Wray, Colorado BiO2 Solution™ Pilot Project
Prior to the summer of 2008, the City of Wray, Colorado was experiencing problems with sludge accumulation, odor and effluent quality at its wastewater facility. The existing mechanically aerated, three cell lagoon system was not meeting effluent discharge permit limits and experienced high operational costs.
The City’s Engineer explored several alternatives in an extensive search to find a solution that did not exhaust city funds or require the need to raise sewer rates. Ultimately, The BiO2 Solution™ system provided the best option based on substantially lower capital and lower operational costs.
Figure 2 and Figure 3 summarize the information developed by the Engineer for the City of Wray. The data is based on 2007 prices for the design, construction and operation of a 0.50 MGD wastewater treatment facility. The analysis includes information for lagoon remediation systems as well as mechanical alternatives. Costs are included on a per gallon basis and for total project costs.
Figure 2 - Comparison of Capital Cost Alternatives
NRC = Nutrient Removal Components
Figure 3 - Comparison of Operational Cost Alternatives
NRC = Nutrient Reduction Component
- Compliance with permit discharge requirements
- Elimination of odor
- Greater than 50% reduction of electrical costs
- Substantial reduction of sludge deposits
- Reduction of personnel time at wastewater plant
- Operator's licensing requirements kept at same level
Nutrient Removal
A side stream test was conducted in July, 2011, at the Wray, Colorado facility using an electrocoagulation (EC) unit. The unit successfully reduced ammonia, phosphorus and total nitrogen. Results from the operation of the EC unit were not affected by water temperature or altitude. A summary of the nutrient removal efficiencies is shown in Figure 4.
| NH3 | NO2NO3 | Total P | TKN | |
|---|---|---|---|---|
| Influent to EC | 0.47 | 1.90 | 3.03 | 8.3 |
| Effluent from EC | 0.10 | 0.94 | 0.12 | 1.2 |
| % reduction | 78.72 | 50.53 | 96.04 | 85.54 |
Short Circuiting
Fabric baffle curtains were installed in November, 2011, to eliminate short circuiting issues which affected the primary and secondary lagoon cells. Testing completed after the installation of the baffle curtains demonstrated immediate and substantial improvement in the operation of the lagoon system.
