The maximum permissible limit for suspended solids is 30 mg/l.

Explanation:
Suspended solids are solid particles that are present in a liquid but do not settle down under the influence of gravity. They can be organic or inorganic in nature and are typically measured in milligrams per liter (mg/l). The maximum permissible limit for suspended solids is set to ensure the quality and safety of the water or liquid being tested.

- Definition of Suspended Solids:
Suspended solids are particles that are larger than a certain size and do not dissolve in water. They can include silt, clay, sand, algae, bacteria, and other insoluble materials. Suspended solids can be visually observed as particles floating in the liquid.

- Importance of Monitoring Suspended Solids:
Monitoring suspended solids is important in various industries and applications. In water treatment plants, it helps assess the effectiveness of filtration processes. In industrial wastewater treatment, it indicates the efficiency of solids removal systems. In drinking water sources, it ensures that the water is safe for consumption.

- Maximum Permissible Limit:
The maximum permissible limit for suspended solids is determined by regulatory bodies and varies depending on the application. In this case, the limit is set at 30 mg/l. This means that the concentration of suspended solids in the liquid being tested should not exceed 30 milligrams per liter.

- Justification for the Chosen Limit:
The chosen limit of 30 mg/l for suspended solids is based on various factors such as water quality standards, environmental considerations, and the ability of treatment systems to effectively remove solids. Exceeding this limit can lead to adverse effects on the environment, human health, and the operations of treatment systems.

- Compliance and Monitoring:
To ensure compliance with the maximum permissible limit, regular monitoring of suspended solids is necessary. This can be done through laboratory testing using techniques such as gravimetric analysis or turbidity measurement. Compliance with the limit can also be achieved through the implementation of proper treatment processes and filtration systems.

In conclusion, the maximum permissible limit for suspended solids is 30 mg/l. This limit is set to maintain water quality and ensure the safety of the liquid being tested. Regular monitoring and compliance with this limit are crucial in various industries and applications.