What needs to be removed from sewage and agricultural wastewater before it is released into the environment?

The need to remove organic matter, harmful microbes, and fertilizers and pesticides from sewage and agricultural wastewater before releasing it into the environment is crucial for several reasons.

Organic matter, when released into natural bodies of water, can lead to eutrophication. This process promotes excessive algae growth, which depletes oxygen in the water and endangers aquatic life. Harmful microbes present in wastewater can pose serious health risks to humans and wildlife, facilitating the spread of diseases. Additionally, fertilizers and pesticides can contain nutrients and chemicals that can disrupt ecosystems, leading to long-term environmental damage and bioaccumulation in food chains.

While excessive minerals, harmful microbes alone, or soluble pollutants are concerns, they do not encompass the full range of harmful substances present in wastewater that can adversely impact the environment. Thus, the comprehensive removal of organic matter, harmful microbes, fertilizers, and pesticides ensures a more complete purification of wastewater, protecting ecosystems and human health when the treated water is eventually released.