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Analysis The Good And Bad Of Wastewater Instrumentation: Pros, Cons, And Opportunities Instrumentation is heavily pushed to achieve efficiency, but it only works when you use it correctly – and many utilities don't. By Oliver Grievson W astewater instrumentation is set, especially in the U.K., to become more and more important moving forward. As the industry moves to a production mindset and the drive to reduce carbon and improve operational efficiency becomes more and more important, the water industry will be forced to adapt and keep an almost constant "eye" on what is going on. Moving forward, unless a structured approach is taken, there are a lot of pitfalls that the industry faces. This article will attempt to highlight at least a few of those pitfalls that exist. The first question to ask when installing any instrumentation is "why?" There is always a case to install an instrument, and there is always a case not to. Any instrument has got to tell any wastewater operator something about the way the process is operating. The answer to the question could be regulatory, and it could be operational. In the U.K., the only instrument that is required by the Environmental Permit is a flow monitor, and yet a permitted plant has a lot more instruments than that. For example, dissolved oxygen monitors and power monitors (on efficiency grounds); ammonia and turbidity monitors (compliance grounds); and pressure, flow, and level monitors (operational grounds). Moving forward, this is set to increase; final effluent monitoring and measurement of product flow through the plant (be it wastewater or sludge) will need to happen. This needs to be tempered and limited, however, to those monitors that cannot only provide "data," but "information," on the process operation. This is, of course, the first pitfall that exists and why the question of "why" needs to be asked. If an instrument is being put in place to monitor data, then the question "What am I going to do with that data?" needs to CASE STUDY 1: THE COST OF INSTALLATION Consider the dilemma: You need to install a flow meter at a treatment plant, and you have a limited space to do it in. What do you do? The options are: (a)Repair the flume – difficult to do, but not impossible – and keep the old flow meter. (b)Install a new electromagnetic flow meter at the outfall to the plant where the flow meter is relatively cheap, but comes with some civil installation. (c)Use a new technology where the meter is 24 wateronline.com ■ expensive, but the installation is relatively simple. The answer that I chose was (b) as (c) wasn't available at the time and (a) looked to be impractical and expensive. The result: The total cost was more than $150,000, with the actual flow meter costing less than $5,000. The point of the case study is that, although the instrument was relatively cheap, the installation certainly wasn't, as it involved a large hole and asbestos. The cost of installation needs to be taken into account. Water Online The Magazine