Karachi is the largest and most populous city in Pakistan, with an estimated population of over 16 million people. It is also the economic, cultural, and industrial hub of the country, attracting millions of migrants from rural areas every year. However, Karachi faces a serious challenge of providing safe and adequate water to its residents, as the city suffers from water scarcity, pollution, and mismanagement.

According to a report by the Pakistan Council of Research in Water Resources (PCRWR), the water quality in Karachi is rapidly deteriorating, posing a threat to public health and the environment. In this article, we will discuss some of the top water contaminants in Karachi and how tank cleaning can help to improve the water quality and safety.

top water contaminants in karachi

Water Contaminants in Karachi

The main sources of water supply in Karachi are the Indus River, the Hub Dam, and the Kinjhar Lake. However, these sources are not sufficient to meet the growing demand of the city, which requires about 1,100 million gallons per day (MGD) of water. The actual supply is only about 550 MGD, leaving a huge gap of 550 MGD. This gap is filled by groundwater extraction through tube wells and hand pumps, as well as by private water tankers that sell water at exorbitant prices. However, both groundwater and tanker water are often contaminated with various pollutants, such as:

  • Bacteria: Bacteria are microscopic organisms that can cause various diseases, such as diarrhea, typhoid, cholera, dysentery, and hepatitis. Bacteria can enter the water supply through human and animal feces, sewage leaks, improper sanitation, and poor hygiene practices. According to the PCRWR report, 89% of the water samples collected from Karachi were found to be bacteriologically unsafe for drinking. The most common bacteria detected were E. coli, fecal coliforms, total coliforms, and Salmonella.
  • Heavy metals: Heavy metals are metallic elements that have high atomic weights and densities. Some of the heavy metals that can contaminate water are lead, arsenic, mercury, cadmium, chromium, and copper. Heavy metals can enter the water supply through industrial effluents, mining activities, agricultural runoff, corrosion of pipes and fittings, and household wastes. Heavy metals can cause various health problems, such as kidney damage, neurological disorders, cancer, anemia, and birth defects. According to the PCRWR report, 69% of the water samples collected from Karachi were found to have high levels of heavy metals. The most common heavy metals detected were lead, arsenic, chromium, and iron.
  • Nitrates: Nitrates are compounds that contain nitrogen and oxygen. Nitrates can enter the water supply through fertilizers, animal manure, sewage sludge, and industrial wastes. Nitrates can cause methemoglobinemia (blue baby syndrome), a condition that reduces the oxygen-carrying capacity of blood in infants. Nitrates can also increase the risk of cancer and thyroid disorders. According to the PCRWR report,

35% of the water samples collected from Karachi were found to have high levels of nitrates.

How Tank Cleaning Can Help

Tank cleaning is an essential part of water hygiene and safety. Over time, dirt, dust, debris, mould, and harmful bacteria can build up in the water tank. This can affect the taste, smell, color, and quality of the water. Tank cleaning can help to remove these contaminants from the system and ensure that the water is clean and safe for consumption.

Tank cleaning can also prevent the growth of biofilm and algae in the tank walls and pipes. Biofilm is a slimy layer of microorganisms that can harbor pathogens and reduce the effectiveness of disinfection. Algae are aquatic plants that can produce toxins and clog the filters and pipes.

Tank cleaning should be done regularly according to a risk assessment-based schedule. The frequency of tank cleaning may depend on various factors such as:

  • The type and size of the tank
  • The source and quality of the water
  • The usage and demand for the water
  • The environmental conditions
  • The maintenance history

Tank cleaning should be done by trained professionals who have the proper equipment and personal protective equipment (PPE). Tank cleaning should follow a standard procedure that complies with the relevant guidelines and regulations. A typical tank cleaning procedure may involve:

  • Isolating the tank from the inlet and outlet pipes
  • Draining the tank completely
  • Inspecting the tank for any cracks or leaks
  • Removing any debris or sediment from the tank floor
  • Scrubbing or jet-washing the tank walls and roof
  • Disinfecting the tank with chlorine or other suitable agents
  • Rinsing the tank thoroughly with clean water
  • Refilling the tank with fresh water
  • Testing the water quality for residual chlorine and other parameters
  • Documenting the tank cleaning process and results

Tank cleaning can help to improve the water quality and safety in Karachi by reducing the risk of waterborne diseases and infections. Tank cleaning can also help to enhance the performance and efficiency of the water system by preventing blockages and corrosion. Tank cleaning can also help to save water and energy by reducing wastage and leakage. Tank cleaning can also help to comply with the legal and ethical obligations of providing safe and adequate water to the residents of Karachi.

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