Surface Water and Groundwater Quality in South Africa and Mozambique—Analysis of the Most Critical Pollutants for Drinking Purposes and Challenges in Water Treatment Selection

According to a recent report by the World Health Organization (WHO), the countries which still have limited access to water for drinking purposes are mainly those in the Sub‐Saharan region. In this context, the current study provides an overview of the quality of surface water and groundwater in rural and peri‐urban areas of the Republic of South Africa (RSA) and Mozambique (MZ) in terms of concentrations of conventional pollutants, inorganic chemicals, microorganisms, and micropollutants. Their values were compared with the drinking water standards available for the two countries. Regarding surface water, it was found that microorganisms occur at high concentrations; nickel (RSA) and boron (MZ) are other critical parameters. Regarding groundwater, arsenic and lead (RSA) and boron, sodium, and chloride (MZ) are the main critical substances. With regard to micropollutants, their surface water concentrations are much higher than those in European rivers. The highest values were for ibuprofen, acetylsalicylic acid, clozapine, and estriol. Suitable treatment is necessary to produce safe water depending on the main critical pollutants but, at the same time, action should be taken to improve wastewater treatment in rural areas to improve and safeguard surface water bodies and groundwater which are sources for drinking need

Quantitative and qualitative approaches for CEC prioritization when reusing reclaimed water for irrigation needs – A critical review

The use of reclaimed water for irrigation is an option that is becoming increasingly widespread to alleviate water scarcity and to cope with drought. However, reclaimed water, if used for irrigation, may introduce Contaminants of Emerging Concern (CECs) into the agroecosystems, which may be taken up by the crops and subsequently enter the food chain. The number of CECs is steadily increasing due to their continuous introduction on the market for different uses. There is an urgent need to draw up a short list of potential high priority CECs, which are substances that could be taken up by plants and accumulated in food produce, and/or that could have negative effects on human health and the environment. This review presents and discusses the approaches developed to prioritize CECs when reclaimed water is (re-)used for irrigation. They are divided into quantitative methodologies, which estimate the risk for environmental compartments (soil and water), predators and humans through equations, and qualitative methodologies, which are instead conceptual frameworks or procedures based on the simultaneous combination of data/information/practices with the judgment of experts. Three antibiotics (erythromycin, sulfamethoxazole and ciprofloxacin), one estrogen (17-α ethinylestradiol) and one analgesic (ibuprofen) were found on at least two priority lists, although comparison among studies is still difficult. The review remarks that it is advisable to harmonize the different methodologies in order to identify the priority CECs to include in monitoring programs in reclaimed water reuse projects and to ensure a high level of protection for humans and the environment

Activated carbon coupled with advanced biological wastewater treatment: A review of the enhancement in micropollutant removal

This study consists of a review on the removal efficiencies of a wide spectrum of micropollutants (MPs) in biological treatment (mainly membrane bioreactor) coupled with activated carbon (AC) (AC added in the bioreactor or followed by an AC unit, acting as a post treatment). It focuses on how the presence of AC may promote the removal of MPs and the effects of dissolved organic matter (DOM) in wastewater. Removal data collected of MPs are analysed versus AC dose if powdered AC is added in the bioreactor, and as a function of the empty bed contact time in the case of a granular activated carbon (GAC) column acting as a post treatment. Moreover, the enhancement in macropollutant (organic matter, nitrogen and phosphorus compounds) removal is analysed as well as the AC mitigation effect towards membrane fouling and, finally, how sludge properties may change in the presence of AC. To sum up, it was found that AC improves the removal of most MPs, favouring their sorption on the AC surface, promoted by the presence of different functional groups and then enhancing their degradation processes. DOM is a strong competitor in sorption on the AC surface, but it may promote the transformation of GAC in a biologically activated carbon thus enhancing all the degradation processes. Finally, AC in the bioreactor increases sludge floc strength and improves its settling characteristics and sorption potential

Selection of indicator contaminants of emerging concern when reusing reclaimed water for irrigation — A proposed methodology

Organic and microbial contaminants of emerging concern (CECs), even though not yet regulated, are of great concern in reclaimed water reuse projects. Due to the large number of CECs and their different characteristics, it is useful to include only a limited number of them in monitoring programs. The selection of the most representative CECs is still a current and open question. This study presents a new methodology for this scope, in particular for the evaluation of the performance of a polishing treatment and the assessment of the risk for the environment and the irrigated crops. As to organic CECs, the methodology is based on four criteria (occurrence, persistence, bioaccumulation and toxicity) expressed in terms of surrogates (respectively, concentrations in the secondary effluent, removal achieved in conventional activated sludge systems, Log Kow and predicted-no-effect concentration). It consists of: (i) development of a dataset including the CECs found in the secondary effluent, together with the corresponding values of surrogates found in the literature or by in-field investigations; (ii) normalization step with the assignment of a score between 1 (low environmental impact) and 5 (high environmental impact) to the different criteria based on threshold values set according to the literature and experts' judgement; (iii) CEC ranking according to their final score obtained as the sum of the specific scores; and (iv) selection of the representative CECs for the different needs. Regarding microbial CECs, the selection is based on their occurrence and their highest detection frequency in the secondary effluent and in the receiving water, the antibiotic consumption patterns, and recommendations by national and international organisations. The methodology was applied within the ongoing reuse project SERPIC resulting in a list of 30 indicator CECs, including amoxicillin, bisphenol A, ciprofloxacin, diclofenac, erythromycin, ibuprofen, iopromide, perfluorooctane sulfonate (PFOS), sulfamethoxazole, tetracycline, Escherichia coli, faecal coliform, 16S rRNA, sul1, and sul2.publishedVersio

Surface and Groundwater Quality in South African Area—Analysis of the Most Critical Pollutants for Drinking Purposes

According to a recent report by World Health Organization, the countries which still have limited access to water for drinking purposes are mainly those in the Sub-Saharan region. (Potential) water sources for drinking needs may contain different contaminants. In this context, the current study consists in an overview of the quality of surface water and groundwater in the Republic of South Africa (RSA) and Mozambique (MZ) and provides the variability ranges of the concentrations of the main pollutants in the two countries. Chemical and physical characteristics and concentrations of macropollutants, inorganic compounds (metals) and selected microorganisms were collected for surface water and groundwater and compared with the standards for drinking water set in the two countries. It was found that in surface water, microorganisms were always at very high concentrations. In addition, nickel (in RSA) and boron and chlorine (in MZ) were the most critical compounds. It emerged that in groundwater, arsenic, lead and chlorine (in RSA) and boron, sodium and chlorine (in MZ) were the main critical pollutants. Adequate treatments in the construction of new drinking water plants in rural areas should be selected on the basis of these most critical compounds and their observed variability over time

SWOT-SOR Analysis of Activated Carbon-Based Technologies and O3/UV Process as Polishing Treatments for Hospital Effluent

The management and treatment of hospital wastewater are issues of great concern worldwide. Both in the case of a dedicated treatment or co-treatment with urban wastewater, hospital effluent is generally subjected to pre-treatments followed by a biological step. A polishing treatment is suggested to promote (and guarantee) the removal of micropollutants still present and to reduce the total pollutant load released. Activated carbon-based technologies and advanced oxidation processes have been widely investigated from technical and economic viewpoints and applied in many cases. In this study, the potential exploitation of these technologies for the polishing treatment of hospital effluent is investigated by combining a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis with a Strategic Orientation (SOR) analysis. This approach allows a coherent strategy to be extracted from the SWOT-SOR data, increasing the chances of success of each technology. It emerges that both technologies present relevant and sometimes similar strengths and can present opportunities. At the same time, activated carbon-based technologies are more likely to contain the main identified threats than O3/UV technology. The study also finds that, for both technologies, further research and development could improve their potential applications in the treatment of hospital wastewater

First autochthonous clinical case of Hepatozoon silvestris in a domestic cat in Italy with unusual presentation

Hepatozoon spp. is the causative agent of a vector-borne parasitic disease in many animal species. In felids, Hepatozoon felis, Hepatozoon canis and Hepatozoon silvestris have been molecularly isolated. Hepatozoonosis usually causes asymptomatic infections in domestic cats, but clinical cases have recently been reported in Europe. We describe the first Italian case of hepatozoonosis in a cat with an unusual presentation. An 11-year-old neutered European shorthair cat was urgently hospitalized for intestinal intussusception. Hematology, biochemistry, FIV-FeLV tests, blood smears and molecular investigation targeting the 18S rRNA gene of Hepatozoon spp. were performed on blood samples; in addition, histological and molecular investigations were performed to analyze surgical samples to identify Hepatozoon infection. Hepatozoon gamonts were detected in granulocytes in the blood smear, and Hepatozoon spp. DNA was confirmed by PCR on blood. The intussusception was caused by a sessile endoluminal nodule that was surgically removed. Histologically, many elements referring to parasitic tissue forms were identified in the intestinal cells, and then the specimens were molecularly confirmed to harbor H. silvestris. This is the first description of symptomatic hepatozoonosis in a domestic cat in Italy. Hepatozoon silvestris has been described in wild felids, which are usually resilient to the infection, whereas the domestic cat seems to be more susceptible. Indeed, H. silvestris in cats usually presents tropism for skeletal muscle and myocardium with subsequent clinical manifestations. This is the first description of a domestic cat with H. silvestris localized in the intestinal epithelium and associated with intussusception