Step 2 - Identify Efficiency Opportunities

The water balance developed in the previous step allows us to uncover opportunities for water efficiences and to develop a sustainability policy, or expand an existing one, into the water space.

A water savings policy is a crucial part of a company’s sustainability policy and should be reported in the Corporate Sustainability Report (CSR). It is an effective way to communicate expectations with customers, employees, shareholders and other stakeholders.

An effective way to identify opportunities is to perform a water solution technologies review. For this purpose, it is highly recommended to form a water savings team staffed by water, finance and engineering/operation experts.

The following will help you find 10 to 20% inlet water savings, achieve it quickly, and improve water quality:

Rank Your Water Usage

Based on your water balance, rank the various components by water usage and focus on the largest water users. Identify leakages and sources for waste like excess cleaning and washing.

Sources for Water Reuse and Recycling

Source: “At the Crest of a Wave: A Proactive Approach to Corporate Water Strategy” – The Pacific Institute and the Business for Social Responsibility

Cooling Towers – For many facilities, cooling towers represent the single largest opportunity for greater water efficiency. Cooling towers should be investigated to determine how many times water circulates before it is bled off and discharged. Increasing the recycle rate of the tower results in multiple savings, from water and sewer costs to savings on the purchase of chemicals used to treat both incoming and discharged water. Typically, cooling towers consume a significant portion of total water. As a rule of thumb, an increase from 5 to 8 cycles of concentration would reduce makeup volume by 9%. Since you will need to increase chemical treatment, this will likely be close to revenue neutral. Now you need to calculate the effect on total inlet water.

Example: In a 1000 GPM plant, 600 GPM go to cooling towers. An increase from 5.5 cycles of concentration to 8 cycles result in a 9% makeup water savings, which is a 5.4% of total influent volume.

9% x 600 = 54
54/1000 = 5.4%

 

Source: Water Efficiency manual, North Carolina Department of Environmental and Natural Resources

Equipment Cooling – Replace single-pass cooling systems, where water is circulated once through a piece of equipment and then discharged to a sewer, with a process or cooling loop. This loop provides water at a pre-set temperature to cool equipment. When a process loop is not possible, reusing single loop discharge water for irrigation or other nonpotable water requirements is another way to increase water efficiency.

Equipment Rinsing and Cleaning – There are many efficient rinsing options for facilities. Countercurrent rinsing is typically the most water efficient method for rinsing equipment. In this process, the cleanest water is used only for the final or last stages of a rinse operation; water for early rinsing tasks, when the quality of the water is not as important, can be collected from water that is used during later stages in the process. Other forms of efficiency rinsing include batch processing, when several pieces of equipment are cleaned at the same time, using rinses from one process in another. Cleaning process equipment can be a significant part of many food, beverage and pharmaceutical companies’ manufacturing costs and in some cases can account for as much as 50 to 70% of a facility’s total water use. As such, this presents a tremendous opportunity for water savings.

Alternative Water Sources – Large facilities are good candidates for alternative water sources due to the fact that they typically use large amounts of non-potable water. Companies may be able to update processes to allow for the use of saline and wastewater instead of fresh water. This approach reduces the impact on freshwater resources with subsequent benefits to the local community and the ecosystem. The two most useful “alternative” water sources for facilities are air-conditioning condensate recovery and rainwater harvesting.

  • Condensate recovery: The condensate from air conditioners, dehumidifiers, and refrigeration units can provide facilities with a steady supply of relatively pure water for many processes. Because condensate water is relatively free of minerals and other solids, it could be used for cooling tower, boiler makeup and reverse osmosis feed water, or for drip-irrigation.
  • Rainwater harvesting: Rainwater is another excellent source of non-potable water and can be used in many of the applications in which condensate recovery is used. Facilities in the U.S. considering the use of rainwater should check with local or state governments about possible restrictions. Some states allow facilities to detain water for irrigation and other uses that return water back to the system, but do not allow water to be retained permanently on a site.

Additional Savings Sources –

  • Use domestic water efficiency techniques
  • Ultra low flush toilets, urinal, faucet aerators, low flow showerheads, etc.
  • Reduce landscaping irrigation time schedules, repair leaks, install spray nozzles, install and/or replace automatic shut-off nozzles

Engage Your Employees as a Source for Water Savings Ideas

  • Survey your employee base by asking them to identify sources of waste. Employee awareness is a great way to uncover savings opportunities and to engage them in an execution program.
  • Launch an employee awareness program. Provide them incentives and awards such as the most eco friendly employee award, for being proactive in helping your company save water.
  • Communicate with them on weekly basis – progress, regulation and success stories.
  • Hold managers accountable for adopting ideas and executing them.

The output of this step is a master list of water saving initiatives. Step 3 will build more rigor into this list with estimated water and pollutant savings as well as associated financial impact.

Continue to Step 3 - Prepare an Optimization Plan