Description

Given the average flow and tributary BOD, the average depth and the average area of the lagoon, calculates the incoming BOD load, the volume of the lagoon, the retention time and the organic loading rate.

Grades

1. Recommended hydraulic detention time:

   Average temperature of the lagoon in the coldest month (°C)	Initial and final detention time (day)	BOD removal efficiency (%)
   $\ge 20$	$\le 4d; \le 6D$	$\le 50$
   $\gt 20$	$\le 3d; \le 5D$	$\le 60$

2. Organic load application rate:

   = 100 g BOD/m³.d; <= 400 g BOD/m³.d. Higher loads are applicable to higher temperature conditions.

3. Depth: between 3 and 4 m. If there is no prior desanding, add an additional depth of at least 0.50 m, next to the entrance, extending over at least 25% of the bottom area of the lagoon

4. Length/width ratio: on the order of 2 to 3.

5. Maximum area per pond: 5