Applied Design demonstrates the integration of our system to tackle real-world problems. The first possible integration for our system is in wastewater treatment plants. There are two types of wastewater treatment plants: biological and physical. Biological plants use organisms to clean household wastewater, while physical plants use both chemical and physical treatments for industrial wastewater [1]. As part of our Human Practices, we toured our local biological wastewater treatment plant and recognized the processes that occur, in addition to a potential place where we could integrate it. Integrating our system in the biological treatment plant would be useful by aiding the metal removal process; however, due to the low heavy metal concentrations in average wastewater, our system is most suitable for physical/industrial wastewater treatment plants.

To remove the metals from industrial wastewater, there are many current methods, such as chemical precipitation. Chemical precipitation involves the use of chemicals such as lime to convert the metal ions into solid particles. From there, chemical coagulation occurs to destabilize the solid particles to allow for their precipitation by adding a negatively charged flocculant to react with the positively charged particles; this allows for the creation of larger particle groups [2]. Chemical precipitation is efficient and generally safe. However, there are many flaws. For example, chemical precipitation produces toxic sludge, which requires additional processing to remove, increasing the cost of production. Additionally, the sludge has a low settling rate in addition to being gelatinous, which is difficult to dewater. An alternative option to chemical precipitation is electrocoagulation; however, it results in unachievable heavy metal recovery [3]. Chemical precipitation also requires a very specific pH range; beyond the range, the reagent is likely to re-solubilize into the solution [4].

Our system in comparison is more ideal because it does not produce a toxic sludge, it does not require a specific pH, and its efficiency is much higher. The sludge produced by the precipitation of the metals using our phage and bacteria does not contain chemicals. Theoretically, our phage and bacteria do not require a specific pH, although we will need to perform further tests to prove it. Furthermore, due to our system’s self-renewability, it is greater in both functional efficiency and cost efficiency. Our system is more complex in comparison to chemical precipitation, due to its requirement of heat and UV disinfection; however, our system proposes a solution that solves the issues faced with chemical precipitation in an effective manner, providing a sustainable alternative.