Bring the water to a boil in a medium saucepan over high heat. Add the wild rice and return to a boil. Reduce the heat to low. Cover and cook for 4 minutes, or until the liquid has been absorbed.
Warm the oil in a large pot over medium heat. Add the onions, carrots, celery, and garlic. Cook for 10 minutes. Stir in the peas, bay leaf, thyme, mustard, and sage. Add the broth. Bring to a boil. Reduce the heat to medium-low, cover and cook for 45 minutes, stirring occasionally.
Add the wild rice and lemon juice. Season with the salt and pepper. Reduce the heat to low. Cook, stirring, for 5 minutes, or until the soup is thick and the peas are soft. Remove the discard the bay leaf.