Towards Real-time sludge dewatering process optimization using ultraviolet-visible spectrophotometry and torque rheology

The treatment of biosolids is becoming a larger focus of wastewater treatment facilities due to the growing associated costs and optimization potentials. Presently, most operations are controlled manually, which often results in sub-optimal process performance. The goals of this research were to develop systems to optimize sludge treatment processes. The first study in this thesis analyzed and improved the sensitivity of UV-Vis spectrophotometry for the detection of polymer in dewatered sludge supernatant. The second study developed a two-stage in-line and real-time optimum polymer dose monitoring system. This system employed torque rheology as the upstream monitor and UV-Vis spectrophotometry as the downstream monitor relative to the dewatering process. Laboratory scale experiments found the system to be generally reliable and accurate. The third study developed a method for nutrient recovery optimization in sludge supernatant after dewatering. This method employed UV-Vis spectrophotometry as a monitor for struvite formation through magnesium addition.