This is the recipe (in Romanian) for the meatball soup. Here is the ingredient list translated:  Servings: a pot of 5 L  Ingredients - savoriurbane.com  2 carrots  1 parsley root  1 root parsnips  1 celery root (medium)  2 tablespoons of oil  1 onion  2 potatoes  500 ml broth of tomatoes (of the house) or the tomato paste to the box (mashed) or 3-4 fresh tomatoes (summer)  approx. 500 g vegetables of your choice: pod of beans, peas, florets of cauliflower, diced turnip, etc.  1 small bunch of thyme dry   For the meatballs:  500 g minced pork (or mix with beef) 50 g rice (about 2 tablespoons) 1 small onion chopped 1 tablespoon of oil salt, freshly ground pepper 1 teaspoon of sweet paprika (paprika) 1 teaspoon dry thyme, chopped 1 egg white raw  In addition:  sour cream tart for dres soup 1 raw egg yolk lemon juice, vinegar, bors or dies a handful of greenery (leaves of parsley and dill) optional: chopped leaves of lovage  Additional translations re the amount of water and the total amount of soup the recipe makes:  I added the rest of the roots and I dropped everything with 4 L of hot water. From the ingredients below we obtained a soup pot of approx. 5 L.  
After looking at many very similar recipes (in English) for Romanian sour meatball soup, or Ciorba de Perisoare, I'm inclined to think that this recipe does indeed make 5 liters.  Most all of the recipes I've looked at start with 500g of meat and have pretty much the same ingredient list. This recipe found on  CookingGlory says to :     Add about 12 to 16 cups of water (about 4l).    Based on this, I find it easy to believe that the finished soup would easily be 5 liters. (Also, in the translation provided by another user, it shows an amount of 5 liters.)  Also, translated from the link provided in the question:     From the ingredients below we obtained a soup pot of approx. 5 L. You can reheat without problems and it is tastier every day (kept in the refrigerator lasts for 3-5 days).   And:     I added the rest of the roots and I dropped everything with 4 L of hot water.   The recipe on Cooking Glory states that it makes 8 - 10 servings.   So, basic math in hand, 5 L of soup, multiplied by 6 = 30 L of soup. That would give you sixty 500 ml portions.  The link above to the Cooking Glory page also gives a lot of information about the soup and its ingredients. 