In March 2019, FWPCOA had another excellent and well-attended state short school in Fort Pierce. Our organization is helping train for the future and our membership in our profession and I’m lucky to be a part of that. My thanks go to all who helped in this mission by giving up their free time to teach and be involved. I also thank those who attended as students to increase their knowledge base and learn from experienced folks; may you get wiser every day. Continued education in what you do as a profession never gets old, so keep your knowledge “fresh.”
Speaking of freshness, sparkling clean and safe water is the goal for all of us in the water profession. We must all work together at every phase of treatment to ensure that our customers get the water they need. “Keeping it fresh” is a common theme amongst our crew in Plant City, were I work.
The Distribution System and Water Quality
As water distribution system operators, cross connection control technicians, and water treatment plant operators do their daily tasks, they must remember to think about water quality and how their actions can affect and improve the characteristics of the water in the distribution system.
After treatment, the water entering a distribution system may meet drinking water standards, but the quality of the water may degrade within the system or be affected by other conditions, so we must all work together as a team to keep it fresh. Water quality can be changed by aging pipes and cross connections within the system with the intrusion of dangerous pathogens. Proper distribution system management is essential to protect the community from both aesthetic and public-health threats due to deteriorating water quality in the water system.
Some problems in the distribution system that can affect water quality are:
- Color
- Taste and odor
- Biofilm formation
- pH stability
- Cross connections
Color
Color issues (white/milky, red/orange, bluish/green, black/brownish) are caused by very low flows, aging water, and the plumbing materials used. When these occur in the field, be sure to check the system conditions. Color problems are mainly isolated issues, so you need to get out there and start checking.
White/milky colored water is usually found to be air in the system, which could be in a single home or in a certain area. A quick way to check is to fill a clear glass with water and let it stand; the glass will clear from the bottom. Air relief and pumps should also be checked. I’ve also seen white particles in water, which turned out to be a bad dip tube out of a water heater; the internal tube deteriorates over time, causing the white particles.
Red- or orange-colored water is usually caused by piping material containing iron or steel. A corrosive water, or water sitting in a pipe over time, can corrode the pipe material, causing the color. A good flushing and corrosion control program will help in this area. Good distribution maintenance will keep systems looped and you need to replace bad piping when needed.
Bluish/green water is usually caused by piping material contain copper or brass in a very-low-flow line or where there is low-pH water. This is usually found in a customer’s home where a fixture isn’t used much. Customers should be educated about fixture usage in the home and how critical it is to water quality. The use of phosphates for control of corrosion is very common, which can also be used for copper, as well as lead, control. Speaking of lead, if any lead services or goosenecks are found in a system they should be removed immediately; a replacement program for that particular neighborhood may need to be a priority.
Water that’s black or brownish in color is from a number of issues, including sediment or manganese. A flushing program should be developed by your utility to flush dead ends in your system quarterly, as well as determining system flushing points to improve quality. Unidirectional flushing can be done by closing valves with increased flow and scouring to remove sediments. These sediments can also harbor taste and odor imbedded in them, so by addressing them you’re taking care of two problems at once, so flush my friend!
Manganese can cause dark colors as well, which is caused in very-low-flow areas where it settles out. Remember, manganese is a naturally occurring element and has no health effects. Here too, flushing is the key to removing manganese deposits. Piping changes may also be needed to increase flow in an area. High manganese at the treatment plant effluent would need further treatment to remove above the secondary maximum containment level (SMCL) of 0.05 mg/l.
Taste and Odor
Taste and odor in water, in most cases, are usually no sign of a public health risk, but they do indicate an issue inside of a home or in a distribution system. These problems related to the system are usually due to aging water, poor source water, inadequate treatment, loss of chlorine residual, low alkalinity, or changing water quality in the distribution system. All of these can be tricky to troubleshoot, if found in the system.
Customer expectations are for clear water with no taste or odor issues, so complaints should be investigated by the system or treatment operator. Most of these cases are sulfurous in nature. Check to make sure that water heaters are not set at too low or too high of a temperature, and that they are being serviced as needed. Water heaters should be flushed a least once a year in a home that has these issues. Also check any unmaintained home treatment units, low-flow areas, or no-use bathrooms.
In some homes with earthly/musty/moldy odors, the cause is bacteria growing in sinks and other fixtures. The customer thinks it’s the water, but the infested areas just need to be cleaned with bleach. If taste is an issue, remember that the cooler the water the better is tastes. Recommend to your customers that they keep drinking water in the refrigerator, which will help.
A cross connection backflow can also have taste and odor issues, so investigate this as well. Remember you are required to flush dead ends in your water distribution system quarterly, which will really improve the freshness. Better yet, install auto flushers in problem areas for increased flow and freshness will be achieved.
The types of tastes and odors that are found in water include chemical, solvent, sulfurous, earthy/musty, medicinal, metallic, and many more. Common troubleshooting for any chemical tastes and odors looks at chlorine feed rates at the treatment plant to make sure that they are consistent and not excessive. For solvent taste and odor issues, look for a cross connection or source water relating to hydrocarbons that may need to be removed. Earthly and musty issues are commonly found with surface water sources that have algae blooms or organic material with chlorine disinfection; ozone or advanced oxidation will help to remove these. Sulfurous problems may indicate low or no chlorine residual, low flow, or stagnate water.
Biofilm Formation
Biofilms are slimy microorganisms that live on the interior of pipe walls. Typically, these films are benign and are heterotrophic or nitrifying in nature. The problem is when growth gets out of hand they can really cause issues with taste, odor, and color, and could possibly hold pathogens or bad bacteria. This growth is triggered by the availability of elements such nitrogen, carbon, and phosphorus. If you have too much of these in problem areas, biofilms will grow faster. With a stagnated pipe or low-velocity flow, low disinfectant residual, or corrosion of piping material, poor water quality conditions are ripe for excessive growth.
A key factor in biofilms is the availability of a carbon sources, like total organic carbon (TOC), and in this case, the lower the better. Controlling TOC can be done through treatment-effective processes like advanced coagulation, biologic filters, granular activated carbon, or source water protection active, which will go a long way in prevention of these biofilms.
Other operational techniques for the distribution system is a good corrosion control program, optimization of your disinfectant, water storage tank turnover practices, good maintenance practices for repairs and pipe work, and water main rehabilitation and replacement projects. Flushing at velocities above 2 feet per second will really keep it fresh!
pH
It’s very important to have stability in your water distribution system for pH and alkalinity. A pH range of 7.3 to 8.2 is optimal for water distribution systems, while a pH lower than 7 is corrosive in nature and will cause leaching of lead and copper in the drinking water, as well as imparting a metallic taste in the water. Lead and copper are never a good thing, so be sure you are testing your system regularly according to your plan.
Effective pH control and corrosion control can go a long way to prevent this issue. With a pH of greater than 9, excessive scaling will form on the piping in low velocity pipe runs, which can cause scaling and pipe volume capacity loss. A lack of alkalinity can be corrosive to the water in the distribution system and cause many of these same issues. Having a stable alkalinity will allow the water buffer itself when needed.
Cross Connections
An active cross connection control program really does help in water quality protection. Having trained and certified personnel who can check a water system to protect against contamination is critical. The requiring of backflow prevention devices for possible hazards can provided great protection for the water system. Contamination for hazardous connections would be hard to trace if there was no device in place for the prevention of backsiphonage. Regular testing of these units ensures they are working correctly.
Working as a Team
Having a good team around you goes a long way in trying to correct and preserve water quality.
- Remember to evaluate the areas affected, look at the piping map, and be sure it’s looped.
- Dead ends must be flushed regularly to keep the water fresh.
- Work with your distribution system operators to get their take on the issue. Many times, things may not be on map, but are relative to finding on issue.
- Test and look at valves in the system to be sure they are open; closed values will only act to increase low flow and stagnation.
- Test disinfectant residuals, as the lack of them with cause you grief.
- Check water storage tanks in the system to be sure they are routinely turned over and cleaned regularly.
- Use auto flushers in low-flow areas. Routine flushing goes a long way to improving circulation and water quality. Manual flushing at high velocity is some of the best ways to keep it fresh.
Water quality is not the only thing you need to keep fresh. As we try to become better water professionals, your character and professionalism is another thing to work on. As operators, coordinators, mechanics, and technicians, we must strive to be excellent in our craft and carry ourselves with good conduct. We must look professional in what we wear and how we act. We must be dedicated ourselves when we are at work to our work. We must stand together for the good of us all going forward.
Together we can move our skilled craft to a place where it needs to be for our advancement and for that of the industry. By keeping it fresh with your training, skills, personality, character, work ethic, and accountability, I see our profession getting stronger.
So, keep it fresh!