Rising energy consumption in domestic wastewater management

Table of Contents

The energy demand is increasing throughout the world in all sectors because of population growth and inefficient devices. This matter will get worse over the years if energy-efficient systems are not introduced in different industrial, commercial and domestic sectors. The annual global energy consumption is estimated to be 580 million terajoules per annum with different countries having different consumption rates. 

The variation in the consumption of different countries depends on several factors namely climate zone, varying income, type of fuel used, and implementation of energy-efficient systems, with the population being the major reason for rising energy consumption as variation in population corresponds to variation in energy consumption. 

This makes China the biggest consumer of energy with its one billion people. For nearly half a decade energy consumption has increased worldwide but that is not the case for every country. 

Some countries, especially richer countries, have a decrease in energy consumption as they try to improve energy efficiency by adopting energy-efficient systems.

Energy consumption in Europe:

Energy consumption in Europe was estimated to be 39,351 Petajoules in 2021. It seems to be slowly decreasing from 2006 to 2021 due to adopting energy efficient measures.

it had decreased by 5.1% with the biggest share of energy being used in energy transformation -24.4 %, followed by transport activities- 19.3 %, households- 18.4 %, the industry sector- 16.9 %, services- 9.1 %, non-energy use- 6.6 % and other sectors- 5.2 %. 

Even though Europe has adopted different measures to decrease energy usage and has succeeded in its quest, more steps should be taken to reduce energy consumption even further.

Energy consumption of domestic wastewater treatment plants in Europe:

The EU’s Urban Wastewater Treatment Directive aims to protect the environment from the urban wastewater discharges and thus it directs the collection and treatment of wastewater from cities and towns of 2000 people and more advanced treatment of the wastewater from towns of more than 10,000 people.

In cities, the water and sewerage sector are responsible for the greatest energy consumption amounting to almost 40% of total urban energy consumption with wastewater treatment plants utilizing more of that percentage. 

All the essential components of a wastewater treatment plant, namely; air compressors, pumps, aerators, mixers, and analysis equipment, all require energy to function. 

A sewer treatment plant with 5 ML (megaliter) capacity consumes around 130,000 kWh per month worth 17,650 EUR. This will cost 0.13 Euro per kWh for the consumer to treat 50 liters capacity of water.

The most energy-consuming processes in a wastewater treatment plant are pumping and aeration. Pumping requires more energy as the plants are usually located away from residential areas. 

The aeration of activated sludge consumes a significant amount of energy due to the need for a non-stop air supply to the chamber for the digestion of organic matter by aerobic bacteria.

Energy sustainability in domestic wastewater treatment plants:

Sewage water treatments are the most energy-consuming facilities worldwide. Approximately 1-3% of a country’s total electrical energy output goes to wastewater treatment plants and in the case of Europe’s electrical energy output approximately 1% of energy is consumed by the wastewater industry. 

Depending on the plant size, type of treatment etc., the overall wastewater treatment plant electricity use in Europe was estimated at 24,747 GWh per year.

It is high time that energy-conserving methods are employed for domestic wastewater management as the energy use for utilities is expected to significantly grow anyway due to the population growth around the world. 

Through domestic wastewater treatment plants, energy can be conserved in three ways.

  • Making domestic wastewater plants more energy-efficient
  • Generating energy through wastewater plants
  • Employing treatment plants at the domestic level to conserve energy

Generating energy through wastewater plants:

Wastewater treatment plants with high capacity potentially have very high energy-generating capacity. They can be transformed into self-sufficient facilities working on the resource-recovery principle. Sewage sludge can be used to produce Biogas. 

Furthermore, Chemically Enhanced Primary Treatment (CEPT) can be applied which may increase the production of Biogas by 21%, reduce the energy demand in aeration by 8%, and decrease sludge quantity by 12%. 

Energy consumption can be further reduced to 20% by removing nitrogen in an autotrophic manner. Therefore, it is completely plausible to say that water treatment plants can operate with up to 93% self-sufficient energy.

Turning wastewater plants energy-efficient:

Wastewater treatment plants with high capacity can be made more energy efficient by producing hydrogen/oxygen (electrolysis) and methane (anaerobic digestion) to enhance purification processes and make them more energy-efficient. 

Additionally, methane and/or hydrogen oxygen can be used for seasonal energy storage. These two examples are potential and reasonable approaches that can improve energy sustainability in plants.

Employing treatment plants at the domestic level:

There are many strategies through which the energy consumption bills of domestic wastewater can be reduced. If you want to install an efficient energy saver domestic wastewater look for these specs:

  • Highly efficient motors will reduce 10 % of your energy consumption.
  • Motors with VFDs (Variable Frequency devices) control and adjust the motor output/efficiency according to load/demand.
  • Recyclable effluent quality enables you to replace portable water for washing and horticultural purposes which in return saves you a lot of energy consumption. 
  • Renewable energy options for domestic wastewater systems are a very feasible method to reduce your energy consumption.  

Installing treatment plants at the domestic level can majorly reduce energy consumption as it removes the need for pumping by using a gravity flow mechanism. 

One such product that can be installed at the domestic level is BioTornado Domestic Wastewater Treatment Plant. BioTornado uses cutting-edge technology to reduce the energy consumption by 50%. It removes the need for pumping as well as cuts the energy consumption in the aeration process significantly as its first chamber has an anaerobic zone to break down complex organic matter into simpler forms making the aeration process shorter. 

BioTornado is not only energy efficient, but it is ecologically better as it uses recycled matter for its components that are not only eco-friendly but also environmentally resistant making it durable and long-lasting. 


Where does all the domestic sewage water go?

All the sewage is collected through wastewater collection systems, and the wastewater from homes goes into drains, which go to the larger sewer pipe. This sewer pipe is connected to a network of sewer pipes that take the wastewater to wastewater treatment plants.

What does energy efficiency mean in the case of a domestic wastewater treatment plant?

The literal meaning of energy efficiency is to use less energy for a particular task. For example, energy-efficient systems require less energy to heat, cool, and produce goods. 

The energy-efficient domestic wastewater treatment plant is the plant which produces a high capacity of treated water per kWh.

Why is energy efficiency important for wastewater treatment plants?

Wastewater treatment plants require a substantial amount of energy to treat wastewater. 1-3% of global energy output goes to WWTPs and with the rise in energy consumption around the world it is crucial to implement energy-efficient systems wherever possible, to meet growing energy demands.

How does energy efficiency improve over time?

Betterment in technology and economic growth leads directly to improvement in energy efficiency. Using better-insulated equipment to eliminate the risk of wasting energy, installing more efficient equipment or employing renewable energy sources.

What process of domestic wastewater uses high energy?

The major chunk of energy is consumed in the aeration process and pumping operation of domestic wastewater treatment plants.

What are the innovative energy-saving trends in domestic wastewater treatment plants?

Many innovative energy-saving trends are being introduced in the marketplace place like advanced treatment processes, integration of renewable energy and the use of AI and Data analytics to improve energy consumption.