The benefits of sampling and testing are many, regular sampling and testing of the treated effluent (taken from the designated sampling point of the installation) enables the owner of the plant to do the following:
- Determine compliance against all current and ongoing legislation including consent to discharge limits as set down by the local water authority or the Environment Agency.
- Maintenance costs can potentially be reduced by ensuring tanks are only emptied when required. Many tanks are emptied unnecessarily.
- Provide a record of the condition of the plant by detemining whether the use of excessive quantities of surfactants (detergents, bleaches and other chemicals) is affecting the quality of the final effluent, identifying potential issues before they arise.
- Produce over time, an historical analysis record providing evidence of compliance
Added Value of Sampling and Testing
Sample Chambers
A suitable sample chamber should normally be provided to enable a good representative sample of the final effluent to be taken. However, sometimes the age of the treatment assets means that a sampling chamber is not present. We have, at that point, to make a judgement where the best location is to take the representative sample.
We have advised clients as to the requirement, type and location of sample chambers – personnel from the governing authorities would expect a safe and easy access when they visit site to sample the effluent.
Worn Access Covers
Our customer report will not only present the results of the analysis of the sample(s), we will also report back any issues found with the asset.
A frequent problem we find is worn or broken access covers and surrounds. Ageing covers that have been lifted over the years may have worn lifting key holes. This not only makes our job tricky even with our specialist equipment, but makes maintenance of the tanks difficult. Should the worst happen, recovery of the covers can be expensive involving confined access crews and should be be avoided where possible.
Correct application for the tank
On a number of occasions, we have identified that the asset is incorrectly used in its’ current application.
This may be due to exceeding to original design limits – serving an expanded population for example. Other problems have been found in an interceptor originally specified for car wash run-off being used to treat in addition vehicle washing effluent – On the face of it, a simple change of use but resulting in ineffective treatment of the effluent.
Discharge consent conditions
Trade effluent consent to discharge documents specify the nature and composition, quantity and rate of discharge of the final effluent.
We have had occasions where the activity that produces the effluent is not taking place in the correct area of the site – resulting in the trade effluent not entering the treatment asset and leaving the premises effectively untreated. An example of this was a third party contractor used for vehicle washing not cleaning the vehicles in the wash bay, resulting in the wash waters not draining into the interceptor and no treatment occurring – a clear breach of the conditions set down by the discharge consent. Our report highlighted this to the client’s Environmental Manager.
Other unexpected items….
We have encountered some other problems that have taken a while to solve.
A good example of this was when one of the tests in the results of the analysis of a wash bay final effluent was literally ‘through the roof’. We always take images to support our work on site, and it was in re-examining the images after receiving the results that we noticed that the client was storing salt for deicing the pathways around the site next to the bay – the salt was dissolving and washing in to the catch pit on rainy days and causing an anomaly in the results. Needless to say the bags of salt were relocated!