There is nothing suggesting that it is recommended to face the Qiblah while drinking, whether one is drinking Zamzam water or anything else.

-Reciting Al-Fatihah and a specific Du`a before eating is not part of the authentic Sunnah. -While Islam encourages supplication, communal Du`a in a structured manner is considered an innovation. -The Prophet (peace be upon him) supplicated for his host after eating, and authentic Du`as exist for mealtime etiquette. -Muslims should adhere to the established Sunnah and avoid unfounded practices.

It is not obligatory to wash the mouth after eating or drinking, whether you want to pray or read the Quran. But it is recommended for you to do that especially if what he ate or drank was at all greasy.

It is not permissible to throw leftover food and drink that can be used down the drain or to put them out with the trash. With regard to food that is not good or that has gone off, and drinks that cannot be used, such as leftover tea and coffee, there is nothing wrong with throwing them out with the trash or into drains.