potable water and waste treatment

Potable Water

Water that is safe for drinking, free from harmful substances and pathogens.

Sources of Potable Water

Groundwater (aquifers), surface water (rivers/lakes), and desalination.

Difference Between Pure and Potable Water

Pure water contains only H₂O molecules, while potable water may contain dissolved minerals but is safe to drink.

Stages of Water Treatment

1. Screening - Removes large debris using metal screens. 2. Sedimentation - Allows heavy particles to settle. 3. Filtration - Removes fine particles 4. sterilisation - Kills microbes and pathogens. 5. Desalination (if required) - Removes salt using distillation or reverse osmosis.

Screening Stage in Water Treatment

Large solid objects removed

Sedimentation in Water Treatment

Heavy particles settle, allowing cleaner water to move forward in the process.

purpose of Filtration in Water Treatment

removes fine particles such as bacteria and dirt.

Chlorination in Water Treatment

To kill harmful bacteria and pathogens, making water safe to drink.

Desalination for Potable Water

The process of removing salt from seawater.

Two Methods of Desalination

Distillation and Reverse Osmosis.

Reverse Osmosis Process

Seawater is forced through a fine membrane, filtering out salt and impurities.

Distillation Process

Water is boiled to produce steam, which is then condensed to form pure water.

Hard vs. Soft Water

Hard water contains calcium and magnesium ions; soft water has fewer minerals.

how to remove Hardness from Water

Temporary hardness can be removed by boiling; permanent hardness by ion exchange filters.

Testing Water Purity

By measuring boiling point or testing for dissolved solids using conductivity.

Why are Some Minerals left in Potable Water

because minerals like calcium and magnesium are beneficial for humans

pH Balance of Potable Water

To ensure safety—extreme pH levels can be harmful.

what are the Natural Pollutants in Water

Microorganisms, organic matter, and dissolved minerals.

Human activities that pollute drinking water

Industrial waste, agricultural runoff, and sewage discharge.

Fluoridation of Drinking Water

To reduce tooth decay by strengthening enamel.

Water scarcity as a global issue

Freshwater supplies are limited, and demand is increasing due to population growth.

Water conservation strategies

Using water-efficient appliances, fixing leaks, and collecting rainwater.

Stages of sewage treatment

1. Screening - Removes large debris (e.g., plastic and solids). 2. Sedimentation separates sludge and oils. 3. Biological processes break down organic matter. 4. sterilisation - Kills bacteria using chlorine or UV light.

Screening in sewage treatment

Large objects like plastics and debris are removed.

Primary sewage treatment (Sedimentation)

Heavy solids settle, and fats/oils float to the surface.

Secondary sewage treatment (Biological Treatment)

Microorganisms break down organic waste in aerated tanks.

Final disinfection in sewage treatment

Chlorine or UV light is used to kill harmful bacteria.

Renewable sources of drinking water

Rainwater collection and treated wastewater.

Ethical concerns in water treatment

Water access, cost, environmental impact, and privatization.

Global inequality in demand for clean water

Many developing regions lack safe drinking water due to pollution and scarcity.

Carbon footprint of water treatment

Energy-intensive processes like desalination and pumping water increase carbon output.

Impact of industrial waste on water quality

Factories discharge harmful chemicals into rivers and lakes, contaminating drinking water.

Agricultural runoff and water pollution

Fertilizers and pesticides wash into rivers, causing contamination.

Importance of wetlands in water filtration

They trap pollutants and filter water through vegetation.

Water treatment plant operations

They purify water by removing contaminants, filtering solids, and disinfecting it.