Using off-gas testing to map mixing gradients and audit blower capacity.

A water resource recovery facility sited in a region at a high elevation has experienced the effects of over-designing its blowers. In this case study, we used off-gas analysis and site-specific power tariffs to quantify actual process loading and air requirements, and we quantitatively evaluated various options for blower replacement or upgrade. Off-gas analysis mapped the oxygen uptake rate at the surface of the tank, suggesting that the tanks were not evenly loaded across their sections.

Assessing cost-effective nutrient removal solutions in the urban water system.

Many states are adopting more stringent nutrient load restrictions, requiring utilities to invest in costly improvements. To date, substantial research has been done to independently assess the nutrient removal efficacy of wastewater treatment technologies and stormwater control measures. The analysis presented here provides a unique assessment by evaluating combinations of nutrient load reduction strategies across water supply, wastewater, and stormwater sectors.

Development of generalized empirical models for comparing effectiveness of wastewater nutrient removal technologies.

The effectiveness of nutrient removal approaches was quantified at four wastewater treatment facilities (WWTFs) using mechanistic models. Generalized empirical models were developed applying statistical methods on the predicted values characterizing nutrient removal as a function of influent wastewater quality. The empirical models provide a framework to estimate nutrient removal effectiveness and inform system-level decisions on technology adoption.