Question

You are a regulator charged with drawing up plans for controlling water pollution. Briefly describe one idea for controlling water pollution from each of the following sources: (a) an effluent pipe from a factory going into a stream, (b) a parking lot at a shopping mall bordered by a stream, (c) a farmer's field on a slope next to a stream.

Short answer

Treat industrial effluents, use permeable surfaces and bioswales for runoff, and install vegetative buffers for agricultural runoff.

Step-by-step solution

Factory Effluent Pipe

To control water pollution from a factory's effluent pipe discharging into a stream, one effective method is to implement an effluent treatment plant. This involves installing a system that treats industrial wastewater to remove harmful pollutants and chemicals before the water is discharged. The treatment could include physical, chemical, and biological processes to ensure the water meets environmental safety standards.

Runoff from Parking Lots

For controlling pollution from runoff in a parking lot at a shopping mall, implementing permeable pavements and bioswales can be effective. Permeable pavements allow water to percolate through surfaces, reducing runoff volume. Bioswales, which are landscaped elements, can filter pollutants from the water before it reaches the stream, thus reducing contamination.

Agricultural Field Runoff

To address pollution from a farmer's field on a slope next to a stream, creating buffer zones with vegetation between the field and the stream can be beneficial. These vegetative buffers can trap sediments, nutrients, and pesticides from runoff, preventing them from entering the water body. Additionally, contour farming and terracing can minimize soil erosion and runoff.

Key concepts

Effluent Treatment Plant

Industrial factories often generate wastewater containing harmful pollutants. An effluent treatment plant (ETP) is essential for treating this wastewater before it reaches natural water bodies.
The process inside an ETP involves several stages:

• Physical Treatment: Solid particles are separated from the water through sedimentation and filtration.
• Chemical Treatment: Chemicals are added to remove toxins or neutralize harmful substances.
• Biological Treatment: Microorganisms break down organic materials in the wastewater.

After treatment, the resulting water should meet regulatory standards for environmental safety, ensuring it is safe enough to be discharged into streams or rivers. By using ETPs, industries significantly reduce their environmental footprint and contribute to the prevention of water pollution.

Permeable Pavements

Urban areas, with their vast expanses of concrete, contribute to water pollution through stormwater runoff. Permeable pavements offer a solution by allowing water to seep through the surface and soak into the ground below.
Unlike traditional impermeable surfaces, these pavements are made from porous materials such as:

• Porous concrete
• Permeable interlocking pavers
• Asphalt with open-graded aggregates

These materials help manage stormwater at the source, reducing runoff volumes and flooding risks.
Moreover, as water travels through these permeable surfaces, it undergoes natural filtration that helps remove pollutants such as oils, heavy metals, and other contaminants.
Incorporating permeable pavements in urban designs not only helps manage water pollution but also boosts groundwater recharge and enhances the natural water cycle.

Vegetative Buffer Zones

On agricultural sloped fields, water runoff can carry sediments, nutrients, and pesticides directly into streams. Establishing vegetative buffer zones is an effective strategy to combat this. These buffers often consist of various plant species strategically planted between farmland and waterways.
Key Benefits of Vegetative Buffers:

• They trap and filter out sediments and pollutants before they can enter water bodies.
• Roots of the vegetation help stabilize soil, reducing erosion.
• These zones provide habitat for wildlife and help maintain biodiversity.

In addition to creating buffer zones, integrating practices like contour farming and terracing can further lessen runoff and soil erosion.
Ultimately, vegetative buffer zones act as a first line of defense against water pollution from agricultural runoff, promoting a healthier watershed environment.