The total area of surrounding land that slopes towards and drains into a river (4)

Ceramic filtration

Filtration of water using a ceramic pot (10)

Cloth filtration

A means of removing solids from water using fine cotton cloth (10)


Chemical used in water treatment to neutralise the charge on fine particles (5)


Neutralisation of the electrical charge of particles by using a coagulant (5)

Coarse screens

(in water treatment) steel bars that have a spacing of 5–15 cm (5)

Compliance monitoring

Analysis of water to check that it is within required standards (8)


Amount of a substance in a given volume of water or air (2)

Contact time

Length of time for which the water undergoing treatment is exposed to a disinfectant (5)


Process whereby a metal gets weaker due to a reaction with its environment (7)


Degree of importance (6)

Last modified: Sunday, 2 October 2016, 12:16 PM