Driven by EU and national environmental legislation, Romania is mid-way through a 10 year wastewater treatment investment bonanza and the volume of sewage sludge is rocketing. In 2010 the country generated 97,000 tonnes of sludge. By 2018 the quantity will exceed 400,000 tonnes. Appointed by the government, we have drawn up a strategy to guide management of this waste stream.
The strategy mapped out alternatives, identifying seven cement kilns capable of using dried sludge as a fuel, plus four sites where waste to energy sludge incinerators could be built. Using anaerobic digestion or thermal treatment technologies to produce combustible biogas are attractive options. And sludge can be spread on agricultural land to replenish and improve soil.
A fifth of agricultural land is suitable for sludge application, the criteria being a gradient of less than 10% and alkaline soil. However, crops must be compatible with sludge disposal and land must be close enough to a wastewater treatment facility for cost-effective transport. In parts of the country concentrations of heavy metals in the sludge are too great to allow agricultural use.
Alongside the management strategy we developed a communication plan explaining agricultural sludge reuse to farmers and the wider public. This was accompanied by workshops and trials to demonstrate benefits. Wastewater companies are sharing information and expertise so that entrepreneurial successes can be copied and adapted country-wide. With less than 1% of sludge going to agriculture in 2012, the aim is to dispose of 50% in this way by 2019. Entering the next decade, it is hoped that waste to energy facilities will be up and running, usefully diverting the other half from landfill.