Pumps, Screens, SCADA
What is the main purpose of a coarse intake screen?
Remove larger debris and protect downstream plant. Specific fish/eel screens have additional protection requirements.
Riverwater coming in clear at 2NTU. How ready is it for consumption?
Contamination still present from microogranisms, dissolved chemicals and NOMs.
What do we call water before treatment for drinking-water supply?
Raw water.
Which measurement indicates cloudiness caused by particles, commonly reported in NTU?
Turbidity.
Which organisation regulates water abstraction in England?
The Environment Agency.
What is the difference between instantaneous flow and totalised volume?
Flow is the rate at that moment, such as L/s. A totaliser records accumulated volume, such as m³.
An algal bloom develops in raw-water storage. Name two possible problems.
Screen/filter loading, taste and odour, or toxins from some cyanobacterial species. The risks depend on the organisms present.
Give one example of a surface-water source and one groundwater source.
River, lake or reservoir; groundwater abstracted through a borehole, well or spring.
Name two chemical contaminants that agricultural activities can introduce into raw water.
Nitrate and pesticides. Accept other relevant examples with an explanation.
Name three conditions an abstraction licence might control.
Examples: abstraction rate, daily/annual volume, season, permitted use, abstraction point and river-flow or groundwater-level restrictions.
What does a variable-speed drive allow an abstraction pump to do?
Change its speed to control output within its permitted operating range.
A raw-water quality result deteriorates. Does that automatically mean the supplied drinking water has failed a legal standard?
No. Assess the source risk, treatment capability and supplied-water results. Raw-water changes can require action before a supplied-water failure occurs.
What is a catchment, and why do activities within it matter?
The area contributing water to a source. Activities there can affect the quality and quantity of water reaching abstraction.
Why can a rise in raw-water ammonia cause problems for chlorination?
Ammonia reacts with chlorine, increasing chlorine demand and potentially changing the residual and disinfection conditions.
What is a Drinking Water Protected Area? (Water Environment Regulations 2017)
Drinking Water Protected Areas, and the aim of preventing deterioration of raw-water quality. Distinguishes statutory protected areas from non-statutory safeguard zones and, for groundwater, Source Protection Zones where relevant.
Where should you sample to understand an individual source’s quality before it is changed by treatment or blending?
At a representative sampling point upstream of treatment or blending. It can be away from the abstraction point if representative.
Two boreholes join into one main. Does this prove the site operates a managed raw-water blend?
Does this prove the site operates a managed raw-water blend?No. A joining point alone does not demonstrate deliberate blending. Explain the purpose, source proportions and controls—or the actual arrangement where blending is not managed.
Why might river-water quality change quickly after heavy rain? Name examples
Runoff can rapidly carry sediment, animal waste, chemicals and organic matter into the river.
Which parasite associated with human or animal faeces is particularly challenging because it resists chlorination? *BONUS* How is it treated?
Cryptosporidium. Effective removal or inactivation barriers are needed.
What is the purpose of a Drinking Water Safeguard Zone?
To focus pollution-prevention measures where drinking-water sources are at risk of deterioration.
Your online turbidity reading stays perfectly flat during a storm, but a separate measurement rises. What would you investigate?
Sample flow, blocked lines, instrument faults, calibration and data transmission; verify using independent measurements and apply the site’s safeguards while information is uncertain.
Your main source becomes unavailable. Give four checks before bringing a standby source into use.
Permitted use/licence conditions; current source quality and treatment suitability; available flow and asset condition; approved operating procedure and authorisation.
Trace one of your site’s sources from abstraction to its first treatment stage. Identify ALL monitoring points along the route.
Use the actual site arrangement: intake/headworks, pumps, mains, storage where present, monitoring and first treatment stage.
Give three reasons why increased natural organic matter can challenge treatment.
Increased coagulant demand, increased disinfectant demand and greater disinfection by-product potential, including THMs. Reduced UV transmission is another acceptable example where relevant.
Match Regulations 17, 27 and 28 to these duties: source monitoring, risk assessment, and reporting/action following risk assessment.
17: identify abstraction points and monitor raw water. 27: assess risks across the supply system. 28: report assessments, with provision for required actions or restrictions.