Sustainable solutions for organic waste management: nitrogen emission reduction in parallel with greenhouse gases

氨挥发是一种主要的大气污染物，导致氮在影响水生生态系统、土壤二氧化碳排放和敏感作物的地点以一定速率沉积。超过70%的氨排放来自有机废物管理，特别是牲畜粪便。在未来，更多的食物垃圾堆肥将增加氨挥发。厌氧消化是一种解决方案，但生产者承诺需要一个清洁的食物垃圾来源。随着过去的技术发展，可持续地管理有机废物和废水，本研究的目的是引入减少氨挥发的系统。更具体地说，拟议的研究将进一步开发一种可行的系统，即储存-厌氧-消化（ISPAD），减少牲畜粪便等储存超过100天的废水中的温室气体、气味和氨的排放。该研究将开发一种酸化方法来处理ISPAD中保留的粪肥，这样，一旦移走用于土地扩散，氨的挥发就会受到限制。研究将：建立猪粪中铵和氨的平衡常数，作为温度和pH的函数，因为这个常数不同于水的平衡常数；然后，测量猪粪缓冲能力（抗酸化能力）及其根据所使用的动物饲料的变化；然后，找出各种粪便处理（包括降低铵含量）去除了多少缓冲能力；最后，测试ISPAD条件，以充分酸化处理过的粪便。同时，可以开发铵回收系统来生产肥料。除了可持续发展方案外，还建议开始开发一种系统，以便生产者以最小的努力对食物废物进行清洁来源分离。此外，将寻求减少堆肥氨挥发的策略。拟议研究的意义在于将加拿大的氨排放量减少50%，并将这项技术推广到世界各地，例如欧洲，那里的N沉降也是一个主要问题。如果转化为肥料，这种氮的节约可以减少北美和欧洲天然气使用量的6-7%。

Ammonia volatilization is a major atmospheric pollutant resulting in the deposition of nitrogen at rates in locations affecting aquatic ecosystems, soil carbon dioxide emissions and sensitive crops. Over 70% of ammonia emissions originate from organic waste management, especially livestock manures. In the future, more food waste composting will increase ammonia volatilization. Anaerobic digestion is a solution but producer commitment is required for a clean source of food waste. Along with past technologies developed to sustainably manage organic wastes and wastewaters, the aim of the present research is to introduce systems attenuating ammonia volatilization. More specifically, the proposed research will further develop a feasible system, In-Storage-Anaerobic-Digestion (ISPAD), reducing greenhouse gas, odour and ammonia emissions from wastewaters stored over 100 days such as livestock manures. The research will develop an acidifying method for the manures retained in ISPAD such that, once removed for land spreading, ammonia volatilization is limited. The research will: establish the equilibrium constant between ammonium and ammonia in swine manures, as a function of temperature and pH, because this constant differs from that of water; then, measure swine manure buffer capacity (resistance to acidification) and its variability depending on the animal feed used; then, find how much buffering capacity is removed with various manure treatments, including lowering ammonium levels; finally, test ISPAD conditions required to adequately acidify the treated manure. In parallel, an ammonium recovery system can be developed to produce fertilizers. In addition to ISPAD, it is proposed to initiate the development of a system for the clean source separation of food waste with minimum producer effort. Also, strategies to reduce ammonia volatilization from compost will be pursued. The significance of the proposed research is to reduce ammonia emissions in Canada by 50%, and to extend this technology to the world, such as Europe where N deposition is also a major concern. If transformed into fertilizers, this nitrogen conservation can drop by 6-7% of the use of natural gas in North America and Europe.