in livestock farming?

It impairs hydration and digestion, reduces growth and reproduction, and spreads waterborne diseases.

How does contaminated irrigation water affect food safety?

It can transfer pathogens like $E.\text{ coli}$ and Salmonella to crops, posing public health risks when consumed by humans.

How does poor water quality damage engineering infrastructure?

Acidic, saline, or corrosive water corrodes pipes, pumps, and tanks, damages concrete and steel, and shortens the lifespan of dams, canals, and treatment plants.

How does poor water quality affect water treatment plant performance?

It requires more complex and expensive treatments, increases energy and chemical consumption, and reduces filtration and disinfection efficiency.

What are the main environmental engineering concerns regarding polluted water?

Algal blooms and eutrophication, loss of aquatic biodiversity, and challenges in maintaining sustainable water cycles.

How do water impurities affect industrial engineering processes?

Impurities reduce process efficiency, cause product contamination, and lead to equipment fouling and failure.

What are the five levels of the Water Quality Control Engineering Hierarchy shown in this diagram?

1. PREVENT, 2. MINIMIZE, 3. INTERCEPT, 4. TREAT, 5. MONITOR.

What is Tier 1 (PREVENT) in the water quality control engineering hierarchy?

Avoid or reduce pollutant generation directly at the source.

What is Tier 2 (MINIMIZE) in the water quality control engineering hierarchy?

Improve process efficiency and implement good management practices.

What is Tier 3 (INTERCEPT) in the water quality control engineering hierarchy?

Use buffers, sediment controls, drainage controls, or containment.

What is Tier 4 (TREAT) in the water quality control engineering hierarchy?

Apply physical, chemical, biological, or nature-based treatment processes.

What is Tier 5 (MONITOR) in the water quality control engineering hierarchy?

Verify system performance and regulatory compliance to continuously improve the system.

What does an Agricultural and Biosystems Engineer (ABE) do in the 'Assess' phase?

Characterizes water sources, wastewater, pollutant loads, and agricultural production systems.

What does an ABE do in the 'Design' phase of water quality control?

Develops treatment units, drainage controls, waste-management systems, wetlands, and Best Management Practices (BMPs).

What tools and models are used by ABEs in the 'Model & Analyze' phase?

Mass balance calculations, hydraulics, GIS, data analysis, and water-quality models.

What activities are performed by ABEs in the 'Manage' phase?

Developing monitoring plans, operation and maintenance procedures, and pollution-prevention strategies.

What must ABEs balance in the 'Integrate' phase?

Engineering performance with cost, environmental protection, farm productivity, and social needs.

What are four typical ABE applications in farm water quality control?

Design of farm wastewater treatment systems, control of sediment/nutrient runoff, design of constructed wetlands/lagoons, and management of irrigation return flows.

What global water challenges are faced currently regarding scarcity and sanitation?

Over 2 billion people live in high water stress areas, 1 in 4 lack safely managed drinking water, and 2.6 billion lack basic sanitation.

Which waterborne diseases are associated with lack of access to safe drinking water?

Diarrhea, Cholera, Dysentery, Typhoid, and Hepatitis A.

What percentages of the total Nile River flow were awarded to Egypt, Sudan, and Ethiopia under the 1959 treaty?

Egypt: 66%, Sudan: 22%, Ethiopia: 0% (with 12% lost to evaporation).

In what year did Ethiopia begin construction of the Grand Renaissance Dam on the Nile?

In 2011.

What preliminary agreement was signed in 2015 regarding the Nile River?

Egypt, Ethiopia, and Sudan signed a preliminary deal agreeing in principle to share water and not harm each other's interests.

What is water temperature, and why is it an important physical parameter?

Temperature measures the thermal condition of water in $^\times\text{C}$. It controls reaction rates, gas solubility, microbial activity, aquatic metabolism, and treatment performance.

What is the relationship between water temperature and dissolved oxygen (DO) solubility?

Warm water holds less dissolved oxygen than cold water.

What is color in water and what units are used to measure it?

Color is a visual characteristic caused by dissolved substances, suspended matter, organics, metals, or industrial wastes. It is measured in True Color Units (TCU) or Platinum-Cobalt units (Pt-Co).

What is the difference between apparent color and true color in wastewater?

Apparent color (suspended color) is caused by colored suspended particles. True color (dissolved color) is caused by substances dissolved in water after suspended matter is filtered out.

How does the removal method differ for apparent color versus true color?

Apparent color is removed by physical processes like settling or filtration. True color requires chemical or advanced treatments like oxidation, activated carbon adsorption, or biological treatment.

What are three major sources of dissolved (true) color in wastewater?

Vegetable or mineral dyes (textile/paper industries), inorganic industrial wastes (plating/chemical industries), and organic material from stormwater runoff (decaying leaves/humus).

What two methods are used to measure color quantitatively in wastewater?

Visual comparison with standard platinum-cobalt solutions, and spectrophotometric absorbance measurement at $455\text{ nm}$.

What is turbidity and what causes it?

Turbidity is the cloudiness of water caused by fine suspended and colloidal particles scattering light.

What unit is used for turbidity and what instrument measures it?

Nephelometric Turbidity Units (NTU), measured using a nephelometer or turbidity meter.

How does turbidity differ from Total Suspended Solids (TSS)?

Turbidity is an optical measurement of light scattering, whereas TSS is a gravimetric mass measurement of filtered particles.

What is Total Suspended Solids (TSS) and how is it measured?

TSS is the mass of particles retained on a $0.45\text{ }\frac{1}{2}\text{--}\text{µm}$ filter from a sample volume, dried at $103\text{--}105^\times\text{C}$ for 1 hour, and weighed gravimetrically.

What is the mathematical equation for calculating Total Suspended Solids (TSS)?

$\text{TSS (mg/L)} = \frac{(W_2 - W_1) \times 1000}{V}$, where $W_1$ is dry filter weight (mg), $W_2$ is filter+residue weight (mg), and $V$ is sample volume (mL).

What is Total Dissolved Solids (TDS) and how is it measured?

TDS represents dissolved inorganic salts and small amounts of organic matter in the filtrate, determined by evaporating the filtrate and drying at $180^\times\text{C} \times 2^\times\text{C}$ for 1 hour.

What is the formula for calculating Total Dissolved Solids (TDS)?

$\text{TDS (mg/L)} = \frac{(D_2 - D_1) \times 1000}{V_1}$, where $D_1$ is empty dish weight (mg), $D_2$ is dish+residue weight (mg), and $V_1$ is filtrate volume evaporated (mL).

What equation expresses the fundamental relationship between TS, TSS, and TDS?

$$\text{TS} = \text{TSS} + \text{TDS}$$

What are settleable solids and how are they measured?

Solids that settle by gravity in quiescent wastewater, measured as mL of settled solids per liter (mL/L) accumulated after 1 hour in an Imhoff cone.

What are floatable solids (FSS)?

Solids that rise and accumulate at the liquid surface when wastewater is left quiescent.

How are volatile solids defined and determined in a laboratory?

Volatile solids are organic solids destroyed by burning in a muffle furnace at $550^\times\text{C} \times 50^\times\text{C}$ for 15-20 minutes. The weight loss equals the volatile solids.

What equations relate volatile and non-volatile fractions of TS, TSS, and TDS?

$\text{TS} = \text{TVS} + \text{TNVS}$, $\text{TSS} = \text{TVSS} + \text{TNVSS}$, and $\text{TDS} = \text{TVDS} + \text{TNVDS}$.

What was the Jackson Turbidity Unit (JTU/TU) method, and why is it obsolete?

An old method that measured candlelight extinction through a sample; it was inaccurate at low turbidities and replaced by nephelometric light-scattering.

What optical angle is standard in nephelometric turbidity measurement?

Light scattered at a $90^\times$ angle to the light source.

What is the definition of odor in wastewater?

Odor is a measure of the effect of a stimulating substance on human olfactory receptory membranes.

What test is standard for quantifying odor in water?

The Threshold Odor Test (TOT).

How is Minimum Detectable Threshold Odor Concentration (MDTOC) defined and calculated?

$$\text{MDTOC (OU)} = \frac{\text{Initial Sample Volume}}{\text{Barely Detectable Sample Volume}}$$

If 100 mL of sample is diluted with pure water and odor is barely detectable at 25 mL sample volume, what is the MDTOC?

$\text{MDTOC} = \frac{100\text{ mL}}{25\text{ mL}} = 4\text{ Odor Units (OU)}$ (or $1:4$ dilution).

What testing conditions are required for the Threshold Odor Test?

A trained panel of 3-6 people, odor-free dilution water at room temperature, randomized sample order, and reporting the dilution where at least 50% of the panel detects odor.

What are the four true basic tastes recognized by human tongue and palate nerves?

Bitter, Salty, Sour, and Sweet.

What chemical sources cause bitter, salty, sour, and sweet tastes in water?

Bitter from alkaloids/medicines; Salty from dissolved salts ($\text{NaCl}$); Sour from acids/low pH; Sweet from sugars/organic compounds.

What are the three standard methods to determine taste in water?

1. Flavor Threshold Test, 2. Flavor Rating Assessment, 3. Flavor Profile Analysis.

How is Flavor Threshold reported?

Reported as Flavor Units (FU), equal to the dilution factor where taste is just barely detectable.

According to Table 3.1, what are the permissible and desirable limits for color in public water supplies?

Permissible = 75 color units; Desirable = $< 10$ color units.

According to Table 3.1, what are the desirable levels for odor and turbidity in public water supplies?

Virtually absent.

According to Table 3.2, what are typical domestic wastewater TSS values for weak, average, and strong sewage?

Weak: $100\text{ mg/L}$; Average: $240\text{ mg/L}$; Strong: $350\text{ mg/L}$.

According to Table 3.2, what are typical domestic wastewater TDS values for weak, average, and strong sewage?

Weak: $250\text{ mg/L}$; Average: $500\text{ mg/L}$; Strong: $850\text{ mg/L}$.

According to Table 3.2, what are typical 5-Day BOD values for weak, average, and strong domestic wastewater?

Weak: $120\text{ mg/L}$; Average: $225\text{ mg/L}$; Strong: $400\text{ mg/L}$.

According to Table 3.2, what are typical COD concentrations for weak, average, and strong domestic wastewater?

Weak: $175\text{ mg/L}$; Average: $325\text{ mg/L}$; Strong: $575\text{ mg/L}$.

According to Table 3.2, what are typical Total Nitrogen values for weak, average, and strong domestic wastewater?

Weak: $20\text{ mg/L}$; Average: $35\text{ mg/L}$; Strong: $80\text{ mg/L}$.

According to Table 3.2, what are typical Phosphorus concentrations in weak, average, and strong domestic wastewater?

Weak: $5\text{ mg/L}$; Average: $10\text{ mg/L}$; Strong: $15\text{ mg/L}$.

Which physical parameters can be continuously monitored using automated sensors?

TDS (via conductivity meter), color (via spectrophotometer), temperature (via thermistor/probe), and turbidity (via turbidimeter).

Which physical parameters cannot be continuously monitored and require manual sampling?

TSS, Settleable solids, Floatable solids, Volatile solids, Odor, and Taste.

What key collection rule ensures representative sampling for settleable solids?

Collect samples away from channel top, bottom, and walls, at a well-mixed location at representative depth.

How should volatile solids samples be preserved after collection?

Preserved at approximately $4^\times\text{C}$ to prevent changes caused by biological activity.

What is pH and what does it measure?

pH is the negative logarithm of the hydrogen ion concentration, measuring the intensity of acidic or basic character on a 0-14 scale.

Why is pH critical in water and wastewater engineering?

It controls chemical speciation, corrosion rates, chemical coagulation, biological treatment activity, contaminant toxicity, and disinfection efficiency.

What is Dissolved Oxygen (DO)?

The concentration of molecular oxygen dissolved in water, expressed in mg/L or % saturation.