How is the environmental quality of a watershed related to surface water supply?
Water shed off a field or pasture may have dirt and weed seeds floating in it, but this is easily cleaned by sedimentation, allowing the water to sit and the sediment fall to the bottom of a pond. Water shed off of city streets takes more to clean, i.e. make drinkable. All the oils from cars and trucks as well as dog droppings, dead birds, the ooz from trash containers are all washed into the water supply and have to be cleaned before we can use it. A field may have a lot of dirt, but it is easier to make clean drinkable water from, were a city area will have to deal with heavy metals, oils and other chemicals that need to be clean out of it as well as bacteria.
Is underground water really pure and safe to drink?
This questions seems to have attracted a lot of poor-quality answers from people ignorant about what constitutes good drinking water quality. Water that is deep underground, such as that from an aquifer, is more likely to be pure and of drinking water quality than water that is just below the surface (usually referred to as "groundwater"). This relative purity has not changed despite the use of pesticides or fracking or the other horrible things that other perhaps well-meaning responders with political agendas would have you believe so you can join their bandwagon. A group that does excellent work, Engineers without Borders, has dug wells in Africa to supply good quality water to people there who were previously burdened with horrific disease rates from poor water quality. The villagers do not need to boil the well water (or treat it in any way) to make it safe to drink but they draw from the well as they need water and do not attempt to store it in tanks. What makes water unsafe to drink in Africa and other places is poor (yet completely natural and often pesticide and fracking-chemicals free) sanitation. This lack of sanitation results in water contaminated with microorganisms that cause diseases with symptoms of diarrhea or worse. Chlorine or chloramines in low quantities are added to water in developed countries to prevent the growth of these microorganisms, not to create poor health among unsuspecting civilians. People who store large quantities of pure water in tanks for their own use risk the growth of microorganisms if the turnover of water is not sufficient (so be careful Mr "Snowy Whatever" when you come back from a month away from home - be aware that the pure water in your tank is not then as likely to be safe to drink). In brief, it is rare that chemicals cause water to be unsafe to drink. It is common that microorganisms contaminate water through completely natural processes.
What is the standard value of BOD in drinking water?
Hey.A BOD level of 1-2 ppm is considered very good. There will not be much organic waste present in the water supply. A water supply with a BOD level of 3-5 ppm is considered moderately clean. In water with a BOD level of 6-9 ppm, the water is considered somewhat polluted because there is usually organic matter present and bacteria are decomposing this waste. At BOD levels of 100 ppm or greater, the water supply is considered very polluted with organic waste.Generally, when BOD levels are high, there is a decline in DO levels. This is because the demand for oxygen by the bacteria is high and they are taking that oxygen from the oxygen dissolved in the water. If there is no organic waste present in the water, there won't be as many bacteria present to decompose it and thus the BOD will tend to be lower and the DO level will tend to be higher.At high BOD levels, organisms that are more tolerant of lower dissolved oxygen (i.e. leeches and sludge worms) may appear and become numerous. Organisms that need higher oxygen levels (i.e. caddisfly larvae and mayfly nymphs) will not survive.Hope this helped.
At what point does a pond become a lake?
Flora required Photosynthesis process to prolong.Now,A pond is a body of water shallow enough to foster rooted plants. That is sunlight can penetrate up to the depth of pond.Whereas, A lake is too deep to not allow sunlight to penetrate up to the depth. hence does not support rooted plants except near shore.Now, statistically there might be an accurate date to predict it meticulously,but coming to the question there are various possibilities according to me.A. Suppose you keep pond as it is, then due to conglomeration of waste(Degradable or nondegradable) or soil dumping, the overall depth of pond might decrease so eventually Pond will become more like Pond rather than Lake.B. There is a chance to lake becoming Pond as explained earlier.C. Suppose soil is taken from the pond for some purpose(To use it somewhere or to increase the storage volume) or because of erosion of soil beneath, the depth of pond will increase. So in the long run there is a chance that Pond will become Lake!I hope I could answer your question!
Is water in the well cleaner than river water?
THis question isn’t entirely subjective for it depends on where you are in the world and your (very local) location. By this I mean, you could be in Bangladesh where the river water flow is from the Himalayas and has a high heavy metal content, so despite appearing clean, is dangerous to the health. The well n this case could perhaps be cleaner due to percolating through rock.You could be in an area where fracking from shale gas is conducted and the river water may then be cleaner than the well.Or you could be in a part of the world where every person and animal share the river water with high bacterial and protozoan content in the river and the count is somewhat lower from the well.Equally industrial pollution and local sewage contamination of wells is common, and when ground waters are affected, because they are a static water source it is usually forever, whereas river water can be cleaned more quickly by removing the source of contamination due to constant through-flow.
What is the difference between an oxidation pond and an oxidation ditch for sewage treatment and, which one is preferred?
The oxidation ditch (OD) is a sort of equipment used for a long-term aeration. It consists of a long channel of an elliptical or circular shape equipped with an aeration equipment called a rotor for generating a water flow and stirring water in the channel to supply oxygen. Thought it requires a relatively large area, it has a simple structure and can be easily operated as well as being able to remove nitrogen easily. Thus, it has recently been widely used in relatively small wastewater treating plants.#Advantages and DisadvantagesAdvantages of the oxidation ditch are as follows.1) It can be easily maintained.2) It is hard to be effected by load fluctuations and forms only a little sludge.3) OD can be easily controlled by changing the rotation of the rotor and the dipping depth.4) It requires relatively little energy as the rotor is operated efficiency.5) It can perform nitrification and denitrification easily.Disadvantages of the oxidation ditch are as follows.1) As the tank is large and the depth is small, it requires a large area.It can be said the OD method is particularly suitable for a small scale equipment.Oxidation pond is one of the biological systems which are used for the treatment of wastewater. It is considered as the secondary treatment method by which natural purification and stabilization of wastewaters like domestic sewage, trade waste and industrial effluents is accelerated. The biological treatment process in oxidation pond mainly involves an interaction between bacteria, algae and other organisms.Oxidation pond typically operate in an extended aeration mode with long detention and solids retention time  and is a widely adopted technique for the treatment of domestic and trade wastes. It is one of the methods used extensively in the tropical areas of the world for treating the wastewaterThis method would also have disadvantages that it requires extensive land area, potential odour problem, mosquito menace, little control over the effectiveness of the treatment process and the main disadvantage is seepage of effluents into soil which may also lead to ground water pollution.Oxidation Ditch is preferred over oxidation pond !