In Arcata marshes, cleaning of wastewater involves :

Options

A. Utilization of microorganism only for pollution control
B. Filteration chlorination like chemical process
C. Removal of dissolved heavy metals through biological process
D. Only conventional method sewage treatment

Answer

To solve the question regarding the cleaning of wastewater in Arcata marshes, we will analyze the options provided and determine which one is correct based on the information given in the video transcript.

### Step-by-Step Solution:

1. **Understanding the Context**:
- The question pertains to the wastewater treatment process in Arcata marshes, located in California, USA. The treatment involves both natural and artificial methods.

2. **Analyzing the Options**:
- **Option A**: Utilization of microorganisms only for pollution control.
- This option suggests that microorganisms are used solely for pollution control. However, the transcript indicates that a variety of biological processes are involved, not just microorganisms. Therefore, this option is incorrect.

- **Option B**: Filtration, chlorination like chemical process.
- This option implies that the treatment relies on chemical processes like filtration and chlorination. While these methods are part of the treatment, the transcript emphasizes the use of natural systems, making this option incorrect as well.

- **Option C**: Removal of dissolved heavy metals through biological process.
- This option states that dissolved heavy metals are removed through biological processes. The transcript confirms that a series of marshes and biological systems (including plants, algae, and bacteria) are employed to absorb heavy metals, making this option correct.

- **Option D**: Only conventional method of sewage treatment.
- This option suggests that only conventional methods are used. The transcript clearly states that an integrated wastewater treatment system was developed utilizing both conventional and natural methods, thus making this option incorrect.

3. **Conclusion**:
- The correct answer is **Option C**: Removal of dissolved heavy metals through biological process.