It is difficult for you. and ...

It is difficult for you. and it does depend on the treatment plant, which follows.  I have used the mixture of surfactant, bacteria and enzymes under certain circumstances.  Where there is a significant level of FOG it takes a long time to clear pipework.  It is hoped that the enzyme and bacteria will digest the fat, but it does depend on the temperature of the water and how far it is from the treatment plant.  Almost certainly some fat will flow down undigested and some will be partly digested.  If the system is aerated then there is a group of bacteria called Nocardia (Nocardioform) which use fats and component of fats to form a detergent which helps them become dominant.  They are highly branched and when aerated with air blowers, they are forced to the surface where they can grow advantageously.  The problem is that even if a DAF is used before the aeration system, by using the mixture means that fat components may carry through the DAF.  Nocardia also trap floc in the matrix so the material looks brown or grey.

It is also possible that the COD loading has increased caused by additional fat or fat components reaching the plant and there is insufficient oxygen in the plant.

Other filamentous bacteria can also grow under these conditions adding to bulking issues.

Because I don't work with sewage plants but industrial, food and dairy effluent treatment plants, I am careful what is added.  Enzymes can alter the food so that  the floc-forming bacteria can't recognise the food, other normally slower growing filamentous bacteria so they tend to out grow them.  So I am very wary about adding enzymes on a continuous basis. 

On the other hand, I have successfully used a mixture similar to what you have used without a problem taking place.  In each case it was only for a short time to remove a specific problem of fat forming a thick layer on the surface of a tank.  In that case it was carefully dosed including spraying the surface with a liquid mixture and mixing from underneath.  The filamentous bacteria did not have time to become dominant.

As far as smell is concerned, you don't describe the smells involved.  There are two which could be caused by it.  If certain filamentous bacteria grow they can produce a smell, which is best described as drain smell.  If the oxygen level of the plant drops or there is insufficient oxygen transfer anaerobic bacteria grow and these produce smells ranging from rotten cabbage to bad egg smells.  This is because they use sulphur as the electron acceptor in place of oxygen.  Whereas the end point of oxygen is carbon dioxide, the end point using sulphur may vary from hydrogen sulphide to mercaptan to carbon disulphide. They are a sign that there is insufficient oxygen being transferred into the water.  By increasing air it will reduce the anaerobic growth, but may cause sludge to rise because of the high filamentous growth.

To assist further, you would need to tell us what the treatment plant is and how it is controlled.

Please note I am not saying that bacteria or enzymes shouldn't be added because under certain circumstances they can be very useful.  They should done under careful control and with understanding.