A Fats, Oil and Grease (FOG) system including: a reservoir defining an effluent containing zone; and a FOG collector provided in the reservoir in the effluent containing zone, the FOG collector including: a plurality of floating members which are configured operatively to float in the effluent containing zone; a plurality of heaters configured to warm effluent in the effluent containing zone, thereby liquifying, at least partially, FOG in the effluent, wherein the floating members and heaters are arranged in a plurality of groups, each group including at least one of the floating members coupled to at least one of the heaters; a collecting arrangement configured to draw in at least some of the warmed effluent including the liquified FOG out of the effluent containing zone for further treatment, processing and/or separation, wherein the collecting arrangement includes a weir or overflow arrangement to draw in the liquified FOG from the effluent containing zone; and a fluid inlet configured to direct fluid towards the collecting arrangement, wherein the fluid inlet is configured to receive warm fluid and direct the warm fluid around the collecting arrangement, thereby simultaneously to warm the effluent and liquify the FOG further and to clean or flush the collecting arrangement. a reservoir defining an effluent containing zone; and a FOG collector provided in the reservoir in the effluent containing zone, the FOG collector including: a plurality of floating members which are configured operatively to float in the effluent containing zone; a plurality of heaters configured to warm effluent in the effluent containing zone, thereby liquifying, at least partially, FOG in the effluent, wherein the floating members and heaters are arranged in a plurality of groups, each group including at least one of the floating members coupled to at least one of the heaters; a collecting arrangement configured to draw in at least some of the warmed effluent including the liquified FOG out of the effluent containing zone for further treatment, processing and/or separation, wherein the collecting arrangement includes a weir or overflow arrangement to draw in the liquified FOG from the effluent containing zone; and a fluid inlet configured to direct fluid towards the collecting arrangement, wherein the fluid inlet is configured to receive warm fluid and direct the warm fluid around the collecting arrangement, thereby simultaneously to warm the effluent and liquify the FOG further and to clean or flush the collecting arrangement. a plurality of floating members which are configured operatively to float in the effluent containing zone; a plurality of heaters configured to warm effluent in the effluent containing zone, thereby liquifying, at least partially, FOG in the effluent, wherein the floating members and heaters are arranged in a plurality of groups, each group including at least one of the floating members coupled to at least one of the heaters; a collecting arrangement configured to draw in at least some of the warmed effluent including the liquified FOG out of the effluent containing zone for further treatment, processing and/or separation, wherein the collecting arrangement includes a weir or overflow arrangement to draw in the liquified FOG from the effluent containing zone; and a fluid inlet configured to direct fluid towards the collecting arrangement, wherein the fluid inlet is configured to receive warm fluid and direct the warm fluid around the collecting arrangement, thereby simultaneously to warm the effluent and liquify the FOG further and to clean or flush the collecting arrangement. <EOS>