糖蜜发酵工业废液农用的环境安全风险

糖蜜是甘蔗或甜菜制糖工业的一种副产物。糖蜜发酵工业主要指制糖工业的下游工业中以糖蜜为发酵原料的酒精和酵母等发酵工业。在糖蜜发酵酒精和酵母过程中可产生大量废液（即糖蜜发酵工业废液）。出于对这类糖蜜发酵工业废液的资源化利用考虑，很多产糖国（如巴西、印度和中国等）都有将这类废液以直接土地处置方式用于农作物灌溉施肥或土壤改良。由于糖蜜发酵工业废液属于处理难度大的高浓度有机废水，还属于多种重金属污染废水，随着一些产糖国对糖蜜发酵工业废液的长期农田处置，所引发出土壤-作物-水系生态环境问题也日益暴露。目前，我国部分企业以这类废液为原料生产有机水溶肥料，其产品在水溶肥市场上占一定比重（约占32%），但对这类废液长期农用的环境安全风险研究及其监测数据尚不充足。本文收集了1980年以来国内外公开发表的关于糖蜜发酵工业废液水质污染特征及其农用的环境影响等相关科研文献，通过对相关研究数据调研和综述分析，评估糖蜜发酵工业废液农用的环境安全风险：（1）糖蜜发酵工业废液水质严重超标，且具有生态毒性特征。这类废液含高负荷有机污染物、强酸性、高盐度，并含多种重金属等污染物，除As、Hg、Cd、Pb和Cr等5种重金属外...

Environmental Safety Risks in Agricultural Application of Effluents from Sugar Molasses-Based Fermentation Industries

Sugar molasses is a by-product from sugar industries. The sugar molasses-based fermentation industries mainly refer to the fermentation industries using molasses from sugar mills as raw materials for alcohol or yeast fermentation. A large volume of effluents can be produced in the process of sugar molasses-based alcohol or yeast fermentation. Considering the possibility of resource utilization with such effluents, many sugar-producing countries (such as Brazil, India, and China) use the effluents for crop irrigation and fertilization or soil remediation directly into the farmlands by waste disposal methods. Because the effluents from sugar molasses-based fermentation industries are both high concentration organic wastewater, and heavy metal-polluted wastewater, which are difficult to be treated. With the long-term disposal of such effluents into the farmlands in some sugar-producing countries, the problems about ecological environment pollution in soil-crop-water systems are increasingly exposed. At present, some fertilizer production enterprises in China use such effluents as raw materials to produce organic water-soluble fertilizers (accounting for 32%), but the long-term research and monitoring data about environmental safety risks for agricultural application of the effluents from sugar molasses-based fermentation industries are still lack. This paper collected the relevant scientific research literatures since 1980 on the pollution characteristics of the effluents from sugar molasses-based fermentation industries, and their environmental impacts on agricultural application. Through the investigation and review on the relevant research data, this paper evaluated the environmental safety risks for agricultural application of the effluents from sugar molasses-based fermentation industries: (1) Such effluents were at a risk of seriously exceeding the limits for water quality standards, and a risk of ecotoxicity to plants. For example, such effluents had strong acidity, and high salinity, and contained not only high load organic pollutants, but also several heavy metals including 5 heavy metals (As, Hg, Cd, Pb and Cr), as well as other pollutants (such as Mn, Cu, Zn, Ni and Se, etc.). The concentrations of these pollutants mostly exceeded the limits of the Standards for Irrigation Water Quality (GB 5084—2021). (2) Such effluents for agricultural application were at a risk of farmland pollution. The concentrations of pollutants (such as Cu, Cd, Cr, Zn, Ni, Mn, Pb and Cl) detected from the soil samples irrigated with such effluents were about 10-641 times higher than those in the control soil. (3) Such effluents for agricultural application were at a safety risk of agricultural products. The concentrations of pollutants (such as Cu, Cd, Cr, Zn, Ni, Mn and Pb) detected in the grains of crops (wheat and mustard) irrigated with such effluents were about 3-12 times higher than those in the control crops, in which all the pollutants detected in the crops irrigated with such effluents exceeded both the allowable limits specified by FAO/WHO, but also the Maximum Levels of Contaminants in Food (GB 2762—2017) specified by China. In view of the issue of environmental safety risks for agricultural application of such effluents, therefore, it is necessary to strengthen the quality detection and risk control on the organic water-soluble fertilizer products with such effluents as raw material, to enable the safety of effluent utilization in agriculture.