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UK Focus Testing options


In order to demonstrate compliance with a discharge consent, it is normally necessary to send a small number of samples to a UKAS certified laboratory. However, most operators also conduct their own testing and monitoring to ensure that the process remains within consent and to help manage the process efficiently.


Process operators that measure flow continuously are able to provide their wastewater treatment provider with accurate data from which the treatment charge can be calculated. A further advantage of flow measurement is the cost saving opportunities that it provides. For example, an operator may discover that certain parts of the process generate high levels of discharge, such as wash down, so that the process can be adjusted to reduce discharge costs.


A wide range of flow monitors are available, employing a number of technologies to suit a variety of applications. The choice of technology is often dictated by the application or physical constraints.


Qualitative measurements can be performed on collected samples


or alternatively, continuous water quality monitors can be installed. A wide range of options exist for qualitative measurements and these are summarised in the table below. HACH LANGE manufactures all of these instruments and the company's technical staff are able to offer advice on the best solution for every application.


Sampling


Samples can be collected from the waste stream either manually or automatically. However, manual sampling is generally less favoured for a number of reasons. Firstly, manual samples do not usually provide a representative sample because they are taken at one moment in (usually day) time – a spot check. Secondly, manual sampling may suffer from sampling errors of sampling variability between staff and finally, manual sampling represents an ongoing operational cost.


Water quality testing options


Pocket


comparators/ test strips


Portable meters Portable photometers Laboratory spectrophotometers Online analysers Automatic samplers


Continuous, highly accurate


Create representative samples


More expensive


Semi-continuous or non-continuous


Automatic samplers are able to take samples at various times throughout the process cycle in order to deliver a representative sample. The collected samples can even be refrigerated so that they do not change prior to analysis. However, some samplers offer more


Highly accurate More expensive More accurate More accurate Advantages Low cost Disadvantages


Spot check. Less accurate


Spot check Spot check


sophisticated options. For example, they can monitor flow rates and adjust the sampling frequency accordingly. Alternatively, some samplers are able to monitor water quality in the waste stream and take samples when readings reach specified limits or alarm levels.


Qualitative measurements


BS 1427 describes methods for the analysis of industrial and other waters. These methods can be undertaken outside of the laboratory, for example on-site tests. This guide is for testing when the purpose of the test is to characterise the water under test for quality or process control purposes. A range of options exist for analysis on-site.


Spectrophotometer with tube reagents


Simple colorimetric tests (test strips, sticks or comparators) provide quick, low-cost results albeit with limited accuracy and resolution. Alternatively portable photometers can provide much better levels of accuracy and remove many of the causes of error.


Portable test kits can be used by non-chemists and offer a number of advantages. They enable simple, rapid results, so the frequency of testing can increase; no chemical preparation is required and waste chemicals are recycled by responsible providers (such as HACH LANGE). It is important to note however, that analysis by test kit is simply indicative and does not match the level of accuracy and reliability that can be achieved in a UKAS certified laboratory.


Portable photometers are available for individual parameters or multiple parameters. The main advantage of photometers is that, following the addition of the reagents, they measure the colour of the solution digitally and are able to remove the effects of background colour. Multiple parameter analysis is made possible through the employment of multiple filters, which in some units, are selected automatically.


Laboratory photometers add even further levels of sophistication.


Standard methods are pre-programmed into the units and they are able to recognise specific cuvettes that are supplied with exactly the correct quantities of reagents for specific tests. Results can be stored on these photometers or exported to a printer or PC.


Continuous monitors log recorded data and provide constant access to live readings. This enables the rapid detection of alarm conditions and the easy identification of process trends. Continuous monitors can also be connected to controllers that are able to feedback into the wastewater treatment system in order to optimise the treatment process. For example. HACH LANGE has been involved in numerous trials that have demonstrated substantial cost savings in the energy costs of wastewater treatment through the continuous monitoring of dissolved oxygen and ammonium.


Summary


Wastewater monitoring can deliver substantial savings for a number of reasons: it can ensure that a process complies with its discharge consent; it can ensure that treatment charges are accurate; it enables rapid response to pollution incidents; it identifies abnormal concentrations and peaks and provides an accurate picture of the process so that efficiency opportunities can be identified, such as reduced waste and recycling.


Automatic sampler


CONTACT DETAILS


Hach Lange LTD Pacific Way, Salford, Manchester. M50 1DL Tel: +44(0)161 872 1487 Fax: +44(0)161 848 7324 Email: info@hach-lange.co.uk Web: www.hach-lange.co.uk


Water Level Alarms Sent from Inaccessible Locations


Aegis (UK) has introduced the recently developed DataCell L wireless data-logger to the UK market. DataCell L is designed for use in harsh environmental conditions, and each unit is factory configured with up to four float switches each fitted with a predetermined length of cable.


The unit is self powered by a lithium battery pack and in typical applications, such as daily reporting, will provide up to 10 years of field service. A GSM / GPRS communications engine provides two-way remote communications allowing


device set up and data retrieval. An alarm is generated once the level rises to a height to tilt any of the float switches, and the data is transmitted as an SMS and e-mail (if configured). The unit will continue to send alarms at regular intervals until it receives an Acknowledge SMS from the user or the system it is connected to.


Significant cost savings can be obtained by using these devices in inaccessible locations, providing advance warnings of rising levels of water/waste-water which could otherwise result in significant damage.


Reader Reply Card no 167


Highly-Skilled NDT Expert Joins Ashtead Technology


Leading instrumentation specialist Ashtead Technology is delighted to announce the appointment of Non-Destructive Testing (NDT) and Remote Visual Inspection (RVI) specialist Peter Myatt as its new Sales Manager.


Peter, who joins the company from a similar role at Olympus, brings a wealth of experience to his new role, as a former aircraft technician in the Royal Navy for over 25 years.


He will now head up Ashtead Technology’s focus on the company’s extensive range of NDT and RVI instrumentation, covering the most advanced thermal cameras, videoscopes, ultrasonic testing and phased array products available to hire, for a range of applications within the aerospace, manufacturing, automotive and engineering sectors. Peter explained: “I am delighted to be Ashtead Technology’s new Sales Manager and look forward to working with our skilled team of instrumentation specialists. My experience within the NDT and RVI sectors will enable me to recommend the best instrument for the job, so that our hire customers can carry out accurate testing with the very latest equipment on the market.”


Alan Hasson, General Manager at Ashtead Technology, added: “I am very pleased to welcome an NDT specialist of Peter’s calibre to the team and I am confident that both new and existing customers will be able to able to benefit from his considerable knowledge and expertise.”


Reader Reply Card no 168


IET


November/December 2010


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