WATER QUALITY INFORMATION
Umgeni Water is equipped with a modern state-of-the-art laboratory with specialist technical expertise in the fields of Chemistry, Microbiology and Hydrobiology. Water and wastewater sampling and testing is undertaken by a team of highly-skilled scientists and technicians and covers an average of 12 000 analyses on a monthly basis. The importance and relevance of physical, chemical and microbiological testing cannot be overemphasised. Test results are used in all water-related matters ranging from quality compliance to infrastructure development, process optimisation and research and development. Laboratory results are the single most important parameter used to deem any treated water fit for human consumption. Some of the more specific functions of the laboratory are to:
- ensure compliance of the treated water with the South African National Standard, SANS 241
- monitor the quality of raw water in rivers and dams
- ensure compliance of wastewater discharge with legal standards
- provide early warning alerts when water quality problems are detected.
Over and above its core business activities, the laboratory has developed and implemented a marketing strategy by providing specialised analytical services on a commercial basis. This has been a huge success, and showed steady growth over the past ten years, with a current annual revenue of R4 m. The laboratory has developed considerably over the past two decades and is well-recognised as the first water-testing facility in the country to achieve accreditation status in terms of the South African National Accreditation System (SANAS) code of practice.
Potable Water Quality Compliance
The quality of potable water is paramount to Umgeni Water’s business. Umgeni Water ensures it provides water of suitable quality that will not impact negatively on consumer health over a lifetime of consumption. This was ensured in the past year, as in previous years through relevant water quality monitoring, assessment and compliance programmes covering its entire bulk water supply business. The SANS 241: 2006 Drinking Water specification was used to assess compliance for the organisation’s twelve waterworks.
The overall compliance for the bulk potable waterworks, based on health-related chemical and microbiological tests, and volume-weighted, was 99.99 percent (Figure 7). Of a total of 6 791 analyses conducted, only seven results did not comply with the national standard.
Based on SANS 241: 2006, this quality of water is classified as excellent. Similar assessments were done for off-site and reticulation reservoirs fed by Umgeni Waterworks, and excellent water quality compliance was achieved for both types with 99.9 and 99.7 percent respectively.
Potable Water Quality Target
- Target 2006/7: 0.01% failures
- Actual: 0.01%
- Target 2007/8: Maintain the quality target
These results continue to be in line with the organisation’s targets for excellent quality provided over the past years as shown below (Figure 10).
Table 12: Potable water compliance per waterworks
|Bulk Potable Waterworks||Average Daily Volume Treated (MI/D)||% Total Supply Volume||Compliance with SANS 241: 2006|
|Craigieburn-Saiccor Mix Final||6.2||0.57%||100||92.6|
SANS 241 Classification:
- Excellent water quality: ≥ 99% compliance with Microbiological requirements, ≥ 95% compliance with Class I Chemical requirements and ≥ 97% compliance with Class II Chemical requirements.
- Poor water quality: < 97% compliance with Microbiological requirements, < 85% compliance with Class I Chemical requirements and <90% compliance with Class II Chemical requirements
In respect of the detailed results, the non-compliant microbiological results at the Craigieburn-Saiccor mixed final, which contains treated water from Craigieburn Final mixed with filtered water from Sappi Saiccor, were attributed to lack of chlorine contact time in the on-site mixing chamber. A more representative off-site sample site is being sought.
The non-compliant results (E. coli, turbidity and total aluminium) at Umbumbulu Waterworks were related to poor source water quality. The community was supplied by water tankers while the problem was being addressed. This works supplied a very small fraction of potable water to the community, as the bulk of the potable water was supplied by the Eston-Umbumbulu pipeline. The Umbumbulu Waterworks was decommissioned in December 2006.
Wastewater quality compliance
Wastewater Works Compliance
The compliance of the effluent emanating from the wastewater works managed and/or owned by Umgeni Water was based on the number of tests that passed the prescribed standard per wastewater works:
- Darvill Wastewater Works compliance was measured against DWAF General/Special effluent discharge standards and Exemption Permit 2045B.
- Howick Wastewater Works compliance was measured against DWAF General/Special effluent discharge standards and Exemption Permit 1887B.
- Ixopo Waste Water Works compliance was measured against DWAF General Authorisation General Limits.
- Albert Falls North and South Wastewater Works compliance was measured against DWAF General Authorisation General Limits.
The historical wastewater works compliance for the past five years for all sites is shown in Figure 11. The wastewater works achieved an overall effluent compliance of 89.9 percent between July 2006 and June 2007. This compliance matches the compliance reported in the previous period, between July 2002 and June 2003. Generally, the effluent compliance trend appears to be deteriorating since July 2004. This is mainly due to process problems encountered at the Darvill Wastewater Works. This has been addressed by increasing the maintenance expenditure and will include a refurbishment of the two Albert Falls Works.
The effluent compliance at the Umgeni Water-owned and operated wastewater works at Ixopo and Darvill was satisfactory to unsatisfactory, 94% and 81.2% respectively, while the effluent compliance at the Albert Falls North and South Wastewater Works was poor with both at 60% compliance. The poor effluent compliance at Albert Falls North and South Wastewater Works were primarily due to E. coli and ammonia results. In the interim, while plans to refurbish the plants are underway, the small effluent volume produced at both plants is directed to a pond as a mitigation measure towards effluent impacts on the water resource downstream.
The effluent compliance at the Howick Wastewater Works, which is operated by Umgeni Water on behalf of the Municipality, was also unsatisfactory at 74% due to noncompliant E. coli results. To address this problem, an additional chlorine contact tank is currently being constructed to allow adequate disinfection to occur.
Wastewater Quality Target:
- 2006/7: 10% wastewater quality failures
- Actual: 10.1%
- 2007/8: Maintain the 2006/7 target quality target
Sewage Sludge Compliance
Sludge disposal from Darvill, Ixopo and Howick Wastewater Works is evaluated in terms of protecting the public and the environment from the negative impacts of sludge disposal, and each works is scored on its planning, execution and monitoring of a responsible sludge disposal programme. The compliance of sludge disposal at Darvill Wastewater Works remained very high at 87%, while compliance at Ixopo and Howick were satisfactory at 66% and 63% respectively.