Technical Research Centre of Finland, P.O. Box 1603, 40101 Jyväskylä, Finland E-mail:
Lurederra Technological Centre, Area Industrial Perguita, Calle A, 31210 Los Arcos, Spain.
Water Sci Technol. 2021 Sep;84(6):1389-1402. doi: 10.2166/wst.2021.326.
Intense pressure on water resources has led to efforts to reuse reclaimed processing wastewater in the food industry. There are tight rules for water quality, but efficient separation technologies such as reverse osmosis possess good possibilities for water reuse. This study developed a membrane-based reuse water concept for wastewater from the candy industry emphasizing the pre-treatment stage in the concept to reduce fouling. The wastewater contained suspended solids, sugar compounds and the ingredients for candy gelation, which had a tendency to foul membranes, making pre-treatment essential for a successful concept. Cross-rotational ultrafiltration, which featured enhanced fouling prevention for membranes, functioned well for the removal of challenging substances. Conventional filtration technologies were impractical due to a low flux, even when the viscosity of the wastewater was reduced using surfactants. The wastewater had a high chemical oxygen demand, meaning that there was a strong fouling potential for reverse osmosis membranes, but also high osmotic pressure. A spiral wound reverse osmosis functioned well when the wastewater was pre-treated, and it produced good quality water with respect to all the other studied parameters except the chemical oxygen demand. However, chemical oxygen demand rejection was 99% since the concentration in the wastewater was originally very high.
水资源压力巨大，促使食品行业开始尝试重复利用经处理的回收废水。尽管对水质有严格的规定，但反渗透等高效分离技术在水再利用方面具有很大的潜力。本研究为糖果工业废水开发了一种基于膜的再利用水概念，该概念强调预处理阶段，以减少结垢。废水中含有悬浮固体、糖化合物和糖果胶凝成分，这些物质容易使膜结垢，因此预处理对于成功的概念至关重要。交叉旋转超滤技术对膜具有增强的防污性能，可有效去除具有挑战性的物质。由于通量较低，即使使用表面活性剂降低废水的粘度，传统的过滤技术也不实用。废水的化学需氧量很高，这意味着反渗透膜有很强的结垢潜力，但渗透压也很高。当废水经过预处理时，螺旋缠绕式反渗透装置运行良好，除化学需氧量外，其他所有研究参数的产水水质都很好。然而，由于废水中的浓度本来就很高，化学需氧量的去除率达到了 99%。
