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Wastewater Treatment – A New Technology Promises Greater Competency at Lower Cost





Updated: 2018-04-09T05:41:03Z

 



WordPress.comAll You Need to Know About Removing Solid Particles From Wastewater With Imhoff

2008-08-22T14:18:53Z

Recycling and reuse of wastewater will do away with the need of using fresh water. The extent to which the processes involved in wastewater treatment are cost effective and easy to follow will act as an impetus. Hence discussing about the processes involved in wastewater treatment and their relative merits and demerits becomes pertinent. Like […]Recycling and reuse of wastewater will do away with the need of using fresh water. The extent to which the processes involved in wastewater treatment are cost effective and easy to follow will act as an impetus. Hence discussing about the processes involved in wastewater treatment and their relative merits and demerits becomes pertinent. Like Sedimentation tanks, Septic tanks (Imhoff tanks) can play a major role in the process of removing solids from wastewater. Designed by Karl Imhoff of Germany, an Imhoff tank is an improved septic tank in which the incoming sewage or influent is not allowed to get mixed up with the sludge produced. Also, the outgoing sewage or effluent is not allowed to carry with it any large amount of the suspended matter as in the case of a septic tank. **Construction and operational features** It is a double chamber tank, the upper chamber is called the sedimentation tank or flowing-through chamber, through which sewage flows at a very low velocity; the lower chamber is the digestion chamber in which anaerobic or septic decomposition occurs. Solids of the sewage settle to the bottom of the sedimentation chamber through the sloping bottom walls (slope 5 vertical to 4 horizontal). They are made to fall in the digestion chamber through an entrance slot at the lowest point of the sedimentation chamber. The slot is trapped or overlapped in such a way that the gases generated in the digestion chamber cannot enter the sedimentation chamber. A gas vent, also called scum chamber is provided with the digestion chamber to take care of the gases escaping to the surface. The chief gas is methane (CH ) having a considerable fuel value and may, therefore, be separately collected for use. In order to prevent particles of sludge or scum from penetrating into the sedimentation chamber, the sludge and scum must be maintained at a distance of at least 45 cm below and above the slots respectively. The free or clear zone is called neutral zone. The digestion chamber is made up of two or three inverted cones called hoppers with sides sloping (1 : 1) so as to concentrate the sludge at the bottom of the hopper. The sludge is removed periodically through sludge-pipe, the flow being under a hydrostatic pressure of 1.2 to 1.8 m. All the sludge is not removed, only the lower layers which are completely decomposed are withdrawn, leaving some sludge to keep the tank seeded with anaerobic bacteria. To permit uniform distribution of settled solids throughout the length of the digestion chamber, so as to utilize the storage capacity in the greatest measure, arrangements for reversing the direction of flow through the tanks are commonly made. **Merits** Imhoff tanks combine the advantages of both the septic and sedimentation tanks and, as such find use in case of small treatment plants requiring only preliminary treatment. They have better economy and give good results without skilled attention with minimum problems of sludge disposal. **Demerits** (i) Greater depth means greater costs and especially where excavation is to be done in quick sand or solid rock, they become uneconomical. (ii) Unsuitable to acidic wastewater exists. (iii) There’s no adequate control over their operation. This makes them unsuitable for use in large treatment plants where separate sludge digestion tanks are preferred. Author Bio: Richard J. Runion is the President of Geostar Publishing & Services LLC. Rich loves net research & blogging. His new blog on Wastewater Treatment is fast becoming popular, as it is comprehensive and well-researched. To learn all about waste water, click: http://www.all-about-wastewater-treatment.com . This has also been published as: methods of cleaning water on Tumbl[...]



All You Need to Know About Removing Solid Particles From Wastewater Using Imhoff

2008-08-22T14:17:31Z

Recycling and reuse of wastewater will do away with the need of using fresh water. The extent to which the processes involved in wastewater treatment are cost effective and easy to follow will act as an impetus. Hence discussing about the processes involved in wastewater treatment and their relative merits and demerits becomes pertinent. Like […]Recycling and reuse of wastewater will do away with the need of using fresh water. The extent to which the processes involved in wastewater treatment are cost effective and easy to follow will act as an impetus. Hence discussing about the processes involved in wastewater treatment and their relative merits and demerits becomes pertinent. Like Sedimentation tanks, Septic tanks (Imhoff tanks) can play a major role in the process of removing solids from wastewater. Designed by Karl Imhoff of Germany, an Imhoff tank is an improved septic tank in which the incoming sewage or influent is not allowed to get mixed up with the sludge produced. Also, the outgoing sewage or effluent is not allowed to carry with it any large amount of the suspended matter as in the case of a septic tank. **Construction and operational features** It is a double chamber tank, the upper chamber is called the sedimentation tank or flowing-through chamber, through which sewage flows at a very low velocity; the lower chamber is the digestion chamber in which anaerobic or septic decomposition occurs. Solids of the sewage settle to the bottom of the sedimentation chamber through the sloping bottom walls (slope 5 vertical to 4 horizontal). They are made to fall in the digestion chamber through an entrance slot at the lowest point of the sedimentation chamber. The slot is trapped or overlapped in such a way that the gases generated in the digestion chamber cannot enter the sedimentation chamber. A gas vent, also called scum chamber is provided with the digestion chamber to take care of the gases escaping to the surface. The chief gas is methane (CH ) having a considerable fuel value and may, therefore, be separately collected for use. In order to prevent particles of sludge or scum from penetrating into the sedimentation chamber, the sludge and scum must be maintained at a distance of at least 45 cm below and above the slots respectively. The free or clear zone is called neutral zone. The digestion chamber is made up of two or three inverted cones called hoppers with sides sloping (1 : 1) so as to concentrate the sludge at the bottom of the hopper. The sludge is removed periodically through sludge-pipe, the flow being under a hydrostatic pressure of 1.2 to 1.8 m. All the sludge is not removed, only the lower layers which are completely decomposed are withdrawn, leaving some sludge to keep the tank seeded with anaerobic bacteria. To permit uniform distribution of settled solids throughout the length of the digestion chamber, so as to utilize the storage capacity in the greatest measure, arrangements for reversing the direction of flow through the tanks are commonly made. **Merits** Imhoff tanks combine the advantages of both the septic and sedimentation tanks and, as such find use in case of small treatment plants requiring only preliminary treatment. They have better economy and give good results without skilled attention with minimum problems of sludge disposal. **Demerits** (i) Greater depth means greater costs and especially where excavation is to be done in quick sand or solid rock, they become uneconomical. (ii) Unsuitable to acidic wastewater exists. (iii) There’s no adequate control over their operation. This makes them unsuitable for use in large treatment plants where separate sludge digestion tanks are preferred. Author Bio: Richard J. Runion is the President of Geostar Publishing & Services LLC. Rich loves net research & blogging. His new blog on Wastewater Treatment is fast becoming popular, as it is comprehensive and well-researched. To learn all about waste water, click: http://www.all-about-wastewater-treatment.com . This has also been published as: method[...]



Water Pollution — The Justification For Wastewater Treatment

2008-08-19T13:15:04Z

Water as a chemical: Pure water is a compound of hydrogen and oxygen. It is colorless, odorless and tasteless. It exists as liquid at ambient temperature. Water – what it contains: Water has both living and non-living organisms and substances in it. The living organisms can be further subdivided into macro- and micro- organisms. Macro […]

Water as a chemical:

Pure water is a compound of hydrogen and oxygen. It is colorless, odorless and tasteless. It exists as liquid at ambient temperature.

Water – what it contains:

Water has both living and non-living organisms and substances in it. The living organisms can be further subdivided into macro- and micro- organisms. Macro organisms, which are biological, are those that are visible to the naked eye or can be seen through a microscope.

In contrast, microbiological micro-organisms are not visible even through a microscope.

Water quality criteria:

The quality of water is a function of several factors. These include its source, location, geological conditions, depth of water level, seasonal changes, domestic activity, agricultural activity, industrial activity, etc.

Excessive exploitation of natural resources and the use of technological advances with no concern for the ecology adversely affect air, water and land, alike.

The substances present in water can be classified as floating matter and suspended matter. Floating matter takes the form of leaves, twigs, dead organisms and algae. Examples of suspended matter present in water are silt, clay, decaying vegetable matter, bacteria, microorganisms, algae, insoluble iron, and manganese.

There are also dissolved impurities which include gases like carbon dioxide, hydrogen sulfide, etc., as well as chemical substances, minerals and salts.

Water sources and water quality:

Water quality differs according to the source. For instance, the turbidity in surface water is usually high, while ground water and sub-soil water on river beds are colorless and clear. Again, sub-soil water and ground water are more likely to have totally dissolved solids than surface water. The presence of hardness, alkalinity, fluoride, chloride and nitrate are all more likely in ground water than in surface level or sub-soil water. Bacteria and organic matter are more likely to be found in surface level water than in ground or sub-soil water.

Water pollution:

Water is essential for living, just like air. One may live without air for a few minutes. But, without water, one is sure to die within a few days. We all know about air pollution. Water pollution is also the gift of modern man to posterity.

How water gets polluted:

Pollution of water sources is caused by sewage and sullage from human settlements, dumping of solid wastes, wastewater from industries, and chemicals in agriculture. When foreign materials harmful to us are added, the water is sure to get polluted. Two readily such foreign materials that come readily to mind are industrial waste and sewage from cities.

Why we need good water:

We need good water for drinking by humans and animals, supporting aquatic life, generating electric power, irrigating crops in fields, and recreation such as water-based sports.

Thus the need for wastewater treatment can never be overemphasized.

Author Bio:

Richard J. Runion is the President of Geostar Publishing & Services LLC. Rich loves net research & blogging. His new blog on waste water is fast becoming popular, as it is comprehensive and well-researched. To know more about wastewater treatment, click here: http://www.all-about-wastewater-treatment.com .

This has also been published as: water quality on Zimbio




Why Treat Wastewater?

2008-08-18T14:13:00Z

It’s not a widely published fact, but that’s no reason why it should not be a widely acknowledged problem. The world’s supply of fresh water is slowly running dry. Forty percent of the world’s population is already reeling under the problem of scarcity. Most of the diseases plaguing the world are water-borne. And while there […]It’s not a widely published fact, but that’s no reason why it should not be a widely acknowledged problem. The world’s supply of fresh water is slowly running dry. Forty percent of the world’s population is already reeling under the problem of scarcity. Most of the diseases plaguing the world are water-borne. And while there is a child born every eight seconds in America, there is a life taken every eight seconds by some water-borne disease in other parts of the world. Is it the lopsided distribution of fresh water that is causing climate change, or is it the climatic change that is causing this lopsided distribution? The fact is that there is a significant climate change, and as a consequence of this change, some regions are becoming drier while others are getting wetter. Some parts of the world are experiencing greater desertification, while others are suffering category 4 and 5 hurricanes. According to the United Nations, water scarcity is amongst the most serious crises facing the world. And things are only getting worse. Uzbekistan and Kazakhstan of the erstwhile USSR, Chile, Mexico, Paraguay, Argentina, Peru and Brazil in Latin America, parts of China and the Middle East especially Iran, and more than 25 countries of Africa are all suffering from varying degrees of desertification. Global weather has gone awry. It is making poor countries poorer. Countries that are already facing drought and famine are getting less and less water. For how long can these countries run on dry? Nowhere is the situation worse than in Africa. Almost 40 million people in 19 countries are facing imminent food shortage. Much of the livestock there will perish. The growing water shortage will make food scarcer, potable water less accessible and water-borne diseases even more rampant. And the number of people who will suffer all this is expected to touch more than 500 million by the 2025. And the global consequence: A greater dependence on international aid. And this problem is not just limited to Africa. No one can tell which part of the globe will be next. Blame this on nature. It’s most convenient. But fact is, much of the blame belongs to increasing consumption and improper usage. At every opportunity nature reminds us by what it does and what it doesn’t, that it is one of the forces we have little control over. So there’s no way we can stop the rain or start it. But what we can do is become more water-efficient – get more from every gallon of water. And the only way to do this is to recycle and reuse waste water. Water is the giver of life. It has no substitute. And every drop counts! Many believe that the next world war is likely to be fought on the issue of water. Even though the world is two-thirds water, most of it is not potable, and much of it is not usable for any other purpose as well. And we are busy consuming and contaminating whatever is left of it, as if it were a non-depletable resource. This article is one of several aimed at identifying ways to make the best use of water, an increasingly scarce resource, by recovering it from wastewater, whether we intend to reuse the water so recovered or let it just charge our ground water reserves. This is aimed at a wide cross-section of people involved in taking corrective action across the world policy makers, administrators, municipal engineers & scientists, engineers & administrators in industries vested with the responsibility of wastewater treatment and management, industrial & residential property builders, academics, students and just about everyone who cares about posterity. Author B[...]



Why Treat Wastewater?

2008-08-18T14:06:38Z

It’s not a widely published fact, but that’s no reason why it should not be a widely acknowledged problem. The world’s supply of fresh water is slowly running dry. Forty percent of the world’s population is already reeling under the problem of scarcity. Most of the diseases plaguing the world are water-borne. And while there […]It’s not a widely published fact, but that’s no reason why it should not be a widely acknowledged problem. The world’s supply of fresh water is slowly running dry. Forty percent of the world’s population is already reeling under the problem of scarcity. Most of the diseases plaguing the world are water-borne. And while there is a child born every eight seconds in America, there is a life taken every eight seconds by some water-borne disease in other parts of the world. Is it the lopsided distribution of fresh water that is causing climate change, or is it the climatic change that is causing this lopsided distribution? The fact is that there is a significant climate change, and as a consequence of this change, some regions are becoming drier while others are getting wetter. Some parts of the world are experiencing greater desertification, while others are suffering category 4 and 5 hurricanes. According to the United Nations, water scarcity is amongst the most serious crises facing the world. And things are only getting worse. Uzbekistan and Kazakhstan of the erstwhile USSR, Chile, Mexico, Paraguay, Argentina, Peru and Brazil in Latin America, parts of China and the Middle East especially Iran, and more than 25 countries of Africa are all suffering from varying degrees of desertification. Global weather has gone awry. It is making poor countries poorer. Countries that are already facing drought and famine are getting less and less water. For how long can these countries run on dry? Nowhere is the situation worse than in Africa. Almost 40 million people in 19 countries are facing imminent food shortage. Much of the livestock there will perish. The growing water shortage will make food scarcer, potable water less accessible and water-borne diseases even more rampant. And the number of people who will suffer all this is expected to touch more than 500 million by the 2025. And the global consequence: A greater dependence on international aid. And this problem is not just limited to Africa. No one can tell which part of the globe will be next. Blame this on nature. It’s most convenient. But fact is, much of the blame belongs to increasing consumption and improper usage. At every opportunity nature reminds us by what it does and what it doesn’t, that it is one of the forces we have little control over. So there’s no way we can stop the rain or start it. But what we can do is become more water-efficient – get more from every gallon of water. And the only way to do this is to recycle and reuse waste water. Water is the giver of life. It has no substitute. And every drop counts! Many believe that the next world war is likely to be fought on the issue of water. Even though the world is two-thirds water, most of it is not potable, and much of it is not usable for any other purpose as well. And we are busy consuming and contaminating whatever is left of it, as if it were a non-depletable resource. This article is one of several aimed at identifying ways to make the best use of water, an increasingly scarce resource, by recovering it from wastewater, whether we intend to reuse the water so recovered or let it just charge our ground water reserves. This is aimed at a wide cross-section of people involved in taking corrective action across the world policy makers, administrators, municipal engineers & scientists, engineers & administrators in industries vested with the responsibility of wastewater treatment and management, industrial & residential property builders, academics, students and just about everyone who car[...]



Wastewater Treatment Aspects To Think Of – Part ii

2008-08-14T09:09:36Z

In a previous article, I listed some important factors you must take into account before you treat wastewater. These include the presence, in the wastewater, of acidity, alkalinity, hardness, and chloride, as well as the BOD and COD of wastewater. In this article, I have added substantially to the list. Before wastewater treatment begins, the […]In a previous article, I listed some important factors you must take into account before you treat wastewater. These include the presence, in the wastewater, of acidity, alkalinity, hardness, and chloride, as well as the BOD and COD of wastewater. In this article, I have added substantially to the list. Before wastewater treatment begins, the following factors must also be considered. Ammonia nitrogen: This is derived from ammonium compounds and organic compounds in wastewater by aerobic or anaerobic digestion. Un-ionized ammonia is toxic to fish life. Free ammonia, in concentration above about 0.2 mg/l can cause fatalities to fish. Ammonia toxicity is not a problem in receiving waters with pH below 8.0. This can be estimated by distillation of wastewater at pH above 9. The ammonia liberated is neutralized in sulfuric acid. The excess sulfuric acid is back titrated with alkali. The estimation of ammonia can be done by any other methods like nesslerization or digestion. Nitrate nitrogen: Nitrate nitrogen in drinking water with high nitrate content often causes methemoglobinemia (blue-baby disease) in infants. The maximum concentration should not be allowed to exceed 45 mg/l. Nitrate is reduced to nitrite in digestive system which, in turn, attacks the hemoglobin in infants resulting in methemoglobinemia. Nitrate nitrogen can be estimated by measuring the optical density at 220 nm and 275 nm in spectrophotometer. Nitrite: Nitrite can also interact with amine chemically or enzymatically to form nitrosoamines which are carcinogens. This is measured by colorimetric determination using sulfanilamide. Sulfate: Sulfate is one of the major anions occurring in natural waters. Sulfates form hard scales in boilers and heat exchangers. Sulfate assumes significance in water and wastewater, as it is associated with odor and sewer-corrosion problems resulting from the reduction of sulfate into hydrogen sulfide under anaerobic conditions. Sulfate in water or wastewater can be estimated by precipitation with barium chloride, acidified with hydrochloric acid. Phosphates: Most of the synthetic detergents designed for the household applications contain large amounts of polyphosphates as builders. Many of them contain 12-13% phosphorous or over 50% poly-phosphates. The organisms involved in the biological processes of wastewater treatment require phosphorous for reproduction and synthesis of new cellular material. Phosphorous in wastewater causes eutrophication, which affects transportation in sea/lakes. The presence of phosphorous in wastewater needs to be controlled before it is discharged into the receiving water bodies. Phosphorous present in wastewater can be estimated through colorimetric technique, by adding acidified ammonium molybdate solution to form a molybdophosphate complex. Nutrients: Wastewater often contains large amounts of the nutrients like nitrogen and phosphorus in the form of nitrate and phosphate, which promote plant growth. In severe cases, excessive nutrients in receiving waters cause algae and other plants to grow quickly depleting oxygen in the water. Deprived of oxygen, fishes and other aquatic organisms die, emitting foul odors. Nutrients from wastewater have also been linked to ocean “red tides” that poison fishes and cause illness in humans. Author Bio: Richard J. Runion is the President of Geostar Publishing & Services LLC. Rich loves net research & blogging. His new blog on wastewater is fast becoming popular, as it is comprehensive and well-researched. Read his blog at: http://www.all-about-wastewater-treatm[...]



How to Remove Solids From Sewage Water

2008-08-08T04:31:52Z

Wastewater treatment has taken on a different scope now, against the background of the peril of fresh water sources running dry. Wastewater is constituted of water used differently, sewage and storm-water, enveloping the community. More groups of citizens produce sewage from both domestic and nondomestic causes. Except when rightly treated, sewage water can cause illness […]Wastewater treatment has taken on a different scope now, against the background of the peril of fresh water sources running dry. Wastewater is constituted of water used differently, sewage and storm-water, enveloping the community. More groups of citizens produce sewage from both domestic and nondomestic causes. Except when rightly treated, sewage water can cause illness or disease to the society and pollute the surroundings. Here I have discussed solids removal from wastewater. How may we withdraw solids sinking to the bottom from the sewage water? Easily said and done. By means of a settling tank. It comprises of the parts given below: (a) Sedimentation tanks: either chemical or plain precipitation (b) Septic (Imhoff) tanks (c) Sludge digestion tanks **Sedimentation tanks** This procedure is effected with the goal of withdrawing undissolved mineral and organic matter from sewage water. Subsequent to its being made to be filtered through screens and grit chamber. These are the modules inside which sedimentation is effected. The less heavy organic wastewater solids, which settle down in the sedimentation tanks, are labelled as sludge. Meanwhile the wastewater that has been partly cleared by the settling down of the solid particles is termed the effluent. Both sludge and effluent should be additionally processed to render them lasting and not objectionable. The settling in of the solids may be attributed to aggregation, flocculation, or gravity of sewagewater-particles. If congealing chemicals are not added to the sewage, the tanks are termed as ordinary sedimentation tanks. As against this, if chemicals are employed for the aim of bringing the smaller coagulated and suspended solids into solid masses of large volume, these are then termed chemical precipitation tanks. Chemicals addition is resorted to, to speed up the settlement process. The chemicals employed are chlorinated copper, alum, lime, ferric chloride, ferric sulphate etc. **Types of sedimentation tanks** Sedimentation is achieved in either vertical-flow or horizontal-flow tanks. The horizontal-flow tanks are normally rectangular while the others are normally circular. In a 4 walled tank, sewage flows in steadily at one side and passes out at the other side, generally above a small breakwater. Sludge is removed manually and passed into sludge-digestion tanks. Scum formed above the mass is taken out by the mechanical scraper, with the help of a 2nd blade labelled skimmer, through a scum trough. Inside an upward-flow or circular tank, sewage comes in at the middle, rises upwardly to be pulled out by moving as a stream over a circumferential dam. That is assembled on the surface. Such tanks are specifically constructed to make use of the procedure of flocculation. By Which, fine congealed granules are gathered into voluminous wooly masses, which are settled with ease as sludge on the bottom of the tank. Mechanical blades collect the sludge, accumulating it towards the middle, from which spot it is withdrawn for further treatment. The sediment removed effluent flowing as a stream above the weir in the outlet is accumulated in an outlet tube for further processing. When only primary sewage is to be considered for treatment here, They might well be ordinarily labelled as primary settling tanks or primary clarifiers. Meanwhile when sewage undergoes second level of treatment, as in trickling filters or aeration tanks, like tanks may then be termed as secondary settling tanks or secondary clarifiers. **Design criteria for primary sed[...]



The Way To Take Away Solid Matter From Sewage Water

2008-08-08T04:30:09Z

Wastewater treatment has assumed a new magnitude itself now, against the background of the risk of fresh water sources running dry. Wastewater comprises storm-water, water used for varied purposes, and sewage, enveloping the community. Most communities produce sewage from both domestic and nondomestic sources. Unless properly treated, sewage can injure the society and pollute nature. […]Wastewater treatment has assumed a new magnitude itself now, against the background of the risk of fresh water sources running dry. Wastewater comprises storm-water, water used for varied purposes, and sewage, enveloping the community. Most communities produce sewage from both domestic and nondomestic sources. Unless properly treated, sewage can injure the society and pollute nature. Here I have discussed eliminating solid matter from wastewater. How may we withdraw solids sinking to the bottom from the sewage? Easily said and done. By means of a settling tank. It is constituted of the parts given below: (a) Sedimentation tanks: effecting plain or chemical precipitation (b) Septic (Imhoff) tanks (c) Sludge digestion tanks **Sedimentation tanks** This process is implemented with the aim of withdrawing undissolved mineral and organic matter from wastewater. After it has been made to be filtered through screens and abrasive particles chamber. These are the units where sedimentation is brought about. The lighter sewage solids of organic origin, which settle in the sedimentation tanks, are labelled as sludge. Meanwhile the wastewater that has been partly cleared by the settling down of the solids is termed the effluent. The sludge and effluent both should be additionally processed to cause them to be established and unobjectionable. The settling down of the solids may be caused by aggregation, flocculation, or gravity of sewage-particles. If congealing chemicals are not deployed in the sewage, the tanks are termed as ordinary sedimentation tanks. As against this, if chemicals are employed for the aim of bringing the smaller coagulated and suspended solids into solid masses of large volume, these are in that case called chemical precipitation tanks. Chemicals are added to hasten the settlement process. The chemicals used are ferric chloride, ferric sulphate, chlorinated copper, alum, lime etc. **Types of sedimentation tanks** Sedimentation is achieved in either of vertical-flow or horizontal-flow tanks. The horizontal-flow tanks usually have 4 walls while the others usually have a circular cross section. In a rectangular tank, sewage enters continuously at one end and leaves the chamber at the other side, generally above a small breakwater. Slush is withdrawn physically and dumped into sludge-digestion tanks. The scum or skin of the sludge is removed by the mechanical scraper, with the help of a second sharp edge called skimmer, via a scum receptacle. In the case of a circular and upward-flow tank, sewage enters at the center, rises upwardly to be pulled out by flowing over a circumferential dam. That is arranged at the surface. Similar tanks are particularly designed to employ the procedure of flocculation. By Which, fine congealed granules are agglomerated into bulky wooly masses, that are more easily settled as slush on the bottom of the tank. Mechanical blades gather the slush, accumulating it towards the middle, from which place it is removed for further processing. The sediment removed effluent running over the outlet weir is gathered in a pipe in the outlet for further processing. When only raw sewage is to be processed here, They might well be ordinarily labelled as primary settling tanks or primary clarifiers. Meanwhile when sewage receives secondary treatment, as in trickling filters or aeration tanks, such tanks then may be called as secondary settling tanks or secondary clarifiers. **Design criteria for primary sedimentation tank** As wit[...]



Everything You Wish To Know About Discharging Solids From Sewage, Using Imhoff Tanks.

2008-08-05T12:14:03Z

Recycling and reusing wastewater will remove the need of consuming virgin water. The degree to which the procedures comprising wastewater treatment are costwise viable and provide easy following will give a kick start to employing water treatment. Therefore discussing the procedures comprising treatment of wastewater and their pros and cons, becomes relevant. Like tanks using […]Recycling and reusing wastewater will remove the need of consuming virgin water. The degree to which the procedures comprising wastewater treatment are costwise viable and provide easy following will give a kick start to employing water treatment. Therefore discussing the procedures comprising treatment of wastewater and their pros and cons, becomes relevant. Like tanks using sedimentation, Septic tanks (Imhoff tanks) can maximise the process of removing solids from sewage. Designed by Karl Imhoff belonging to Germany, an Imhoff tank is an amended septic tank in which the inflow of wastewater is not allowed to be combined with the mud brought forth. Besides, the effluent coming out is not allowed to carry with it any significant volume of the suspended silt as with a septic tank, characteristicswise. **Construction and Operational characteristics** It is a double chamber tank. The top chamber may be referred to as the deposition of sediment tank or moving in a stream chamber, beyond which effluent emanates at a very low velocity; the chamber below constitutes the ingestion chamber where oxygenless or microorganisms caused decay/breakdown occurs. Solid matters in the sewage sink to the deepest part of the sedimentation chamber through the sloping bottom walls (slope 5 vertical to 4 horizontal). They are made to fall in the lower chamber past a narrow opening at the bottommost part of the sedimentation chamber. The slot is provided with an airtrap in such a manner that the vapors formed in the bottom chamber cant escape into the sedimentation chamber. A vapor outlet, also called, surface skin chamber is fitted in the digestion chamber to remove the vapors going up to the surface. The principle vapor is methane having a sizeable energy value and hence may be gathered independently for expending. To stop pieces of scum or mud from invading the upper chamber, the slush and offscourings should be sustained at a space of minimum forty five centimeters beneath and on top of the apertures, accordingly. The free or clear zone is labelled neutral zone. The chamber below is made up of two or three cones turned upside down labelled hoppers, with sides sloping (1 : 1) so as to accumulate the mud deep down in the hopper. The slush is evacuated intermittently using a sludge-pipe, the flow conforming to a fluid pressure of 1.2 to 1.8 m. All of the mud is not eliminated, only the bottom layers which have rotted completely. Some mud is kept behind to maintain the tank seeded with anaerobic bacteria. To uniformly distribute subsided solids over all areas of the digestion chamber, so as to utilize the storage capacity to the greatest extent, plans for reversing the line of flow at every part of the tanks, are commonly made. **Merits** Imhoff tanks couple the advantages of the septic and sedimentation tanks together and, as such find use in the case of limited size plants requiring only preliminary treatment. They are more economical and give satisfactory results in the absense of close attention and with least problems of getting rid of slush. **Demerits** (i) Greater depth of tanks installation spells lack of economy specially where foundations are to be laid in rocky terrain or loose sands. (ii) The above tanks are unsuitable to acidic wastewater (iii) There’s no adequate control over their operation. This makes them unsuited for being deployed in large size plants where unique mud digestion tanks are resorted to. Author Bio: Richard J. R[...]



The 4 Types Of Affliction Produced By Organisms Via Polluted Water

2008-08-02T09:18:00Z

Polluted water can cause four types of diseases : water borne, water washed, water based and water related. Diseases brought forth by water could get transmitted fecally or orally. Some are caused by bacteria; these comprise typhoid and cholera. Some others originate from the phage virus or bacteriophages. Infectious hepatitis and jaundice belong to these. […]Polluted water can cause four types of diseases : water borne, water washed, water based and water related. Diseases brought forth by water could get transmitted fecally or orally. Some are caused by bacteria; these comprise typhoid and cholera. Some others originate from the phage virus or bacteriophages. Infectious hepatitis and jaundice belong to these. Still others are the handiwork of protozoans. Amoebic meningo and amoebic dysentery are prominent instances of these. Diseases brought forth by water may be forestalled by either: securing the quality of drinking water, or shunning usage of water from unclean sources. Then there are some ailments that can be classified as water washed diseases. These are passed from person to person, water being the medium. Skin diseases, like conjunctivitis and leprosy rank among these. To stop the advance of water washed diseases, you must guarantee access to a reliable residential water supply source. And make greater the quantity of water at hand, for washing, cleaning, etc. so as to forestall handling of the same water by many persons. Liver fluke and guinea worm diseases feature among water based diseases. Curbing snail populations, and straining the water employing a porous woven fabric, so as to eliminate cyclops, snails or larvae will stop the onset of these ailments. That aside disinfecting polluted water may also be tried. Water related diseases refer to those spread by vector organisms. Malaria, filaria and dengue fever occupy a front position among these. These can be prevented by exterminating breeding spots of insects. Also, you should try and decrease physically going near these sites, and use mosquito repellants while retiring nocturnally. Diseases originating from organisms, arising out of polluted water include Dracunculiasis, which is a guinea worm infestation. The disease afflicts adult humans, when fresh water crustaceans cyclops are in the larval stage. The symptoms of the disease include a stinging or burning sensation observed by the affected person, prior to the coming into view of a swelling on the skin. The blister then bursts, and an ulcer forms, when the afflicted portion of the skin becomes wet. This happens when the female worm is on the point of discharging larvae on the skin surface. Nausea and vomiting may also occur with the first appearance of the bubble on the skin. Other ailments originating from organisms caused through tainted water are Cholera and other vibrios, Typhoid and Paratyphoid, Giardiasis, Cryptosporidiosis, and Schistosomiasis, and Cyclospora, Naegleria, and illness caused due to cyanobacteria. Then, the diseases given below also originate from organisms in polluted water : Shigellosis (bacillany dysentery), Campylobacterios, and Escherichia coli, Yersinia infections, Plesiomonas infections, and Aeromonas infections, and Melioidosis, Legionnaire’s disease, and Pseudomonas infections, (aerobic, nonspore forming, gram negative bacilli). Additionally, there occur a few more ailments originating from organisms in polluted water : Leptospirosis, Mycobacterial disease, and Tularaemia, Viral gastroenteritis, Helicobacter infections, and Viral hepatitis, and Enterovirus infections, Poliomyelitis, and Adenoviral infections. Among these, Schistosomiasis can be fatal sometimes, if Katayama fever, happens within 4 to 6 weeks of infection. The symptoms include nausea, vomiting, anorexia, flatulence, bloating, diarrhoea, and abdominal pain.[...]