Strathkelvin Instruments Limited

Strathkelvin Instruments Limited

Strathkelvin Instruments was founded in 1981, to develop instruments based upon precision dissolved oxygen measurement, for use in the biomedical research field. This remains a significant part of the company`s instrumentation range. In 1998, the opportunity arose to exploit the technology of a respirometer designed for biomedical research, for use in activated sludge respirometry. Initially the respirometry product development was directed towards toxicity testing, since there was no method anywhere in the world that would measure and calculate toxicity of wastewater to the actual activated sludge of the receiving works, in as little as 5-10 mins. Subsequently it became clear that, since respirometry is one of the 3 major processes in biological treatment (biodegradation, growth and respiration), by adding additional software, the respirometer could be used as a major tool in process control in treatment works.

Company details

Rowantree Avenue , North Lanarkshire , Scotland ML1 5RX United Kingdom
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Business Type:
Manufacturer
Industry Type:
Water Monitoring and Testing
Market Focus:
Globally (various continents)
Year Founded:
1981
Employees:
1-10

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We are the world’s leading supplier of precision respirometry and dissolved oxygen instruments for the Biomedical Research, Wastewater Treatment, and Product Testing markets.

The company, based in Scotland, sells it’s instruments worldwide. It has a policy of continuous development and innovation, and of ensuring quality in all aspects of its products. It also prides itself on an excellent record in after-sales service and customer satisfaction. Support for all instruments is provided by highly qualified technical staff, who are also available for pre-purchase advice.

In 2014 we launched our ASP-Con - Activated Sludge Plant Controller - a Self- Cleaning, Self-Calibrating instrument, measuring 16 wastewater parameters, including DO, Ammonia, SVI etc. This instrument is in-situ and allows feed forward/feed back control. The instrument will reduce energy costs substantially, whilst maintaining or further improving compliance. It’s Like Having Your Best Operator 24/7! Strathkelvin Instruments are a leading global supplier of precision respirometry and dissolved oxygen instruments for the Biomedical Research, Wastewater Treatment, and Product Testing markets. Our own research and development of new products and services continuously produces world-class products.

In Wastewater Treatment we have developed Strathtox, a world leader in closed cell respirometry and have gone on to launch Bioscope, a first in portable in-plant bacterial analysis. In Biomedical research our precision respirometry system for mitochondria and isolated cell research provides automatic recording, analysis and reporting for State 3 and State 4 respiration rates, ADP/O ratios and RCR in as low as 50ul samples. Customer care is our core value and we have built our reputation on this. Strathkelvin pride ourselves on our customer care and support and we continue to oversee this directly and through our network of distributors.

Our expertise is in the field of Activated Sludge Bacteria which are used to treat wastewaters.
Our instrumentation can quickly and directly measure Activated Sludge bacterial performance saving our clients time and money by determining the toxic effects of influents on your activated sludge and also the effects of optimising feeding and aeration programmes. The company has been making high quality instrumentation in the field of Respirometry since 1981 and has established an enviable reputation for quality, robustness and ease of use.

Strathtox is a fully integrated Respirometer where all testing is quick and simple, and tests are routinely completed within 10 minutes. Easy-to-use software provides automated results and graphs allowing a wide range of personnel to make effective use of Strathtox.

Bio-scope is a portable instrument that measures the respiration rate of bacteria in the plant under the prevailing load and environmental conditions. This provides operators with a real insight into the operation of their wastewater treatment plant.

Our expertise is in the field of Activated Sludge Bacteria which are used to treat wastewaters.

Our instrumentation can quickly and directly measure Activated Sludge bacterial performance saving our clients time and money by determining the toxic effects of influents on your activated sludge and also the effects of optimising feeding and aeration programmes. The company has been making high quality instrumentation in the field of Respirometry since 1981 and has established an enviable reputation for quality, robustness and ease of use.

ASP-Con (Activated Sludge Plant Controller) is our newest addition to the Strathkelvin line and we believe it is set to take the Wastewater Market by storm.  Click on our ASP-Con page to look at the amazing features and capabilities.

Strathtox is a fully integrated Respirometer where all testing is quick and simple, and tests are routinely completed within 10 minutes. Easy-to-use software provides automated results and graphs allowing a wide range of personnel to make effective use of Strathtox.

AS Bioscope is one of our newer developments,  providing a portable instrument that measures the respiration rate of bacteria in the plant under the prevailing load and environmental conditions. This provides operators with a real insight into the operation of their wastewater treatment plant.

Clients such as Water Companies, Consulting Engineers, Industrial Waste Generators, Utility Operators and Academic Establishments have purchased the instrument for a wide range of applications including:

  • Toxicity management
  • Plant profiling
  • Aeration optimisation
  • Plant efficiency
  • Pilot plant monitoring
  • Tankered waste testing
  • Feed programme optimisation
  • Nitrification management
  • Audit and conformance management

Strathtox (™) is a highly flexible and robust Respirometer used for the measurement of:

  • Respiration inhibition (toxicity of influents to activated sludge)
  • Nitrification inhibition
  • Aeration efficiency
  • Sludge health monitoring
  • Critical Oxygen Point Analysis
  • Short-term BOD
  • Process optimisation testing including Nutrient optimisation and Aeration set point optimisation
  • BOD and Nitrification capacity testing

AS Bioscope is a robust multiple parameter respirometer for in-plant basin bacterial analysis and is used for:

  • Comparative analysis of bacterial respiration at single or multiple points over a number of plants
  • DO and temperature measurements
  • SVI or SSVI settlement characterisation

Working in combination these two instruments allow Plant Operators to gain the operational and financial benefits of achieving full control over their wastewater treatment operation. Many of our customers have been able to recover their investment in well under 12 months.

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  • Process Optimisation
  • Wastewater Toxicity Testing
  • Wastewater Toxicity Tracking
  • Toxicity-Based Consents
  • Toxicity Reduction Tests
  • Monitoring Sludge ‘Health’

Process Optimisation

Respiration rate of activated sludge has been recognised as a key controlling element in the modelling of process control, by the International Water Association Task Group. Actual respiration rate of the sludge in the aeration tanks, as well as the endogenous and maximum respiration rates are variables that indicate the rate of BOD removal and aeration requirements. The maximum respiration rate is also closely linked to the Critical Oxygen Concentration point, that is, the point at which diffusion over the bacterial cell walls ceases and therefore biodegradation is significantly compromised.

Strathtox™ simply and quickly provides the endogenous and maximal respiration rate of the bacteria, as well as the in-depth analysis of the critical oxygen concentration points. AS Bioscope provides the data concerning the activity of the bacteria in the aeration basins and return lines under the prevailing load conditions. Further tests allow the settlement characteristics to be ascertained. Therefore these two instruments in combination allow a treatment works to be optimised for both performance and aeration efficiency.

Wastewater Toxicity Testing

If industrial wastewater entering a treatment works contains toxic components the rate of biodegradation will be inhibited or stop completely. This can result in failed consents and will certainly give rise to operational problems. Visible indications include deflocculation, bulking and the appearance of filamentous bacteria. Sometimes, there are no visible effects. When the sludge bacteria are inhibited, there is the possibility of toxicity carry over in the effluent that is discharged to receiving waters. With new environmental legislation being introduced, worldwide, to protect the natural environment, toxin discharge is now a serious concern for treatment plant managers. Toxicity, therefore, results in:

  • Increased costs of treatment
  • Failure to comply with discharge consents
  • Financial penalties for discharging toxic effluent

In order to protect a treatment works, from unknown toxic influents entering by sewer, a toxicity management regime is required. Tests with a laboratory respirometer are then required to measure the toxicity of the effluent, in order to determine the safe rate of discharge into the aeration tanks. For tankered waste, laboratory tests on samples of the wastewater are carried out prior to its acceptance for treatment. Manufacturing companies who treat their own waste and are concerned to minimise treatment costs, use the respirometer to monitor the toxicity of effluent streams. In this way, discharge rates can be controlled in order to ensure that toxicity does not inhibit the activated sludge bacteria of the aeration tanks.

Wastewater Toxicity Tracking

If toxicity is identified in a mixed sewage entering a treatment works, the problem for the plant manager is to track and identify the source of the toxicity. This can be done by sampling the effluent stream at various points in its length. By working in a logical sequence back up the sewer network the number of samples can be minimised. This type of testing should be rigorously enforced for new product introduction by a waste producer, as well as sampling the effluents directly at source. The samples should be tested against the activated sludge of the receiving works, using the Respiration Inhibition Test or the Nitrification Inhibition Test.

Toxicity Based Consents

Water companies, water authorities or publicly-owned treatment works (POTW) need to have some knowledge of the composition of the wastes they it receive. In addition to testing for ammonia and BOD or COD levels, treatment works can license industrial discharges on the basis of concentrations of some of the known toxic compounds. However, it is recognised that very many non-regulated toxic materials still enter the treatment works and reduce the efficiency of biodegradation, and may cause toxic shock. The way is now open for more widespread use of direct toxicity tests as a basis for toxicity-based consents. Samples of the industrial effluent are collected at source, for testing on the actual bacteria of the receiving activated sludge. The tests used are the Respiration Inhibition Test and the Nitrification Inhibition Test. Note that this approach mirrors that of the regulators of discharges to receiving waters, who are now using direct toxicity tests (DTA) or whole effluent toxicity tests (WET tests) in order to protect the receiving environment.

Toxicity Reduction Tests

In industrial manufacturing companies, before a new process comes on-line, it is important to measure the toxicity of the effluent stream. This is especially the case for companies who treat their own waste. From the toxicity value (EC50) obtained, it may be a cost-effective solution to simply discharge the effluent to the treatment works at a slow and defined rate to minimise damage to the activated sludge. Following a period of acclimatisation it is often possible to increase feed rates to the plant and this can again be measured and managed using the Strathtox Respirometer. An alternative approach is to undertake toxicity reduction procedures, such as neutralisation or acid hydrolysis, in pilot-scale laboratory studies. The Respiration or the Nitrification Inhibition Test may be used for this. In the future, toxicity reduction may be stipulated by local authority, water company or publicly-owned treatment works prior to giving discharge consents. Toxicity reduction may be evaluated using toxicity tests on activated sludge provided by the treatment works.

Monitoring Sludge Health – SOUR Test

Respiration rate monitoring of Antwerp treatment works showed periods when the activated sludge was up to 40% inhibited, with resultant sludge washout episodes. Using the Health monitoring test, a pattern of ‘normal’ respiration rates for a plant can be determined. Lower respiration rates will alert the treatment works to a chronic toxicity problem, allowing corrective actions to be taken. Toxicity monitoring can now be carried out on a routine daily basis, at all treatment works receiving potentially toxic wastewaters. This is especially important if there has been a history of poor plant performance.

History

Strathkelvin have been developing and marketing laboratory dissolved oxygen instrumentation since 1981, and are recognised as the leader in this field, with our instruments in use in leading laboratories throughout the world.

All our Biomedical Range Instruments are based upon micro-cathode oxygen electrodes, which were originally developed for use in the demanding conditions of clinical blood gas analysis, and which can be used, when required, without stirring of the medium.

The electrodes are utilised with purpose built accessories, which have been designed for specific laboratory applications. The appropriate information is configured and clearly displayed on our user-friendly oxygen meters and software.

Customer Care Policy

We pride ourselves on the precision, quality and ease of use of our products. Everything from individual accessories to instrument manuals comes under quality control scrutiny. In addition we offer excellent technical backup. Our technical advisors are research scientists involved in dissolved O2 measurement. If you would like to contact us by phone, fax or email, you will be able to communicate directly with someone who will understand your application and will be able to advise.

Measuring the Oxygen uptake rate of aerobic organisms is the simplest way to determine the activity level of the sample. Oxygen consumption under controlled conditions is also fundamental measure of organism health and depending on the test methodology used can give insights into many different aspects of the processes underway. For Activated Sludge Bacteria a Resprirometer can be used to measure :

  • Respiration rate, which measures the rate of biodegradation by sludge bacteria
  • Toxicity of influents for both Carbonaceous and Nitrifying bacteria.
  • Respiration rate measurements are used for both toxicity management and process optimisation

Respiration Basics

In the aerobic tanks of a biological treatment plant, the complex molecules of the wastewater are broken down by the combined activities of heterotrophic bacteria (that break down organic carbon compounds), autotrophic or nitrifying bacteria (that break down ammonia) and other micro organisms. In terms of process control, there are three major processes at work:
Biodegradation (the breakdown and removal of organic carbon and ammonia), Growth (growth and multiplication of the bacteria, which results in new biomass) and Respiration (oxygen consumption that provides the energy that the bacteria require for growth).

The three processes are interdependent. As a result, by measuring the rate of respiration, a measure of the rate of biodegradation can be obtained. For this reason, a respiration may be used as the control variable in process optimisation. If toxicity in the influent wastewater inhibits the respiration rate of the activated sludge, it follows that there will be an associated reduction in the rate of biodegradation.

A simple explanation of the relationship between biodegradation, growth of biomass and respiration is provided in a paper by Davies and Murdoch (2002).

On-line v laboratory respirometers

On-line and laboratory respirometers have complementary roles in toxicity management. Laboratory respirometers have an additional role to play in process control and management.

On – line respirometers and other early warning devices. Prior to the development of the ASP-Con by Strathkelvin Instruments Ltd – online respirometers were prone to giving false readings and difficult to interpret data. The ASP-Con overcomes this by measuring other factors simultaneously such as pH, Ammonium, Dissolved Oxygen, MLSS and Settlement all of which are combined to determine an in-basin measure of toxicity. Even the ASP-Con is limited as it can only measure the toxicity affect in the basin and at a single concentration. The laboratory based Strathtox therefore complements the ASP-Con in providing a rapid and detailed analysis of influent streams off-line. 

Laboratory respirometers. The Strathkelvin respirometer was developed by technology transfer from the biomedical division of the company. It is a closed chamber respirometer requiring only small (20ml) samples of activated sludge. By using multiple electrodes and dedicated software, respiration rates can be measured in only 5-10 mins. All of the time-consuming aspects of respirometry have been removed. Wastewater treatment plant staff can be readily trained to operate the instrument, for a wide range of applications in both process control and toxicity management.