As technology advances, new opportunities emerge for revenue that were not considered when the billing system was selected.  A Washington County sewer utility found a way to get rid of some of its most troublesome pollutants: sell them to gardeners.  Clean Water Services installed a system at its Durham treatment plant that pulls phosphorus and ammonia from sewage waste and processes them into fertilizer pellets that are then sold to nurseries. The system, which began operating last month, is the first of its kind in the United States, and it’s drawing some big-name attention.  Let’s hope their billing system can handle it.