engineering

Hornsey water treatment works

Hornsey water treatment works is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hornsey water treatment works rather than just read about it. In short: The Hornsey water treatment works in north London abstracts raw water from the New River and supplies treated potable water to Hornsey and surrounding districts. The treatment works were first constructed in 1862 and have been modernized and remodeled several times and still provide clean water to consumers in north London.

Key takeaways

Hornsey water treatment works belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hornsey water treatment works to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hornsey water treatment works from memory before moving on to harder problems.

Reference excerpt

The Hornsey water treatment works in north London abstracts raw water from the New River and supplies treated potable water to Hornsey and surrounding districts. The treatment works were first constructed in 1862 and have been modernized and remodeled several times and still provide clean water to consumers in north London.

History The New River supplied water to Islington, but water was also abstracted by settlements along its route. Hornsey was supplied with water from such an offtake. In 1862 a treatment works was established. This comprised a reception basin with an area of about one acre (0.4 ha), from which water was transferred to a reservoir which allowed solids to settle out. The main water treatment was sand filter beds. Water was introduced above a thick layer of sand, and flowed down by gravity through the sand bed. Solids were trapped in the upper layer of sand. Clarified water from the bottom of the filter was pumped to local consumers. Hornsey works initially comprised three filter beds. Gradually the beds became clogged with matter and had to be drained down and the contaminated layers of sand were scaped off and removed.

Development By 1876 a further filter bed had been constructed, and by 1900 there were nine filter beds in operation. Water was transferred by new pumps at 2.5 million gallons per day (11.4 Ml/d) to Crouch Hill reservoir and to Hornsey Lane reservoir. The two reservoirs were capable of storing 12 million gallons (55.0 Ml) and supplied Islington, Hornsey and part of the City. In 1887 a 215 feet (65.5 m) deep well was sunk into the chalk aquifer and supplemented the water supply. A 1.25 million gallon (5.7 Ml) contact tank was constructed on the site. Water was dosed with chlorine as a bactericide, the contact tank allowed the chlorine to take effect before water was distributed to consumers. By the 1990s the plant comprised six slow sand filters with a granular activated carbon (GAC) sandwich. Comprising typically 300 mm lower sand, 135 mm GAC, 450 mm upper sand. This was followed by disinfection using super-chlorination and de-chlorination. In addition to the New River water was abstracted from four boreholes. By 1990 both Hornsey and Stoke Newington water works were recognised as being old and inefficient. Stoke Newington closed in 1991 and Hornsey was scheduled to close in 1996. However, with increasing demand for water the decision was made to retain and upgrade Hornsey water works. By 2000 Thames Water wished to decommission the slow sand filters, using modern technology to increase capacity.

Hornsey water works today The treatment plant comprises:

Raw water abstraction Coagulant and pH correction (acid dosing) Coagulation/flocculation Three dissolved air flotation (DAF) units pH correction (caustic dosing) Five Rapid gravity filter (RGF) units Eight catalytic granular activated carbon (cGAC) units Disinfection High lift pumping The capacity of the plant is 50 Ml/day. This is sufficient to supply a population of about 350,000.

See also London water supply infrastructure

References

Worked examples

Example 1 — a first encounter with Hornsey water treatment works

Start with the simplest possible case. Write down what Hornsey water treatment works claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hornsey water treatment works before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hornsey water treatment works ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hornsey water treatment works

In research: Hornsey water treatment works appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hornsey water treatment works in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hornsey water treatment works is common in secondary-school and first-year university syllabi. It links to neighbouring topics London water infrastructure, Thames Water, so understanding it makes those chapters shorter.
In everyday life: Look for Hornsey water treatment works outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hornsey water treatment works in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hornsey water treatment works means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hornsey water treatment works out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hornsey water treatment works in simple terms?

Why does Hornsey water treatment works matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hornsey water treatment works?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hornsey water treatment works.