Table 6.
Comparison of tertiary treatments
| Tertiarty treatment | Removal | Operational parameters affecting process | Negative effect/problems | Costs | Reference | |
|---|---|---|---|---|---|---|
| Biological process | Microalgae |
UC 62.2% COT 48.3% TOC 34% NO3= 32% Ortophososphates 41.4% |
Biomass, pH | Nitrate removal was not particularly high | No calculated | This study |
| Dye Removal 30% | Effect of dye concentration, contact time, pH, nutrients | High dye concentration | High production cost under autotrophic laboratory conditions | Behl et al. (2019) | ||
|
NO3–N: 62.5% COD: 4.7% |
pH, nutrients concentrations | Type of pre-treatments | Dual roles of nutrient reduction and valuable biofuel feedstock production | Wang et al. (2010) | ||
| TDN > 79.0% Phosphorous > 98.0% TN 88.6–96.4% TP 99.7–99.9 | Temperature, light, pH, biomass productivity, CO2 solubility in the culture medium, CO2 consumption rates | There are sometimes allelochemicals production | Microalgal production in open systems is less expensive (construction and operation) | Arbib et al. (2014) and Gonçalves et al. (2017) | ||
| Physiochemical process | Ozonation (AOP) | COD 54.9% Micropollutants > 90.0% | Temperature, pH, Effluent organic matter concentration levels, alkalinity scavengers, ozone reactive inorganic | Increase of toxicity; low reactivity in dyes aromatic, heterocyclic and nitrogen-containing; low solubility at acidic pH | High production cost, and high investment and operational costs | de Arruda Guelli Ulson de Souza et al. (2010), Chys et al. (2018) and Arzate et al. (2019) |
| Electrochemical advanced oxidation (AOP) | Color 55.0% (BDD anode) color 14.9% (Pt anode) TOC 17.8% (BDD anode) TOC < 2.0% (Pt anode) | Time, anode type, current density | Production of carboxylic acids (highly recalcitrant organic compound) | Technology impractical and costly (long operational times and increases in current density) | Jhones dos Santos et al. (2018) | |
| Heterogeneous photocatalysis (AOP) | COD of 10% (only photolysis) COD ~ 45.0–77.0% (TiO2) COD ~ 19.0–50.0% (TVA) COD ~ 5.0–40.0% (Volcanic ashes) | Adsorption capacity and type of the materials, amounts of materials, turbidity, light intensity | Some effluent final has got a high level of genotoxicity or that grow inhibitor of green algae | Increased costs occasioned by separation of photocatalyst from water after treatment | Borges et al. (2014) and Rueda-Marquez et al. (2020) | |
| Photocatalytic ozonation (AOP) | TOC 9.0–25.0% COD ~ 70.0% | Pollutant concentrations, ozone dose, photocatalytic load and properties,pH, temperature, irradiation wavelength | An initial increase in the concentration of phenolics compound and toxicity of effluent | Process considered expensive for wastewater treatment (UV generation with conventional lamps) | Mehrjouei et al. (2015) and Quiñones et al. (2015) | |
| Sonolysis (AOP) | TOC 28.4% COD 16.2% BOD5 8.3% TN 39.6% NH3-N TP 14.5% | Temperature, ultrasound range, power density, power input, pollutant concentration | Process has a low mineralizing ability that it is not enough to comply with an acceptable water quality; the increased temperature by the ultrasound affecting the disinfection efficiency | When sonolysis is combined with processes like ozonation, demands high economical costs. The economic cost t is in function of energy consumption | Torres-Palma and Serna-Galvis (2018) and Vázquez-López et al. (2019) | |
| Photo-fenton (AOP) |
Total polyphenols ~ 90.0% COD ~ 90.0% DOC 4.0–36.0% Micropollutants > 90.0% |
pH, sales (FeSO4), UV radiation, H2SO4, H2O2 and KOH conectration | Waste generated are low biodegradabilit (ratio rbCOD/COD 0.45); Required a strongly acidic pH to avoid precipitation of iron. CO2 liberation during acidification stage | High cost associated with its installation and the energy demand | Lucas et al. (2012) and Arzate et al. (2019) | |
| Ultrafiltration (membrane processes) | COD 78.8% BOD 87.5.4% | Cross-flow velocity, trans-membrane pressure and backflushing methods | Operative problems in wastewater with high solids | High cost | Tchobanoglous et al. (1998) | |
| Coagulation/filtration (Membrane processes) | COD 24.5–35.2% TS 50.0–74.0% TN 3.8–19.2% TP 55.0–80.0% | TSS, Temperature, pH, Filtration rate of D/V filter (m/h), hydraulic retention time of coagulation tank | Increase of 61% of total GHG emissions generated from electricity use; coagulation/filtration processes had no significant effect on TN removal causing eutrophication by NO3-N permanence | High consumption of electricity increased cost of technology; depending on filter type the costs fluctuate between 324.6 and 84.8 USD/t COD eq removed | Wang et al. (2018) | |
| Filtration (Sand) | Turbidity 80.0% SS 72.0% TSS 83.0–98.0% COD 43% BOD 47.0–74.0% | Filtration rates (m/h), size of suspended solids, filters with an effective size filters and uniformity coefficient filters | Operative problem with particles less than 20 microm because are not removed efficiently | The technology is more economical using local sand | AI-Jadhai (2003) and Zahid (2003) | |