What are the main sources of domestic sewage in the collection system?

The primary sources of domestic sewage in the collection system are household and commercial establishments. This category encompasses wastewater generated from residential homes, restaurants, offices, and other businesses. The domestic sewage typically includes water from sinks, toilets, baths, and laundry, which is rich in organic material and nutrients.

In contrast, industrial facilities contribute their own types of wastewater, which are usually classified as non-domestic sewage because they can contain a variety of chemicals, heavy metals, and other contaminants not typically found in household waste. Agricultural runoff primarily consists of surface water that collects fertilizers and pesticides used in farming, leading to potential pollution, but it is separate from the collection of sewage specifically generated from domestic sources. Hazardous waste sites involve toxic substances that pose health risks and do not directly relate to the normal flow of domestic sewage in municipal systems.

Therefore, the answer accurately reflects the typical contributors to domestic sewage that municipal wastewater treatment plants aim to manage and treat.