ABSTRACT
A comparative assessment of the risks of the three current wastewater effluent disposal options and three other potential options was conducted for Southeast Florida communities. The question was how the risk to humans from the use of potable reuse compares to the other five available wastewater disposal alternatives. The need for this type of risk assessment is due to the potential to use potable reuse as a water supply and the potential resistance from the public as a result of such a proposal. Water quality data relevant to disposal of wastewater treatment plant effluent from South Florida utilities along with water quality data on the receiving waters and drinking water standards were obtained for the project. The comparison of the public health risks associated with these disposal alternatives indicated that health risks associated with deep wells and direct potable reuse were generally lower than those of the other alternatives.
ABSTRACT
Struvite accumulation is a costly problem in many water resource recovery facilities (WRRFs) that use anaerobic digestion, causing significant labor and equipment costs and potentially impacting facility performance and permit compliance. A comprehensive study was undertaken to evaluate possible solutions to struvite control at two similar Miami-Dade County, Florida, WRRFs. Alternatives analyzed included periodic cleaning and repair of damaged piping and equipment; optimum ferric salt dosing, use of in situ scaling coupons; and engineered struvite precipitation. The effectiveness and cost of each alternative was evaluated using a newly constructed dynamic process model and a net present worth analysis. Results indicate that nutrient recovery was a potential benefit at both facilities. This study establishes a comprehensive process and specific testing protocols for evaluating struvite control alternatives.
