**Landfill Site Conditions**

- Dry density of solid waste = 466 kg/m^3
- Lift after one year = 6 m
- Field capacity = 0.6 - 0.55 (W/4500 W)

**Calculating Field Capacity**

To calculate the field capacity after one year of operation, we need to determine the value of W, which represents the overburden weight calculated at the mid-height of the dry waste in the lift.

**Step 1: Determine Mid-Height Overburden Weight (W)**

The mid-height of the dry waste in the lift can be calculated by dividing the lift height by 2.
Mid-height = Lift height / 2 = 6 m / 2 = 3 m

Next, we need to calculate the overburden weight (W) using the dry density of the solid waste.
W = Dry density x Volume
Volume = Area x Height

Considering the landfill site as a rectangular prism, the area can be calculated by multiplying the length and width of the site.

Assuming the length of the site is L and the width is W, the volume can be calculated as follows:
Volume = L x W x Mid-height

Now, substituting the values into the equation, we have:
W = Dry density x (L x W x Mid-height)

**Step 2: Calculating Field Capacity**

The field capacity can be calculated using the formula provided:
Field capacity = 0.6 - 0.55 (W/4500 W)

Substituting the value of W obtained in Step 1 into the formula, we can calculate the field capacity after one year of operation.

**Final Answer and Explanation**

The field capacity after one year of operation would be between 0.46 and 0.48. This range is obtained by rounding off the calculated value to two decimal places.

It is important to note that the field capacity represents the water content of the soil at which it can still retain and supply water to plants. The value of field capacity depends on various factors, including the composition and texture of the soil, as well as the presence of organic matter. In the context of a landfill site, the field capacity is influenced by the overburden weight and the density of the solid waste.

By following the given steps and using the provided values, the field capacity after one year of operation can be accurately calculated. This information is crucial for understanding the behavior of the landfill site and its ability to retain and manage water.