Table 2.
Pros constraints and main characeristics of wastewater treatments
| Technology | Main characteristics | Pros | Cons |
|---|---|---|---|
| Adsorption |
Nondestructive process Use of a solid material (Crini and Lichtfouse 2019) |
Adsorption has a versatile range of uses in eliminating various contaminants, such as Cr, CN−, Mn, F, and more, from effluents produced by the steel industry. Leveraging waste by-products generated at various stages of steel production for the creation of cost-effective adsorbents offers a promising solution to address the challenge of managing sludge disposal (Rawat et al. 2023). |
Adsorption relies on pH conditions, requires extended treatment durations, and experiences a gradual decline in adsorption capacity as the number of cycles increases. Additionally, regenerating adsorbents demands a source of either steam or vacuum (Das, Mondal, et al. 2021). |
| Electrocoagulation | Electrolysis (Crini and Lichtfouse 2019) | The electrocoagulation process is widely embraced because of its uncomplicated installation and maintenance system, economical operational costs, minimal sludge production, and its compatibility with other treatment methods like ultrasonic, microwave, and ozone treatments (Ebba et al. 2021) | The primary factor that exerts influence on the electrocoagulation process is the current density. Therefore, optimizing current density is essential to achieve efficient and cost-effective wastewater treatment (Rawat et al. 2023). |
| Photo-degradation and UV irradiation | Destruction by combustion (Crini and Lichtfouse 2019) | Robust radical-driven reactions, rapid contaminant removal, thorough degradation of pollutants, recycling capabilities, and harnessing visible light (Majumder et al. 2021) . | One drawback of the method is its reliance on UV light for activation (Aziz et al. 2016). |
| Ozonation | Use of an oxidant (Crini and Lichtfouse 2019) |
No chemicals are required. Effective removal of a broad spectrum of microorganisms, both organic and inorganic chemicals. No necessity to alter pH or temperature. Enhanced germicidal efficiency (Guo et al. 2019) |
The phenomenon of ozone reacting with diverse inorganic and organic compounds within the effluent is characterized by either direct ozone attack or an indirect process involving the generation of hydroxyl radicals during ozone decomposition (Das, Mondal, et al. 2021) |
| Flocculation | Uptake of the pollutants and separation of the products formed (Crini and Lichtfouse 2019) |
Straightforward procedure. Incorporated physicochemical approach. Numerous chemicals are already available commercially. Minimal initial investment. Effective settling and dewatering of sludge. Substantial decrease in chemical and biochemical oxygen demands (Crini and Lichtfouse 2019). |
Necessitates the addition of non-recyclable materials. Demands constant monitoring of effluent pH levels. Leads to increased sludge generation, necessitating additional management, treatment, and costs. Inefficient for the removal of arsenic (Crini and Lichtfouse 2019). |
| Precipitation | Uptake of the pollutants and separation of the products formed (Crini and Lichtfouse 2019) | Chemical precipitation is acknowledged as the most efficient approach for eliminating heavy metals from wastewater. It finds extensive application in industries due to its cost-effectiveness and straightforward operational procedures (Yadav et al. 2019) | The generation of sizable sludge volumes can result in challenges related to dewatering and disposal. Additionally, the amphoteric nature of metal hydroxide precipitation can be affected by the presence of complexing agents (Qasem et al. 2021). |
| UltraFiltration |
Nondestructive separation Semipermeable barrier (Crini and Lichtfouse 2019) |
It can be efficiently delivered via micro-pores evenly distributed across the membrane’s surface. With its uncomplicated design, high level of automation, user-friendly operation, and small footprint in iron and steel wastewater treatment processes, it offers significant benefits in the removal of suspended solids and microorganisms (Zhang et al. 2022) | The key factors influencing ultrafiltration performance include filtration cycle, flux, cleaning method, and the configuration of membrane modules. Among these, the packing density and effective length of membrane fibers hold the utmost importance in module design, serving as crucial areas of research for manufacturers (Zhang et al. 2022) |
| Constructed wetland | Substrate is saturated long mechanism that creates oxygen-poor conditions in the substrate, limiting the vegetation to those species that are adapted to low-oxygen environment (Oscar Omondi and Caren Navalia 2021) | Cost-effective and efficient wastewater treatment technology (Stefanakis 2018) | Among the primary drawbacks of wetland clogging is the decline in oxygen levels within the wetland, subsequently hindering the oxidation process and bacterial activity. This can lead to system failure and potentially reduce the designed lifespan by a considerable margin (Liu et al. 2016) |
| Oxic-anoxic-oxic | Strong nitrogen removal requires less oxygen for ammonium oxidation and less carbon source for nitrite reduction (Wang et al. 2016) | The combined anoxic and oxic process offers unmatched advantages, including stable operation and high efficiency, for the complete removal of nitrogen (Chen et al. 2023) |
The substantial expenses associated with recirculation. The production of nitrogen oxides as end products, instead of N2, due to the microaerophilic conditions resulting from recirculation (Alzate Marin et al. 2019) |