Industrial effluent should be central to all processes

While focusing on production, effluent water treatment can easily become an expensive afterthought for companies. Gavin Mwanza – head: Engineering at Aquamat – talks to WASA about water treatment for various industries.

Gavin Mwanza, head: Engineering, Aquamat

What is a discharge licence? GW Before discharging water into a sewerage network (for industries based in cities), industries need to apply for a discharge licence, which will specify the water quality standards the effluent must reach before it is discharged, as well as the maximum quantity that can be discharged. This licence is supposed to protect the wastewater treatment works (WWTW) – ensuring that it is not overloaded. If the quality of the discharged water is not up to standard, a company can be issued with a fine and a warning; if it does not rectify the problem, it may lose its discharge licence.

The conditions in each licence may vary with every city and every industry. A company producing steel will not have the same discharge licence as a company producing cheese. With a steel company, water contaminants may include electric conductivity and metals, whereas a cheese-making factory may include CODs, fats and oils. It would be pointless to monitor a company for a contaminant it does not produce.

What is the process once a company has approached Aquamat? Companies approach us when they need to meet water quality requirements to discharge effluent. As discussed, effluent will differ according to the industry. Effluent even differs within the same industry.

Water analysis is therefore the starting point because a solution needs to be specifically designed according to the current water quality/water problems, as well as the standards to which the water must be treated. We also run trials. It is important to determine a worst-case scenario and design for that.

Based on the analysis and trials, we then develop a solution and propose a quote. That is part of the precontract agreement. If the client approves the quote, Aquamat then commissions and installs the plant. From there, our services can continue with training and regular consultations regarding water compliance.

Effluent seldom remains consistent and its quality should, therefore, be consistently analysed and changes implemented to address any fluctuations. Some clients will have their own laboratories and quality systems in place, while others will contract Aquamat to do all the testing.

The reason the composition of effluent from a company may change could be attributable to the use of a different raw material supplier or the introduction of a new chemical into their process.

How do you reduce water treatment costs for companies? We encourage water reuse. Yes, we help companies avoid municipal penalties by treating the water, but companies can save a lot more money if they reuse water. This is because industrial effluent is metered. The less effluent a company discharges, the less it pays – on both discharge rates and incoming water.

Treated industrial effluent can be used for flushing toilets or cleaning factories, and can even be treated to potable standards.

The higher the required water quality standards, the higher the cost of water treatment. Drinking water and water to flush toilets should not come from the same water supply. If these sources can be separated, then it will be easier to use recycled water to flush toilets. This would mean that not all the wastewater would need to be treated to potable standards.

It is also important to remember that the nature of contaminants in water will dictate the type of treatment needed, which will dictate the cost.

What is the best approach when dealing with industrial effluent? I will start with two don’ts: • Do not move industrial effluent down the priority list while focusing on your core business. If you do not make industrial effluent a part of your production process, it becomes very expensive to treat. It will end up costing more owing to fines and potential lawsuits. • Do not put up a plant and assume that industrial effluent will always be treated to the required water standards. It is an ongoing process that needs constant monitoring. Then I would advise the following: • Water treatment should not be a grudge purchase – it is about responsibility and keeping the environment safe for future generations. • Valuable resources can be recovered from wastewater – e.g. recyclable oils, fertilisers and energy. • Aim to discharge as little water as possible – always look to water reuse. • People believe that they can only use water fit for human consumption.

Less than 20% of water is used for drinking and cooking. Most water is used for flushing toilets, which does not require a potable supply.