THE RIVER MUST LIVE

[Music] [Music] [Music] foreign hey [Music] [Applause] [Music] this water is life it flows as the sap and the bloodstream it brings food to the living cell and carries away the body's [Music] waste it is the same with the town water is just as vital but its use is more varied once used it is discarded the wastes carried away [Music] carried away to the nearest river to be diluted and absorbed lost in the gathering flow [Music] absorbing waste is a river's natural role getting rid of it in this way only becomes a problem with the growth of the modern city and the need to keep it clean to wash a cathedral can take 25 million gallons we take water for granted crowded together in our millions each of us uses 50 gallons every day so much water where does it come from some of it comes from reservoirs in the hills but these are often far from the growing centers of industry some from underground but already supplies are being withdrawn faster than rain is replacing them increasingly we must depend on lakes and rivers for the water we need but even this is not enough unless the same water can be used time and time again before it returns to the sea used for washing cars one day for processing peas the next but the more water we use the more we pollute too much for the river to absorb even in nature water is never pure as it trickles over rocks and soil it picks up traces of minerals and organic matter these impurities give rise to life in water life revealed only by the microscope it is the activity of these microorganisms that keeps water clean and healthy that gives the stream and river the power to overcome pollution to dispose of nature's waste [Music] it may take a year or more for a leaf to decay to be broken down into the simpler substances from which it was made first to attack are the fungi [Music] then the bacteria so small that a million can live in a drop of water [Music] like most living things these bacteria consume oxygen they use the free oxygen in the water to break down and feed on the waste and they grow by subdividing multiplying into large colonies [Music] so a leaf becomes nothing more than simple chemicals building materials for other forms of life [Music] algae primitive microscopic plants [Music] diatom and desmid spirogyra volvox [Music] like all plants algae produce oxygen under the influence of sunlight oxygen vital to the breakdown of waste [Music] some forms of algae mashed together become visible to the naked eye [Music] microscopic again but animals the protozoa vorticella carcesium actinospherium [Music] the protozoa are scavengers feeding on waste feeding on algae and bacteria too helping to maintain the balance of life in the stream [Music] and finally the more familiar forms of life [Music] together with the microorganisms they make up the life of a healthy stream all of them interdependent all of them involved in the endless cycle of growth and decay of pollution and purification [Music] but dump the waste of a single town and the balance of life is upset [Music] now the bacteria multiply at a furious rate as they feed on the waste as a result the level of oxygen falls dangerously low [Music] [Applause] [Music] given a chance the river can recover but recovery takes time time for the wastes to be broken down only then will the bacteria begin to die off time for lost oxygen to be replaced dissolving in from plants and through the surface only then will balance be restored [Music] but today for many of our rivers discharges are too close together the load of pollution too heavy now the growth of bacteria is overwhelming the river's oxygen is exhausted [Music] everything dies killed off by lack of oxygen or by poisons in the waste everything from the fish to the cleansing microbes themselves [Music] thank you [Music] [Music] the river is dead nothing stirs the surface but the foul gases of slow putrefaction waters sterile and useless abandoned to the sea [Music] and from the sea water returns to the land renewed as fresh as ever [Music] [Laughter] [Music] as water is renewed so is the chance to use it more wisely [Music] how can we keep out of us clean clean enough to be used again and again before they return once more to the sea [Music] we cannot avoid producing waste but by treating it before we dispose of it we can reduce the load on the river the cost must be faced the know-how already exists [Music] simply by giving solids the chance to settle or by skimming sludge from the surface more than half the waste can be removed but this is rarely enough [Music] chemicals can be added to get rid of more they make the finer particles of waste coagulate and separate out [Music] and nature's own method can be used and improved on the time and space that a river would need can be condensed the process intensified the water is aerated to build up a rich supply of oxygen and inoculated with billions of bacteria [Music] when the waste is broken down the bacteria are allowed to settle [Music] another method the trickling filter [Music] the water percolates through loosely packed stones coated with microorganisms and again the wastes are broken down [Music] none of these processes gives pure water what they do is remove most of the organic matter the little that remains can safely be discharged to the rivers for now they can live again no longer overloaded they can resume their natural role they will still be industrial rivers it would be unrealistic to expect them ever to be as pure as an upland stream but by reducing pollution to the point where the river can look after itself we can achieve our aim water that is fit for everyone to use [Music] you