Water of water to drink, irrigate their lands and

Water PollutionBangalore LakesIntroductionIn the last few years the water conditions in Karnataka have steadily worsened. This has resulted in high to extremely high water stress in Karnataka. This is especially evident in the capital city of Karnataka: Bangalore. Bangalore was earlier known as ‘The City of Lakes’. Kempegowda, the founder of Bangalore, who had great foresight, established several tanks and lakes to collect runoff water, so that it could be utilized for better purposes and enhanced the beauty of our garden city. The farsighted founder dotted the city with numerous lakes/tanks in and around the city to ensure, that its citizens would always have abundance of water to drink, irrigate their lands and use for secondary purposes.The earliest instance of construction of tank in Bangalore dates back to the latter part of the 16th century, when the founder of Bangalore, Kempegowda built the Ulsoor Tank of an area of 125 acres. The first instance of contamination of Ulsoor tank by sewage was reported way back in 1883 after which the use of lake water for public consumption was prohibited. Records show that till 1960 there were 262 water bodies in Bangalore. Today the figures have declined to about 81 of which 34 are recognized as live lakes. ProblemOverviewFigures denote a reduction of water bodies as high as 35%, while in terms of water spread area it shows a decrease of 8.6%. 98% of Bangalore’s lakes are encroached and 90% are polluted. I have calculated the amount of sewage produced by Bangalore below:On average each person consumes180 LD (Liters per day)Population of Bangalore (2012 consensus)8 millionPopulation growth rate5% / yearPopulation of Bangalore (2017)10 millionWater used by Bangalore180 LD 10 million1800 MLD (Millions of liters per day)Water that turns into sewage80%Sewage produced1800 MLD * 80%1400 MLDSewage that is treated20 – 40%30%1400 MLD * 30%420 MLDSewage that is not treated1400 MLD – 420 MLD980 MLD70%As seen in the above calculation, Bangalore produces a whopping 1400 millions of liters of sewage produced in a day. Out of this, we only treat 20% – 40% of this 1400 MLD. Another nail in the coffin is that the BWSSB growth rate is less than the population growth rate of bangalore. This means that the lack of STPs (Sewage Treatment Plants) is increasing. The water situation in Bangalore is worsening. PollutantsSewageSewage is a type of wastewater that is produced from a community of people. It is fundamentally liquid waste. It consists of the following:GreywaterThe relatively clean waste water from baths, sinks, washing machines, and other kitchen appliances.BlackwaterThe wastewater and human excreta from toiletsSoaps / DetergentsAs calculations had mentioned earlier, Bangalore produces 1400 MLD of sewage. Most of this is produced by domestic households and other commercial spaces. By law, new residential projects with 20 units or commercial spaces with an area of at least 2000 m2 must have an STP, and existing apartments with more than 50 units or commercial spaces with an area of at least 5000m2 need to have their own STP. This is to ensure that the wastewater they release is clean.The reason for cleaning the sewage is due to it containing pollutants such as:PathogensSewage contains many pathogens such as bacteria, viruses, parasites and protozoans. Many of these organisms are disease causing, and if ingested, it can have severe health consequences. These pathogens can also affect aquatic life and can disrupt the ecosystem.Soaps / DetergentsSoaps and detergents contain phosphorus. Phosphorus acts as a nutrient and this can cause eutrophication. Phosphorus content in detergents in India isn’t regulated. This also causes excessive foam in the lakes. Solid wasteSolid waste has a similar effect to encroachment. The waste reduces the lakes volume itself. This can cause many problems such as flooding of lakes and also, it can cause blockages. The Bangalore lake system is interconnected by natural channels. These can also be blocked by the dumping of waste. The wwaste before being dumped is generally put in a plastic bag. Plastic isn’t biodegradeable, and it gradually breaks down into smaller granules. These are ingested by aquatic life, and this lleads to their death. As the waste is not segregated it can leechh chemicals that are harmul to the lake’s ecosystem.EncroachmentOver 90% of Bangalore’s lakes are enchroached by mafia. The dumping of soil around or into the lake is a major concern. These lake, which are natural wetlands are now drasticaly reduced. Did you know, that if only clean water was pumped into Varthur Lake, in about 3 months, it would become clean. The lake has the ability to clean itself. The enchroachment of these lakes has reduced the area, and thus also the lake’s ability to clean itself. It is a well known fact that flowing water natuallay cleans itself. One hears of floods in the Koramangala/Indranagar region. What most perople fail to realise is that we our losing our natural water sinks. The lakes used to hold rain water, but thanks to encroachments, we have replaced the lake with concrete structres. We are destroying nature’s self-cleanign mechanism.NutrientssThe increaed concentration of nutrients in a water body is known as eutrophication. Eutrophication results in a rapid increase in the growth of surface algae. This is known as an algal bloom. The increased concentration of algae drasticaly increases the biological oxygen demand (BOD). this results in an oxygen deficecy for other organisms living in the lake. The algae doent allow sunlight to reach the lake bed, and this inhibits the growth of auatic plants. The water then turns brown and murky. This is water of poor quality. Toxic materialsSynthetic pesticides are toxic to fish in low concentrations resulting in their death and a decline in the overall population of the fish. Some fish are more sensitive than others and die at lower concentrations. Pesticides enter lakes when they aer used, and excess is washed into the water when it rains, or if the spray drifts when applied. The burning of fossil fuels results in the output of heavy metals into the atmosphere which deposit into water bodies. Heavy metals in water stunt growth and impair fish’s sense of smell, which hampers its ability to find food or avoid predators. Some of these metals which are toxic result in the poisoning of fish.Fish feed on invertebrates that live in the water. These invertebrates include waterborne insects; pesticides are toxic to them in low concentrations. However, if the pesticide does not kill the insect, it is transferred to a fish eats it. Over time, pesticide builds up in the fish until it reaches fatal level. Sediment is another pollutant that kills invertebrates. A thick layer of silt can smother bottomdwelling invertebrates. Heavy sediment can also smother fish eggs, reducing their populations.Whenever a drug is ingested, a part of it is excreted through urine and faeces and flushed down toilets. Most wastewater treatment plants are not capable of removing pharmaceuticals during the treatment process, so drugs pass through the system into waterbodies where treated wastewater is discharged. A University of Colorado Boulder study shows that fish found in waterways laced with traces of endocrine-disrupting synthetic chemicals exhibit gender-bending; a phenomena in which male fish look and act like females and some possess both male and female organs. The study also shows that waters with traces of antidepressants affect fish behaviour.The result of these chemicals in the food chain is magnified whit each level in the food chain. When an organism ingest the toxic material, it is known as bioaccumulation. Bioaccumulation always leads to biomagnification. It is a phenomenon in which the concentration of this toxic material increases with each level in the food chain. So a predetor will have a higher amount of toxic chemicals in its body. This can prove to be fatal.Acid RainAcid rain is caused due to air pollution. However, the acid rain lowers the pH of the water. This facors the growth of certain organisms and hinders the growth of others. This results in a reworking of the ecosystem.Everyday UseCertain social and religious practices such as the dumping of the mortal reains into waterbodies, bator the dipping of idols have negative effects on the lake. Everyday use by the people such as for bathing and so on also tend to pollute the lake. One of the most well-known examples of such pollution, is of the River Ganga. Due to the consideration of it as holy, many pilgrims come and bathe in in or release ashes of their family members here. Due to the sheer volume of this and the lack of proper facilities to clean this, the river has become one of the most polluted rivers in the world. Solutions