How to Save Energy in a Wastewater Plant
Wastewater plants are very energy intensive, they need a huge amount of electricity to process, clean and get the water back to a level where it is safe to be used again or to be released back into the waterways. The issue of rising energy costs and the need for businesses to reduce their energy consumption is increasing. Net zero targets have been put in place by governments to force the reduction of the emissions released into the atmosphere. This has led to a significant shift in the focus of many businesses to become more environmentally friendly and reduce their overall carbon footprint
Wastewater companies account for 3% of the total US energy consumption per year. 90-95% of the energy used at a sewage treatment facility is electricity. There are several ways in which wastewater treatment facilities can minimise the amount of electricity used to become more environmentally friendly.
Evaluate current efficiency
The first step to reading energy usage in any business is to evaluate the current processes and procedures. Companies can then find out which procedures use a high amount of energy and if there are any easy fixes that can be achieved. It may also show that some equipment is defective or needs replacing to improve the energy efficiency. Once a thorough investigation has taken place companies can begin to understand the key areas where change is needed.
Aeration step
This is the process in a wastewater treatment facility that uses the most electricity. The process pumps oxygen into the wastewater. The oxygen is then used by the organic material in the water to allow it to break down further so it can be collected and removed from the water. The incoming organic matter cannot be bio-degraded in a reasonable time frame without adequate oxygen. If oxygen is not used the process can take much longer and the organic matter may not be fully broken down. Some companies provide more efficient ways to add oxygen to the wastewater. This step is a key stage that should be considered to improve efficiencies, new and more efficient technology can reduce the electricity needed in this step by up to 50%.
Using an anaerobic digester
Sludge is a waste product that is removed during the wastewater treatment process. This sludge can actually be used to create energy to power the facility. If implemented in the correct way the wastewater treatment facility can become self-powering, meaning the plant would not need any electricity from the grid to run.
The process requires a large upfront investment to purchase the anaerobic digester which takes the sludge material and starves it of oxygen. The organic material then breaks down and forms a number of different gases. The main gas of interest to the plant is biogas, which is formed of methane, this gas can be used to create heat and electricity to power the wastewater facility.
Biogas must be carefully monitored using a biogas analyser to carry out methane leak detection and make sure it has enough methane for it to be used as a source of energy. The process can take time to build up enough gas for it to be able to run and may require additional forms of substrate. Local farmers who have cattle often need somewhere to dispose of their livestock feed waste. Often farmers and other similar businesses will pay companies to take the waste of their hands. So not only can an anaerobic digester remove the need for the wastewater facility to pay bills but it can also provide a source of income.
If the facility is connected properly it can also inject gas back into the gas network. This can provide another source of income for the plant and provide homes and other businesses with a renewable form of energy.
Staff training
Wastewater treatment facilities often employ a large amount of staff. Each member of staff will have an impact on the environmental statistics of the overall wastewater treatment facility. Small changes such as turning off things when not in use and minimising heating large office spaces can have a significant difference in the cost of energy at a wastewater treatment facility. Employees should be trained and provided with key information to help them to understand the impact of the energy they use. If staff are on board with saving energy it can be much easier to implement new equipment and find new ways of increasing efficiencies within the facility.
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