Q2. What are the main reasons for the occurrence of micropollutants in the aquatic?
The occurrence of micropollutants in the aquatic environment have been frequently associated with a number of negative effects, including short-term and longterm toxicity, endocrine disrupting effects and antibiotic resistance of microorganisms (Fent et al., 2006 and Pruden et al., 2006).
Q3. What is the effect of the competition for adsorption sites and/or particle solids?
As the elimination of the trace contaminants depends largely upon particle–contaminant interactions, the competition for adsorption sites and/or pore blocking (by particle solids) can reduce the removal efficiency of activated carbon (Bolong et al., 2009).
Q4. What is the main concern of applying oxidation processes?
Since oxidation processes do not commonly result in complete mineralization ofmicropollutants, the major concern of applying these processes is the formation of oxidation by-products (or transformation products) from micropollutants.
Q5. What types of wastewater media are used to transport micropollutants to aquatic systems?
The major types of wastewater media that convey micropollutants to aquatic systems viaWWTPs include domestic wastewater, hospital effluents, industrial wastewater and stormwater runoff, rural runoff and manure.
Q6. What is the role of excretion rate in determining the introduction of pharmaceuticals into raw?
As orally ingested products containing potential contaminants (e.g. pharmaceuticals) are metabolized in human body and are subsequently excreted via urine and feces, excretion rate plays a role in determining the introduction of pharmaceuticals into raw wastewater.
Q7. Why was ozone less reactive to organic matter in the synthetic secondary effluent?
This is because ozone was less reactive to the inorganic and organic matters (non-target compounds) in the synthetic secondary effluent as compared to OH (generated at high pH) and a greater amount of O3could thereby be preserved for the reactions with target compounds.
Q8. What are the advantages of MBRs over conventional wastewater treatment?
MBRs possess the following advantages over conventional wastewater treatment in the following aspects (Ngo et al., 2012) such as high effluent quality, excellent microbial separation ability, absolute control of SRTs and HRTs, high biomass content and less sludge bulking problem, low-rate sludge production, small footprint and limited space requirement, and possibilities for a flexible and phased extension of existing wastewater treatment plants (WWTPs).
Q9. What is the main reason for the low concentration of micropollutants in groundwater?
the processes governing subsurface flow and transport (such as dilution, adsorption to aquifer material, degradation and travel time) can decrease micropollutants' concentrations from the sources (e.g., landfill leachate and septic tank leakage) to groundwater (Teijon et al., 2010).
Q10. What are the advantages of membranes in conjunction with anaerobic reactors?
membranes in conjunction with anaerobic reactors have been gainingpopularity due to their intrinsic advantages over aerobic systems, such as low sludge production, net energy generation and a fully enclosed environment (Hu and Stuckey, 2006).
Q11. What are the main factors that influence the removal of micropollutants?
During MBR processes, several operational parameters (e.g. SRT, HRT and temperature)can influence the reduction of micropollutants.
Q12. What are the challenges of micropollutants in the aquatic environment?
Micropollutants are commonly present in waters at trace concentrations, ranging from a few ng/L to several µg/L. The ‘low concentration’ and diversity of micropollutants not only complicate the associated detection and analysis procedures but also create challenges for water and wastewater treatment processes.
Q13. What is the importance of the evaluation of the fate and removal of micropollutants?
the evaluation of the fate and removal of micropollutants during wastewater treatment is imperative for the optimization of treatment processes, in order to prevent the release of these potentially harmful micropollutants.
Q14. What conditions could lead to the removal of iodinated X-ray contrast media?
For instance, anoxic conditions could lead to improved elimination of iodinated X-ray contrast media, while aerobic environments witnessed minor removal (Drewes et al., 2001).
Q15. Why did of the studies at real plant scale show insufficient removal of pesticides?
Due to the fact that pesticides have been typically considered of agricultural rather than of urban origin, few studies have been performed at real plant scale and most of reported plants coincide in showing insufficient removal of pesticides (Köck-Schulmeyer et al., 2013).
Q16. What are the options for improving the removal of micropollutants?
Several potential options are available for improving the elimination of micropollutants, including source controls (e.g. application of micropollutant-free products, source separation, pretreatment of hospital and industrial effluents, etc.), reassessment and optimization of current treatment processes, and end-of-pipe upgrading of WWTPs.
Q17. What is the reason for the higher amount of biosolids in the conventional treatment processes?
This could be attributed to the higher amount of biosolids and better aeration condition (leading to more effective aerobic degradation) in the conventional treatment processes.
Q18. What are the external factors that affect the removal of micropollutants in WWTP?
External factors are WWTP-specific, which are linked to the treatment conditions of wastewater treatment processes, the mixture of micropollutants that can act as competitors and nature of wastewater (pH and temperature).