Where is Probac Needed?
Probac may be used in any application where biological problems are experienced in most types of wastewater treatment systems. In some cases odour problems can be resolved quite quickly whereas other problems such as fat & grease build up or control of sludge will be corrected over time.
Odour and grease are common problems in sewerage systems. Probac has been successfully used to reduce odour and remove surface slimes and grease from pipes and walls of pump stations. By doing so, Probac prevents sewage turning sour, particularly in mains with long retention times.
Probac treatment is currently used in many rising and gravity mains in Australia. Its use has resulted in a significant reduction in odour as well as built-up grease. A secondary benefit of grease reduction in downstream pump stations is that a simple hose down can replace manual removal of grease from pump station walls without entering the well.
The elimination of odour and grease from mains and pump stations can save much time and money dealing with odour complaints. Significant cost savings may also be achieved by preventing premature infrastructure replacement caused by corrosion. Many Australian sewerage systems are successfully using Probac to control odour and grease build-up.
Example: If we consider a typical sewage plan, similar to the one shown in figure 1. If PS1 and surrounding areas have a heavy odour problem, septicity is likely occurring in RM7 or RM2 or further upstream. Probac dosing would be considered at PS8 and PS3. Dosages would be calculated not only to eliminate septicity in the rising main, but also to enhance the wastewater treatment plant performance. Dosage depends upon flow, retention time, ambient temperature and other site-specific factors.
Once Probac treatment commences, the long term build-up of fat & grease in the mains and pump stations will be stripped. The time scale for this process will be totally dependent on the quantity of fat etc. involved, but the result will be clearly evident and dramatic.
Sewage Treatment Plants
A major benefit of Probac treatment is the positive impact to sewage treatment plants. This is because the plants are designed to receive sewage in a reasonably “fresh” state and Probac will ensure that raw sewage arriving at the works will be biologically re-activated but in no way chemically altered.
Trickle Filters: Probac treatment generally results in thicker and greener slimes on the filter medium increasing its efficiency. There is a noticeable reduction of odour. Grease on the medium and on the tank wall is also reduced reducing ponding.
Imhoff Tanks: Recent trials on an Imhoff tank in South East Asia resulted in a reduction of odour early in the program. Within 30 days the scum on top of the sedimentation tank decreased and this continued to a point where the incoming raw sewage actually passed through the tank instead of bypassing the system. There was also a noticeable improvement in the effluent.
Sludge Digesters: Sludge is an inevitable by-product of the collection and treatment of sewage. Probac treatment of digesters has resulted in reduced odour, a clearer supernatant and sludge that is easier to handle.
Community Septic Tanks: Odour is a major concern with this system and due to the location of such systems near the community, is a significant problem to deal with. Cleaning is difficult and expensive because of the size. The problems of this kind are biological and it stands to reason a biological treatment is the answer. Probac dosed into the system will reduce the scum, reduce the organic component of the sludge and clear up the supernatant. The result is a fully operating system providing clear effluent from the tank and most important, greatly reduced level of odour.
Package Plants: There are many types of plants in this category. They vary greatly in daily flow, but many have problems with odour and effluent quality possibly due to lack of often costly maintenance. Trials for approval of Probac in one Asian country consisted of a non performing 400 kilolitre per day package plant demonstrated what Probac will do. The summary of the report stated “Dosing of Probac had effectively removed odour within one week and brought the plant to Standard A discharge within two weeks”.