ASL Limited case studies about drainage Skip to main content
These case studies are all about drainage and private sewage systems

ASL Limited believe in helping you understand all the detail so that you can make an informed decision.

Case Studies with ASL Limited

The case studies you will read about on these pages are created from live jobs that ASL Limited has attended and reports that ASL Limited has written for those jobs. All names, locations and identifying details have been changed for privacy purposes. We hope that you find the information you would like to learn about and get a feel for the detail of care that we strive to deliver for our customers. If you think you have a similar problem that we can help you with then do get in touch and we will certainly do all we can to help.

From here you can view the latest case studies below and filter them by category.

When upgrading to a treatment plant, sometimes the old septic tank can still be used in addition.
This case study is based on the proactive action of one of our customers when they were moving house. On request, we estimated the installation of a new treatment plant as a result of the commercial survey before the exchange.  Observations & Findings A “state of the art” domestic sewage…
This is a picture of a treatment plant installation taking place
Re-estimate for drainage works required: main sewer connection or septic tank conversion. This case study sets out the benefits of planning for every eventuality regarding private sewage system handling capacity.   This image shows a 12 population treatment plant being installed.…
This picture shows ASL Limited Engineers carrying out a CCTV drain survey.
When we buy a house, the last thing we tend to think about is whether or not the drains are working properly. This is also not included in a regular house purchase survey that your conveyancer will organise for you. And yet, if the drainage system is not connected to the main sewer, it could be a…
This picture shows a pump with signs of fat and grease in the system.
We hope this case study will help to understand the effects of grease, fat & oil on your private sewage system, drainage field and the environment. This example is of a Klargester Biodisc that has a wheel as part of the mechanism.  Observations & Findings This is an example of the…
Maintenance checks being carried out on a customer's treatment plant
Once we have a treatment plant installed, it is easy to put it out of our minds and expect everything to function perfectly. Well, at ASL, we want that to be the case for all our customers and for that reason, we come back and check on the treatment plants that we install. We do this A to check…
A broken pipe discovered when emptying the septic tank.
A sewage pipe renewal and connection to foul drains. We’ve all done it – grabbed that opportunity for someone to do something on the side. We know it’s taking a risk, but the temptation to save some money is all too damning when the result is less than adequate OR even very damaging. The final…
A photo of Ken with the ASL Limited sewage tanker.
When installing a private sewage treatment plant, discussions about the right solution for you are so important. To trust is imperative. As drainage specialists, our aims are to:  Save time.  Achieve quality.  Be cost-effective. AND  Protect our land, rivers, and streams.   The following…
Surface water pollution in a stream
Roof water overwhelms treatment plants. Large quantities of roof water contaminated by sewage, wet wipes, and foreign objects end up in rivers or polluting the land, streams, and rivers. See our case study observations & findings on surface water pollution. The images in this case study are…
Case Study | Surface Water Pollution is preventable with understanding and planning.
Roof water and surface water was entering the sewage system, discharging sewage water, ten times the amount allowed. A photo of CCTV drain survey to investigate suspected surface water presence in the sewage system. We attended a property to investigate suspected surface water and roof water…
This image shows a tape measure being used as part of a drainage survey in order to install a domestic sewage treatment plant.
This case study highlights the lack of knowledge and understanding of why many do not display the high level of commitment needed to protect the environment. People use 'horses for courses' – to mean that people and things have different qualities and skills and are suitable in different…