In domestic sewage, suspended solids, colloidal and dissolved materials constitute

Options

A. 0.1
B. 0.056
C. 0.027
D. 0.001

Answer

To solve the question regarding the composition of suspended solids, colloidal, and dissolved materials in domestic sewage, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Domestic Sewage**:
- Domestic sewage is a mixture that includes various materials such as suspended solids, colloidal substances, and dissolved materials.
- These components are primarily organic in nature and include fats, proteins, and carbohydrates.

2. **Identify the Role of Microorganisms**:
- The sewage contains a large number of microorganisms, particularly bacteria, which play a crucial role in breaking down organic matter.
- These bacteria consume the organic components, leading to changes in the composition of the sewage.

3. **Determine the Proportion of Suspended Solids, Colloidal, and Dissolved Materials**:
- It is important to recognize that the total solid content in wastewater is relatively small compared to the overall volume of sewage.
- The specific question asks for the percentage of suspended solids, colloidal, and dissolved materials in domestic sewage.

4. **Refer to Known Data**:
- Based on studies and data regarding wastewater composition, it is established that suspended solids, colloidal, and dissolved materials constitute about 0.1% by weight of the total sewage.

5. **Select the Correct Option**:
- Given the options provided (0.1, 0.056, 0.027, and 0.01), the correct answer is clearly 0.1%.

### Final Answer:
The suspended solids, colloidal, and dissolved materials in domestic sewage constitute approximately **0.1%** by weight.

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