The dewatered sludge cannot be disposed by acid fermentation.

Acid fermentation is not a suitable method for disposing of dewatered sludge. Acid fermentation, also known as acidogenesis, is a biological process in which organic materials, such as sludge, are broken down by acid-producing bacteria in an anaerobic environment. This process results in the production of organic acids, alcohols, and other byproducts.

Reasons why acid fermentation is not a suitable method for disposing of dewatered sludge:

1. Insufficient volume reduction: Acid fermentation does not significantly reduce the volume of sludge. The process mainly focuses on the breakdown of organic materials into simpler compounds, but it does not lead to significant volume reduction. As a result, the sludge would still require proper disposal after acid fermentation.

2. Odor and pathogen control: Acid fermentation may not effectively control the odor and pathogen content of the sludge. While the process does contribute to the stabilization of organic matter, it may not eliminate all odor-causing compounds or pathogens. This could pose a potential risk to the environment and public health if the sludge is not properly treated before disposal.

3. Limited resource recovery: Acid fermentation does not offer significant resource recovery potential. The process mainly aims at breaking down organic materials, but it does not result in the recovery of valuable resources or energy. Other methods such as composting or heat drying can provide better resource recovery options from dewatered sludge.

4. Environmental impact: Acid fermentation may release greenhouse gases such as methane and carbon dioxide into the atmosphere. Methane, in particular, is a potent greenhouse gas that contributes to climate change. Other disposal methods like incineration or heat drying can minimize the environmental impact by reducing or eliminating the release of such gases.

In conclusion, acid fermentation is not a suitable method for disposing of dewatered sludge due to its limited volume reduction, challenges in odor and pathogen control, limited resource recovery potential, and potential environmental impact. Other methods like composting, heat drying, or incineration can be more effective and sustainable options for sludge disposal.