When discharged into wastewater, pharmaceuticals and personal care products (PPCPs) become microorganic contaminants and are among the largest groups of emerging pollutants. Human, animal, and aquatic organisms’ exposures to PPCPs have linked them to an array of carcinogenic, mutagenic, and reproductive toxicity risks. For this reason, various methods are being implemented to remove them from water bodies. This report critically reviews these methods and suggests improvements to removal strategies. Biological, physical, and chemical methods such as biological degradation, adsorption, membrane filtration, and advanced electrical and chemical oxidation are the common methods used. However, these processes were not integrated into most studies to take advantage of the different mechanisms specific to each process and are synergistic in the removal of the PPCPs that differ in their physical and chemical characteristics (charge, molecular weight, hydrophobicity, hydrogen bonding, structure). In the review articles published to date, very little information is available on the use of such integrated methods for removing PPCPs. This report attempts to fill this gap with our knowledge.

Oxidation-reduction potential (ORP) sensors would constitute a robust surveillance and control solution for aeration and external carbon dosing in wastewater biological treatment processes if a clear correlation exists between the ORP values and process variables (e.g., dissolved oxygen (DO), nitrate, and chemical oxygen demand (COD). In this study, ORP values and other water quality variables were analyzed, and principal component analysis (PCA) and analysis of variance were used to study the relationships between ORP and main reactive substances under anoxic conditions. Mathematical models were then established using multiple regression analysis. The results showed that under anoxic conditions, ORP was positively correlated with nitrate, DO, and COD and negatively correlated with ammonia nitrogen, phosphate, and pH. COD had a low correlation with the ORP value change. PCA showed that the mathematical model of ORP can be established by using DO, nitrate, and phosphate, for which the adjusted R² value was 0.7195. The numeric relationships among ORP, COD, and nitrate were clearly established and applied to control external carbon dosing. A precise and clear relationship between ORP and COD offers the possibility to substitute COD monitoring for process control.

Real-time monitoring of antibiotics in hospital and pharmaceutical wastewater using ultraviolet–visible (UV–Vis) spectroscopy is considered a promising method. Although gas chromatography–mass spectrometry (GC–MS) and other methods can detect antibiotics with quite low limits of detection (LOD), they possess various limitations. UV–Vis spectroscopy combined with chemometric methods is a promising choice for monitoring antibiotics. In this study, two immersed in situ UV–Vis sensors were used to explore the relationship between absorption spectra and antibiotics and study the influence of the optical path length on the LOD. The LODs of sensor 2 using a 10 cm optical path is up to 300 times lower than that of sensor 1 using a 0.5 mm optical path. Moreover, multiple antibiotics in the wastewater were investigated in real-time manner. The absorption spectra of 70 groups of wastewater samples containing different concentrations of tetracycline, ofloxacin, and chloramphenicol were measured. The results indicate that the nine wavelengths selected by interval partial least squares (iPLS) after the second derivative pretreatment have better predictability for ofloxacin and the six wavelengths selected by competitive adaptive reweighted sampling (CARS) after the first derivative. The multi-fold cross-validation results indicate that the model has a good predictive ability.

Membrane bioreactor (MBR) is a progressive alternative to conventional waste-water treatment. However, membrane fouling is one of the most significant barriers to further development of the MBR technology since it has a detrimental effect on system performance and stability. Therefore, a number of studies have been developed to comprehend the fouling nature and distinguish the effective flux enhancers, so as to develop a highly effective fouling control strategy. Key findings of these studies are summarized in the current review. Polysaccharides, proteins and humic substances tend to play the prime role in inducing fouling. The main factors affecting fouling behaviour in MBRs are membrane characteristics, membrane operation conditions and activated sludge properties, and recent evidence points out that the modification of the biomass characteristics with the use of chemical agents and adsorbents is among the most efficient fouling-hindering techniques. The current review not only aims to provide a comprehensive overview of the up-to-date methods of fouling alleviation using membrane flux enhancers in MBR but also intends to shed light on the mechanisms of their action, which, together with the experience of previous findings, can be the basis for developing a new advanced fouling mitigation strategy.

Biochar and chitosan are considered as green and cost-effective adsorbents for water purification; the combination of these two materials may lead to an improved adsorption capacity of the generated adsorbents. Most sorption studies have been focused on the ability to adsorb one contaminant or the same type of contaminants. Thus, this study aimed to produce chitosan-biochar beads (CH-BB) and test their efficiency in the simultaneous removal of a metal-complexing antibiotic, ciprofloxacin (CIP), and three metal(loid)s (As, Cd and Pb). Modification of raw pig manure biochar resulted in an increase in its adsorption capacity, except for Pb. The highest increment was observed for As (almost 6-fold) and the lowest was observed for CIP (1.1-fold). The adsorbent was able to simultaneously remove all targeted contaminants, individually and in the mixture. The adsorption capacity of CH-BB followed the order: Pb > Cd > >As > CIP. When Pb and As were present in the same mixture, their removal efficiency increased from 0.13 ± 0.01 to 0.26 ± 0.05 mg/g for As and from 0.75 ± 0.08 to 0.85 ± 0.02 mg/g for Pb due to their co-precipitation. The CIP–metal complexation probably resulted in a reduced adsorption ability for inorganics due to the decreased concentration of free ions. The presence of metals and metalloids led to alterations in CIP’s mobility.