Due to the rapid spread of the Internet, energy saving becomes important issues of ICT area. Particularly, a significant part, around 70%, of overall internet energy consumption is consumed by access networks. However, some studies show that TDM-PON (Time Division Multiplexing - Passive Optical Network) are low utilized in most of the day, which is major part of access networks. Most energy saving solutions in TDM-PON consider downlink traffic only. In that case when uplink traffic comes to ONU, ONU`s sleep is interrupted. It imposes extra energy consumption due to frequent sleep mode transition. Also, as downlink and uplink are managed independently, there would be additional control message overhead than the cases where both uplink and downlink are managed together. To solve this problem, some researches propose synchronized uplink and downlink transmission. But these solutions do not take into account traffic delay requirement. In this study, it has been found that there are still room to save energy in those solutions. In this paper, Delay Aware Synchronous Bidirectional Transmission (DASBT) Scheme for Energy-Efficient TDM-PON is proposed. In detail, novel sleep interval decision algorithm is proposed that considers the uplink and downlink traffic conditions, and delay requirements. In addition, the uplink and downlink traffic is transmitted at the same time to reduce energy consumption. Simulation results show that proposed scheme minimizes energy consumption up to 15% in comparison with previous schemes.