This Lagoon treatment process usually works well for wastewater treatment in small communities; however, the regulated effluent quality is not always met. The most frequent problems are elevated BOD5, TSS and ammonia (where regulates), and high or low pH. Also odor from lagoons can be a problem. Troubleshooting lagoons for effluent quality problems is not straightforward as the biological and chemical process involved are numerous and complex and not fully understood by most engineers and operators. In this course all the above will be discussed along with troubleshooting keys and solutions.