Defining the goal of an industrial process helps establish what initial water analysis is needed. Whether for steam electric power generation, paper production or water treatment, the design, function and troubleshooting of any industrial water and wastewater treatment program will only be as good as the water analysis data provided at the start.
Making sure water analysis is robust is a topic covered in detail in the “Analyzing a Water Analysis” technical session at the 2017 International Water Conference.
Water Analyses Guidelines
A range of water analysis methodologies exist to examine the chemical state of water samples. Standard water testing occurs in specialty laboratories, plant labs or is done by personnel in the field. The resulting analytical data helps to determine process design for a project and varies depending upon the defined end goal, process or outcome.
Caution should be observed for water analysis where plant or facility construction is undertaken on previously undeveloped land — greenfield projects. While the local public utility may be able to offer potable water analysis, this is usually an insufficient source of data because the level of investigation is for a different end requirement.
Analyzing Water Analysis
Unfortunately, not all water analysis reports are sufficient or accurate in providing the water chemistry information for a plant or industrial process design. Identifying incomplete analysis reports or inaccurate analyses is the first step.
To obtain the water analysis insight required to plan an industrial project, be prepared to ask questions and dig into the analysis. For an industrial water supply systems analysis, inquire about possible upstream sources of contamination that could affect the results. Understand where the water originated and what the rate of turnover is for seasonal variation. Determine if an ionic balance exists in the data and, if not, question the findings.
Another consideration for determining if the analyses are complete includes comparing the reported total dissolved solids (TDS) to the summation of the reported ions. By adding up the “as species” ions and making assumptions, where necessary, regarding the alkalinity breakdown, this data can be compared against the reported TDS to determine completeness of the analysis.
There are several other ways to undertake a quality control-like check on water analysis reports, including comparing measured and calculated TDS and comparing cations to anions. We use these techniques on virtually all projects that require water analysis to prevent unnecessary project delays or unexpected planning costs.
Water Analysis Best Practices
For any plant design, construction or operation, source water and wastewater analyses are critical to support a successful project. Accurate, high-quality water analysis data will help define specific project variables, affect plant instrumentation and process design decisions and may influence the long-term profitability of an industrial site.
By following a few key best practices, operators can make sure projects are designed and constructed based on comprehensive and high-quality water analysis.
- Identify or inquire about the defined outcome or overall objective of the project to determine the water resource requirements and resulting water analysis needs.
- Where possible, ask for comprehensive water analysis for projects and, at a minimum, insist on complete water analysis for plant design projects to avoid surprises.
- If water sources are variable, make sure the analyses acquired as many source samples as possible, including a range of conditions, such as seasonal samples.
- Understand the basis of units of all water analysis lab reporting. Quality reporting will include the basis for each analysis to avoid misunderstanding.
- Even if the basis of units is defined, check to make sure the units reported are consistent and not mixed, which can mislead interpretation of the data.
- Ask questions, clarify interpretations and query data or sampling methods for any data that is not clear or is confusing.
Water planning is critical to industrial users, but they don’t always know it.