RTW >Engineering Services > Dolores
Dolores Water Treatment Plant
Tetra Tech RTW provided planning, evaluation, design, and construction engineering services for a water treatment plant with adequate capacity and treatment capabilities to handle the widely variable raw water turbidities of the Town's water supply, the source of which was the Dolores River. Tetra Tech RTW's approach was to modify the conventional water treatment concept by revising the inlet and outlet piping to the existing facility onsite ponds to take advantage of the two-day detention time for presettling and to provide for addition and mixing of alum with the flowstream prior to the ponds. Pretreating the water before entrance to the main part of the plant reduced turbidity loads to levels treatable by an adsorption clarification system and good mixed-media filtration. Adsorption clarification was used because it efficiently and easily operated at loading rates considerably higher than normal clarification facilities. This increased loading allowed for a reduction in building size necessary to house the facility.
After construction was completed, the plant was able to consistently produce water with turbidities of less than 1 unit, as compared to previous turbidity levels in excess of 30 units.