Export your learner materials as an interactive game, a webpage, or FAQ style cheatsheet.
Unsaved Work Found!
It looks like you have unsaved work from a previous session. Would you like to restore it?
Total Categories: 5
The primary function of the sand grains in a slow sand filter is to directly trap particulate matter for purification.
Answer: False
The sand in a slow sand filter primarily serves as a substrate for the biological layer (*Schmutzdecke*), which is responsible for purification. Direct physical straining of particulate matter by the sand grains is a secondary mechanism.
The biofilm layer, known as the Schmutzdecke, takes approximately one to two days to fully develop on a new slow sand filter.
Answer: False
The development of the *Schmutzdecke* layer typically requires a maturation period of 10 to 20 days following the initiation of filter operation.
The sand medium in a slow sand filter is primarily responsible for removing bacteria through physical straining.
Answer: False
The primary mechanism for bacterial removal in a slow sand filter is the biological layer (*Schmutzdecke*), not the physical straining action of the sand grains themselves.
The typical operational depth of the sand bed in slow sand filters ranges from 1 to 2 meters.
Answer: True
Slow sand filters are generally constructed with sand beds ranging from 1 to 2 meters in depth to provide sufficient volume for the development and function of the biological layer.
The *Schmutzdecke* layer, responsible for purification in slow sand filters, is composed exclusively of bacteria.
Answer: False
The *Schmutzdecke* is a complex biological layer comprising a diverse community of microorganisms, including bacteria, fungi, protozoa, and other organisms, not solely bacteria.
The sand used in UK slow sand filters typically has a diameter between 0.2 and 0.4 millimeters.
Answer: True
Standard specifications for slow sand filters in the UK include fine sand particles with diameters ranging from 0.2 to 0.4 millimeters.
The substructure at the base of a slow sand filter bed typically consists of a system of herringbone drains, overlain by layers of pebbles and coarse gravel.
Answer: True
The foundation of a slow sand filter bed is designed with a drainage system, typically herringbone drains, covered by graded layers of pebbles and gravel to support the sand bed and facilitate water collection.
What is the principal mechanism responsible for the purification efficacy of a slow sand filter?
Answer: The biological layer (*Schmutzdecke*) that develops on the sand surface.
The biological layer, known as the *Schmutzdecke*, is the primary agent responsible for the purification processes occurring within a slow sand filter.
What is the standard operational depth range for slow sand filters?
Answer: 1 to 2 meters
Slow sand filters are generally constructed with sand beds ranging from 1 to 2 meters in depth to provide sufficient volume for the development and function of the biological layer.
What is the designation for the biological layer responsible for purification in slow sand filters?
Answer: The *Schmutzdecke*
The principal biological agent responsible for purification within a slow sand filter is a gelatinous layer known as the *Schmutzdecke* (derived from German).
What is the typical hydraulic loading rate range for slow sand filters?
Answer: 200 to 400 liters per square meter per hour
The typical loading rate for slow sand filters is between 200 and 400 liters per square meter per hour (0.20–0.40 m³/m²/h), quantifying the volume of water processed per unit area and time.
Which of the following is generally NOT considered a typical component of the microbial community within the *Schmutzdecke* layer of a slow sand filter?
Answer: Viruses
The *Schmutzdecke* comprises a diverse microbial consortium, including bacteria, fungi, and protozoa. Viruses are generally not considered a primary component of this biological layer.
What is the approximate maturation period required for the *Schmutzdecke* to fully develop in a newly established slow sand filter?
Answer: 10 to 20 days
The development of the *Schmutzdecke* layer typically requires a maturation period of 10 to 20 days following the initiation of filter operation.
Which of the following represents a unique characteristic of slow sand filters relative to other water filtration technologies?
Answer: They utilize biological processes for purification.
Unique attributes of slow sand filters include their reliance on biological processes (biofilm) for purification, operation as non-pressurized systems, and independence from chemical additives or electricity.
What layer is situated immediately above the sand bed within a slow sand filter?
Answer: A supernatant layer of unpurified water
A layer of untreated water, referred to as the supernatant layer, is maintained above the sand bed within the filter.
What characteristic of raw water can lead to accelerated clogging of slow sand filters, potentially necessitating pre-treatment?
Answer: High turbidity levels
Slow sand filters function optimally with raw water exhibiting low turbidity. Elevated turbidity, particularly during periods of increased microbial activity, can lead to accelerated clogging ('bioclogging'), thus necessitating pre-treatment.
What is the typical effective size range for the sand particles used in slow sand filters, as exemplified by UK standards?
Answer: 0.2 to 0.4 millimeters
Standard specifications for slow sand filters in the UK include fine sand particles with diameters ranging from 0.2 to 0.4 millimeters.
What is a defining characteristic of the hydraulic flow rate through slow sand filters?
Answer: It is slow and constant, crucial for biological processes.
A slow, constant flow rate is indispensable for the optimal development and sustained metabolic activity of the biological processes within the *Schmutzdecke*, thereby ensuring effective purification.
James Simpson is credited with the installation of the world's first treated public water supply system employing sand filtration, which occurred in London in 1829.
Answer: True
Engineer James Simpson installed the pioneering sand filtration system for the Chelsea Waterworks Company in London in 1829, establishing the first treated public water supply of its kind.
The Metropolis Water Act of 1852 mandated that all water supplied to London must undergo effectual filtration by December 31, 1855.
Answer: True
The Metropolis Water Act of 1852 was landmark legislation that imposed stringent requirements on London's water suppliers, mandating the implementation of effective filtration for all supplied water by the specified deadline.
The slow sand filtration plant established in Poughkeepsie, New York, in 1872 operated for 87 years before its replacement in 1959.
Answer: True
The Poughkeepsie, New York, slow sand filtration facility, commissioned in 1872, demonstrated remarkable longevity, serving the community for 87 years until its decommissioning and replacement in 1959.
Robert Thom is recognized for developing the first slow sand filter utilized for a public water supply in London.
Answer: False
Robert Thom developed an experimental sand filter in Paisley, Scotland, in 1804. The first treated public water supply using sand filtration in London was installed by James Simpson in 1829.
John Gibb installed the first experimental sand filter created by Robert Thom.
Answer: True
John Gibb, a bleachery owner in Paisley, Scotland, installed the experimental sand filter developed by engineer Robert Thom in 1804.
The first documented instance of sand filters being used for water purification occurred in the United States in 1872.
Answer: False
The earliest documented application of sand filtration for water purification dates to 1804 in Paisley, Scotland. The first U.S. plant was established in Poughkeepsie, New York, in 1872.
Which historical figure is credited with the development of an experimental sand filter in Paisley, Scotland, circa 1804?
Answer: Robert Thom
Robert Thom, an engineer, is credited with developing an experimental sand filter in Paisley, Scotland, circa 1804, representing an early milestone in documented sand filtration for water purification.
Which engineer is credited with installing the first treated public water supply system that utilized sand filtration in London in 1829?
Answer: James Simpson
James Simpson, an engineer, pioneered the first treated public water supply system utilizing sand filtration in 1829 for London's Chelsea Waterworks Company. This system served as a precedent for subsequent water treatment installations throughout the United Kingdom.
What legislative act, passed in 1852, mandated the effective filtration of London's water supply?
Answer: The Metropolis Water Act
The Metropolis Water Act of 1852 established regulatory standards for water supply companies in London, mandating effectual filtration by December 31, 1855.
In which country did the first documented instance of sand filters being employed for water purification take place?
Answer: Scotland
The earliest documented application of sand filtration for water purification dates to 1804 in Paisley, Scotland.
According to the provided information, what was John Gibb's contribution to the early adoption of sand filtration technology?
Answer: He installed Thom's filter and sold the surplus water to the public.
John Gibb, a bleachery owner in Paisley, Scotland, facilitated the early adoption of sand filtration by installing Robert Thom's experimental filter in 1804 and making surplus filtered water available to the public.
Slow sand filters are predominantly utilized in developed countries owing to their substantial energy requirements.
Answer: False
Slow sand filters are characterized by their minimal energy requirements and robustness, making them particularly suitable and widely utilized in developing countries, not developed countries due to high energy needs.
Slow sand filters necessitate continuous chemical additives to sustain their purification efficiency.
Answer: False
A key advantage of slow sand filters is their ability to achieve purification through biological processes without the need for continuous chemical additives.
Slow sand filters are deemed inappropriate technology for regions possessing limited resources due to their complex maintenance demands.
Answer: False
Slow sand filters are widely considered an appropriate technology for regions with limited resources because of their simplicity, low maintenance requirements, and lack of need for chemicals or electricity.
Slow sand filters are characterized by high throughput rates, rendering them suitable for large, high-demand urban areas without requiring modifications.
Answer: False
Slow sand filters operate at relatively low rates and typically require integrated storage to meet peak demand, making them less suitable for high-demand urban areas without supplementary measures or modifications.
Slow sand filters are primarily employed for treating highly turbid water during peak summer months without necessitating pre-treatment.
Answer: False
High turbidity levels can cause slow sand filters to clog rapidly ('bioclogging'). Therefore, pre-treatment is often advisable, especially during periods of increased microbial activity like peak summer months.
Slow sand filters operate as non-pressurized systems and do not require electrical power.
Answer: True
A key characteristic of slow sand filters is their operation without requiring external pressure or electricity, relying instead on gravity and biological processes.
Municipal slow sand filter systems frequently incorporate multiple filter beds to guarantee a continuous water supply during maintenance periods.
Answer: True
The use of multiple filter beds in municipal systems provides redundancy, allowing for uninterrupted water supply by isolating individual beds for cleaning or maintenance without compromising overall output.
The 1829 installation by the Chelsea Waterworks Company served as a model for analogous water filtration systems implemented across Europe.
Answer: False
The 1829 Chelsea Waterworks Company installation, pioneered by James Simpson, served as a significant model for similar sand filtration systems adopted throughout the United Kingdom, rather than across Europe.
What factors contribute to the particular suitability of slow sand filters for application in numerous developing countries?
Answer: They are robust and have minimal energy requirements.
Slow sand filters are designated as 'appropriate technology' due to their minimal requirements for mechanical power, chemical inputs, and replaceable parts. Their need for periodic maintenance and minimal operator training renders them highly suitable for regions with constrained resources and technical infrastructure.
What is a significant disadvantage of slow sand filters, particularly when implemented in large municipal water systems?
Answer: They necessitate extensive land area.
A principal limitation of slow sand filters, particularly for large municipal applications, is their substantial land area requirement, a consequence of their inherently slow filtration rates.
What factors drove the shift from slow sand filters to rapid sand filters in numerous U.S. municipalities?
Answer: Rapid sand filters possess superior capability for treating high-turbidity water and accommodating escalating demand.
The transition of many U.S. municipalities from slow to rapid sand filtration was driven by escalating urban demand and the superior capacity of rapid filters to manage source waters with high turbidity, a condition that can rapidly incapacitate slow sand filters.
What is the primary purpose of employing redundancy, typically through multiple filter beds, in municipal slow sand filter systems?
Answer: To ensure maximum throughput can be met during maintenance.
The implementation of multiple filter beds in municipal slow sand filter systems provides redundancy, allowing for uninterrupted water supply by isolating individual beds for cleaning or maintenance without compromising overall output.
A principal advantage of the 'wet harrowing' method for filter refurbishment is its ability to facilitate a more rapid return to service compared to traditional scraping techniques.
Answer: True
The 'wet harrowing' method streamlines the refurbishment process, allowing the slow sand filter to resume operation sooner than is typically achievable with conventional scraping methods.
The 'wet harrowing' method for slow sand filter refurbishment involves drying the filter bed prior to agitating the sand.
Answer: False
The 'wet harrowing' method is characterized by the agitation of the sand while the filter bed remains wet, distinguishing it from traditional scraping which often involves drying the bed.
What constitutes a key advantage of the 'wet harrowing' refurbishment method when compared to traditional sand scraping?
Answer: It allows for a quicker return to service.
The 'wet harrowing' method streamlines the refurbishment process, allowing the slow sand filter to resume operation sooner than is typically achievable with conventional scraping methods.
What is the principal factor contributing to the gradual decline in effectiveness of a slow sand filter over time?
Answer: The *Schmutzdecke* biofilm thickens and obstructs water flow.
The efficacy of slow sand filters diminishes over time primarily due to the progressive thickening of the *Schmutzdecke* biofilm, which impedes water flow and consequently reduces the filter's operational rate and purification efficiency.
John Snow's seminal research during the 1854 Broad Street cholera outbreak provided support for the miasma theory of disease transmission.
Answer: False
John Snow's meticulous investigation of the 1854 Broad Street cholera outbreak fundamentally challenged, rather than supported, the prevailing miasma theory by demonstrating the link between contaminated water and disease transmission.
The Metropolis Water Act of 1852 was enacted subsequent to John Snow's investigations concerning the Broad Street cholera outbreak.
Answer: True
John Snow's influential epidemiological work, particularly his investigation of the 1854 Broad Street cholera outbreak, contributed significantly to the public and political impetus for the Metropolis Water Act of 1852, which mandated effective water filtration.
The principal objective of slow sand filters is the removal of dissolved salts and minerals from water.
Answer: False
Slow sand filters are primarily designed for the removal of pathogens and suspended solids through biological and physical processes, not for the removal of dissolved salts and minerals.
Current research is investigating the application of slow sand filters for pathogen control within nutrient solutions utilized in hydroponic systems.
Answer: True
The efficacy of slow sand filters in managing pathogens within hydroponic nutrient solutions is an area of active research, indicating potential novel applications beyond traditional potable water treatment.
A well-functioning slow sand filter is capable of achieving a bacterial reduction rate of up to 50%.
Answer: False
Exemplary slow sand filters can achieve significantly higher bacterial reduction rates, typically ranging from 90% to 99%, far exceeding 50%.
The World Health Organization (WHO) classifies slow sand filtration as an inefficient method for small water systems.
Answer: False
The World Health Organization (WHO) recognizes slow sand filtration as a highly efficient, economical, and simple method for water treatment, particularly for small water systems.
The image 'Snow-cholera-map-1.jpg' is a cartographic representation illustrating the geographical distribution of cholera cases during the 1854 London epidemic.
Answer: True
The 'Snow-cholera-map-1.jpg' is an original map created by John Snow, visually depicting the spatial clustering of cholera cases during the 1854 epidemic in London.
What prevailing theory regarding disease transmission did John Snow's research on the 1854 Broad Street cholera outbreak challenge?
Answer: The miasma theory
John Snow's research contested the prevailing miasma theory, which posited that diseases such as cholera originated from noxious atmospheric effluvia ('bad airs'), rather than from contaminated water sources.
What was the demonstrable impact of the Poughkeepsie, New York, slow sand filtration plant on local public health?
Answer: It significantly reduced instances of cholera and typhoid fever.
The Poughkeepsie plant demonstrably reduced the incidence of cholera and typhoid fever within its service area. Its design principles proved so effective that they were subsequently adopted as a model for other municipalities throughout the United States.
Which prominent international organizations recognize slow sand filters as a superior technology for small water systems?
Answer: WHO, Oxfam, and EPA
Prominent international organizations, including the World Health Organization (WHO), Oxfam, and the United States Environmental Protection Agency (EPA), endorse slow sand filters as a superior technology for surface water treatment in small-scale water systems.
What is the typical bacterial reduction rate achieved by a properly functioning slow sand filter?
Answer: 90% to 99%
A well-functioning slow sand filter is capable of achieving substantial bacterial reduction, typically in the range of 90% to 99%.
The image 'Snow-cholera-map-1.jpg' is historically associated with which significant event and individual?
Answer: The 1854 Broad Street cholera outbreak investigated by John Snow
The 'Snow-cholera-map-1.jpg' is an original cartographic representation by physician John Snow, illustrating the spatial distribution and aggregation of cholera cases during the 1854 London epidemic.
Which of the following is cited as a potential emerging application for slow sand filters?
Answer: Controlling pathogens in hydroponic nutrient solutions
Current research is exploring the efficacy of slow sand filters for pathogen control in hydroponic nutrient solutions, suggesting novel applications beyond conventional water purification.