Corrosion has many serious economic, health, safety, technological, and cultural consequences to our society.
Economic effects
Studies in a number of countries have attempted to determine the national cost of corrosion. The most extensive of these studies was the one carried out in the United States in 1976 which found that the overall annual cost of metallic corrosion to the U.S. economy was $70 billion, or 4.2% of the gross national product. To get a feeling for the seriousness of this loss, we may compare it to another economic impact everyone is worried about – the importation of foreign crude oil, which cost $45 billion in 1977.
Health effects
Recent years have seen an increasing use of metal prosthetic devices in the body, such as pins, plates, hip joints, pacemakers, and other implants. New alloys and better techniques of implantation have been developed, but corrosion continues to create problems. Examples include failures through broken connections in pacemakers, inflammation caused by corrosion products in the tissue around implants, and fracture of weight-bearing prosthetic devices. An example of the latter is the use of metallic hip joints, which can alleviate some of the problems of arthritic hips. The situation has improved in recent years, so that hip joints which were was at first limited to persons over 60 are now being used in younger persons, because they will last longer.
Safety effects
An even more significant problem is corrosion of structures, which can result in severe injuries or even loss of life. Safety is compromised by corrosion contributing to failures of bridges, aircraft, automobiles, gas pipelines etc. – the whole complex of metal structures and devices that make up the modern world.
Technological effects
The economic consequences of corrosion affect technology. A great deal of the development of new technology is held back by corrosion problems because materials are required to withstand, in many cases simultaneously, higher temperatures, higher pressures, and more highly corrosive environments. Corrosion problems that are less difficult to solve affect solar energy systems, which require alloys to withstand hot circulating heat transfer fluids for long periods of time, and geothermal systems, which require materials to withstand highly concentrated solutions of corrosive salts at high temperatures and pressures. Another example, the drilling for oil in the sea and on land, involves overcoming such corrosion problems as sulfide stress corrosion, microbiological corrosion, and the vast array of difficulties involved in working in the highly corrosive marine environment. In many of these instances, corrosion is a limiting factor preventing the development of economically or even technologically workable systems.
Cultural effects
International concern was aroused by the disclosure of the serious deterioration of the artistically and culturally significant gilded bronze statues in Venice, Italy. Corrosive processes will accelerate the deterioration of precious artifacts such as those in Venice by the highly polluted environments that now are prevalent in most of the countries of the world. Likewise, inside the world's museums conservators and restorers labor to protect cultural treasures against the ravages of corrosion or to remove its traces from artistically or culturally important artifacts.

Consequences of bacteria and algae

Bacteria
http://en.wikipedia.org/wiki/Bacteria

A bacterium (plural: bacteria) is a unicellular microorganism. Typically a few micrometres in length, individual bacteria have a wide-range of shapes, ranging from spheres to rods to spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, seawater, and deep in the Earth's crust. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5×10 ) bacteria in the world, forming much of the world's biomass. Bacteria are vital in recycling nutrients, and many important steps in nutrient cycles depend on bacteria, such as the fixation of nitrogen from the atmosphere. However, most of these bacteria have not been characterised, and only about half of the phyla of bacteria have species that can be cultured in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.
There are approximately ten times as many bacterial cells as human cells in the human body, with large numbers of bacteria on the skin and in the digestive tract. Although the vast majority of these bacteria are rendered harmless or beneficial by the protective effects of the immune system, a few pathogenic bacteria cause infectious diseases, including cholera, syphilis, anthrax, leprosy and bubonic plague. The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people a year, mostly in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and in various agricultural processes, so antibiotic resistance is becoming common. In industry, bacteria are important in processes such as wastewate treatment, the production of cheese and yoghurt, and the manufacture of antibiotics and other chemicals.
Bacteria are prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotic life consists of two very different groups of organisms that evolved independently from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.

Algae
http://en.wikipedia.org/wiki/Algae

Algae are a large and diverse group of simple plant-like organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are considered 'plant-like' because of their photosynthetic ability, and 'simple' because they lack the distinct organs of higher plants such as leaves and vascular tissue. Though the prokaryotic Cyanobacteria (commonly referred to as Blue-green algae) were traditionally included as 'algae' in older textbooks, many modern sources regard this as outdated and restrict the term algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group: they do not represent a single evolutionary direction or line, but a level or grade of organization that may have developed several times in the early history of life on Earth.
Algae lack leaves, roots, and other organs that characterize higher plants. They are distinguished from protozoa in that they are photosynthetic. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus.
All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a byproduct of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria.

The consequences of Bacteria in applications where Hydropath Technology can be effective in combating the problem.

Bacteria causing diesis in cooling towers and swimming pools.

Bio fouling of heat exchangers power stations condenser and cooling towers and sea water heat exchangers. Increasing energy requirement.

Increase maintenance requirement due to blockage of filters.

Considerable increase of anti bio fouling chemicals causing damage to the environment.

Aluminium sulphate, written as Al2(SO4)3 or Al2O12S3, is a widely used industrial chemical. It is sometimes incorrectly referred to as alum, as it is closely related to this group of compounds. It occurs naturally as the mineral alunogenite. It is frequently used as a flocculating agent in the purification of drinking water and waste water treatment plants, and also in paper manufacturing.
Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate Al2(SO4)3•16H2O and octadecahydrate Al2(SO4)3•18H2O are the most common.
It can also be very effective as a molluscicide, killing spanish slugs.
Recent research suggests aluminum sulfate may contribute to dementia and Alzheimer's disease.
http://en.wikipedia.org/wiki/Aluminium_sulfate

Preparation
Aluminium sulphate may be made by dissolving aluminium hydroxide, Al(OH)3, in sulfuric acid, H2SO4:
2Al(OH)3 + 3H2SO4 + 3H2O → Al2(SO4)3·6H2O
Uses
Aluminium Sulphate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it causes impurities to coagulate which are removed as the particulate settles to the bottom of the container or more easily filtered. This process is called coagulation or flocculation.
When dissolved in a large amount of neutral or slightly-alkaline water, aluminium sulphate produces a gelatinous precipitate of aluminium hydroxide, Al(OH)3. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the clothing fibres by rendering the pigment insoluble.
History
Due to its name, it has been linked to the legendary Camelot, and even Camlann, but historians have been quick to refute these suggestions.
The town elected two members to the Unreformed House of Commons. It was considered a rotten borough and its franchise was abolished in 1832.
In July 1988, the water supply to the town and the surrounding area was contaminated when 20 tons of aluminium sulphate was poured into the wrong tank at the nearby Lowermoor water works on Bodmin Moor near Bodmin. An independent inquiry into the incident (the worst of its kind in British history) was started in 2002, and a draft report issued in January 2005, but questions still remain as to the long-term effects on the health of local residents. Michael Meacher, who visited Camelford in his post as environment minister, was said to have called the incident and its aftermath, 'A most unbelievable scandal.'