Introduction of Dam and its usages

Dam is a structure that is built across the river or stream to control water. Dams provide water for human use, for irrigation purposes, and for industries. Dams provide water which is then used to generate hydroelectric power. After storm or heavy snow melt down water level rises then dams are useful to reduce peak discharge. Depth of water is increased which allows easy navigation for boats and ships to travel easily. The dam water can be used for recreational purposes. E.g. swimming, boating, fishing etc.

Sometimes dams are created for more than one purpose. Same dam water can be used for generation of hydroelectric power, for an irrigation system support and fishing. Many modern dam structures are multi purposed. Spillways, movable fates and valves help dams to work properly in for release of water downstream from the dam. Dams have intake structures as well which transfer water from dams to canals, pipelines or power stations. These carry stored water of dam to different far regions. Some other auxiliary works include evacuation and flushing of accumulated things or particles in the dam, there are locks present which lock and control water and release when required to facilitate movement of ships by allowing passage. There are other devices for catching fish and to assist their swimming around the dam.

In a multipurpose scheme for conservation of water, dams can serve as main structure on regional basis. Multipurpose dams are of great importance in developing countries, where even a single dam can be of great importance as they generate hydroelectric power, contribute in development of agriculture an allows industries to grow. Dams are main concern for environmental purposes as they great impact on migrating fish and riparian ecosystems. Moreover, the dams take over large proportion of land and take over the land portion which is home for many poor people so the question that arises is whether the benefits which are enjoyed from manufacturing dams and occupying the land are worth the cost?

In terms of engineering, construction of dams fall under known categories which are separated by structural type and building material. Construction of dam greatly depends upon its area, building material available, access of transportation in the area of work, experience of workers and engineers, finances, promoters of the project. In terms of modern engineering of dams, material of choice in building dams is concrete, rock fill and earth fill. Past practices show that dams are made by mixing masonry, this strategy is no longer in practice and is replaced by concrete. Concrete is used to make gigantic gravity dams, thin arch dams and buttress dams. Roller compacted concrete allows to make high quality dams made with equipment which allows to move, distribute and consolidate earth fills. Embankment dams are constructed by mixing earth fill and rock fill, and huge mounds of earth and rocks are combined and assembled into man made embankments.

Thermal technology has 3 main purposes:

Treatment of waste water

Waste byproduct reduction

Biogas production

Plants of waste water treatment are made in such a way that they deal with large amount of sludge which is produced in the result of treatment of waste water of industries. On the other hand, thermal hydrolysis plants sludge is not a waste but a resource for production of energy.

After treatment of waste water, sludge is collected which helps in production of biogas. Heat is given to sludge and compressed on large vats. Required temperature range is 160-165 Celsius. High pressure from 7-11 or 12 bars is required. Two technologies of thermal hydrolysis technologies are:

Batch or bioethyls

Exelysis

Bioethyls thermal hydrolysis of Dam

Each plant of bioethyl thermal hydrolysis requires large tracts of land and great quantity of wastewater is provided in order to produce greater amount of biogas ad keep it viable. For large municipalities, requisite is an issue and biogas production is a considerable steam.

Exelys thermal hydrolysis of Dam

This type is functional in small spaces. Small amount of waste water is required to remain viable.  It produces 130% more biogas becoming the next most productive thermal hydrolysis system by using the same amount of sludge. End waste amount is also reduced. Development of an Exelys thermal hydrolysis plant can be expensive. Operating cost of such plants is far low than bioethyls thermal hydrolysis plant.

Microbial fuel cells of Dam

 This technology is capable of performing three functions. In this technology microbes are used to treat waste water. Most impressive part of use of this technology is the production of electrons as the result of end product which is helpful to generate electricity. In lab conditions scientists have been successful for electricity production by the aid of these efficient bacteria. These electrons are produced during bacterial oxidation process which transfers electrons to the electrode.

If MFC is successful on large scale, lesser fossil fuels will be used for the production of electricity.

Solat photo catalytic wastewater treatment of Dam

Major issue in treatment of waste water is the sludge. Solar photo catalytic technology reduce amount of sludge to 80% which is more than any other water treatment method. Sludge is known to Organic Content. Due to solar irradiation, which is the result of bacterial oxidation amount of sludge, is dramatically reduced. Solar irradiation is the synergetic effect when it is combined with hydrogen peroxide. This process reduces the amount of carbon in sludge, as carbon is the main component of sludge because it is organic component.

Natural technologies for waste water treatment of Dam

Roofs and streets are considered biggest source of waste water. Water that is accumulated in streets or any other place after flood or storm falls back in river or streams along with toxins, pathogens and waste material. But rather than letting waste water slip in rivers or streams, responsible parties have designed structures to treat waste water before.

Natural technologies include;

Sediment ponds

Evacuated wetlands

These have natural filtration system and act as large scale soil filtration systems. They slow water flow and trap garbage and microbes giving cleaner water.