INDUSTRY JOURNAL Vol . 8
If we accept that all our drinking water is sourced from the nearest river , and once we understand that the municipality responsible for the safe treatment of sewage before disposal into the same river is in distress , we start to gain some perspective of the problem . Stated simply , a distressed municipality is unable to manage its wastewater properly , and we consequently have a growing flow of sewage contamination in our rivers . Let us give this some numbers to grasp the size of the problem . Our current population is around 60 million people , each of whom consumes about 200 litres of water per day . That equates to 12 billion litres of water daily that must be pumped from rivers , processed , reticulated and made available to each member of society . Of this , about half returns as waste to the sewage works . This gives us around 6 billion litres of waste per day , being treated by the 824 sewage works known to exist in the 850 municipalities . This consumes about a quarter of all electricity supplied to municipalities , with around 5 % going just to the treatment of waste . These numbers are staggering , but they exclude the thousands of package plants located in residential estates , dotted around the country , often along waterfronts or rivers . Delving deeper , we discover that wastewater contains a wide range of potentially harmful substances . We can divide these into chemical and biological . The chemically harmful elements include metals , some of which are a natural byproduct of corrosion in the municipal and domestic plumbing systems that use lead , copper and zinc . A distinct subset of these chemical hazards is related to the medications we use daily . All medicine is passed through the body and excreted as waste , often in a partially metabolised format . Sewage return flow therefore contains elevated levels of the types of drugs we use in society , including estrogen , antiretrovirals , antibiotics and mood-changing substances like antidepressants and recreational narcotics . A second subset of hazards relates to biological organisms , many of which are pathogens such as cholera , typhoid , legionella , hepatitis-A and a range of viruses .
In wastewater works these two streams of waste come together . Biological organisms thrive in organic waste , but they are allowed to multiply in the presence of low doses of the very chemicals we use in medicines to destroy them as harmful pathogens . This runs the growing risk of breeding multi-drug-resistant organisms
. If we accept that our 824 municipal wastewater works , and many thousands of smaller package plants found in residential estates , collectively discharge into the same rivers and dams from which our 1,085 bulk water treatment plants produce potable water , we start to understand the nature of the problem we are confronted with . None of those potable water plants was ever designed to produce safe drinking water from sewage-contaminated raw water . This is the core challenge we face as a society today .
Our wastewater systems are all in crisis . Some of those are under the control of residential estates , so let us dwell for a moment on this specific aspect . Wastewater discharge standards for package plants are more lenient than those for municipal plants , based on the assumption that their volumes are lower , so the dilution factor plays in their favour . This is no longer the case , however , because we lost our dilution capacity when municipal wastewater plants became dysfunctional . Of the 6 billion litres of waste produced daily across the country , about 5 billion litres are outside the safety parameters for discharge into the environment . This means that our lakes and dams are now sources of nutrients upon which bluegreen algae thrive . This needs a special article dedicated just to the implications of cyanobacteria , so all we can say in the space available is that we collectively need to become increasingly aware of the implications of our distressed wastewater management systems .
In closing , it is safe to predict that municipalities are unlikely to self-correct any time in the foreseeable future . This means that every citizen will need to understand the implications of our failing sewage infrastructure , and , where possible , start to internalise the solution . By this I mean that people living in residential estates are collectively capable of mandating their managing agents and bodies corporate for taking on the role of failing municipal service providers . This means that a savvy residential association will increasingly demand answers from their elected leadership .
Dr Anthony Turton
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