Piles fail to heat for two reasons there is either too little biological activity, or the heat generated by biological activity is lost as fast as it is produced. The latter situation is not common in large scale composting. It may occur with small piles during cold weather. As shown in Table 1, there are many possible causes for reduced biological activity. Nearly all of the causes are related to the essential microbial needs discussed earlier.
Factors related to poor aeration are common as well.
Odor Problems Odors can present health and safety issues within contained areas at composting facilities. For example, ammonia concentrations can potentially reach levels that would not pass OSHA standards. However, more frequently, odors are a nuisance problem. VOAs are heavier than air, tend to stay close to the ground and can travel for miles. Somebody down wind is going to know when VOAs are being generated in abundance.