Research on recovery of nitrogen released in composting process

在堆肥过程中，氨气体在井下消化期释放。另一方面，低脂肪酸易在堆肥初期产生，因为其消化速率高于供氧速率，释放出的氨气不仅造成环境污染，而且还会造成氮素资源的损失。如果能回收氨或将其吹入产生脂肪酸的堆肥中，1)解决了环境污染问题，2)减少了堆肥中的氮素损失，3)通过中和提高了消化速度。本研究为利用堆肥本身作为吸附介质回收释放的氨气提供了基础知识。1)堆肥过程中氨气释放造成的氮素损失达到原料氮素的50%；2)堆肥可吸附氨量与水/干固体比和酸浓度呈线性关系；3)堆肥填充塔去除氨气的量与气体浓度无关。4)吸附氨气即使控制在最适的pH和温度范围内，在第一消化阶段也很难硝化，因为堆肥中的液态氨浓度远高于最适范围。

In composting process, ammonia gas is released in well digesting period. On the other hand, low fatty acids tends to generate in initial period of composting, because of higher digestion rate than oxygen supply rate.The released ammonia gas causes not only environmental polution but also lossof nitrogen as a resource. If it is abailable to recover ammonia or to blow it into the compost generating fatty acids, it well 1) solve environmental pollution problem, 2) minize the nitrogen loss in compost and 3) promote the digestion rate by neutralizing in pH.The research has conducted to get fundamental knowledge to recover the released ammonia gas by compost itself as adsorption media.The results are as follows;1) The loss of nitrogen by releasing of ammonia gas in composting process reaches 50% of nitrogen in raw material.2) Adsorbable ammonia quantity by compost is linear both to water/dry-solid ratio and acid concentration.3) The removable ammonia gas quantity by compost-packed-tower is independent from gas concentration.4) The adsorbed ammonia is hardly nitrified in first digestion period even if it is controlled in optimal pH and temperature range, because the ammonium concentration in liquid phase of the compost is much higher than optimal range.