Abstract: A server according to an embodiment includes a processor configured to receive a friend add request for a target account from a user terminal accessed with a user account; based on one of the user account and the target account being a protected account, transmit an approval request for the friend add request to a protector account connected to the protected account; and based on receiving a reply to the approval request from the protector terminal, add the target account to a friend list of the user account.

Abstract: According to an embodiment of the present disclosure, there is provided a hydro crusher for water treatment, for removing living organisms from water to be treated, the hydro crusher including: a body portion which has a cylindrical shape having an inner space, and includes an inflow portion to allow the water to be treated to be drawn into the inner space therethrough, and a discharge portion to discharge the water to be treated, drawn in through the inflow portion; and solid particles which are movable by the water to be treated, wherein the movable solid particles are filled in at least a portion of the inner space.

Abstract: According to an embodiment of the present disclosure, there is provided a hydro crusher for water treatment, for removing living organisms from water to be treated, the hydro crusher including: a body portion which has a cylindrical shape having an inner space, and includes an inflow portion to allow the water to be treated to be drawn into the inner space therethrough, and a discharge portion to discharge the water to be treated, drawn in through the inflow portion; and solid particles which are movable by the water to be treated, wherein the movable solid particles are filled in at least a portion of the inner space. Accordingly, there is an effect that physical sterilization is possible by killing or inactivating living organism included in water to be treated by applying a shock to the living organism.