An important research direction in the field of district heating and cooling (DHC) systems is to enhance the flexibility of the networks by increasing their capability to integrate different heat sources and sinks. Reducing the network temperature to adequate levels (below 40°C) and using reversible heat pumps reduces the heat losses and enables consumers to exchange heat with the network in both directions, thus becoming prosumers. Moreover, this concept unlocks the potential of low-grade, locally available heat sources such as waste heat. However, when the share of uncontrolled, decentralized heat supplied to the network is high, a suitable control system must be present to guarantee a correct hydraulic and thermal balance of the system. In the current paper, a low-temperature district heating system specifically designed for the south-west district of the Danish city of Aarhus, consisting of 22 aggregated consumers with an estimated peak load of 6 MW, is used as a case-study to investigate the integration of prosumers in heating networks. The main heat supply of the considered system consists of a CHP (gas-fired internal combustion engine) coupled with a hot water tank and of an auxiliary gas boiler. These units are owned and operated by the network manager. Additionally, two substations supply waste heat to the network; however, the network manager does not control them directly. To schedule the operation of its own supply stations, the network manager uses forecasts of heat load, waste heat availability and electricity prices. The goal is to minimize the cost of the overall heat generation mix of the DH system. This control problem is modelled as a mixed integer linear programming (MILP) optimization problem, which is solved in a rolling horizon scheme. An economic performance indicator is used to evaluate the performance of this advanced control method compared to a basic control based only on local feedbacks from the system.