F. Silva

Biochars in soils: towards the required level of scientific understanding

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar’s effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar’s contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.

Molasses as an external carbon source for anaerobic treatment of sulphite evaporator condensate.

Failures in stability and COD removal performance often occurred in full-scale anaerobic reactors treating the evaporator condensate from a sulphite pulp mill due to substrate inhibition and occasional contaminations with red liquor (wood cooking liquor). With this work, the beneficial effect provided by the continuous addition of an external carbon source (sugarcane molasses) on the overall performance and stability of the biological process was evaluated. With a moderate addition of molasses the inhibition was mitigated which led to an increase of the COD removal rate from 52% to 77% and a methane production increase from 460 to 1650mld(-1) at an organic loading rate of 2.61g CODl(-1)d(-1). A similar conclusion can be drawn for the case when contamination with red liquor occurs. These results suggest that sugarcane molasses addition may be regarded as a low-cost operational strategy for the anaerobic treatment of sulphite evaporator condensate.

Acidogenic Valorisation of High Strength Waste Products from Food Industry

Awareness concerning the environment and the use of clean technologies is growing worldwide. As a consequence, research on biodegradability and use of renewable resources for industrial processes has been intensive in the last years. In addition, product and process innovation in food industries is widely regarded as an essential element of competition between food companies, as it will improve their business performance. To face these new challenges, relevant changes in the food manufacturing processes may occur, involving for example the use of different raw materials as an ingredient in new food products. As a result, food processing wastewater will contain complex organic compounds with refractory properties that may compromise the biological treatment processes already existing in the wastewater treatment plants (WWTP) and consequently the fulfilment of legal requirements for wastewater discharge. To overcome this situation, segregation of specific wastewater process streams with refractory characteristics and its individual pre-treatment will be important for a viable and stable treatment in the already existing WWTP.