Case Study 1 - A small package treatment plant at a Golf Club.

The Golf Club had suffered for a number of years from septic sewage odours drifting across the main entrance to the clubhouse. This was not only a source of problems with the members but also resulted in difficulties marketing the facilities for social events.

The golf club tried a number of methods to cure the problem without any success whatsoever. One of the club members suggested contacting EnvEnt Ltd. to gain a better understanding of the problem.

We found the club had a package treatment plant with three chambers: primary sedimentation, aeration and final sedimentation. The design capacity was about 60 Persons Equivalent (12m3 per day).

EnvEnt Ltd. firstly measured the redox potential, soluble sulphide, ammonia and pH through the plant. This immediately confirmed that whilst incoming sewage was fresh, it was already very septic in the primary sedimentation zone with several mg/l of hydrogen sulphide in solution. The hydrogen sulphide was then going forward with the sewage and being stripped off by the air sparges in the aeration zone.

Unfortunately for the golf club, the exhaust gas was then vented from a small stack at a height of four metres from where the prevailing South West breeze transferred the smell to the front of the clubhouse. We also observed that the plant had no nitrification capacity at all.

For the primary tank to be septic, the incoming sewage had to be remaining there too long. EnvEnt Ltd. re-estimated the actual waste water production of the clubhouse, and developed a simple flow model. It was then straightforward for us to diagnose the root cause of the serious odour problem - a plant with a design flow of about 12,000 litres per day that during most weekdays was receiving only 2-3,000 litres of sewage.

We also noted a range of problems on the plant that needed correction if it was to have a chance of working correctly. These however would take time to implement and the smell had to go straight away.

We decided to make the primary tank act as a denitrification zone to resolve the smell problem immediately. A temporary dosing system was installed and within a couple of days the hydrogen sulphide had been eliminated from the primary tank, redox potentials in the aeration zone were rising and the smell had largely abated.

Over the next few months, EnvEnt Ltd tested the airflow from the pumps, diagnosed one faulty air pump which was replaced, and readjusted another airpump to ensure a correct airflow through the zone. Much to the relief of the golf club's members, the odour problems were completely cured, thanks to the unique expertise of EnvEnt Ltd.