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。未来，更多的餐厨垃圾堆肥将增加氨挥发。厌氧消化是一种解决方案，但需要生产者承诺才能获得清洁的食物垃圾来源。除了过去开发的可持续管理有机废物和废水的技术外，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个可行的系统，即储存-厌氧-消化(ISpad)系统，减少储存100天的废水(如牲畜粪便)的温室气体、气味和氨排放。这项研究将为iSpad中保留的粪便开发一种酸化方法，这样一旦被移到土地上传播，氨的挥发就会受到限制。这项研究将：建立猪粪中铵和氨之间的平衡常数，作为温度和pH的函数，因为这个常数不同于水；然后，测量猪粪的缓冲容量(耐酸性)及其随所用动物饲料的变化；然后，找出各种粪便处理(包括降低氨水平)后缓冲容量的减少程度；最后，测试充分酸化处理后的粪便所需的iSpad条件。同时，可以开发一种氨回收系统来生产化肥。除iSpad外，还提议开始开发一个系统，以最小限度地减少生产者的工作量，实现厨余的清洁来源分类。此外，还将寻求减少堆肥中氨挥发的策略。这项拟议的研究的意义是将加拿大的氨排放减少50%，并将这项技术推广到世界各地，例如欧洲，那里的氮沉积也是一个主要问题。如果转化为化肥，这种氮素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.