Water racket: it’s time to turn the noise down
Many UK water companies and contractors are taking action to cut down on noise levels. Wakefield Acoustics provided expert input for a new sludge plant in Yorkshire.
Important changes have been taking place to environmental noise policies, legislation and management. What is also apparent is that public attitudes towards environmental noise also appear to be changing as people become less tolerant of excessive and intrusive noise levels, particularly where there is an impact on their quality of life and well being.
This is further emphasised with the growing number of websites and literature available specifically focusing on the subject, and which highlight how noise pollution is responsible for a wide range of detrimental health problems. As the obligation to tackle noise issues is now firmly placed upon companies, the challenges these important changes pose to the water industry continue to grow, with many water utilities increasingly taking action to reduce the risk of exceeding environmental noise levels.
Major water utilities and contractors such as Morgan Est, one are already addressing such noise-related issues.
Prior to the installation of an Activated Sludge Plant for Yorkshire Water at Neiley sewage treatment works, Morgan Est commissioned some noise surveys and assessments to predict resultant background levels post installation.
This was to ensure that background noise levels would not be increased at the site boundary and at the nearest residential properties, in-line with the requirements of BS4142.
As noise levels at night are the most sensitive, night time background levels were chosen to determine the noise criteria for the site. However, during commissioning tests, several individual factors were identified in the as-built installation, resulting in noise level outputs exceeding the design target.
Morgan Est commissioned as-built noise assessments to identify the key contributors to the noise and identified options to correct.
For added security to ensure that any noise control measures were practical and cost efficient as well as effective, Morgan Est brought in Wakefield Acoustics to conduct further noise assessments to identify the preferred solution for attenuation through cost-benefit analysis.
Wakefield Acoustics visited the Neiley site to assess the location and any potential issues that may arise from future noise levels.
After undertaking the detailed noise survey, the company confirmed that there were two dominant noise sources to be treated in order that background levels would meet design targets.
The two key noise sources being reflected from the blowers and vibration in the common discharge pipe from the blowers.
Wakefield Acoustics’ recommendation was to treat the discharge pipe by installing a bespoke circular absorptive silencer at the base of the vertical discharge pipe and to contain the blower package reflection by fully enclosing three blower packages in a secondary common enclosure. To support airflow requirements a fan-assisted ventilation system was also incorporated.
Minor maintenance requirements would be supported by incorporating three sets of double leaf doors complete with glazing panels.
Major maintenance access would be provided by incorporating lift off panels into the roof thereby allowing crane access.
Once Wakefield Acoustics completed the design, manufacture and installation of the necessary equipment, third party noise assessments were undertaken which confirmed that noise level limits had been achieved.
Richard Etheridge, from Morgan Est, says: “Wakefield Acoustics provided extremely valuable input, not only providing support and assistance in helping us understand the noise issues, but also in providing cost-benefit solutions that were required to ensure that environmental noise levels were met.”