absorption - the filling of pores in a solid. aactivated sludge units - a feed enters an uniform aeration zone of air bubbles adn liquid that are in good contact
adsorption - the binding of olecules or particles to a surface.
anabolism - synthesis
BOD - Biological Oxygen Demand
biological waste treatment - a method which converts dissolved and colloidal pollutants to cell mass, water and gases.
bubble aeration - a rising air bubble from a sparger provides sufficient mixing, at a discharge high enough to over come the hydrostaic pressure, to initiate activity and decrease the surface area.
catabolism - degradation
CBOD - Carbonaceous Biological Oxygen Demand: oxidizable organic carbon source.
chlorination - most commonly method for public water supply disinfection.
coagulation - a process used to destabilize colliodal particles by adding a chemical which has positively charged colloids, to water containg negatively charged colloids, thus reducing the tendancy for them to repel each other. Rapid mixing for a short period of time is used to evenly disperse the coagulant.
composting - converts easily degraded organics into humus and produce a nutrient rich, stable product useful for reclaiming land and improving soil.
coliforms - organisms that grow in the colon and are used to indicate the presense of sewage in a water source.
diauxie - the shift in metabolism from a common to an uncommon substate.
disinfection - to free water of harmful bacteria.
dissolved oxygen sag curve - represnet the amount of dissolved oxygen in a stream and the rate of comsumption of oxygen by organisms, fish and other activity in the water.
filtration - a method of collecting solids by straining a liguid through a medium, such as sand or a membrane filter.
floatation - gas bubbles are used to lift particles to the surface, clarifying the lower region and concentrating the upper layer for particle collection.
flocculation - gentle mixing of suspension to promote particle contact, follows coagulation process to influence colloidal particles to agglomerate and form larger solids called flocs.
ion exchange resins - hard water is passed through this to remove Ca+2 and Mg+2 from water and releases Na+ ions which form salts.
lagoons - anaerobic - 3 to 5 meter deep pond used as an intermediate degree of treatment, the only oxygen supply is from algae and atmosphere. aerobic - air is introduced mechanically, such as air tubing, air distributer or mechanical mixers to reduction of surface area
leachate - contaminated liquid draining from a sanitary landfill, varies in composition depending on age of the landfill and what type of waste it contains.
limiting nutrient - the nutrinet in short supply relative to others and will be exhausted first, thus limiting the cellular growth.
NBOD - Nitrogebous Biological Oxygen Demand: oxydizable nitrogen present.
ozonation - method of disinfection that is used widely in France that leaves no residual, taste or odor and acts as a powerful oxidant of orgainics and inorganic impurities.
phage - a viruse for microorganisms.
pleomorphic - organisms that assume various shapes depending on their environment.
reverse osmosis - fresh water is forced through a semi-permeable membrane in the direction opposite to that ocurring in natural osmosis, which is high to low.
screening - used to remove large solids such as, logs, branches,rags and fish in the first stage of treatment.
sedimentation - a process, whereby a suspension settles, leaving the upper region depleted of particles and the lower region concentrated. Used in waste water treatment to collect inorgain percipitants and organic flocs.
step aeration - a organic load is distributed throughout a bioreactor, where spargers, to make better use of the aeration,
surfactant - an agent that modifies surface tension and act with disinfecting chemicals.
tapered aeration - at the inlet of the bioreactor, where the oxygen demand is the greatest, there are more spagers and fewer near the end.
trickling filters - act as 'contact beds' where settled sewage is spread by a rotary distributer over two meters deep, circular beds with diameters of up to fifty meters, containing fifty to one hundred millimeter stones. Colloidal and soluble organics in wastewater support the growth of microbiological slimes on the medium as it passes through the bed.
zeta potential - the net charge difference between a particle environment and the solution.