New Challenges In The Treatment Of Wastewater In Aussie Treatment Plants

Challenges on wastewater treatment differ depending on legislations for effluent control and regional characteristics. Social-economic conditions also pose challenges in the treatment of wastewater. There is, therefore, difficulty in identifying some of the common challenges in the treatment of wastewater applicable in all situations. However, no doubt using high performance and cost-effective treatment systems can help solve some of these problems.

Excessive sewage sludge produced

During the treatment of wastewater, a lot of sewage sludge is produced and the sludge needs to be appropriately treated. The sludge is converted or utilised in agricultural lands in some places and other places it is converted to energy and used in the treatment plant. Because 80 percent of the sludge produced consists of organic carbon, transforming it into biogas seems to be a feasible solution. However, a scale of anaerobic digestion system needed to transform it into biogas is not sufficiently large to capitalise on the merit of scale. Additionally, maintenance and capital costs are very high. It is also hard to harness the energy content present in sludge using anaerobic digestion.

Nevertheless, according to current research, sludge is the main sedimentation tank suitable for fermentation of methane.

Energy problems

A lot of treatment facilities don’t have enough energy to sustain their operations. Energy saving in treatment plants helps to reduce the emission of greenhouse gases. However, sewerage utilities emit a lot of carbon dioxide. They also emit nitrous oxide which has caused a lot of attention in most wastewater treatment plants. Although most companies do not have regulations to control the emission of greenhouse gases, it will be established in the near future. Currently, a new framework of maintaining a low carbon footprint is being incorporated where high performance and cost-effectiveness have been challenges in the treatment of wastewater. Hence, an optimum point is supposed to be investigated to allow for the development of technologies where these challenges can be dealt with.

A new paradigm shift

The field of biological treatment of wastewater is entering a new paradigm where conversion of nitrite and ammonium into N2 in absence of oxygen, anaerobic ammonium oxidation, becomes central for the removal of nitrogen from the wastewater streams. Researchers in the Netherlands discovered this unique reaction in the mid-90s and is considered beneficial in the standpoint of being cost-effective. Removal of nitrogen via anammox reaction reduces hydrogen donor demand, oxygen demand and excessive production of sludge. However, the reaction of anammox necessitates partial oxidation of ammonium to nitrate as a preliminary step. This brings a potential risk of producing a substantial amount of N2O.

This means that the mitigation of N2O production in the anammox process and partial nitration is highly desirable to yield multiple demands such as improving cost-effectiveness and reducing the emission of greenhouse gases.

However, it is important to understand that every wastewater treatment process has got its unique challenges. The challenges may vary by location, the type of wastewater being treated, the type of the desired results and the types of processes used to treat wastewater.