Wastewater Package Plants – are they fit for purpose ?
Compliance in the packaged plants industry
Our long history of compliance strategy within the wastewater treatment industry has shown some very conflicting outcomes. The main concern has always been the regulatory town councils and, of course, the government authorities, both often being at odds with each other - neither accepting responsibility for compliance.
Once we had built and installed our first package plant system, down in Drummond – KZN - on the late John Bizzel’s smallholding, we have been pressured to test the product. When the plant was in, and running, Durban Metro insisted we perform 12 weekly water analysis tests – note that there were already two 'endorsed' products, which had been pre-approved without even a sniff (or snort) from head of Water and Sanitation, Neil McCleod.
Our first attempt was thwarted by Durban Metro (DM), after we were already in our 5th week of weekly tests by Talbot & Talbot Laboratories - DM claimed they had not been informed at the start, and they felt that the results were too good to be accepted. DM indicated we were cheating. While this set us back, we were getting some really good water quality results. Once they were taking samples, DM were also getting good results from their in-house laboratory, which they begrudgingly admired.
In the meantime, Umgeni Water, offered to test our system, and they themselves found full compliance. Scarab achieved special standards on key indices. In comparative and simultaneous tests on two other commercial wastewater package plants, Umgeni found that those had failed miserably.
We felt that our Scarab system was, at that stage, the most tested design, and, that never has there been any other program for judging packaged plant design, based on water quality alone. After all, this is the sole purpose of an on-site sewage system, right? Water quality!
Water Research Commission (WRC) tests sewage systems
Then . . . I recall Umgeni Water, the Water Research Commission (WRC) and Dept of Water and Sanitation (reference here) doing a full 6 month on-site, constant attention research program, in 2005. 3 different plant suppliers were asked to provide a trial system based on their own technologies, and the following technologies were supplied.
- submerged biological contactor (SBC) (this is the most common of all systems available today)
- rotating bio contactor(RBC) (Not a popular technology and you wont find this in your garden)
- sequencing batch reactor (SBR) (based on the activated sludge process, and not a popular technology)
The test site was a large municipal WWTW near Pietermaritzburg in Natal.
The test program ran from February until September 2005, and so to include a winter period when the biological process does slow down. All designs had the same value of incoming sewage quality, and so there was no quality variation. Each of the three wastewater systems were offered, by the manufacturers, as a viable solution to domestic on-site treatment, where the authorities could promote their general use, thus relieving the pressure on council owned WWTW.
Whilst there were initial teething problems on all the trial units, the RBC and the SBR performed reasonably well. The SBC, on the other hand, did not comply once, logging 198 faults during the test period.
So, was this the end of the embarrassing product?
Not at all.
It went on for another decade before the wheels started falling off. (see below).
So, how many other products don’t perform as promised?
We were offered a design from the UK (as understood) that did not include disinfection as a standard feature, and would never have passed the local requirements. Then, there was one of those silly little compact, electric free, underground units that offered a compliance certificate signed by the owner of the company. Both these products can now be found on South Africa shelves, and often buried - gone and forgotten.
As of this year there are at least 42 companies selling their own brand of wastewater recycling products in South Africa - but how many have been independently tested for compliance, prior to product launch and marketing? And how many designs are buried, and therefore compliance cannot be easily checked?
If you cannot see the water quality, it cannot be verified - perhaps on purpose.
The package plant association
The association of sewage treatment package plants - South Africa - offered like minded manufacturers a self regulatory platform, in which issues like these would be dealt with, for the benefit of both the manufacturers and the trusting public.
However, this association was considered the brainchild of the same guy whose system logged the 198 faults, and never complied once.
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Scarab Systems - Tested and endorsed - like no other !
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