Until now, the design and development of wastewater treatment plants (WTTPs) has been primarily aimed at optimising the efficiency of the treatment of wastewater, as measured by the quality of the effluent. However, recently, it has started to be recognised that municipal wastewater might be a valuable source of energy and minerals such as phosphates, thus potentially contributing to the closing of material and energy life cycles - cradle-to-cradle. To date, however, no economically viable process has been developed.
The treatment of wastewater requires energy. However, the Dutch water boards have targeted a new technological approach that should make WWTPs net energy producers rather than consumers. They have demonstrated that methane production by digestion of sludge can alter the energy profile of the process. However, the economic costs involved in this process outweigh the benefits, presenting a major obstacle to its implementation.
Phosphates are an essential precondition for food production. However, present rates of consumption suggest that the natural resources risk being exhausted in just 50-100 years time. Globally, 14.9 million tonnes of phosphate are yearly abstracted from natural resources. On average, 20% of this abstraction ends up - via food production and human faeces - in wastewater. An economically viable procedure to recover phosphate from wastewater, would significantly decrease the pressure on the limited natural resources.
The main objective of the OMZET project is to develop a new approach to wastewater treatment that will demonstrate net energy production, optimal recovery of phosphates and economic viability. Its main innovation will be to implement an extra de-nitrification process for the reject water coming from sludge dewatering. The beneficiary will seek to demonstrate its innovative water treatment approach - called "OMZET" - in a municipal wastewater treatment facility. It specifically aims to increase the energy self-sufficiency of the process and recover phosphate, whilst maintaining the high effluent quality. The hydrolysis of biomass will also lead to a significant reduction in sludge production and the associated costs of transporting and incinerating sludge. The combination of energy savings, phosphate recovery and the reduction of sludge requiring additional treatment offer significant overall economic advantages.
The project aims to demonstrate the cost effectiveness and economic viability of the OMZET process by reducing the operational costs for wastewater treatment by 15%. The project expects to demonstrate the high replication possibilities for OMZET in both new and existing wastewater treatment plants across Europe. It will network to disseminate its results and awareness of the new process. It also hopes to contribute to the achievement of European objectives and the development of policy with regard to: waste reduction; recovery of phosphate and limiting of the exhaustion of natural resources; limiting the environmental footprint of WWTPs; reducing CO2 and other greenhouse gas emissions; and improving surface water quality, as required by the Water Framework Directive.
Increase biogas production by 60%; Recover up to 80% of phosphates; Reduce sludge production by 17%; Reduce WWTP operational costs by 15%; and Maintain high effluent - and therefore surface water – quality.