Paddles: A mechanical device for mixing that uses broad surfaces for pushing against liquids.
Parasite : An organism that survives by using a host.
Pathogens (PATH-o-jens): Pathogenic or disease causing organisms.
Perforated: Holes punched into a surface to allow the movement of substances from one side to the other.
Peripheral equipment: Equipment
that is to the edge or fringe of a process, that is not a main
part of a process but which is still needed (eg values, sensors etc).
Personal protective equipment (PPE):
Personal protective equipment (PPE) is any clothing, equipment or substance
designed to protect a person from risks of injury or illness. PPE can
include ear muffs and ear plugs, respirators, eye and face protection
(goggles, safety helmets and sun hats), gloves and safety boots, clothing
(high visibility vests or life jackets). You must wear PPE if your workplace
says it should be worn.
pH (pronounced as separate letters): Measure of the degree of acidity or alkalinity, expressed on a scale of 1 to 14. A pH of 7.0 denotes neutrality; higher values indicate alkalinity and lower values acidity. Natural waters usually have a pH between 6.5 and 8.5.
Phosphates: A compound containing a central phosphorous atom surrounded by four oxygen atoms, all of which is banded to another (eg PO4).
Phosphorous: Chemical element that occurs in human waste and is present in some detergents. It is a plant nutrient and should be controlled in effluent discharge.
Physical characteristics: Attributes of the physical (visual) characteristics of an organism or object.
Point source pollution: Pollution which is discharged at a discrete, identifiable location and can be readily measured - c.f. diffuse source pollution.
Poisonous: The ability to cause illness, damage or death to organisms.
Pollution: The contamination of air, water or soil by some form of matter to an undesirable level.
Polymer: A chemical formed by the union of many monomers (a molecule of low molecular weight). Polymers are used with other chemical coagulants to aid in binding small suspended particles to larger chemical flocs for their removal from water.
Polymer Coagulant: Polymer based coagulants work by attaching to a colloid and then enmeshing it and other nearby colloids in a web like arrangement to form floc. Much lower doses of polymers are needed then for metal based coagulants (ten to twenty times less), but they tend to work over a much narrower ranges and can be difficult to manage to achieve effective results. They do have the advantage of not acidifying the water and don't rely on adequate alkalinity levels to work.
Post-chlorination: The addition of chlorine to the plant effluent following plant treatment for disinfection purposes.
Potable water (POE-ta-bl): Water
of a quality suitable for drinking or cooking, usually applied to water
used by humans, and that does not contain objectionable pollution, contamination,
minerals, or infective agents.
PPE: Personal protective equipment (PPE) is any clothing, equipment or substance designed to protect a person from risks of injury or illness. PPE can include ear muffs and ear plugs, respirators, eye and face protection (goggles, safety helmets and sun hats), gloves and safety boots, clothing (high visibility vests or life jackets). You must wear PPE if your workplace says it should be worn.
PPM or Parts per million: Parts
per million parts, a measurement of concentration on a weight or volume
basis. This term is equivalent to milligrams per litre (mg/L) which is
the preferred term.
Pre-chlorination: The addition
of chlorine at the headworks of the plant prior to other treatment processes
mainly for disinfection and control of tastes, odours and aquatic growths.
Also applied to aid in coagulation and settling.
Precipitate (PRE-sip-it-TATE):
(1) An insoluble, finely divided substance which is a product of a chemical
reaction within a liquid. (2) The separation from solution of an insoluble
substance.
Preliminary treatment : The first
stage of the wastewater treatment process which uses physical methods
to remove pollutants in the water.
Pre-sedimentation: Stages in the water treatment process that occur before, but which aid the actual sedimentation process.
Preventive measure: Any planned
action, activity or process that is used to prevent hazards from occurring
or reduce them to acceptable levels.
Propellors: A type of fan which converts rotational movement into forward movement (thrust) for an object through a fluid such as water or air.