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Biozone Manufacturing

ECOLOGICALLY FRIENDLY AND COST-EFFECTIVE ALTERNATIVE TO SALT IN TREATING “HARD” WATER

Biozone Manufacturing’s nanofiltration purification system has proven to be a reliable and efficient solution for Eastplats Crocodile Mine’s water treatment needs. Incorporating advanced nanofiltration technology and an online monitoring system has ensured optimal performance and compliance with quality standards.

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Nanofiltration Purification System – Eastplats Crocodile Mine

Eastplats Crocodile Mine, located in South Africa, is a leading mining operation committed to
sustainable practices. A water analysis revealed the main problem with raw water was its hardness.

Biozone Manufacturing specialises in water treatment solutions with emphasis on ozone oxidation and disinfection. We offered an alternative to conventional “salt” treatment with a cost-effective and eco-friendly solution . This has been the first of its kind successful rollout of this innovative solution to legacy issues.

Challenges

A comprehensive water treatment system was required to deliver softened water for their boilers and purified drinking water for their site’s successful operations. The system needed to meet stringent quality standards set by WHO and SANS241.

Solutions

The conventional systems used to treat “hard” water is to utilise salt, this adds considerable cost and labour to the mine. These systems require sourcing, transporting and storing quantities of “salt” to soften the water. Then, the disposal of brine water posed a further logistical problem, which would have to consider the environmental damage.

Biozone Manufacturing was able to design, manufacture and install a containerised state-of-the-art Nanofiltration Purification System at Eastplats Crocodile Mine to prevent the need for salt treatment.

The system includes a pre-treatment stage using AFM to remove suspended soils and biostatic material, ensuring optimal performance of the nanofiltration membranes. The system is designed to treat water at 12 kilolitres per hour, meeting WHO water supply goals and SANS241 limits.

Containerised Nanofiltration System
IMG 20240306 WA0073

Softener Plant Sizing and Comparison

The size of a softener plant is determined by the amount of Hardness (Ca & Mg) that needs to be removed from the water per/day. This calculation considers the volume of water treated per day and the total hardness of the water. Additionally, the size of the system is influenced by the regeneration cycle, which is recommended to be limited to once per day.

For comparison, see the two scenarios below based on treatment volumes.

Total Hardness: 600 mg/lt.
Scenario 1:
– 12 hrs operation x 12 kL/hr = 144 Kl x 600 mg/lt = 86.4kg of Total hardness to be removed p/day.
– For 144 kL/day @ Total hardness of 600 mg/lt and I x regeneration p/day = 1 570lt softening resin.
– Salt consumption p/regeneration cycle = 185 kg/day (R 4500 p/day, R 135 000 p/month)
Scenario 2:
– 16 hrs operation x 12 kL/hr = 192 kL x 600 mg/lt = 115.2kg of Total hardness to be removed p/day.
– For 192 kg/day @ Total hardness of 600 mg/lt and It x regeneration p/day = 2 100 lt softening resin.
– Salt consumption p/regeneration cycle = 250 kg/day (R 6000 p/day = R 180 000 p/month)

Concerns

Operating expenditure: A water softener’s operating expenditure is significantly higher than the investment for a Nanofiltration system.
Environmental impact: The ecological impact of the salt flushed down the drain from the softener system is substantial, estimated at 70-90 tons per year.
Operator involvement: Softener systems require high operator involvement for maintenance and operation.
Impact on existing sewer plant: The high salt load from the softener system can negatively impact the sewer plant’s operation.

Online Monitoring System

Biozone Manufacturing included an online monitoring system, allowing real-time monitoring of critical parameters such as produced water quality, abstracted borehole volume, and tank levels. This system provided the client with valuable data for optimising the treatment process and ensuring compliance with quality standards.

IMG 20240306 WA0058

Implementation

The treatment process began with pre-treatment using AFM to remove suspended solids and biostatic material. The water then underwent nano-filtration, where it was pumped at high pressure over a semi-permeable membrane to remove salts. A chlorine dosing system was installed post-nano-filtration to sterilise the water and prevent bacterial growth.

Project Philosophy & Engineering Methodology

Biozone Manufacturing focused on achieving several design objectives, including:

  • Low power consumption,
  • Low flux through pre-filtration,
  • Use of long-life filter media,
  • Ease of maintenance,
  • Reducing hardness by a predicted 80%.

The system was designed for longevity and efficient operation, with an expected lifespan of
over ten years for the filter media.

Results

The Nanofiltration Purification System at Eastplats Crocodile Mine has delivered exceptional results. It provides high-quality softened water for the boilers, protecting infrastructure and ensuring efficient operation. The purified drinking water meets the site’s needs, providing a reliable and safe water supply.