Measuring CO2 to optimise bulk storage of food.

24/07/2017

Meeting the food requirements of a growing global population is becoming increasingly difficult. Despite the need for additional food, it is estimated that 50-60% of grain is lost after harvesting, at a cost of about $1 trillion per year. (See note 1 below)

One of the major reasons for lost grain is spoilage due to mould or insect infestation during storage.2 To provide a constant supply of grain year-round, after grains are harvested they are often kept in long term storage. Maintaining the quality of stored grain is crucial, both to ensure the quality of the final food products, and to prevent economic losses for farmers.

Edinburgh Sensors GascardNG Sensor

Insects and moulds can grow in stored grain, and their ability to flourish depends on the temperature and moisture of the stored grain. Moulds are the most common cause of grain spoilage and can cause changes in the appearance and quality of stored grains. Some moulds can release toxic chemicals called mycotoxins which can suppress the immune system, reduce nutrient absorption, cause cancer, and even be lethal in high doses. It is therefore crucially important to prevent the presence of mycotoxins in food products.2

Monitoring Stored Grain
Farmers are advised to check their stored grain weekly for signs of spoilage.3 Traditionally, grains are checked visually and by odour. Grain sampling can allow earlier detection of insects and moulds, but these methods can be tedious and time-consuming. Rapid, simple methods are needed for early detection of spoilage and to prevent grain losses.2

When moulds and insects grow, and respire, they produce CO2, moisture and heat. Temperature sensors detect increases in temperature caused by mould growth or insect infestation, therefore indicating the presence of grain spoilage. However, they are not able to detect temperature increases caused by infestation unless the infestation is within a few meters of the sensors. CO2 sensors can detect the CO2 produced by moulds and insects during respiration. As the CO2 gas moves with air currents, CO2 sensors can detect infestations that are located further away from the sensor than temperature sensors. CO2 measurements are therefore an important part of the toolkit needed to monitor stored grain quality.2

Using CO2 Measurements to Detect Spoilage
CO2 monitoring can be used for early detection of spoilage in stored grains, and to monitor the quality of stored grains. Safe grain storage usually results in CO2 concentrations below 600 ppm, while concentrations of 600-1500 ppm indicate the onset of mould growth. CO2 concentrations above 1500 ppm indicate severe infestations and could represent the presence of mycotoxins.4

CO2 measurements can be taken easily, quickly and can detect infestations 3-5 weeks earlier than temperature monitoring. Once spoilage is detected, the manager of the storage facility can address the problem by aerating, turning, or selling the grain. Furthermore, CO2 measurements can aid in deciding which storage structure should be unloaded first.2

Research published by Purdue University and Kansas State University have confirmed that high CO2 levels detected by stationary and portable devices are associated with high levels of spoilage and the presence of mycotoxins.4,5 Furthermore, they compared the ability of temperature sensors and CO2 sensors in a storage unit filled with grain to detect the presence of a simulated ‘hot spot’ created using a water drip to encourage mould growth.

The CO2 concentration in the headspace of the storage unit showed a strong correlation with the temperature at the core of the hot spot, and the CO2 sensors were, therefore, able to detect biological activity. The temperature sensors were not able to detect the mould growth, despite being placed within 0.3-1 m of the hotspot.6

To enable efficient monitoring of grain spoilage accurate, reliable and simple to use CO2 detectors are required. Gascard NG Gas Detector from Edinburgh Sensors provide accurate CO2 measurements along with atmospheric data, enabling grain storage managers to make decisions with confidence.

The Gascard NG Gas Detector uses a proprietary dual wavelength infrared sensor to enable the long term, reliable measurement of CO2 over a wide range of concentrations and in temperatures ranging from 0-45 °C. Measurements are unaffected by humidity (0-95% relative humidity) and the onboard pressure and temperature sensors provide real-time environmental compensation, resulting in the most accurate CO2 concentration readings.

Conclusion
Easy, fast, and accurate CO2 concentration monitoring during grain storage can provide early detection of grain spoilage, resulting in reduced grain losses, higher quality stored grain, and lower mycotoxin levels. CO2 monitoring could save millions of dollars annually in the grain production industry.4


References

  1. Kumar D, Kalita P, Reducing Postharvest Losses during Storage of Grain Crops to Strengthen Food Security in Developing Countries. Foods 6(1):8, 2017.
  2. http://www.world-grain.com/Departments/Grain-Operations/2016/7/Monitoring-CO2-in-stored-grain.aspx?cck=1 Accessed May 25th, 2017.
  3. HGCA Grain storage guide for cereals and oilseeds, third edition, available from: https://cereals.ahdb.org.uk/media/490264/g52-grain-storage-guide-3rd-edition.pdf Accessed May 25th, 2017.
  4. Maier DE, Channaiah LH, Martinez-Kawas, A, Lawrence JS, Chaves EV, Coradi PC, Fromme GA, Monitoring carbon dioxide concentration for early detection of spoilage in stored grain. Proceedings of the 10th International Working Conference on Stored Product Protection, 425, 2010.
  5. Maier DE, Hulasare R, Qian B, Armstrong P, Monitoring carbon dioxide levels for early detection of spoilage and pests in stored grain. Proceedings of the 9th International Working Conference on Stored Product Protection PS10-6160, 2006.
  6. Ileleji KE, Maier DE, Bhat C, Woloshuk CP, Detection of a Developing Hot Spot in Stored Corn with a CO2 Sensor. Applied Engineering in Agriculture 22(2):275-289, 2006.

 


Demand for IoT testing and monitoring equipment.

28/06/2015

As the trend towards connected living and the Internet of Things (IoT) continues to permeate home, work and city solutions, the need to keep tabs on a myriad of connected devices will thrust the global IoT testing and monitoring equipment market into the spotlight. The incorporation of machine-to-machine (M2M) communication – central to IoT deployment – as well as modules that require less power and bandwidth will bring with it several challenges that turn into a boon for testing and monitoring vendors.

New analysis from Frost & Sullivan, Global fands Equipment Market, finds that the market earned revenues of $346.9 million in 2014 and estimates this to reach $900.1 million in 2021.

“As the escalating number of connected devices adds breadth to the IoT concept, solutions that can proactively monitor, test and zero in on anomalies in the infrastructure will garner a sustained customer base,” said Frost & Sullivan Measurement and Instrumentation Research Analyst Rohan Joy Thomas. “The incorporation of new testing and wireless standards will broaden testing requirements and further aid development in IoT testing and monitoring equipment.”

Educating end users on the importance of interoperability and the requirement for specialised testing equipment is vital for market success. Currently, the lack of end-user awareness on the need for proactive solutions stalls the large-scale use of IoT testing and monitoring equipment. End-user inability to identify the most appropriate solution from a plethora of identical systems too limits adoption.

High capital expenditure associated with procuring equipment coupled with inadequate standardisation around IoT adds to the challenge. Such concerns over high investment costs and standardisation should abate as IoT matures in the years ahead.

“Industry vendors must fill the gaps in their product portfolio in order to facilitate an open testing environment and lay the foundation for long-term growth,” concluded Thomas. “To that end, building partnerships with or acquiring participants from other industry niches will help solution providers extend their horizons in the global IoT testing and monitoring equipment market.”


Successful trial for new remote Phosphate monitor!

12/12/2014

Researchers at Britain’s Centre for Ecology & Hydrology (CEH) have conducted trials on the river Thames to evaluate a new remote phosphate monitoring technology (Cycle-P) as part of a high-frequency (hourly resolution) monitoring programme that is studying river nutrient concentrations and how they are affected by algal abundance. The monitoring system ran continuously over the summer of 2014, measuring total reactive phosphate levels in the river, day and night, seven days a week.

CEH_ThamesTrial2014

These results have now been compared with manually collected samples that were analysed in a laboratory with the traditional Murphy and Riley spectrophotometric method on unfiltered samples, and Dr Mike Bowes, senior nutrient hydrochemist at CEH, says: “The Cycle-P is working really well; the system operated independently for long periods and produced results that tracked our lab samples closely.”

Most water quality parameters are relatively simple to measure with low-power accurate sensors. However, the measurement of phosphate necessitates colorimetric analysis and this presents a significant challenge in remote locations with difficult access or where mains power is not available. The Cycle PO4 from OTT Hydrometry (known as the Cycle-P) is therefore gathering considerable interest because it is battery powered and able to operate unattended in the field, running over 1,000 tests before a field service is necessary to change the reagents.

The Cycle-P is an in-situ total reactive phosphate analyser that has been designed for operation by non-chemists. Combining microfluidics with state-of-the-art optics to provide high levels of precision and accuracy, the Cycle-P stores results in an onboard logger, but when combined with telemetry, delivers almost real-time data at user-selectable intervals (typically 1 to 4 hours). The quality of the instrument’s data is underpinned by QA/QC processing in conjunction with an on-board NIST standard. The Cycle-P methodology is based on US EPA standard methods, employing pre-mixed onboard colour coded cartridges for simple reagent replacement in the field.

Phosphate is a key nutrient in the maintenance of aquatic animal and plant life. However, it is also considered to be one of the most important pollutants in surface waters. Excessive quantities, through natural accumulation or derived from human activities such as wastewater treatment and agricultural runoff, can stimulate excessive growth of algae – algal blooms. This reduces light for plants and can lead to oxygen depletion, bacterial growth and eutrophication. In addition, some algal blooms produce toxins that are harmful to other organisms. High phosphate concentrations can therefore cause enormous ecological and aesthetic damage to streams, lakes, canals, rivers and oceans.

The River Thames basin is facing growing pressures from rapid population growth, intensive agriculture, climate change and water resource challenges. Researchers are therefore investigating the changes in water chemistry and ecology that are taking place as water quality improvements are implemented under the EU Water Framework Directive. These monitoring activities provide vital scientific evidence that inform future catchment management decisions.

thames_testDr Bowes has been running a Cycle-P in the Thames at Goring in Oxfordshire since 18th March 2014, as part of the CEH Thames Initiative Research Platform . He is head of the Water Quality Processes group, which has a long track record of using phosphorus auto-analysers, and is therefore an ideal person to assess the merits of this new technology. Furthermore, his research interests include: the impact of changing water quality on periphyton and phytoplankton biomass in rivers; nutrient loads to rivers from sewage and agriculture, and the identification of factors that control the timing and magnitude of algal blooms.

Mike has tried a number of phosphate monitoring technologies in the past but has found them to be either too unreliable or power-hungry. “Much of our work involves monitoring rivers in remote sites that do not have mains power, so I was naturally very interested to learn about the Cycle-P,” he explains. “Our research is designed to identify the causes of algal blooms and to understand the factors that trigger both blooms and algal dieback; the ability to monitor phosphate in remote locations is therefore critical to the success of our work, because manual or even automatic sampling for laboratory analysis, incurs significant delays and increases costs.”

“We were very pleased to be able to help with this research,” adds OTT Hydrometry’s Nigel Grimsley. “The impact of phosphates from agricultural run-off and wastewater treatment is one of the major issues affecting surface water quality and reliable continuous monitoring is essential if this issue is to be managed effectively.

“The Cycle-P has already worked extremely well in a variety of international projects, but it was vital for its capabilities to be demonstrated in UK waters, and the CEH Thames Initiative provided an ideal platform to do so. I am grateful to CEH for the opportunity that they have provided and I look forward to reporting feedback from a number of recent further UK installations.”


Discrete or Continuous Flow Analysis – which is better?

28/01/2014

A wide variety of factors affect the choice of analytical instrument. These include target workload (samples/hour), variety of chemistries, methods required, bench space, staff availability etc. In the following article Lalicia Potter, Technical Sales & Support Director at SEAL Analytical, examines one of the common decisions facing laboratory managers.

As the manufacturer of an instrumentation range that includes both discrete analyzers and continuous segmented flow analyzers, SEAL Analytical’s technical support chemists are often asked which is the better technique. Both offer fast, automated, colorimetric analysis of multiple samples, however, the answer depends on the current and future analytical requirements of the laboratory.

Descrete Analyser

Descrete Analyser

SEAL’s discrete analysers employ sample trays and discrete reaction wells in which the colorimetric reaction takes place. In contrast, segmented flow analysers (SFA) employ a continuous flow of samples and reagent, segregated by air bubbles within tubing and mixing coils.

In general terms, discrete analysers are ideal when automation is a priority and/or when many and varied tests are needed on different samples. SFA is ideal when a larger number of samples are to be analysed for a smaller number of chemistries. However, both techniques are flexible, so it is important that expert advice is sought in the choice of analyzer and that the instrument is configured to meet the precise needs of the laboratory.

Discrete Analysers
In order to minimise operator involvement, SEAL’s discrete analyzers are highly automated and simple to set up and run, even overnight. A robotic sampling arm works in conjunction with a stepper motor-driven syringe that is responsible for aspirating, dispensing and mixing accurate and precise quantities of sample and reagent. The SEAL AQ1 and AQ2 discrete analyzers can run seven different chemistries from each sample in the same run – and another seven in another run. These instruments have three separate wash stations including a unique probe washer, so cross-contamination is not a problem. This unique washing feature means that even ammonia (using Phenate), nitrate by cadmium reduction– (using ammonium chloride buffer) and low level phenol can be run together with no issues.

SEAL has also built an auto-dilution feature into the discrete analysers for preparing standards automatically and handling over-range samples. These diluted sample results are automatically bracketed by QC sets.

The reproducibility and detection limits of these discrete analysers have been optimised by ensuring that each sample is read in the same optical glass cuvette with a 10mm path length. The sample is always read in the same position in front of the detector, which eliminates any potential issues with scratching or reaction well variability that can be found with direct-read systems. Since the liquid is moved and not the tray; fewer moving
parts maximises reliability.

Most discrete analysers employ miniaturised components to reduce reagent consumption and waste costs. For example, both the AQ1 and AQ2 analysers use just 20 to 400µl of reagent per sample.

Segmented Flow Autoanalysers
Based on the original tried and tested technology of the Technicon™ /Bran Luebbe™ AutoAnalyzer, today’s SFAs deliver fast, accurate analysis for enormous numbers of samples; the QuAAtro for example can run up to 600 tests per hour. SFA’s are also highly automated and once the analyzer is configured and the reagents and samples are loaded, reliable unattended operation is a major benefit.

Flow Analyser

Flow Analyser

A basic SFA system consists of an autosampler, a peristaltic pump, a chemistry manifold, a detector and AACE data acquisition software. Sample and reagents are pumped continuously through the chemistry manifold and
air bubbles are introduced at precisely defined intervals, forming unique reaction segments which are mixed using glass coils. With SFA, even slow reactions run to completion and the ratio of sample to reagents in the detector reaches a constant maximum value; the steady-state condition.

SFAs have been developed for running a few parameters on a larger number of samples, and the SEAL SFAs are the system of choice for marine and seawater organisations and anyone running very low nutrient waters. The SEAL AutoAnalyzer 3 and QuAAtro deliver high levels of performance and reproducibility, and are also the systems of choice for tobacco, soil and fertiliser testing around the world. These analysers provide maximum sensitivity by ensuring that the reaction always goes to completion, and with a digital true dual-beam detection system with real time referencing, the highest reproducibility and very lowest detection limits are achieved.

In summary, when choosing the most appropriate analytical technique, it is important to consider both the current and likely future needs of the laboratory. However, one of the reasons behind the large numbers of SEAL instruments in laboratories around the globe, is that each analyzer has been configured to meet the individual needs of its laboratory. So, it is good practice to contact SEAL’s technical support team at an early stage because if the question is: “Which technique is better,” the answer is: “It depends…”


Thrilling results for nutrient monitors!

13/08/2012

Commenting on the results of a 4 month trial of nutrient monitors, Hach Lange’s John Moroney says he is “absolutely thrilled” with the report on his company’s instruments which outperformed the competition in almost every measure.

Hach Lange Ammonia & Phosphate Monitors

Background
The levels of nutrients, such as ammonium and phosphates, entering natural water resources is of great concern because these nutrients can either remove vital oxygen or lead to excessive plant growth and algal blooms, which harm wildlife through eutrophication. In addition, high levels of phosphate or nitrate in abstracted water significantly add to the cost of drinking water treatment. The management of nutrient levels is therefore dependent on the ability to monitor accurately and reliably, and as a result, a group of British water companies organised a joint monitoring trial to determine the best instruments.

Trial results
The trial involved the installation of turbidity, phosphate and ammonium monitors from the market’s leading manufacturers at two designated final effluent plants within Britain. Hach Lange provided an AMTAX sc ammonium analyser, a PHOSPHAX sc phosphate analyser and a SOLITAX sc turbidity analyser for the trial.

The SOLITAX sc performed better than any of its competitors and as a result, Severn Trent Water has adopted the instrument in a framework agreement.

Summarising the report on the AMTAX sc and PHOSPHAX sc, John Moroney says “We are delighted to report that these analysers came first in almost all of the key performance measures, which included correlation to diurnal data, variance to laboratory data, and maintenance requirements. However, the panel decided to take the List Price as opposed to current framework prices for the commercial part of the assessment. However, the overall results are extremely encouraging and I know that our customers are very impressed with the technical performance of these units coupled with such low levels of maintenance. The manufacturers did not have access to their equipment during the trial, but over the 4 month period, the AMTAX required 2 hours of maintenance and the PHOSPHAX just one hour!”

Monitoring nutrients at a reduced cost from inlet to effluent
The whole life costs of the Amtax sc for Ammonium and Phosphax sc for orthophosphate have been drastically reduced as a result of the chemistries employed. With the Amtax sc, a gas sensing electrode is utilised which means that reagent consumption is halved in comparison with traditional colorimetric analysers. For the Phosphax sc, the stability of the vanado-molybdate method, means that calibration is not necessary and therefore no calibration standards are required.

The results of this trial will be of great interest to process managers who have to comply with tighter discharge consents as a result of the Water Framework Directive. Couple this with the fact that Hach Lange can now offer sample preparation systems that deliver continuous samples from the inlet all the way through to final effluent, John Moroney firmly believes these analysers lead the way in reliability, accuracy, stability and the lowest whole-life costs.


Caffiene concentration

18/11/2011

Measuring caffiene concentration in decaff coffee!

The Reason
While it may mystify those of us that need strong coffee to get through the workday, some people actually drink decaf (decaffeinated coffee), whether for health reasons (high blood pressure, hypertension, sleep difficulties), pregnancy cautions, or personal preference. In lieu of more firm legal standards, decaf is supposed to have its caffeine content reduced by no less than 97.5% of the source coffee (USDA guideline). Accurate validation of the caffeine levels in decaffeinated coffee bean batches would reduce sensitive consumers’ health risks by preventing the wildly inconsistent caffeine levels among available “decaf” blends (as documented by the Journal of Analytical Toxicology –  McCusker, Rachel R., Brian Fuehrlein, Bruce A. Goldberger, Mark S. Gold, and Edward J. Cone. “Caffeine Content of Decaffeinated Coffee.” Journal of Analytical Toxicology 30.8 (2006): 611-13.). Moreover, producers can use real-time caffeine monitoring to conclude the decaffeination cycle as soon as the specified caffeine threshold is achieved, thus wasting no more caffeine solvent or production time than absolutely necessary.

An online analysis solution would provide continuous, live caffeine measurement in an automated fashion. The High-Performance Liquid Chromatography currently used in some caffeine applications is quite costly to own and maintain while delivering slow response.

The Method
While certain selective solvents are extremely effective at removing caffeine from coffee beans, many of these chemicals have been classified as carcinogenic or toxic. Though less powerful, the supercritical CO2 extraction method is a harmless decaffeination process common in large-scale operations. Supercritical CO2 fluid is a hybrid gaseous/liquid resource maintained by exceeding the critical temperature (31 °C) and pressure (73 atm) of CO2; for the supercritical CO2 to act as an effective solvent for caffeine molecules, it actually has to be kept at more extreme conditions (around 94°C and 225 atm). These conditions are expensive to maintain, and the 10-hour process cycle is time-consuming; the caffeine extract is sold off to pharmaceutical and soft drink companies, but this only partially alleviates process cost.

With real-time caffeine monitoring at ±1 ppm accuracy, the OMA-300 Process Analyzer allows decaf coffee producers to automatically end an extraction cycle when the specified caffeine maximum is reached. Doing away with the preset 10-hour cycle, this method banishes both overprocessing (which wastes production resources) and underprocessing (which upsets customers). While highly suitable for monitoring the 0-1,000 ppm caffeine range established by international standards as “legally” decaf, the OMA-300’s UV-VIS spectrophotometer has a true detection limit of 2 ppm caffeine, thus theoretically capable of validating a cup of perfect decaf.

 


New monitoring technology helps reveal Arctic secrets

14/11/2011

Pic: Catlin Arctic Survey!

Last month we featured an article by Quantitech’s Dominic Duggan on technology for measuring the gases trapped in the High Arctic which could tip climate scales. This time we  describe how a group of Arctic researchers have employed the latest monitoring technology from YSI Hydrodata to investigate the effects of climate change, by measuring temperature and salinity in the water column beneath surface ice. The results of the investigation could cast new light on our understanding of the ways in which shifting ocean currents impact upon the climate in northern Europe.

A group of Arctic researchers has employed the latest monitoring technology to investigate the effects of climate change, by measuring temperature and salinity in the water column beneath surface ice. The results of the investigation, which utilised YSI’s new ‘Castaway-CTD’, could cast new light on our understanding of the ways in which shifting ocean currents impact upon the climate in northern Europe.

The Catlin Arctic Survey is a unique collaboration between scientists and explorers, and the Castaway enabled the researchers to work very quickly in extremely hostile conditions because the device is small, portable and can be operated in the field without the aid of a computer.

Previous research looked at ice thickness and ocean acidification, but the latest Catlin Survey work has studied freshwater currents beneath the ice surface to help understand their effect on bottom-up ice melting, which is disrupting global ocean circulation.

Background
It is well established that the Arctic environment has a significant effect upon the global climate. For many years, climate scientists have raised concerns over future shifts in global weather systems and highlighted the role that the Arctic plays in such systems. Changes in the Arctic heavily contribute to the Thermohaline Circulation; a giant aquatic conveyor connecting the planet’s oceans, distributing heat, oxygen and nutrients. Changes to the Thermohaline Circulation combined with vast atmospheric, positive feedback loops (that produce large quantities of methane from the melting permafrost) that occur within the Arctic, can have drastic repercussions on the global climate.

In 2011 the Catlin Arctic Survey was commissioned by The Catlin Group to assess the temporary ice base on the Prince Gustav Adolf Sea,  on the northern most fringe of Canada’s Arctic archipelago, around 800 miles from the North Pole.

Organic Matter
A key measurement parameter for the team was Coloured Dissolved Organic Matter (CDOM), because high levels can result in 40% higher light absorption. In the Arctic, much of the CDOM is derived from three of Northern Russia’s vast river mouths. Commenting on the significance of CDOM, Dr Victoria Hill, a British-born Oceanographer, said: “Locally CDOM should act to increase thermal stratification, trapping heat near the surface. The water becomes more stable and there is reduced mixing. However, if surface ice melts, it creates an upper layer of fresh, cold water which does not mix. In the long run, the surface water becomes warmer and no longer sinks to form the deep and colder water that draws the Gulf Stream to Northern Europe.”

The researchers anticipated that the Arctic Ocean would be highly transparent, because the rivers contributing CDOM were frozen. However, the team determined that this was not the case. In fact, Dr. Hill revealed: “In the Chukchi, between 70 and 80% of solar radiation was being absorbed by CDOM.” In another data set, retrieved by Adrian McCullum, from the Scott Polar Research institute, concerning results were obtained from a sample of the water column; at a depth below 200m, the water was 1 Deg C colder than expected. This significant change in normally stable, deep water, suggests that the surface melt water was sinking, driving warmer water into contact with the surface ice. This sparked further interest into the variation of temperature in the Arctic Ocean.”

Arctic Ocean profiling
Highly specialised equipment is necessary for profiling very deep water. However, YSI’s Castaway CTD has been developed to provide a simple and accurate method for the rapid determination of conductivity, temperature and depth down to 100 meters. Incorporating GPS, sensors, data logging and a display into one compact instrument, the device is literally cast (or lowered) into water and retrieved immediately. The Castaway automatically collects and computes the data and users are able to see the result of their work immediately on a small display. The investigation in to CDOM’s effect on ocean temperatures was therefore an ideal application for YSI’s Castaway-CTD (conductivity, temperature and depth). A light-weight and easy to use hydrographic profiling instrument, with high-resolution sampling of conductivity, temperature and depth, the Castaway was a vital piece of sampling equipment used by the Catlin Arctic Survey team.

Castaway CTD – user feedback
Ann Daniels, of the Catlin Expedition Team was keen to stress the importance of the CTD to the success of the survey, “It was very lightweight, perfect for a long-range scientific expedition. The LCD display was very useful as it allowed the team to view information from the CTD while in the field, and allowed ‘live science’ to be relayed back to HQ by phone. It meant there was interest generated during the expedition rather than having to wait till the unit was returned back to Britain.”

Easily deployed, the Castaway was cast into bore holes created in the Arctic ice, and allowed to free –fall at depths of up to 100 metres, its sensors gathering data, including a temperature system able to respond within 200 milliseconds. The device was especially well designed for surveys in this extreme environment. A rugged, non-corrosive housing, a flow-through design, AA battery power and tool-free operation meant Castaway was perfectly suited for an Arctic survey.

Commenting on the value of the Castaway to the survey team, Science Programme Manager Dr. Tim Cullingford, said: “The Castaway CTD was deployed by the explorer team for the Catlin Arctic Survey 2011 during March to May.  The conditions at this time of year in the Arctic are extreme, with temperatures down to -40DegC.  Nevertheless, the Castaway was successfully deployed through holes drilled in the ice to an ocean depth of 100 meters.  Its compact nature meant that it was easy to handle (e.g. keeping it warm just before deployment was simply done by placing inside the explorer’s jacket).  The screen allowed an immediate return of temperature and salinity readings, which were successfully relayed back to London HQ on a regular basis.  In the round, the Castaway provided an easy and useful back-up to the data returned by our main CTD.”

Maintenance of the Castaway is very simple; a quick rinse with fresh water and the occasional scrubbing of the corrosion-resistant electrodes is all that is required to keep the Castaway-CTD in shape between recommended annual factory calibrations.

Warm water application
Recently, the Castaway-CTD was employed in a similar manner on BBC 1’s Ocean Giants narrated by Stephen Fry.  The first episode in a 3-part series investigated why Blue Whales, usually a migratory species, stay around the Sri Lankan coastline in the warmer waters. Marine biologist Asha de Vos wanted to study the features of this water that sustain these whales year round, using the Castaway to record salinity and temperature levels at differing depths she concluded: “Along our coastline, there are areas of mass upwelling of cold, nutrient rich water from the depths. These upwellings provide the perfect conditions for whale food; krill.”

Whilst Castaway retains all the advantages of a traditional CTD system, its additional appeal lies with its convenience, flexibility and speed – whether the instrument is being used in the freezing waters of the Arctic or the warm tropical waters of Sri Lanka.


Wastewater treatment down-time ‘not acceptable’

07/11/2011
Why monitoring plays such an important role at a manufacturing business in the North East of England.

Reliable 24/7 monitoring and control of a pharmaceutical company’s wastewater facility is fundamentally important to the successful operation of the entire business. This is because failures or down-time in the wastewater treatment process would quickly result in waste stream back up. It follows therefore that monitoring equipment should be extremely reliable and this is why Shasun Pharma Solutions employs Hach Lange monitoring equipment at many locations around their manufacturing facility just north of Newcastle upon Tyne (GB).

Shasun Pharma Solutions provides research and contract manufacture services to the pharmaceutical industry, including small scale manufacture for clinical trials and full scale commercial manufacture of advanced intermediates and active pharmaceutical ingredients. With both large and small customers spread across Europe, North America, Latin America and Asia, the business has to be able to demonstrate a high level of environmental management.

Craig Goodman manages Shasun’s wastewater treatment plant which employs three 2,500m3 tanks to treat industrial wastewater by an activated sludge process that utilises oxygen and a biological floc to break down the waste materials. Craig says he uses liquid oxygen rather than mechanical aeration “because pure oxygen enables the plant to respond much more quickly and requires around one fifth of the volume for aeration.”

The LDO!

The liquid oxygen is stored onsite and provides Craig with almost instantaneous control of dissolved oxygen in the plant. He says: “This is made possible as a result of the new breed of dissolved oxygen sensors that we use – the ‘LDO’.

“In the past, we relied on traditional membrane based DO sensors but these required a high level of maintenance and tended to drift; it was usually necessary to recalibrate every week. However, the new LDO sensors last for over a year without recalibration and we then simply replace the sensor cap, so our monitoring activity is now significantly easier and more accurate and reliable.”

The liquid oxygen is vapourised and fed into the tanks via a single entry point Venturi at around 7bar and the objective is to maintain DO at 3mg/l +/- 0.2. In addition to online sensors for pH and ammonium, the LDO sensors are connected to an SC1000 controller which also monitors the ‘health’ of the sensors and interfaces with the plant’s control systems.

Emphasising the importance of accurate DO control, Craig says: “In addition to the waste stream from our own plant, we also treat waste from third parties so we do not always know what is coming down the line and that is why we need to be able to respond quickly; overdosing oxygen would kill the bugs and underdosing may cause other problems such as bulking.”

Shasun’s wastewater treatment facility effectively removes 95% of COD (Chemical Oxygen Demand) which is a common method for the determination of organic pollution. COD testing is therefore conducted onsite and Craig’s team employ a Hach Lange spectrophotometer for this purpose. The pre-filled, bar-coded Hach Lange COD tubes ensure that every test is conducted in exactly the same way, with exactly the same reagents. Bar-coding ensures that the spectrophotometer recognises each sample and ensures traceability of results.

Craig’s team conducts between 30 and 100 COD tests every week and this data helps in the efficient running of the plant and helps ensure compliance with the discharge consent. It also provides Craig with useful information for the calculation of waste treatment charges for third parties. “This is because 1 tonne of COD requires approximately one tonne of liquid oxygen for treatment,” he explains.

In recent years, all of the laboratory, portable and online wastewater testing equipment has been supplied by Hach Lange. Craig says: “Down-time in our wastewater treatment plant would not be acceptable, so we have to use the most robust and reliable instruments available and in our experience that means choosing Hach Lange.”


Gases trapped in High Arctic could tip climate scales!

07/10/2011
By Dominic Duggan, Quantitech.

Enormous quantities of greenhouse gases (GHG) exist within Arctic ice and frozen soils, so with the threat of global warming, a clear understanding of the relationship between GHG in the atmosphere and in the ice/soil is vital because melting of permafrost could cause a dangerous climate tipping point. There can be few more challenging environments for monitoring gases, but PhD researcher Martin Brummell from the University of Saskatchewan has successfully employed a Gasmet DX4015 FTIR analyser to do so in the High Arctic of Canada. This article explains the procedures and challenges of multiparameter gas detection in freezing remote locations.

Is this beautiful Arctic scene hiding a climate tipping point?

Working in the field imposes a number of requirements for analytical equipment. However, the extreme weather conditions of the High Arctic impose a new level of capability that is rarely available as standard. Field work in such conditions must be simple, flexible and fast, but most importantly, Martin Brummell says, “The equipment must also be extremely reliable because you do not have the luxury of a local Quantitech engineer.

“The Gasmet DX4015 was also the ideal choice because, as an FTIR analyser, it is able to monitor almost any gas, which is normally a feature of mains powered laboratory instruments, but the DX4015 is portable and powered by a small generator, so it is ideal for monitoring in remote locations.”

Sampling and analysis in the Arctic
A set of simple, perforated steel tubes were driven in to the soil, to the point of the permafrost threshold. Inside these tubes gases within the soil were allowed to reach equilibrium via diffusion over 24 hours. This allowed Brummell to analyse gas concentrations to a depth of 1 metre. The procedure was simple and therefore reliably repeatable. Furthermore, measurement of gas concentrations at different depths enabled direct comparison with soil analysis.

Using FTIR in the ‘field’

Ready to measure!

The Gasmet DX4015 is a portable FTIR gas analyser for ambient air analysis. FTIR, an abbreviation for fourier-transform infrared, is an interferometric spectroscopic instrument (interferometer) that uses the infrared component of the electromagnetic spectrum for measurements. A fourier-transform function is applied by the interferometer to obtain the absorption spectrum as a function of frequency or wavelength. Consequently, this unit is able to simultaneously analyse up to 50 gas compounds. The analyser is typically set up to measure a variety of different gases, including VOC´s, acids, aldehydes, and inorganic compounds such as CO, CO2, and N2O.

The DX4015 is operated using a laptop computer running Calcmet™ software, a program that not only controls the analyser but also undertakes the analysis. This software is capable of simultaneous detection, identification and quantification of ambient gases, which gives the DX4015 its ability to simultaneously analyse multiple gases in near-real-time.

The FTIR’s many beneficial traits, such as reliability, precision and flexibility make it a vital piece of analytical equipment in a very wide variety of applications including industrial emissions monitoring, occupational safety surveys, engine exhaust testing, process monitoring, leak detection, emergency response, chemical spill and fire investigations, and many others.

Brummell’s use of the DX4015 on his most recent research expedition investigating the soils in the polar deserts of the High Arctic, highlights the model’s capabilities in the field. Carried out on Ellesmere Island in the Baffin Region of Nunavut in Canada, the DX4015 had to perform reliably in extreme environmental conditions. The analyser was used to monitor the production, consumption and atmospheric exchange of the greenhouse gases Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O); all three being major components of natural biogeochemical cycles. These gases are each released and up-taken by soil microbes in the Arctic.

The DX4015 was used to examine both the flux of gases from the soil surface and the concentration profiles of gases in the soil’s active layer above the permafrost. In doing so the FTIR provides raw data consisting of gas concentrations in parts-per-million (ppm).

Explaining his reasoning behind choosing the Gasmet DX4015, Martin Brummell highlighted some of the analyser’s key advantages: “The real-time nature of the Gasmet FTIR, allows me to see results within minutes of setting up in the field. This permits me to make changes to the experimental design and further investigate unexpected results whilst in the field. This contrasts with traditional methods of soil gas analysis, which employ lab-based gas chromatography systems and collection of samples ‘blind’ in the field.”

Results
Surprisingly, the work revealed areas of strong CO2 and CH4 production immediately above the permafrost. Brummell believed this was the result of the relative disparity in carbon distribution in Arctic soils in comparison with warmer climes. Carbon accumulates far lower in Arctic soils due to a process known as cryoturbation; the constant mixing and burying of organic matter, which fuels microbial activity at a deeper level.

Comparisons between the surface flux and the soil profile for each of the greenhouse gases was a key objective within Brummell’s investigation. Most notably, he observed a negative surface flux for NO2, but no significant regions of consumption were identified. The location of the NO2 sink is not yet clear, nor the organisms and biogeochemical processes responsible.

Conclusions
Martin Brummell’s research provided a new but complex insight into the production, consumption and exchange of greenhouse gases and soil microbe pathways in the Arctic. His work highlighted the importance of reliability, ruggedness, flexibility and accuracy in the equipment which is employed in such work. However, the ability of the DX4015 to provide simultaneous measurement of multiple gases in near real-time was a major advantage.

In comparison with all of the equipment that is necessary for research in Arctic conditions, one might imagine that a highly sensitive analytical instrument would be the most likely to be adversely affected. However, Martin Brummell found this not to be the case with the Gasmet DX4015: “In contrast to other field equipment I have used in the High Arctic, including self-destructing sledgehammers, unreliable generators and broken fibre-optic cables, the Gasmet DX4015 has never failed even in the most difficult field conditions. It has happily survived air-transport, inconsistent electrical supply, low temperatures, rain, snow, mud and all other insults, and always gives me accurate, precise measurements of gas concentrations.”


Successful final effluent monitoring trial at British plant

29/09/2010

Engineers at Intellitect Water have developed a version of the company’s innovative multiparameter water quality monitoring sonde, the ‘Intellisonde FE™’ that can continuously monitor final effluent without the need for chemicals or frequent maintenance and calibration.

A unit has been installed on the final effluent of Wessex Water’s Holdenhurst wastewater treatment plant in Bournemouth (GB) since January 2010 and initial results indicate that this new technology could bring the advantages of online monitoring to a much larger proportion of wastewater treatment plants.

The Intellisonde FE™ is a very small multiparameter monitor that is able to run unattended for weeks. Low capital and operational costs will mean that it will become possible to install continuous monitors at plants for which the costs were previously considered prohibitive.

The Bournemouth trial was conducted adjacent to traditional online monitoring instruments and Wessex Water’s Regional Waste Scientist Mike Robinson, says: “The trial is proceeding very well, with the Intellisonde FE™ producing measurements that closely mirror data from our other monitors and from manual tests. For example, we employ traditional online single parameter monitoring instruments at the outfall and we also utilise portable instruments to measure parameters such as clarity and ammonium.”

The Intellisonde FE™ is located in a flow-through chamber which is fed by a submerged sampling pump located in a sump. A level gauge ensures that the sump does not pump dry. The trial unit has been fitted with a small strainer to prevent any possible accumulation of dirt in the measurement chamber. However, it has only been necessary to occasionally remove small stones and snails, although these did not have any effect on the measurements.

Inside the sonde head, tiny solid-state sensors continuously monitor conductivity, pH, temperature, turbidity and ammonium. The unit can log at intervals between one minute and one hour on all parameters simultaneously. Measurements are retained on an internal datalogger, however data is transmitted via GPRS to a dedicated server which feeds a web site to enable 24/7 access to (almost) live water quality information. The units are also able to provide an analogue output that could interface with a water company’s regional telemetry system, providing a closed-loop system for data protection.

Recorded data during February and March 2010

The graph shows recorded data during February and March 2010, and Mike reports that no calibration or maintenance was necessary during this period. The data shows several weeks of unattended use, with reported ammonia levels agreeing well with a second instrument installed at the same point.  Simultaneous monitoring of other parameters can indicate possible causes of variations in effluent quality, which may in turn lead to more efficient treatment management.  For example, reduced conductivity may indicate a correlation between rainfall and ammonia.  Without this data, it would be significantly more difficult to diagnose causes of variations in effluent quality, particularly at unmanned treatment works where data is restricted to discrete samples during the day.  It should be noted that the ammonium peaks in this data are recorded during the night.

Intellitect Water’s Technical Director David Vincent, believes that recent changes in monitoring requirements will greatly enhance the demand for the new Intellisonde FE™. He explains, “The Environment Agency (EA) is currently engaged upon a programme of passing the responsibility for collecting, analysing and reporting discharge quality to operators. At the same time, the level of monitoring required will depend on the level of pollution risk that each discharge represents. Consequently operators, such as the water industry and the process industries, will have to develop a monitoring strategy that meets the requirements of the EA.”

The EA conducts infrequent audit checks on the plant effluent. However, the responsibility for maintaining effluent quality lies firmly with the water company and Mike Robinson believes that continuous monitoring offers substantial operational benefits. “One of the main advantages of 24/7 data is that it helps to identify spikes and enables process operators to determine the cause of the problem and thereby to adjust the treatment process,” he says. “Continuous data also helps with the identification of treatment deficiency and data for multiple parameters provides a better understanding of the whole process. For example, conductivity and temperature can provide useful supplementary data.”

Occasional sampling and analysis can be lower in cost than online monitoring. However, the main disadvantages are that a pollution incident could go undetected between sampling times and infrequent data does not support process optimisation. In contrast, David Vincent says, “The Intellisonde FE™ will provide continuous access to effluent quality data and thereby help to raise compliance levels even further.”

The Intellisonde FE™ will also provide major financial advantages. It is priced for volume deployment, significantly below traditional effluent monitoring systems, which means that it will become cost-effective for a much larger proportion of works and will save the cost of sampler visits and analysis.

From a water company perspective, Mike Robinson says, “This trial is generating a lot of interest amongst the management team and if we can prove that the lifetime costs are as low as they appear and if the unit continues to perform reliably, the low capital and maintenance costs will mean that the Intellisonde FE™ could find application at a large number of treatment works.”