Gladstone City Council
Use of Actizyme at the Gladstone City Council
Personnel responsible for the operation of the Gladstone Sewerage System believe that the use of Actizyme has been cost-effective in controlling the problems we were experiencing and will be recommending to Council that the use of Actizyme be continued.
Introduction
In the latter half of 1985 and during 1986, the Gladstone City Council was experiencing considerable problems at its Calliope River Treatment Plant. These were:
Sludge was difficult to handle. Sludge from primary sedimentation tanks was thin and not very dense, odorous and would not thicken. This in turn presented problems in the digesters with poor settleable solids and high scum build up, making it very difficult to draw off a reasonable supenatant.
Ponding on the Trickling Filters. The filters were covered with a heavy, dark greyish black growth. Ponding was evident in a number of places and a rotten vegetation odour was very evident.
Problems meeting the water quality standard for effluent discharge. Results of above 60 BOD and N.F.R. were not uncommon.
Also, odour complaints were being received from various locations throughout the city.
Council officers became interested in the possible use of Actizyme as a means of overcoming our problems.
They were impressed with The effects Actizyme was having on the Gympie system and subsequent to this visit, we were requested to draw up a program for the use of Actizyme in the Gladstone system for a trial period of 91 days.
A detailed investigation of the Gladstone system was carried out and a dosing program was prepared. This program was presented to and accepted by Council in early 1987. Dosing with Actizyme started on the 26th February, 1987. The programme called for dosing per automatic ACTIFEEDER at 5 pump stations with daily hand dosing at 11 stations. At the completion of the 91 day trial, Council decided to extend the trial for a further 12 month period. Total Actizyme use for the first 3 months (91 days) was 835.75kg. Present daily dose is a total of 7.85kg of which 5.85kg is ordinary Actizyme, the balance (2kg) Actizyme Liquid G..
Evaluation of Results
1. Pump Stations
Prior to Actizyme, chlorine was used at 4 major pump stations (2, 5, 6, 10) for controlling odours. 550 to 580kg of chlorine per month was being used. Chlorine was discontinued when ACTIZYME started. As well as the 4 stations where chlorine was used, strong odours were present at most of the other stations listed on the program. Since using Actizyme, very little odour, if any, can be detected at any of the pump stations. Prior to Actizyme, at most stations the station walls, pumps and pipework had to be scraped or blasted with a high pressure blaster every 2 to 3 weeks to remove the build up of fats and grease. Now we find, with a small amount of hosing once or twice a week, we have no problems with fat and grease build up. This has resulted in a labour saving of some 20 man hours per week. We also find a significant reduction of pump blockages, in particular at submersible stations.
2. Treatment Plant - Calliope River
Cleaning
We have found, since using Actizyme, the plant is easier to clean. There is much less build-up of fatty slime on the sides of structures and the floors of channels. This has reduced the amount of time spent by the operators in cleaning and allowed them time to carry out work which had previously been done by others.
Sludge Handling
Before ACTIZYME, raw sludge draw off from the primary clarifiers was from 45 to 55 kilolitres per day. Sludge was thin and not very dense, odorous and would not thicken. After ACTIZYME, raw sludge draw off dropped to between 33 to 40 kilolitres per day, sludge was thicker, more dense and had little odour. This in turn overcame the settleable solids problem in the digesters. We now have very little scum build up and the quality of supernatent drawn off has improved greatly. Test results of 150 S.S., 3000 N.F.R., 230 B.O.D, before ACTIZYME were not uncommon, now 10 or less S.S., under 1000 N.F.R., average 165 B.O.D. are the results we achieve. The only problem that we now occasionally experience is that the digested sludge is so dense that it is difficult to draw off and transfer to the drying beds.
Filters
In the first few weeks of Actizyme use, we observed changes taking place on the filters. The dark greyish black growth tended to disappear, in fact, to the extent that the top media was almost clear of any growth, also the rotten vegetation odour was not evident.
Effluent Quality
Changes in effluent quality were much slower to occur than the changes elsewhere in the plant. It wasn't until after 6 months of Actizyme use that the effluent quality started to settle down. Although we are reasonably satisfied with the quality at present, we would still like to see further improvement in BOD5 results.
3. South Trees Plant
Actizyme has improved the quality of influent and reduced cleaning time at the plant. Prior to Actizyme, strong odours were present at the inlet, now no odour is evident. It is impossible to make further comment because of the low inflow that this plant receives.
Conclusions
Personnel responsible for the operation of the Gladstone Sewerage System believe that the use of Actizyme has been cost-effective in controlling the problems we were experiencing and will be recommending to Council that the use of Actizyme be continued.
Acknowledgments
R. Genrich
Sewerage Foreman
26th May, 1988