What type of pipe is used for distribution lines in raised filter beds?

The use of 4" perforated pipe for distribution lines in raised filter beds is appropriate due to its design, which allows for effective drainage and aeration of the soil. Perforated pipe has multiple small holes or openings that facilitate the movement of liquid, promoting uniform distribution of effluent throughout the raised filter bed. This ensures that the wastewater is evenly spread, allowing for optimal filtration and absorption by the surrounding soil, which is essential for treating effluent before it enters the groundwater.

The diameter of 4" also strikes a balance between efficient flow and manageable size, making it suitable for residential and small commercial systems. Using perforated pipe enables the effluent to infiltrate into the filter media, which promotes biological processes that help break down contaminants.

Other types of pipes, such as solid pipes or those with larger diameters, are less effective in this context because they do not provide the necessary perforations for dispersion, potentially leading to pooling or ineffective treatment of wastewater. Therefore, the choice of 4" perforated pipe is critical in ensuring proper function and longevity of the raised filter bed system.