TABLE OF CONTENTS A free draining wall constructed from large steel mesh baskets filled with rocks. Gabions can be used for erosion control.
Granular activated carbon.
See activated carbon filter.
The US spelling of gauge. See gauge height , gauge well.
An iron bacteria that oxidises ferrous iron and produces gelatinous ferric iron deposits.
Corrosion of metal in which anodic and cathodic areas are distinguishable e.g. two dissimilar metals in contact or one metal in two different environments. The cathode does not lose metal; the anode may. The jointing of dissimilar metals can cause electrical current to flow with the result of corrosion of one of the metals. For a connection of lead and copper pipe, the lead tends to corrode.
A list of metals that are increasingly anodic in a particular medium e.g. for sea water:
Steel or iron coated with a thin layer of zinc to protect it from corrosion. The zinc may be attacked by acid or strongly alkaline water or by dissolved chloride. Galvanised metal has low scrap value.
Fish that are exciting to catch and they are good eating. The families of salmon and trout need a dissolved oxygen level of at least 4 to 5 mg/l unlike coarse fish, which can exist with less.
Electromagnetic radiation with a wavelength shorter than X rays.
