欧洲标准通过促进整个循环和可持续发展帮助欧洲实现循环经济的目标。农业是欧洲经济最大的经济部门之一,但同时也是各类污染物的源头。因此欧洲标准化对于确定特定农业领域内的环境友好型工具和方法(如使用淤泥,特别是污水和污泥)方面至关重要。
污泥是城市废水处理中产生的有机副产物,富含营养物,可用作肥料或有机土壤改良物,前景广阔。但它通常富含重金属和难以生物降解的有机化合物、药物和个人护理物成分以及可能致病的有机物。所以,为避免对环境和人体健康产生危害,污泥必须经过充分处理和试验才能在农田施用。在欧洲,《欧盟污水污泥指令》(86/278/EEC)鼓励将污泥用于农业,并对其施用进行规范,以免产生不利影响。
不是所有的欧洲国家都在农业生产中施用污泥,但在《城市污水处理指令》、《污泥施用指令》这些(有关)环境保护特别是土壤保护的欧盟指令推动下,欧洲的污泥产量总体在上升。预计到2020年其产量有望达到1300万吨。
根据欧盟委员会2017年提交给欧洲议会的报告,欧洲的农业污泥施用量大约是其产量的45%。研究显示,正确施用污泥能回收氮、磷等植物营养元素,从而产生效益。因此,污泥能够替代化肥。
一、针对污泥的欧洲标准化工作
在标准化层面,CEN有关“污泥特征描述和管理”的CEN/TC 308技术委员会正在制定用于污泥特征分析的抽样方法以及物理、化学和生物分析法,以加快确定特定污泥的处理工序和对应的施用场景。
CEN 308技术委员会(CEN/TC 308)专门针对污泥的农业应用提出了技术报告:CEN/TR 13097:2010
二、污泥特征分析–污泥农业应用范例
这份技术报告包含了污泥的农业应用规范。任何种类污泥的施用都应遵循规范,得到最大化的作物或土壤效益,把潜在的环境污染风险以及对植物、动物、人体的不利影响降到最低,从而保证较高的可持续性、能源效率和成本效益。
Sludge, an added-value for a cleaner agriculture
European Standards help Europe to achieve its objectives of a circular economy by contributing to recycling and sustainability at large. Agriculture is one of the biggest European economic sector, but is still the origin of different sources of pollution. Hence, European standardization is essential for agriculture in defining tools and methods that are environmental-friendly in specific agricultural domains, such as the use of sludge, mainly sewage sludge.
Sewage sludge is the organic by-product of urban wastewater treatment, which has a lot of potential as a source of nutrients to be spread on land as a fertiliser or an organic soil improver. The sludge tends to concentrate heavy metals, poorly biodegradable trace of organic compounds, of pharmaceutical and personal care products, as well as of potentially pathogenic organisms that are present in waste waters. Therefore, it has to be sufficiently treated and carefully used before it can be applied on farmland to prevent any harmful effect on the environment and on human health. In Europe, the European Union Sewage Sludge Directive (86/278/EEC) encourages the use of sewage sludge in agriculture and regulates its use in such a way as to prevent harmful effects.
Not all European Countries use sewage sludge in agriculture. However, the production of sewage sludge in Europe is generally increasing under the impulse of European Union Directives such as the ‘Urban Waste Water Treatment Directive’ and the ‘Sewage Sludge Directive’ on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture. It is expected to approach 13 million tons of production in 2020.
The use of sewage sludge in agriculture in Europe corresponds to approximately 45 % of the amount of sludge produced (following a report from the European Commission to the European Parliament issued in 2017). Following studies, the good application of sewage provides benefits in the recycling of plant nutrients such as nitrogen and phosphorus. Sludge can therefore replace chemical fertilisers.
European standardization work on sludge
At standardization level, our CEN Technical Committee CEN/TC 308 on ‘characterization and management of sludge’ is developing sampling methods, physical, chemical and biological analyses required for characterizing the sludge with a view to facilitating decisions on the choice of the treatment procedures and of the utilization.
CEN/TC 308 produced a Technical Report specifically related to agricultural uses of sludge:
CEN/TR 13097:2010
Characterization of sludges – Good practice for sludge utilisation in agriculture
This Technical Report describes good practice for the use of sludge in agriculture (where regulations allow). The use of all types of sludge should follow good practice to maximise benefits for the crops or soils, to minimise potential risks of environmental contamination and adverse impacts on plant, animal and human health, and to ensure sustainability, energy efficiency and cost-effectiveness.