The WSA that Carollo has conducted at water treatment plants across the country have helped many of our clients meet regulatory, hydraulic, aesthetic, and performance goals. The major components of a WSA are described below.
Carollo personnel evaluate the impact of all relevant water quality parameters on existing plant performance. Our process experts work with plant personnel to investigate historical trends in the source water quality and their impact on operational performance and finished water characteristics. We often use this expertise to determine the impact that source water quality may have on possible processes used to improve plant performance.
Carollo analyzes historical finished water quality data regarding current and future regulations. Our regulatory experts have drafted parts of the Proposed Long Term 2 Enhanced Surface Water Treatment Rule, as well as a significant portion of the UV Disinfection Guidance Manual. As a result, we have an understanding of these documents and other regulations that few other companies can claim. Using this insight, along with our process expertise, our experts work hand in hand with our clients to ensure that their utilities meet or exceed all regulatory requirements.
Conventional operations typically include coagulation, flocculation, and often sedimentation, as well as pre-oxidation. As part of our Conventional Operations Assessment, we begin with a thorough review of influent water quality, design criteria and historical performance data. Using this information, we then tailor and perform a series of tests specific to each utility allowing us to optimize a wide range of process operational parameters. The results of this testing are enhanced process performance, often at a cost less than that observed before the optimization.
At many water treatment plants, filter performance has the greatest impact on finished water quality. In order to assess filter performance, we perform several tasks that allow us to evaluate a wide range of topics, from operational parameters to structural components. Some of these include: historical review of turbidity and particle count data, filter coring (floc retention profiles, sieve analysis and media compatibility), gravel bed profiling, and filter waste washwater turbidity profiles.

Oxidation and disinfection processes play a vital role in plant performance, maintaining high aesthetic water quality and ensuring public health. However, systems that are not optimized can lead to problems in any or all three of these areas. Carollo’s staff, combined with our state-of -the-art laboratory and equipment, gives us the ability to perform a wide range of oxidation and disinfection related tests including: pre-oxidation evaluations, disinfectant demand/decay tests, disinfection byproduct formation assessments, microbial challenge studies, and UV implementation assessments.
The following case studies are just a few examples of the work we have completed.

Oklahoma City The facility audit at Draper Water Treatment Plant included modeling the hydraulics of the plant and bench-scale evaluations of the various chemical process strategies. A process audit detailed the individual unit process strengths, weaknesses, and capacities in order to facilitate expansion in the most reliable and cost-effective manner, while the regulatory review examined current and anticipated regulations in order to provide Oklahoma City with flexibility to easily modify the process and achieve future compliance needs. The plant evaluation resulted in a $7 million savings in the 15-year net present value cost, and allowed the plant a capacity increase of 65 percent to 150 mgd. Water quality was improved, while preserving the necessary reliability and redundancy in plant operations.

Tempe As part of a filter evaluation study, Carollo staff performed core sampling, floc retention profile analysis, filter waste washwater turbidity profiles, and turbidity/particle count breakthrough evaluations. We also completed a series of bench-scale tests to determine the optimal conditions to treat the Filter Waste Washwater (FWW). The results of these tests helped define the design criteria for chemical addition, flocculation, and clarification procedures, which is especially important because the FWW at the plant is discharged to a “greenline” located in a public recreation area.

Palmdale Palmdale Water District hired Carollo to review a plant evaluation done by another consultant and perform our own WSA to determine treatability of the water and diagnose problems. Carollo’s evaluation included jar testing under a range of water quality, pH, and temperature conditions; filter evaluations; and a comprehensive review of the condition and performance of all plant facilities. Carollo recommended that Palmdale upgrade their flocculation, sedimentation, and filtration processes, flocculant aid polymer storage and feed systems, and add ferric chloride acid for raw water pH adjustment in order to maintain long-term reliability of plant operation. In addition, we recommended investigating enhanced coagulation, alone or in combination with other processes, as a means of complying with the Disinfectants and Disinfection By-products Rule. Carollo was subsequently asked to implement our recommendations at the plant.
Individually, the components of the WSA can help any utility identify treatment problems and find cost-effective solutions to specific challenges. When used together, the WSA components provide a powerful tool that can be used to optimize plant efficiency, reduce costs, and improve water quality.