cover story

Shaping wastewater’s future

East Rand Water Care Company (ERWAT) is implementing new technologies at two of its plants that represent first-time applications for the group.

eading the way in Africa and executive manager: Development, ERWAT. Emmanuel Khomela, acting executive , ERWAT is a visionary “We also have a plan in place to install manager: Development, ERWAT leader in the field of wastewa- biogas-power-generation systems, which will L ter treatment and management. make us more self-sufficient in terms of It continues to introduce new technologies energy usage.” that are passing on greater efficiencies for The current focus is on plant upgrades that About HYBACS consumers in the industrial and residen- are more efficient both in terms of engineer- tial markets across ’s East Rand ing and energy savings across ERWAT’s 19 region. A water reclamation feasibility study treatment facilities (which have a combined is also currently under way in conjunction capacity of some 696 Mℓ of wastewater The HYBACS with Ekurhuleni Metropolitan Municipality, per day). They operate using conventional process consists of ERWAT’s majority shareholder, to investigate biological nutrient removal (BNR) technology two biological stages followed the viability of supplying treated wastewater to treat the wastewater received. The aim by clarification. • The first stage comprises Bluewater for industrial reuse, which will be dependent of the treatment is to reduce the contami- Bio’s Shaft-Mounted Advanced on the specific sector. nants in the waste- Reactor Technology (SMART™) Mining, industry and “Our strategy is to water to an accept- units, containing attached biomass agriculture would be provide the right-sized able quality prior to • The second stage is conventional prime candidates. being discharged activated sludge, with suspended ERWAT is developing works in the best back into the water biomass. a short-term five-year geographical location at resources. infrastructure plan in “A key feature of Key benefits order to incorporate all the most economic cost, BNR plants is their • Advanced biological nutrient projects and then map incorporating the best large-scale size in removal • Reduced power consumption the future of its plants terms of concrete available technology.” associated with aeration in effectively address- infrastructure, typi- • Reduced chemical consumption ing present backlogs. This dovetails with cally taking up the space of several soccer for nutrient removal a longer-term regionalisation and 50-year fields for bigger works. From inception, • Rapid settling in clarifiers master plan in conjunction with the City of these plants were designed to be progres- • Reduced embedded and emitted carbon Ekurhuleni. The integrated model will then sively upgraded with the building of addition • Significant CAPEX benefits form the basis for future expansion, with a modules that share the existing inlet and • Modular construction key focus on maintenance and operational outlets works,” he explains. “Where plants • Rapid deployment savings. “This could potentially result in the are reaching their design capacity in terms of • High leverage of existing closure of smaller plants and the expansion footprint, we need to find other ways to max- infrastructure of existing and larger facilities within the imise their life, which means looking at retro- • Minimal plant disruption group,” says Emmanuel Khomela, acting fit options like the HYBACS (hybrid activated

6 IMIESA March 2017 Cover story

ABOVE Plastic media bio-filtration tank LEFT Hybacs istallation at Tsakane About ERWAT ERWAT serves some 2 000 industries and more than 3.5 million people in Gauteng’s extensive East Rand region.

ERWAT’s plan is to convert other biofilter plants to plastic media in the near future. One of its major benefits is that it allows for more throughput of water inflows to the plant plus sludge process) technology we are installing Tsakane is being equipped with the pro- the surface area for filtration is larger. Phased at our Tsakane facility. This technology takes prietary HYBACS solution from UK-based installation times, which occur during the low up a much smaller space and doubles the company, Bluewater Bio, which is supplied rainfall season, typically take up to two years design capacity with minimal civil works.” and supported locally by Headstream Water. to complete, depending on the size of the An example of a recent large-scale con- This project commenced in March 2016, treatment works. ventional BNR upgrade is the project com- with targeted completion scheduled for April “Effective wastewater treatment and pleted during 2016 at the Welgedacht plant, 2017. This HYBACS system will double the release is particularly critical given our pre- situated near Springs. Module 1, with a design capacity from 10.8 to 21 Mℓ/day. sent water-scarce environment. For engineer- capacity of 35 Mℓ/day, was completed in An optimal solution for upgrading exist- ing specialists and scientists in the field, this 2003 and was struggling to keep pace with ing activated sludge plants, Bluewater is a given, but for many there is no causal link rapid urbanisation. Eventually, it was run- Bio states that HYBACS “can produce or understanding, generally, about safe sani- ning at over-capacity and by 2008 the plant effluents with qualities that comply with tation, effluent treatment, and subsequent was already receiving 59 Mℓ/day against a the most stringent European nutrient- ecosystem replenishment. These areas need design of 35 Mℓ/day. removal standards”. constant consumer education, which starts This necessitated a new Module 2 “HYBACS is a standalone, compact and in the first instance with responsible disposal Extension of 50 Mℓ/day to cope with the modularised plug-and-play technology, which into our sewer systems, an industrial exam- increased demand for wastewater treat- allows us to retrofit an existing treatment ple being heavy metals and bad chemicals, ment from key areas that include Benoni, facility and thereby significantly boost its which impact on downstream process costs , Springs, Bakerton and . capacity and lifespan,” explains Khomela. since more intensive chlorination treatment The new extension actually comprises two “Plus, the installation times are fast, typi- is required. 25 Mℓ/day modules to improve efficiencies cally taking less than 24 months to install “Our number one mandate is service deliv- and maintenance. compared to the much longer periods ery, which is why we’re investing in advanced At 85 Mℓ/day, the plant is now running required for the construction of the heavy- technology to maintain the water quality of the at full capacity. Further upgrade plans are duty civil works needed for new module receiving water resources and to help protect in progress, which entail the addition of a extensions. HYBACS technology is also very South Africa’s water security,” Khomela adds. 50 Mℓ/day module. The process technolo- energy-efficient.” ERWAT is geared to collaborate with the gies are already in place. Plus Welgedacht’s mining sector, the food and beverage indus- inlet works are designed to cope with Plastic media try and other private sector customers in 135 Mℓ/day. Alongside works at Tsakane, Herbert Bickley operating and maintaining their wastewater is the first biofilter plant within the ERWAT treatment plants. Herbert Bickley and Tsakane group to switch over from the age-old stone Currently, upgrades are in progress at the filtration system to plastic-media bio filtra- Tsakane operation (established circa 1973), tion within existing structures. Plastic media serving the and Tsakane areas and exhibit a much higher rate loading process falling within the DD5 drainage district. rate and, again, there are energy savings. www.erwat.co.za

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