Why isn't Biocide In My Cooling Tower Working? :: Momar
Spring is finally here in the northeast! (Well sort of... it's still pretty darn cold.) And that means that it is time to consider how your boiler system will spend the next few months while it sits dormant offline. If you own and/or operate a facility with a commercial steam boiler that only gets seasonal use, then this topic is for you.
For the purposes of this post we will assume that you have the best water treatment company in your area and, during heating season, your boiler water treatment levels are maintained within specific optimal operating ranges to effectively inhibit corrosion and prevent scale. However, for seasonal boilers, during the non-operating months, even the best boiler water treatment program must be supplemented to prevent corrosion.
There are two primary methods of laying up a boiler ? wet lay-up and dry lay-up. As you can guess there are benefits and potential downfalls to each. Choosing the correct method is not always obvious and so it may make sense for you to get some guidance from an experience water treatment service provider. Some factors in the selection of lay-up include the size and type of boiler, the length of time the boiler will be offline, the temperatures that the boiler will be subjected to while offline and the resources needed to refill and monitor the boiler with treated water.
Why do I need to lay-up my boiler anyway?
When a boiler is taken off-line and allowed to cool down for extended periods of time, a boiler lay-up program is highly recommended, to offset the increased levels of oxygen in the boiler. Oxygen can quickly produce pits in tube sheets and boiler tubes. Once oxygen pitting starts, it can easily corrode through a boiler tube in a very short period of time. When it is time to start your boiler back up in the fall, you first have to make a call to a mechanical contractor to plug or replace tubes. Not good for your boiler and very expensive.
What do I need to do when my boiler is taken offline?
When a boiler is taken out of service, the boiler should be cooled until the water is below the atmospheric boiling point, but not below 180 ?F, and then the boiler should be emptied and flushed out. An inspection should be made to determine what repair work is necessary and what cleaning should be done. A decision should then be made on whether to employ dry or wet storage techniques.
WET LAY UP PROCEDURES
A wet procedure may be used for a boiler that is taken offline completely or for one that has been placed in a ?standby?? condition. Wet storage is particularly useful if the standby boiler may be required to go back online at short notice or if it is impractical to employ a dry storage procedure. The method is not generally employed for reheaters or for boilers which may be subjected to freezing or sub-freezing temperatures.
There are a few alternative procedures that may be employed in a wet lay-up. The following is the most typical:
The clean empty boiler should be closed and filled to the top with water that has been conditioned chemically to minimize corrosion during standby. It is important that water pressure greater than atmospheric pressure should be maintained within the boiler during the storage period. A head tank may be connected to the highest vent of the boiler to help maintain pressure above that of the atmosphere.
For short storage periods, caustic soda and sulfite should be added until their levels in the boiler water reach 450 ppm total alkalinity and 200 ppm sulfite. If the superheater is of the drainable type, indoor playground equipment it can also be filled with the same treated water by over flowing from the boiler.
If the superheater is non-drainable, it should be filled only with condensate or demineralized water containing a minimum of dissolved solids, not more than 1 ppm. Before introducing the water into the superheater, mix in uniformly about 200 ppm of hydrazine and sufficient volatile alkali, such as ammonia, cyclohexylamine or morpholine to produce a pH of 10. The treated water may be introduced into the superheater through an outlet headed drain until the water over-flows into the boiler. When the superheater is filled, close the drains and vents. The boiler can now be filled through the feedwater or other filling line with condensate, feedwater or clean service water treated as described, with hydrazine and additional volatile alkali. If the storage period is expected to exceed three months, the concentration of hydrazine should be doubled.
If preferred, the boiler may be filled using feedwater or condensate treated with caustic soda and sodium sulfite after first filling the superheater with condensate treated with hydrazine and additional volatile alkali.
During the Time That Boiler is Offline
The boiler water should be circulated periodically to prevent the chemicals from stratifying or falling out of solution. The burner may be used to warm the water in the pressure vessel to stimulate natural circulation.
It is important to routinely test the water while the boiler offline to monitor the chemical concentrations. If there are any leaks in the system it can cause make-up water to be introduced to the boiler. Untreated make up water will be high in oxygen and carbon dioxide and will aid in corrosion.
Before Boiler Comes Back Online
Before starting a steam boiler that has been in wet lay-up, perform a bottom blow off to reduce the alkalinity. This reduces the chance of carryover. Confirm that all tags and locks are removed, and closely monitor the system cycles for a minimum of three to five cycles to ensure proper functioning of the boiler before allowing it to run automatically.
When is appropriate to use a dry lay-up procedure?
Great question! You can read all about that in the second part of this series: Boiler 101: Dry Seasonal Boiler Lay Up and Why it's Really Important
I want to learn more about other important boiler water treatment services. What can I do?
Well you're in luck! The first step in efficient and safe boiler operation is knowledge. Learning more about what potential issues your steam boilers could face is always a good idea. There is a treasure-trove of informational resources regarding steam boiler operation and water treatment available online. Another great resource is our free boiler operation eBook that is available for instant download: ?10 HUGE Mistakes Facilities Make in Boiler Operation and How to Avoid Them!?? which you can download for free at the link below.
As always, if you have any specific questions or concerns regarding your facilities water treatment program, please feel free to contact one of our expert water treatment consultants at 888-616-3545.
Thanks for reading and please check out our free eBook!
Greg Frazier is an expert in Industrial Water Treatment and is currently the Managing Partner of Clarity Water Technologies, a top Water Treatment and HVAC Cleaning Company in New York. He has over 18 years of Industrial Water Treatment experience and holds a degree in Chemical Engineering from the University of Tennessee.
Tiny Bubbles Clean Oil From Water
World?s first facility designed to integrate used water and solid waste treatment, the energy self-sufficient Tuas Nexus will export excess electricity to the grid that can power up to 300,000 homes.
Tuas Nexus ? the integration of PUB's Tuas Water Reclamation Plant (Tuas WRP) with NEA's Integrated Waste Management Facility (IWMF) ? is the first of its kind in the world planned from the ground up. It marks Singapore's first initiative to harness potential synergies of the water-energy-waste nexus by integrating used water and solid waste treatment processes. Construction of the two facilities is expected to commence in 2019 and will be completed in phases from 2023 onwards.
Tuas WRP Features
Tuas WRP is a key component of Singapore's Deep Tunnel Sewerage System (DTSS) Phase 2 and is expected to be ready by 2025. At an initial treatment capacity of 800,000 m3/day, it will be the largest membrane bioreactor (MBR) facility in the world, with an overall 30 per cent more compact footprint compared to conventional plants. A used water superhighway, the DTSS is the backbone of Singapore's used water management system and also ensures long-term water sustainability by contributing to the goal of increasing NEWater supply from 40% to up to 55% of total water demand in the long term.
Unlike conventional WRPs, the Tuas WRP will receive domestic and high-strength industrial used water flows from two separate deep tunnels. It will also feature a unique combination of advanced physical, biological and chemical treatment processes. This includes space-efficient lamella primary sedimentation tanks, two energy-efficient MBR systems to treat the two used water streams separately to higher quality standards for NEWater and Industrial Water production, and a thermal hydrolysis process to increase biogas production and energy recovery, as well as reduce sludge for disposal. The plant will also be equipped with solar panels on its rooftop in the long term, which is expected to generate up to 8MWpeak of additional power.
In another first, PUB will also reclaim high-strength industrial used water to produce Industrial Water at Tuas WRP. Currently, Industrial Water is produced using treated domestic used water at Jurong and Ulu Pandan WRPs. Tuas WRP's MBR system will effectively treat high-strength industrial used water for reuse by industries mainly in Jurong Island and Tuas.
Tenders for Tuas WRP
A total of about 11 construction tender packages is expected to be called over the next five years for Tuas WRP, estimated to be valued at over S$2 billion. The first tender was called in May 2018 for development works at the Tuas WRP site such as support infrastructure, utilities and a near-shore outfall for discharge of excess treated used water into the sea.
The second tender is scheduled to be called by Q4 2018 for the construction of the plant's Influent Pumping Stations. This pumping station will be PUB's deepest pumping station yet, consisting of five deep shafts up to 80 metres (or 30-storeys) underground, which receives used water from the deep tunnels and pumps it up to the treatment modules. PUB plans to call the third tender by early next year for the construction of the Industrial Liquids Module for the treatment of industrial used water to produce Industrial Water. Tenders for eight more contract packages for the construction of other components of Tuas WRP will be called progressively from 2019 onwards.
IWMF Features
The IWMF is an integral part of NEA's long term plan to meet Singapore's solid waste management needs. Unlike a typical Waste-to-Energy plant which treats only incinerable waste, the IWMF will be built with treatment processes for multiple waste streams namely incinerable waste, household recyclables, source-segregated food waste and dewatered sludge from PUB's Tuas WRP. Integrating these processes in one facility will better enable the IWMF to maximise both resource and energy recovery from waste while minimising its environmental footprint.
The IWMF will be built in two phases, with an initial incineration capacity of 2,900 tonnes per day for incinerable waste when the Waste-to-Energy incineration facility is completed in 2023. The remaining facilities in the first phase of the IWMF comprising the Materials Recovery Facility, Food Waste Treatment Facility and Sludge Incineration Facility, will be completed by 2024, which would mark the completion of Phase 1 of the IWMF.
The current plan is to eventually increase the incineration capacity at the IWMF to 5,800 tonnes per day in 2027. The heat from the incineration process will be recovered to generate electricity. Part of the electricity generated will be used to operate the IWMF and Tuas WRP whereas most of the electricity generated will be fed to the grid and will be sufficient to power 300,000 four-room HDB apartments.
Tenders for IWMF
A total of three Engineering, Procurement and Construction (EPC) tender packages and one build tender, estimated to be valued at over S$3 billion will be called over the next five years. The pre-qualification of EPC tenderers will be called in July 2018 to shortlist potential EPC tenderers for the development of key facilities within IWMF Phase 1. The second stage tender for EPC tenders will be called by January 2019.
Separately, the build tender for the development of a 230kV Electrical Substation for the Tuas Nexus will be called by December 2018.
Harnessing Synergies in Tuas Nexus
The Tuas Nexus will maximise efficiencies in energy and resource efficiency, by employing the latest technologies to harness the synergies of the water-energy-waste nexus from used water and solid waste.
A highlight of Tuas Nexus is its ability to achieve full energy self-sufficiency. The co-digestion of sludge and food waste, and the Thermal Hydrolysis pre-treatment (THP) process at Tuas WRP using steam from IWMF, will enable Tuas WRP to improve the yield of biogas. The biogas will be utilised at IWMF to increase IWMF's overall plant efficiency and boost electricity production.
"The Tuas Nexus is a bold innovation in the action for climate change and sustainability. This pioneering facility was designed to maximise the full potential of the integration of Tuas WRP and IWMF, and marks a new way in which used water and solid waste will be treated in Singapore. We look forward to working with industry partners and technology providers to build Tuas WRP, which aims to be the most energy-efficient MBR plant in the world and the cornerstone of Singapore's used water management strategy," said Mr Yong Wei Hin, Director, DTSS Phase 2, PUB.
Instead of being transported out for disposal, dewatered sludge which is the final by-product from the Tuas WRP's used water treatment process, will be sent to the IWMF for incineration and for energy recovery. Excess treated effluent from used water treatment will also be used by the IWMF for its processes to reduce potable water demand. Integrating both facilities in a compact space also optimises land use.
This integration will result in national carbon savings of more than 200,000 tonnes of CO2 per year, equivalent to taking 42,500 cars off the roads for Singapore.
"The IWMF is an integral part of Singapore's solution towards long term environmental sustainability. Leveraging state-of-the-art advanced technologies for the treatment of solid waste, the IWMF will maximise energy and resource recovery while keeping its environmental footprint to the minimum. IWMF's integration with Tuas WRP will further enhance the performances of both facilities and make Tuas Nexus truly an iconic water-energy-waste nexus" said Mr Joseph Boey, Project Director IWMF, NEA.
PUB and NEA also unveiled a joint Tuas Nexus showcase at the Singapore International Water Week (SIWW) and CleanEnviro Summit Singapore (CESS) 2018. The showcase at Water Expo is located Basement 2, Marina Bay Sands Convention Centre. The Tuas Nexus Business Forum will take place on 11 July 2018 (Wednesday) from 10:30am to 1:00pm, at Level 4 of the Convention Centre.
About PUB, Singapore?s National Water Agency
PUB is a statutory board under the Ministry of the Environment and Water Resources. It is the national water agency, and manages Singapore?s water supply, water catchment and used water in an integrated way.
PUB has ensured a diversified and sustainable supply of water for Singapore with the Four National Taps (local catchment water, imported water, NEWater, desalinated water).
PUB calls on everyone to play a part in conserving water, in keeping our waterways clean, and in caring for Singapore?s precious water resources. If we all do our little bit, there will be enough water for all our needs ? for commerce and industry, for living, for life.
About the National Environment Agency
Formed on 1 July 2002, the National Environment Agency (NEA) is the leading public organisation responsible for improving and sustaining a clean and green environment in Singapore. The NEA develops and spearheads environmental initiatives and programmes through its partnership with the People, Public and Private sectors. It is committed to motivating every individual to take up environmental ownership and to care for the environment as a way of life.
By protecting Singapore's resources from pollution, maintaining a high level of public health and providing timely meteorological information, the NEA endeavours to ensure sustainable development and a quality living environment for present and future generations.
About World Cities Summit, Singapore International Water Week, and CleanEnviro Summit Singapore
WCS, SIWW and CESS will be held concurrently from 8-12 July 2018 at the Sands Expo and Convention Centre, Marina Bay Sands. The three events provide a unique integrated global platform for government and industry leaders to share solutions for sustainable urban development and biocides list the latest innovations in water and clean environment solutions. Exhibitors and participants would be able to explore synergies, network and forge partnerships with a wider range of global industry leaders, policy makers and experts. Together, the three events showcase global thought leadership in sustainable development.
Proper Boiler Commissioning And Boiler Inspections Keep the Islands Safe
Improved wastewater treatment methods that lead to cost savings and energy production are part of Oregon State University?s new Clean and Sustainable Water Technology Initiative.
A $3.28M gift to the OSU College of Engineering from Jon and Stephanie DeVaan enabled OSU to launch the initiative.
?The College of Engineering is grateful to Jon and Stephanie for their visionary gift, an investment that could make a difference for millions of people around the world,?? said Scott Ashford, Kearney professor and dean of the OSU College of Engineering. ?The initiative will build a collaborative community of faculty, graduate students, undergraduate students ? all working together on providing access to clean water throughout the globe, one of the 14 Grand Challenges for Engineering in the 21st century.??
The initiative will include the work of Tyler Radniecki, assistant professor of environmental engineering, who studies the antiscalant chemical, click to read, and biological processes that allow for the decontamination of wastewater and stormwater runoff.
Radniecki is co-director of the OSU-Benton County Green Stormwater Infrastructure Research Facility, an Oregon BEST-funded field laboratory for testing green stormwater infrastructure, also known as low-impact development technologies.
His research focus includes a pair of emerging technologies in microbial resource management:
Anammox ? anaerobic ammonia oxidation ? gets nitrogen gas out of wastewater much less expensively than conventional ?bubbling?? techniques.
FOG ? fats, oils and grease ? codigestion purifies wastewater while increasing the production of methane that can be converted into electricity to power treatment plants, in some cases resulting in electricity being sold back to the grid.
?Nitrogen is a contaminant that is coming under ever-increasing scrutiny due to its primary role in causing eutrophication of rivers and lakes,?? Radniecki said.
Eutrophication refers to what happens when excess nutrients end up in a body of water, causing a biomass load imbalance that depletes oxygen.
?Anammox uses a recently discovered class of bacteria collectively known as anammox bacteria that can use nitrite to oxidize ammonia to form dinitrogen gas, which then bubbles out of the water and into the atmosphere,?? Radniecki said. ?This process can reduce the electricity consumption required for traditional nitrogen removal in a wastewater treatment plant by 60 percent and methanol addition by 100 percent.??
The problem is that so far an anammox setup calls for unit operation systems that require ?immense technical expertise, monitoring and infrastructure.??
?That puts the process out of reach of most small to midsized treatment plants,?? Radniecki said. ?We are trying to revolutionize this technology by taking it out of these demanding, highly technical systems and putting it into low-impact constructed wetlands, a more suitable technology for treatment plants that aren?t huge.??
Adding restaurant waste ? the aforementioned FOG ? to anaerobic digesters to increase methane production is another option available to plants of varying sizes. But for FOG co-digestion to reach its full potential, greater understanding of the digesters? microbial communities is needed.
?The treatment plant in Gresham, Oregon, has used this technology to become net energy positive ? it?s energy independent and actually sells electricity back to the grid,?? Radniecki said. ?While this is a very exciting development, the technology can be better by improving its reliability under high FOG loading rates as well as when the FOG switches from one food source to another.??
There is also the potential for FOG codigestion to produce other resources besides methane, including hydrogen gas and bioplastic precursors, he said.
?However, we need to know a lot more about how the microbial communities within the anaerobic digester responds to operational parameters ? loading rates, for example,?? Radniecki said. ?We are taking both top-down and bottom-up approaches to gain greater understanding of how to shape these microbial communities to maximize their potential.??
Top-down approaches, he explained, include gene sequencing those communities as they experience operational changes, providing insight into how the communities respond and how that affects digester performance.
An example of a bottom-up approach is genome-enabled modeling of representative anaerobic digester microorganisms.
?GEMs are complex models that, based on the genome sequence of a microorganism, can model every metabolic reaction that can occur in that microorganism,?? Radniecki said. ?GEMs give us a tool that allows us to probe the metabolic potential of any given microorganism under any given environmental condition. It may be possible for anaerobic digesters to produce additional economically viable products and not just methane.??
About The OSU College of Engineering:
The OSU College of Engineering is among the nation's largest and most productive engineering programs. Since 1999, the college has more than tripled its research expenditures to $37.2M by emphasizing highly collaborative research that solves global problems. It is a leader in signature research areas, including precision health, clean energy, resilient infrastructure and advanced manufacturing; and targeted strategic areas, including robotics, materials research and clean water.
14 Days To Disinfect Cooling Towers In Nyc Or It's A Misdemeanor!
In pre-Columbian times, the white-tailed deer was among the most abundant and frequently consumed mammals in Panama. It was also an icon, represented on thousands of clay vessels. Through an analysis of deer remains in refuse piles at the Sitio Sierra archaeological site, researchers from the Smithsonian Tropical Research Institute (STRI) discovered signs of "feasting behavior" associated with this animal. Their findings were published in Archaeological and Anthropological Sciences.
Spanish conquistadors left some clues. They noted the abundance of deer in indigenous communities along the Pacific coast near Sitio Sierra and highlighted the existence of larders replete with dried and salted deer carcasses. These details suggest that periodic feasts may have taken place, and were likely important for enhancing social relations and strengthening alliances.
The Sitio Sierra site, a large village on the Pacific coastal plain occupied between 2,200 and 500 years ago, was excavated by STRI archaeologist Richard Cooke in the 1970s. Mar?a Fernanda Mart?nez-Polanco, a former pre-doctoral fellow in Cooke's lab at STRI and first author of the study, analyzed some of the evidence of feasting signs.
She found that, arcade game in certain units, remains of young white-tailed deer predominated, as well as body parts with high meat values. Most of the cut marks on the bones were due to de-fleshing, as opposed to rodent or carnivore gnawing. She also encountered the carcasses of tasty birds and mammals, a contrast from the typical food remains found around houses, consisting of marine and river fish, iguanas and small turtles.
Former STRI pre-doctoral fellow Mar?a Fernanda Mart?nez-Polanco found that, in certain units, remains of young white-tailed deer predominated, as well as body parts with high meat values. In those units, pottery shards were much more numerous and larger than in other contexts. Credit: Smithsonian Tropical Research Institute
In those units, pottery sherds were much more numerous and larger than in other contexts. A large pit with post-holes along the periphery contrasted with smaller cooking pits found in or around the structures of former houses. These findings coincide with characteristics of feasting mentioned in the scientific literature.
"This was an important tradition that could have been practiced for several generations, as we have witnessed based on the cut marks in bones, located in identical positions over different time periods," Mart?nez-Polanco said.
For her, the analyses of deer bone samples in conjunction with the evidence from the pottery and cooking practices, position the feasts at Sitio Sierra as part of a ritual activity. Possible motivations for feasting include ancestor worship, rites of passage, celebrations of cultural awareness and group oral-history and political gatherings designed to enhance the reputation of the provider.
Archaeologists think that Sitio Sierra was probably a low-status village, based on burials in its two cemeteries, suggesting that these feasts were likely not as sumptuous as they could have been in higher-status villages in the area, such as Sitio Conte or El Ca?o. Offering deer meat may have been considered a great honor for the guests and proof of the provider's status.
"Deer were more than just food for Panamanian pre-Columbian populations," Mart?nez-Polanco said. "Deer hunting was restricted and their consumption linked to important occasions, as we observed in the archaeological record of Sitio Sierra, allowing ancient Panamanians to share and reinforce social relations at different levels of society."
