When consulting on buying a new sewage treatment plant, I often discuss the plant location to gauge if noise will be a factor. However, many treatment plants are bought and installed without this consideration. Most (not all), air powered systems will produce a low level vibration that can be heard from 10+ metres away (although it isn’t easy to pick it up on a decibel meter). In this article we will discuss the some tips for making your system quieter so you can enjoy your garden more.
Generally noise will be coming from the blower box, this will be a box sitting above the ground which houses the air blower (often also referred to as an air compressor). However due to the air being pumped into your sewage tank, there might be some sound coming from the tank itself. It is worth knowing which you are dealing with, in some cases it will be both)
If you have a noisy air blower, and the vibration is causing the blower housing to vibrate, you could install a piece of dense foam under the air blower to provide some cushioning – if you have an old computer mouse mat, you could try one of those.
The standard housing for an air blower supplied with a sewage treatment plant is normally made using GRP (Glass reinforced plastic). GRP can be a bit brittle which can resonate and transfer sound into the air. If you have tried the above mouse mat trick, and it’s not enough, then you could consider changing the housing. Brick built housings are good, the solid construction helps a lot with noise transference. However you must ensure you have a way to allow air into the housing. It’s still good to sit the blower on a piece of foam. You may need to get a builder in to construct the chamber, or if you’re a bit handy, it’s a project you could do yourself. Be sure to get a qualified electrician to re wire the air blower if necessary.
Many people opt for a bee hive housing, which should provide a bit more sound deadening than a GRP enclosure. Plus, if there is a bit of vibration, people will think it is bee’s and not go near it, a win win!
As long as the location of the housing isn’t too far away, then it’s fine to relocate the blower and housing to a different location. You could even consider running a pipe into a shed and install the air blower in the shed.
Whilst I try not to knock products, or heavily promote others, some air blowers are cheaper and noisier than others. Hi-blow, JDK, and Nitto are all good quality brands giving high performance with as little sound as possible. Ensure you match the litres per minute (L/min) if you are going to change the air blower. If you are unsure, there should be a sticker on the air blower itself telling you.
Whilst not widely available, there is a device that can be fitted in the air hose between the treatment plant and air blower. This devise is especially good at stopping the transference between the blower and treatment plant. You should speak to a professional treatment plant servicing company about this. If you don't know one in your area you can contact me and I will send you some contact details
I’m not joking here, if you have enough space, it is ok to do this. I’ve included this as an option just so that I can point out that if you do this, make sure you don’t plant where roots could find their way into the treatment plant. This is especially true of you have a drainage field. Root ingress will kill a drainage field in a matter of years. Bushes will help to absorb sound, so it is not a bad tactic.
All of the above tips can and should help to make your sewage treatment plant much quieter. If you don’t feel comfortable doing any of them, then always search for a local servicing company that can perform the amendments to your system. You should also be aware that some systems come with a 1, 2 or 3 year warranty and making amendments in this time will likely affect the warranty. Whilst moving the air blower further away could slightly lower airflow to the plant, it shouldn’t adversely effect it, increasing the size of air blower can mitigate this, and pressure testing before and after is a good idea. If your system starts to smell afterwards then you my have gone too far. Consulting a sewage treatment service company is always a good idea and this article is meant to give you ideas which you can discuss with your service company.