During reconstruction of sewage treatment facilities in Herzliya in 2009 a new biological reactor, consisting of three sections of 6000 cubic meters each with an operating height about 6 m, was installed. Air is pumped by means of three air blowers of 6000 cubic meters each through disc diffusers.
Soon after launching it was obvious that all system is highly uneconomical. In order to keep oxygen concentration at 1.5/2 mg/l we had to continuously work with two-three air blowers (9000-13000 cubic meters) for the whole reactor and it was not always possible. After in the beginning of 2013 rupture marks were detected on some diffusers we decided that it is time to replace them by somewhat more effective. We issued a tender, and one of many offers we have received for consideration contained information about aerators of Esmil Company.
There were a lot of cons: unknown company, lack of experience of work in Israel, disagreement of designers and technical advisors.
However, despite of some concerns and doubts we decided to install these particular aerators. This product attracted us by its simple and reliable design, price, mechanical strength, longevity, 8-year warranty, no need for service checks, easy and quick installation, and also a very tempting offer of company management: possibility to pay the most part of the amount only in case if we are fully satisfied by their operation, which can be done even in six months.
In November 2013 we launched the first section of the reactor with Esmil tubular aerators.
Reality has exceeded our most optimistic expectations. Quantity of used air has significantly reduced as well as quantity of consumed energy.
Saturation of liquid with oxygen has become more stable and homogenous in the whole basin. In 2 months instead of previously agreed 6 months of observation of aerator performance it was decided to replace diffusers installed in two remaining sections by Esmil aerators, which was done in stairstep order.
Today the whole reactor (3 sections) is functioning with installed Esmil aerators, and we are extremely satisfied with obtained results. Required oxygen concentration (about 2 mg/l) is kept in all sections with much less energy consumption. The most part of a day (14-16 hours) we use one air blower (4500 cubic meters) and during peak hours (8-10 hours) two air blowers (instead of 2-3 air blowers used previously, before replacement of aerators). I send you the reactor operation schemes made before and after replacement of aerators.