Ensure you use Accu-Tabs to retain drinking water rating NSF61
Copycat Accu-Tabs are widely available; however chlorine feeders not using the branded product, including those customers with BIPW chlorinators, are not compliant with NSF 61 (drinking water standard).
According to NSF International, “Chlorine feeders are required to be used with and only with the manufacturer’s recommended use chemicals and these chemicals need to comply with the requirements of NSF/ANSI Standard 60.”
Accu-Tabs are a specific approved chemical component (68% calcium hypochlorite) that are specifically designed to erode at the appropriate rate.
The same goes for Accu-Tabs in pools. “Chlorine feeders that are certified to NSF/ANSI Standard 50 for use in pool, spa, and recreational water facilities are evaluated and certified for use with-and only with- the manufacturer’s recommended use chemicals,” according to NSF International.
For more information about chlorinator products, contact Theresa Rendl, customer support.
Does your water treatment system include organics removal to prevent chlorine byproducts?
“We’re not seeing all engineering consultants providing new water system designs that address organics before disinfection systems, such as chlorination and UV, and I’m concerned about it,” says BI Pure Water’s Engineering Manager, Paul Anderson. “Frankly I wouldn’t drink the water if the THMs were over 25 ppb.”
Chlorine byproducts such as THMs (all are called TTHMs), and haloacetic acids (HAA) are formed when chlorine interacts with naturally occuring organic matter in the source water. “There are serious negative health effects with long term exposure to these disinfection byproducts. The City of Vancouver is concerned enough to lower their THMs to 25 ppb. The EPA has lowered the Stage 1 Disinfectants and Disinfection Byproducts Rule to regulate total trihalomethanes (TTHM) at a maximum allowable annual average level of 80 parts per billion (µg/L) from 100 ppb.”
“The water quality of communities, which they should have published on their websites, should indicate THMs well below the max, and we’re not seeing that. The public must demand good water treatment.”
Some UVs may even increase the problem of disinfection byproducts by breaking organic material into smaller particles with more surface area that results in even higher THMs.
BI Pure water’s senior engineer, George Thorpe, who watches the EPA studies, notes that research underway is showing that there are many more disinfection byproducts than are currently known, and long term studies on human health are underway.
Ready for freshet?
Ultrafiltration reduces turbidity without chemicals while also removing viruses, cysts, bacteria and contaminants
With the latest advances in the membrane technology — ultrafiltration — it’s possible to take control of spring flooding conditions that can turn drinking water a mud colour. An ultrafiltration unit integrated into your plant’s existing facility has the benefit of reducing turbidity by filtering colloidal particles (0.002 to 1.0 microns) and some of the largest dissolved contaminants. Ultrafiltration provides a minimum 4 log removal of viruses, cysts and bacteria without chemicals, tested against US EPA Standards. Turbidity is reduced so that the downstream UV-systems can function efficiently.
Ultrafiltration results in a reduced need for chemicals such as coagulants, flocculates, disinfectants and/or pH adjustment. It is a natural size exclusion filtration instead of media depth filtration. UF produces a good and constant quality of treated water in terms of particle and microbial removal without chemicals.
Ultrafiltration is not fundamentally different from reverse osmosis, microfiltration or nanofiltration, except in terms of the size of the molecules it retains. UF membranes will come in different pore sizes, which determine the type and size of contaminants removed.
The ultrafiltration unit has a small footprint and plants are compact with simple automation that is easy to maintain. BI Pure Water’s ultrafiltration setup allows full control over all required peripherals to filter water from any source, waste to well-water.
Automated Membrane testing
Monitoring the signal of a turbidity meter in the filtrate line of the system provides indirect testing of the membrane. The PLC will also trigger the integrated, direct membrane-test.
Treats difficult water
The system is designed to withstand fouling and automatically applies membrane cleaning. Money and time is saved on replacing cartridge filters. The degree of fouling of the membrane is continuously measured based on the function of flow and differential pressure. The ultrafiltration unit automatically reacts to varying feed water conditions and adjusts the frequency of its cleaning cycles accordingly. In addition to a feed-pump it also controls dosing equipment in the feed to be able to treat high-color-containing sources using an inline-flocculation-process. This achieves the highest possible flow rates at maximum rates of removal of color and dissolved organics.
Once the system detects a need for cleaning, it can apply different combinations of cleaning techniques, including pre- and post-flushing, internal backwash or backwash powered by an external pump. Cleaning-In-Place can be performed automatically; for example two different chemicals in sequence can be applied to allow for high- followed by low-pH cleaning steps, to get the system back to start-up conditions.
Remote monitoring and alert system
As soon as the system detects an operating error, including a failed membrane-integrity test, or other differentiated message, e.g. unsuccessful cleaning sequences, water hammer or an empty cleaning chemical tank, it can send out an SMS message to up to ten cell phones or report to an existing remote monitoring system. If the unit is hooked up to an existing cellular network through its internal high speed-modem (optional), latest web-based, remote-control solutions allow the user to access the unit over the internet, change operating parameters and read operating history from the datalogger.
Water treatment on wheels
Move them anywhere for piloting or emergency potable water sources
Flexible water treatment systems are built inside mobile trailers and can be customized for the water source.
- Treating from 10 to 60 USGPM (up to 227 liters per minute)
- Designed to be easy to maintain
- Pilot test for the most efficient treatment for your water source
Inside a treatment plant trailer:
- Optional ultrafiltration for muddy/ turbid waters < 0.1 micron
- Optional activated carbon filters for improving taste and odour, and removimg organics and potential byproducts of chlorination
- Various sizes of filtration technologies from 200 microns down to 1 micron absolute.
- An ion exchange unit
- UV and/or chlorination systems for disinfection
When to use a pilot treatment system
Deciding on how to treat a new water or waste source can be very challenging. Piloting, or employing a small-scale test plant, gives you system, cost and operational details that prove the concept of the full scale system.
While not being required for most water sources, piloting will:
- save significant money if water quality falls on the borderline between clearly defined treatment technologies
- provide info on consumable and operational costs
- demonstrate if an operator is comfortable with the technology and is able to effectively operate the plant
- show if the technology chosen can work and/or meet long-term monetary requirements
Piloting is especially useful:
- Where difficult water exists,
- When there is no detailed water analysis
- When the analysis was not done during freshet or summer heat
- When operations and maintenance data is needed
- The water analysis does not clearly indicate one treatment method or another
- When multiple water sources are used, ie ground water and surface water, or multiple wells (blending).
When piloting IS NOT required is when a series of detailed water analyses taken over a few years are conclusive as to the treatment method.
When designing a pilot treatment plant you will need to:
- gather information on pre-filtration, dosing rates and filtration alternatives
- determine the operational characteristics of membrane systems
- compare the performance of RO membranes supplied by different manufacturers
- verify disinfection operational performance
- obtain data to predict operational costs of a full scale plant
The pilot equipment needs to be scalable up to the eventual drinking water flow rate required. A flow rate of 0.1 to 2.0 percent of plant design is normal. The pilot should represent reality as close as possible.
Typical Types of Pilots and Frequency
Filtration: It is important to select the right water treatment technology for the specific water available at a site. If nano-filtration can be used rather than reverse osmosis, capital costs and pumping/power costs will be reduced. Testing out disinfection technologies — ultraviolet as primary disinfection, advanced oxidation and chlorination as residual disinfection — will show if the filtration selected has improved the turbidity and UVT enough.
Data Collection: A full water sampling and analysis program is required. On site sampling is normally carried out manually through analog signals or every 4-8 hours to obtain:
- Raw and treated water pH
- raw and treated water turbidity
- raw and treated water iron and manganese content
- raw and treated water hardness
- flow consistency and consistent pressure trends
The water analysis reveals:
- Major and minor contaminants
- Potable or process water quality objectives
- Flow rate – peak and average
- Project budgets
- Future expansion possibilities
Costs associated with piloting
The cost can range from $3500 to $250,000. A pilot system can be rented or owned depending on the length of piloting time; pilots can be over 1 month or several years.
The challenges of pilots and designing treatment systems is typically there is 1) a lack of data for new water sources. 2) A few chemical analyses do not necessarily define a water source. 3) Piloting a source helps to define and log trends in water quality.
Without understanding the water chemistry or trending over an extended period of time it is difficult to optimize a water treatment design. BI Pure Water designs pilot systems all the time for our final treatment plants and has a wide variety of systems available to rent.
Case Study 1: Pilot test shows different results at two nearby sources
For the Columbia Valley a small filtration plant was pilot tested a few years ago to determine O&M cost, UV and chlorine disinfection. The results during spring melt showed raw water quality remained acceptable for self cleaning and cartridge filtration. Enough data was collected in the testing to design for a full-scale plant, and showed that the system design was cost effective and met Canadian Drinking Water (CDW) guidelines.
However when the same pilot was moved to another location three hours away to Windemere Lake, the 1 micron absolute filters became plugged every 6 days and the water quality objective of less than 1 NTU couldn’t be consistently met. It was found that the piloted equipment was wrong for that source: it was too expensive to operate and didn’t consistently conform to CDW turbidity guidelines. The next step was to pilot a different technology.
Step 2: Testing an ultrafiltration membrane on the water sourcePilot testing was carried out to determine the efficacy of different ultrafiltration membranes. Results showed the ultrafiltration membrane effectively removed small particle (diatoms) that were plugging the previous cartridge filter pilot, without having to use acid or caustic; this was an important O&M detail. It was also demonstrated that whether the water source was from Williston Lake or ground water, with differing chemistry, the technology could meet performance goals over the long term. The pilot also determined what the flux rate was going to be for the full-scale ultrafiltration plant.
Case Study 2: Reverse Osmosis Pilot Test
Case Study 3: Larger pilot plant prevents large scale errors in system design
For a very challenging water source, a larger mobile pilot in a 10 foot container was employed. In warm July and August months the 1 micron absolute cartridge filter was fouled by algae growth. It seemed the RO technology was too expensive on consumables and didn’t effectively reduce TOCs. But the data provided for the design of the alternate slow sand filtration system, saving money and time in the final system.
Tablet chlorine: safer and simpler for operators to use
The Accu-Tab solid form of chlorine offers safety and low maintenance benefits together with a small capital investment. With no chlorine gas cylinders to handle, chlorine releases are non existent. Process safety management and risk management program compliance worries disappear.
Accu-Tab 3-inch calcium hypochlorite tablets are easy to handle and store. The chlorinators contain no moving parts or small openings to clog, keeping maintenance at a minimum. The Accu-Tab system is accurate and predictable, as easy to adjust as gas, and more consistent than bleach. BIP/Accu-Tab chlorinators are certified NSF Standard 61.
|Safety||Easy to handle, no spills||Spill and leak concerns if near skin or eyes||Major gas leak concerns; deadly when inhaled|
|Changing Chemical||Easy to add tablets, only one person needed||Hard to maneuver, heavy drums or lots of small carboys||Two trained persons needed, breathing protection required?|
|Material Compability||More neutral pH, less corrosive||High pH, corrosive||Low pH, very corrosive|
|Convenience||55-lb pail of tablets is easy to handle||Bleach drums are awkward to handle||Hard to maneuver cylinders, special handling trianing needed|
|Maintains Chlorine Strength||Small change over a year||Significant loss in a week of hot weather||Consistently 100% chlorine|
|Chlorine Delivery Control||Consistent strength makes for easy, reliable control||Ever changing strength makes for control difficulty||Troublesome regulators needed, harder to automate|
|Storage Convenience||55-lb pails stacked three high, same space as 150 lb cylinder, no separate room||Drums or bulk tanks require space and possibly containment pad||Separate room with special access needed, fans, scrubbers|
|Auxiliary Equipment||No moving parts in chlorinator itself||Troublesome metering pumps required||Eductors, regulators have small orifices prone to plugging|
BI Pure Water manufactures, installs, and services an Accu-Tab chlorination system with a small footprint. In most cases the system can be installed by in-house staff in less than a day.
A word about chlorine chemistry
Accu-Tab tablets are available for Potable / Industrial Water Treatment (white) and Commercial Swimming Pools (blue). Product available in 25 kg containers.
Chlorine is available in many different forms. The most common include gas, liquid chlorine (sodium hypochlorite or bleach) and solid calcium hypochlorite. All three forms generate hypochlorous acid – the germ-killing form of chlorine – when dissolved in water. Chlorine is the only chemical that provides residual protection, which is very important and required in many water treatment applications.