Reuse Of Effluent Research Articles

Water reuse as a strategy for mitigating atmospheric emissions and protecting water resources for the circularity of the swine production chain

High greenhouse gas emissions, high water demand, and waste with high pollution potential are critical points for waste management generated in animal production. With significant contributions in global emissions of air pollutants, sustainable practices for agriculture are fundamental to mitigate global climate change, besides ensuring protection to water resources, which is as critical as climate issues. Despite the importance of these issues, some gaps exist in the literature to develop practices capable of fostering water security and mitigation of greenhouse gas emissions. In this sense, the present study aimed to evaluate the impacts of reusing NO3− rich effluents inside the facilities for cleaning the swine houses and consequent atmospheric emissions of nitrous oxide (N2O) and methane (CH4). In swine manure, the generation of volatile fatty acids (VFA) was strongly influenced by temperature; a change in temperature from 10 to 18 °C increased by ten times the rate of VFA production, reflecting directly in methane emission and availability of organic carbon for the denitrification process. The effluent reuse practice, rich in nitrate, considering the organic carbon bioavailability in the pit storage, decreased methanogenic activity with a consequent VFA use as a bioavailable carbon source for denitrification, reducing greenhouse gas (GHG) emissions and consequently, the environmental impacts of swine production. In this way, the water reuse of 40% can mitigate up to 80% of GHG emission, with a minimum C/N ratio of 20, to ensure that at all temperatures the denitrifying process occurs efficiently since the carbon limitation negatively affected the N2O emission due to incomplete denitrification. Therefore, our results demonstrate the importance of this practice for swine sustainability and the capacity to adopt simple measures in favor of circularity in the swine production chain.

The efficiency of sewage treatment plant: A case study at the main campus of Universiti Malaysia Sabah (UMS)

The aquatic nature, including streams, rivers, marine, and groundwater, becomes susceptible to most contaminants’ effects through various pathways known as point and non-point sources. Point source pollution from inefficient sewage treatment plants (STP) will likely produce effluents that could deteriorate the environment. Therefore, this study assesses the efficiency of STP at Universiti Malaysia Sabah (UMS) based on the Malaysian Sewerage Industry Guidelines (MSIG). The design parameters of the STP and its influent and effluent physicochemical parameters are evaluated and compared between usage peak time (lecture-week) and non-peak (semester-break) conditions. The measurement was based on the Standard Methods of Examination of Water and Wastewater. The permissible limits of influent and effluent from Malaysia Sewerage Industry Guidelines (MSIG) are referred. In contrast, the efficiency of the STP is calculated as the percentage reduction of pollutants. The findings revealed that the current STP’s design parameters complied with the MSIG standard. The suspended solids (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), oil and grease (O&G) at influent during peak time is typically higher than during the non-peak time, albeit a timely sudden increase can be observed. The effluent quality is inconsistent but is still within permissible limits, except for O&G, which occasionally exceeds the allowable value. As for the BOD, a consistent 80% removal efficiency is observed. Hence the effluent reuse for agricultural purposed and landscape irrigation is proposed due to the environmental quality potential and reduction to direct released toward the receiving water streams.

Performance of a green wall (Total Value Wall™) at high greywater loading rates and Life Cycle Impact Assessment

Nature-based greywater (GW) treatment and reuse in urban areas has become an up-and-coming option. A 14.4 m2 green wall system called Total Value Wall (TVW) was installed at a terraced house in Gent (Belgium) for treating GW and reusing the effluent for toilet flushing. In a previous study, the TVW was loaded at 7 L.m−2.d−1 and efficiently removed TSS (67%), COD (43%), BOD5 (83%) and total coliforms (log 2), but a number of issues were reported related to nutrient leaching from the substrate, and the excessive retention time in the storage tanks. In this study results are reported from a follow-up study during which an adapted TVW was subjected to both higher hydraulic and pollutant loading rates in order to investigate the treatment capability of TVW. The design of the system, i.e. substrate contained in geotextile bags, did not sustain the higher hydraulic loading rates as excessive leakage occurred. Despite this, the higher pollutant loading rates still resulted in an acceptable effluent quality with 15 mg.L−1 TSS (90%), 85 mg.L−1 COD (82%), and 15 mg.L−1 BOD5 (95%). Ammonium, E. coli and total coliforms were removed with removal rates of 98%, 63% (0.4 log units), and 36% (0.2 log units), respectively. Finally, a life cycle assessment (LCA) was performed for the TVW with and without treating GW to analyze the environmental burden. The LCA impacts showed that replacing tap water and chemical fertilizer by GW, and the reuse of effluent, have a positive impact. However, the energy use for pumping has a major impact and should be minimized by using an efficient pump and distribution system to reduce the overall footprint.

Wetland Applications as Sustainable Wastewater Treatment for Reuse Opportunities in the MENA as Arid Region

In this study, the wastewater treatment performance, reuse of effluents for irrigation purposes in agriculture and its effect on plants, and soil have been investigated in an arid region of Jordan over three years. For this purpose, two pilot plants of wastewater treatment by vertical flow constructed wetlands (VFCWs) in Jordan were selected for reuse application in irrigation purposes in respect to the WHO regulations for reuse and the Jordanian standards for reuse in irrigation JS. The VFCW systems have shown high removal of COD, TSS, and BOD<sub>5</sub> over the monitoring phase, conforming to the JS Category-A. Whereas, effluent TN and NO<sub>3</sub><sup>-</sup>-N concentrations were 55 and 44 mg/L, conforming to the JS Category-B (TN: 70 mg/L and NO<sub>3</sub><sup>-</sup>-N: 45 mg/L). The two-stage VFCW has shown high removal of COD, TSS, and BOD5, conforming to the JS Category-A. The short-term impact of reuse the effluents in irrigation was investigated with different water quality and quantity (11 and 6 mm/day) using a subsurface irrigation system. A significant difference in ECs, SAR, Mg<sup>+2</sup>, Ca<sup>+2</sup>, and Na<sup>+</sup> was observed in the topsoil (0 - 20 cm) as a result of high evaporation and capillary rise that increased salts accumulation. Results showed no significant variation in soil physical properties (texture, structure, moisture, and infiltration rate) among reuse plots. In addition, results revealed an absence of E. coli in the irrigated soils, indicating the effectiveness of using subsurface irrigation as a disinfection step for reuse. During irrigation of lemon trees using subsurface irrigation, soil results exhibited no significant variation in soil physical properties (texture, structure, moisture, and infiltration rate) among reuse plots. Further investigation was helpful to judge the impact of using treated wastewater in irrigation.

Degradation of per- and polyfluoroalkyl substances (PFAS) in wastewater effluents by photocatalysis for water reuse

Wastewater reclamation and reuse have been increasingly practiced in the U.S. as sustainable strategies to meet water demands, particularly in regions threatened by water shortages. However, reuse of wastewater effluents (WEs) as irrigation water (e.g., in agriculture) is challenged by the presence of emerging organic contaminants such as per- and polyfluoroalkyl substances (PFAS), whose presence may result in adverse impacts on crops, soils, aqueous ecosystems, and human health; thus, it is important to remove PFAS in WEs before water reclamation and reuse. In this study, zero-valent iron (Fe0) nanoparticles were investigated for their ability to induce PFAS photocatalytic degradation in WEs under ultraviolet (UV) light. Effective removal of PFAS in WEs was achieved at pH 3.0 in the UV/Fe0 system. Optimal degradation rates of 90 ± 1%, 88 ± 1%, and 46 ± 2% were obtained for PFNA, PFOS, and PFOA, respectively, each starting from 0.5 μg/L using bare Fe0 after 2 h. The process is effective without oxygen removal and hence is a low-cost method. The used iron nanoparticles can be recycled by exploiting their magnetic properties. The treatment method can also be successfully applied to the remediation of PFAS-contaminated groundwater and surface water.

Water reuse in the post-tanning process: minimizing environmental impact of leather production.

Post-tanning wastewater is very diversified, as the post-tanning stage should meet the desirable properties of the leather for the final product, with low standardization of the process (compared to beamhouse and tanning). This makes post-tanning effluent reuse less feasible, and reuse in the post-tanning stage still needs to be explored. This work aims to evaluate the reuse of liquid effluents in the post-tanning process. The work methodology consisted of (i) characterization of water streams (groundwater, liquid effluent after primary treatment, and liquid effluent after secondary treatment); (ii) pilot-scale post-tanning tests using groundwater, primary effluent, and secondary effluent; (iii) characterization of the residual baths from pilot-scale tests (pH, conductivity, total solids, chemical oxygen demand, biochemical oxygen demand, chloride, hardness and oil and grease); and (iv) testing the leather obtained for total sulfated ash and organoleptic properties. Results showed that the primary effluent and the secondary effluent could be reused in pilot-scale post-tanning tests. There was an increase in the conductivity of the residual baths when liquid effluents were reused, which confirms the accumulation of salts in the effluents after their reuse.

Common Effluent Treatment Plants Monitoring and Process Augmentation Options to Conform Non-potable Reuse

The stringency in effluent discharge and reuse standards has made it extremely expensive to discharge the effluents safely or reuse them. Therefore, existing wastewater treatment plants should be evaluated and improved or augmented. With this aim, five existing common effluent treatment plants (CETPs) in North India were evaluated, including: the State infrastructure Development Corporation Uttrakhand Limited (SIDCUL) Haridwar, which processes 4.5 Million Liters per day (MLD); the Industrial Model Township (IMT) Manesar Gurgaon, 55 MLD (comprising two streams of 25 and 30 MLD each); the Lawrence Road Industrial Area (LRIA), Delhi, 12MLD (12MLD LRIA); Mayapuri Industrial Area (MIA), Delhi, 12MLD; and the Integrated Industrial Estate (IIE) SIDCUL Pantnagar, 4.0 MLD. These plants were designed to produce treated effluent for non-potable reuse. Results showed that the integrated efficiency (IEa) of all CETPs was 10–20% larger than standard integrated efficiency (IEs), indicating the suitability of the technology, except for 12MLD at MIA CETP where the IEa was 20% lower than IEs, due to the absence of any biological unit in the process. Combined post-treatment of secondary effluent by coagulation, Ultrafiltration (UF), followed by ozonation for CETP SIDCUL Haridwar, was also conducted for its non-potable water reuse. This process was able to reduce Biochemical Oxygen Demand (BOD) by 77%, Chemical Oxygen Demand (COD) by 76%, turbidity by 96%, and Total Suspended Solids (TSS) by 100%. All these parameters confirmed the effluent standards for non-potable reuse. The color was reduced to 4.0 from 42.0 Pt-Co units by the exposure ozone concentration of 8.3 mg/L for up to 4.0 min on the treated water from SIDCUL CETP, which reduced the color by 90% and complied with reuse standards. Hence Combined post treatment by coagulation, UF followed Ozonation of secondary treated effluent could be a better option for the potable reuse of treated water in various domestic and industrial applications.

MEMBRANE BIOREACTOR APPLIED TO THE TREATMENT OF A FRUIT PROCESSING INDUSTRY WASTEWATER IN NORTHEAST BRAZIL

The market for Membrane Bioreactors (MBR) technology has recently grown due to increasingly strict standards for effluent discharge and the need for alternative water sources. The high quality of the effluent produced, enabling the possibility of reuse is one of the most attractive characteristics of this technology. The objective of this article was to evaluate the treatment efficiency of a pilot-scale MBR plant in a fruit processing industry, including an analysis of the possibilities for effluent reuse. The pilot plant comprised a MBR with approximately 5000L in capacity, with porous type ultrafiltration grade polyethersulfone membranes. Other details for the membranes were: submerged configuration, flat plate type geometry, pore diameter ranging from 0.035 to 0.1 μm and total area of 25m². The industrial effluent came from fruits processing, floors and machinery washing, and was characterized by physical, chemical and bacteriological parameters. Results showed that permeability decreased about 50% during the monitoring, indicating the need of membrane cleaning. The removal efficiency for COD, BOD 5 , total nitrogen and total phosphorus, was 97.1%, 98.7%; 95.7 % and 53.5%, respectively. There was an absence of both total coliform and E. Coli at the inlet and outlet of the system. The permeate fits into agricultural, urban, environmental, industrial and aquaculture reuse modalities.

Effect of leachate effluent water reuse on the phytotoxicity and micropollutants accumulation in agricultural crops

This research comparatively investigated the effects of effluents from three biological wastewater treatment systems on the phytotoxicity, seed germination, and accumulation of micropollutants and heavy metals in plants irrigated with the effluents under study. The three biological wastewater treatment systems were two-stage activated sludge (AS), two-stage moving bed bioreactor (MBBR), and two-stage moving bed bioreactor with microfiltration (MBBR/MF). The systems were operated in parallel with identical landfill leachate concentrations under different hydraulic retention time (HRT) (24, 18, and 12 h). The phytotoxicity experiments were carried out with golden pothos (Epipremnum aureum) planted in soil irrigated with AS, MBBR, and MBBR/MF effluent and those raised in the effluent (without soil). The malondialdehyde (MDA) concentrations in the plants were used to determine the plant stress. To evaluate the effect of water reuse to agricultural crops, this research measured the seed germination rates of lettuce (Lactuca sativa) irrigated with AS, MBBR, and MBBR/MF effluent and the accumulation of micropollutants and heavy metals. The results showed that under 24 h HRT, the AS, MBBR, and MBBR/MF systems could achieve high treatment efficiency of organics and nutrients and micropollutant degradation (73.4 – 100%). With shorter HRT (18 and 12 h), the treatment efficiency and micropollutant degradation of MBBR and MBBR/MF remained relatively unchanged (68.7 – 100%), unlike in the AS system. The MBBR/MF effluent exhibited the comparatively lowest MDA concentrations. Furthermore, the MBBR/MF effluent minimally affected the growth of lettuce, as evidenced by highest seed germination rates. No micropollutants and heavy metals were present in lettuce irrigated with MBBR/MF effluent. However, traces of bisphenol A and di-(ethylhexyl)-phthalate were detected in lettuce watered with AS and MBBR effluents. As a result, the MBBR/MF system is operationally and environmentally ideal for treating landfill leachate for high-quality effluent which can be reused to irrigate crop and replenish surface water.

Feasibility study of the application of treated wastewater for the irrigation of forest species in a Saharan area

Background: After suffering from an acute problem of excess water for a long time, the Oasis of Ouargla benefited from an aerated lagoon treatment plant, producing biologically treated domestic effluents. The aim of this study was to examine the feasibility of reusing this effluent for watering plants. The experiment was conducted in the Ouargla WWTP, which is located in the region of Said Otba (northeast of Ouargla), north of the national road NR 49. Methods: The study area was selected based on the originality of the study and availability of water. The plants used were Acacia farnesiana and Leucaena leucocephala. The selection of Leucaena was based on the following criteria: It is used as a windbreak, it is very tolerant to drought, and it is used as a fodder to maintain soil fertility. And, Acacia was selected because it is used as a fodder, protects the soil against erosion, and to fix nitrogen. The watering of these plants is done jointly by treated wastewater from the WWTP and well water (WW), of which the latter was used as a control. Sampling and analysis of the irrigation water were performed according to the experimental protocol. To show the growth rate of the two plants studied, biometric measurements were taken weekly for 25 weeks. Results: The physicochemical analyses show that the treated wastewater is of poor quality belonging to the last class of Riverside’s C5-S4, with an excessive salinity (EC) of 13.51 dS/m and an Sodium adsorption ratio (SAR) of 12.61 against EC of 2.49 dS/m and 2.13 for the WW. At the end of the experiment, it was found that irrigation with purified wastewater (PWW) gave less growth compared to that with WW. Statistical analyses of the biometric measurements confirmed that there is a highly significant difference at P<0.05. Conclusion: The reuse of WWTP effluent gives less interesting results but is still possible. It is recommended to choose Salt-tolerant crops, as well as the dilution of these waters by the addition of less salty waters.

Impact of biosolids amendment and wastewater effluent irrigation on enteric antibiotic-resistant bacteria – a greenhouse study

Reuse of wastewater effluent and biosolids in agriculture is essential to sustainable water and nutrient resource management practices. Wastewater and biosolids, however, are reportedly the recipients, reservoirs, and sources of antibiotic-resistant enteric pathogens. While decay rates of fecal bacterial indicators in soil are frequently studied, very few studies have reported on the persistence of the antibiotic-resistant sub-populations. Little is known about how multi-drug resistance phenotypes of enteric bacteria in agricultural soil change over time. In this study, germinated carrot seeds were planted in soil that received biosolids amendment and/or wastewater effluent irrigation in a greenhouse setting. We quantified total and antibiotic-resistant fecal bacterial indicators (Escherichia coli and enterococci) weekly in soil and total E. coli at harvest (day 77) on carrots. Antibiotic susceptibility of 121 E. coli and 110 enterococci collected isolates were determined. E. coli or enterococci were not recovered from the soil without biosolids amendment regardless of the irrigation water source. After biosolids amendment, soil E. coli and enterococci concentrations increased more than 3 log10 CFU/g-TS within the first week, declined slowly over time, but stayed above the detection limit (0.39 CFU/g-TS) over the entirety of the study. No statistical difference was found between effluent wastewater or water irrigation in soil total and antibiotic-resistant E. coli and enterococci concentrations or carrots E. coli levels. Soil antibiotic-resistant E. coli and enterococci decayed significantly faster than total E. coli and enterococci. Moreover, the prevalence of multi-drug resistant (resistance to three or more antibiotics) E. coli declined significantly over time, while almost all collected enterococci isolates showed multi-drug resistance phenotypes. At harvest, E. coli were present on carrots; the majority of which were resistant to ampicillin. The survival of antibiotic-resistant enteric bacteria in soil and on harvested carrots indicates there are transmission risks associated with biosolids amendment use in root crops.

Increasing Water System Robustness in the Netherlands: Potential of Cross-Sectoral Water Reuse

Water reuse has the potential to substantially reduce the demand on groundwater and surface water. This study presents a method to evaluate the potential of water reuse schemes in a regional context and demonstrates how water reuse propagates through the water system and potentially reduces pressure on groundwater resources. The use of Sankey diagram visualisation provides a valuable tool to explore and evaluate regional application of water reuse, its potential to reduce groundwater and surface water demand, and the possible synergies and trade-offs between sectors. The approach is demonstrated for the Dutch anthropogenic water system in the current situation and for a future scenario with increased water demand and reduced water availability due to climate change. Four types of water reuse are evaluated by theoretically upscaling local or regional water reuse schemes based on local reuse examples currently in operation in the Netherlands or Flanders: municipal and industrial wastewater effluent reuse for irrigation, effluent reuse for industrial applications, and reuse for groundwater replenishment. In all cases, water reuse has the potential to significantly reduce groundwater extraction volume, and thus to alleviate the pressure on the groundwater system. The water-quantity based analysis is placed in the context of water quality demands, health and safety aspects, technological requirements, regulations, public perception, and its net impact on the environment. This integrative context is essential for a successful implementation of water reuse in practice.

Effect of using effluent from anaerobic digestion of vinasse as water reuse on ethanol production from sugarcane-molasses

Current global prospects of increasing ethanol production face the problem of one of the highest consumptions of fresh water and the generation of large volumes of effluents. This study evaluated the reuse of effluent from the anaerobic digestion of vinasse as a replacement of freshwater in ethanol production. This process combines the use of vinasse and anaerobic digestion effluent to produce biogas energies. The effect of reusing 0, 30, 60, and 100% effluent to dilute sugarcane molasses to produce ethanol was evaluated. The viability and vitality of the cells of the yeast were not altered by using the effluent. The efficiency of ethanol production with effluent (0, 30, 60, and 100%) was 43.3, 42.3, 39.2, 38.4 g/L, respectively. Also, we tested reusing 100% effluent without treatment for dilution of sucrose. This assay gave the highest ethanol production (80.6 g/L). The difference in ethanol production might be due to a wide range of buffering capacity of the combination of molasses and effluent, which moderately affected the performance of Saccharomyces cerevisiae. Nonetheless, additional research is required to determine a causal relationship between the buffer capacity of the molasses/effluent mixture and ethanol production.

Silica Removal from a Paper Mill Effluent by Adsorption on Pseudoboehmite and γ-Al2O3

Effluent reuse is a common practice for sustainable industrial water use. Salt removal is usually carried out by a combination of membrane processes with a final reverse osmosis (RO). However, the presence of silica limits the RO efficiency due to its high scaling potential and the difficulty of cleaning the fouled membranes. Silica adsorption has many advantages compared to coagulation and precipitation at high pHs: pH adjustment is not necessary, the conductivity of treated waters is not increased, and there is no sludge generation. Therefore, this study investigates the feasibility of using pseudoboehmite and its calcination product (γ-Al2O3) for silica adsorption from a paper mill effluent. The effect of sorbent dosage, pH, and temperature, including both equilibrium and kinetics studies, were studied. γ-Al2O3 was clearly more efficient than pseudoboehmite, with optimal dosages around 2.5–5 g/L vs. 7.5–15 g/L. The optimum pH is around 8.5–10, which fits well with the initial pH of the effluent. The kinetics of silica adsorption is fast, especially at high dosages and temperatures: 80–90% of the removable silica is removed in 1 h. At these conditions, silica removal is around 75–85% (<50 mg/L SiO2 in the treated water).

A full-scale anaerobic baffled reactor and hybrid constructed wetland for university dormitory wastewater treatment and reuse in an arid and warm climate

In low-income regions and small/medium communities, the use of conventional/mechanical methods for wastewater treatment is not always financially and technically feasible. Thus, nature-based solutions such as constructed wetlands (CW) appear as a more appropriate option. Additionally, there is limited application and reporting on the use and efficiency of this sustainable technology in arid and warm climates such as in the Middle East. In order to get a better insight into the feasibility of CWs under such climate and socio-economic context, a full-scale demonstration hybrid CW facility was built and monitored for the first time at a university campus in Iran for one year. The facility consists of an anaerobic baffled reactor, a vertical flow CW and a polishing horizontal subsurface flow CW and has a total area demand of 2.5 m2/pe. The goal was to evaluate the system's efficiency and investigate the need for one or two CW stages to reach the national effluent reuse standard. The CW were planted with local species (Arundo donax, Cortaderia selloana, Phragmites australis) and received 20 m3/day from a university dormitory at a hydraulic loading rate of 5 cm/day. The facility proved to be effective and removed 88.9%, 86.0%, 92.2%, 63.5%, 66.5%, and 65.7% of BOD5, COD, TSS, PO4-P, NH4-N, and NO3-N, respectively, while the effluent complied with the reuse standard. This study showed that hybrid CW can be effectively used under dry and warm climates using native plant species providing a technically feasible, cost-effective, and sustainable wastewater treatment solution.

The NEWgeneratorTM non-sewered sanitation system: Long-term field testing at an informal settlement community in eThekwini municipality, South Africa

Globally, there is a dire need for a new class of advanced non-sewered sanitation systems (NSSS) to provide onsite wastewater treatment that is capable of meeting stringent discharge or reuse criteria. These systems need to be simple to operate and maintain, reliable, and resilient to unreliable electrical service. The NEWgenerator (NG) is a compact, automated, solar-powered wastewater treatment system comprised of three major treatment processes: anaerobic membrane bioreactor (AnMBR), nutrient capture system (NCS) with ion exchange and carbon sorption, and electrochlorination (EC). The NG system operated at an informal settlement community in South Africa over a 534 d period, treating high-strength blackwater (BW) and yellow water (YW) from a public toilet facility. Over three test stages (BW, BW + YW, BW) that included several periods of dormancy, the NG system was able to provide a high level of removal of total suspended solids (97.6 ± 3.1%), chemical oxygen demand (94.5 ± 5.0%), turbidity (96.3 ± 9.7%), color (92.0 ± 10.5%), total nitrogen (82.1 ± 24.0%), total phosphorus (43.0 ± 22.1%), E. coli (7.4 ± 1.5 LRV, not detected in effluent), and helminth ova (not detected in effluent). The treatment levels met most of the ISO 30500 NSSS standard for liquid effluent and local water reuse criteria. A series of maintenance events were successfully conducted onsite over the 534 d field trial: two membrane cleanings, two NCS regenerations, and granular activated carbon replacement. Desludging, a major pain point for onsite sanitation systems, was unnecessary during the field trial and thereby not performed. The AnMBR performed well, removing 94.5 ± 5.0% of the influent COD across all three stages. The high COD removal rate is attributed to the sub-micron separation provided by the ultrafiltration membrane. The NCS was highly efficient at removing total nitrogen, residual COD and color, but the regeneration process was lengthy and is a topic of ongoing research. The EC provided effective disinfection, but frequent prolonged run cycles due to power supply and water quality issues upstream limited the overall system hydraulic throughput. This extended field trial under actual ambient conditions successfully demonstrated the feasibility of using advanced NSSS to address the global water and sanitation crises.

An Assessment of Undergraduates’ Perception on Water Resources Management in Pernambuco’s Semiarid Region

The aim of this paper was to explore undergraduates’ perception on water resources management in Pernambuco’s semiarid region, located in the northeastern part of Brazil. The discussion addressed here is mainly focused on water scarcity, water waste and effluent reuse policies. A basic qualitative research was undertaken. The research corpus was composed by undergraduate students of the Academic Centre of Agreste at the Federal University of Pernambuco. The data collection was carried on by semi-structured interviews with the students, which were submitted to qualitative analysis. The findings are suggestive that: (i) the inefficient and ineffective resources management is more severe than the small amount of water that impinges such a semiarid region; (ii) undergraduates are unaware about the range of alternatives to reduce water waste; and, lastly, (iii) they understand the benefits concerning the effluent reuse processes, however, it is necessary to make people aware that the system needs financial investments and security, which will increase the social commitment to suggest sustainable solutions. These findings unveiled the need for this university to promote more educational efforts — whether trainings, or courses, or modules, or policies —, aiming to increase the levels of their awareness on such this subject, so as to decrease water waste in this region.

Detection of Carcinogenic By-Products in Effluents Produced by Biodigester Septic Using of Array Sensor and Nanostructured Polymers: Evaluation and Characterization

A sensory system was manufactured and tested to detect carcinogenic organochlorines, such as trihalomethanes (THM), in effluents produced by a biodigestion septic tank. Gold-coated interdigitated microelectrodes were coated with various nanostructured conducting polymers, single or mixed, under different conditions and configurations. Polymer films were assembled by the self-assembly technique and their impedance was analyzed in a frequency range from 1 Hz to 1 MHz. The results of the sensory system, analyzed by the PCA Main Component Analysis, allowed to identify the discrimination of the different samples tested. Good discrimination between sensors was also observed, when PCA's were obtained, in contamination experiments with standard solutions of total trihalomethanes (TTHM), obtaining a total variance (PC1 = 98.02%; PC2 = 1.98%) of the observations. The sensory system based on global selectivity using interdigitated electrode and nanostructured conducting polymers allowed the statistical discrimination of samples. The future expectation is to update the system and implement monitoring of nanostructured sensors based on the reuse of domestic effluents, mainly for agricultural applications or for other purposes, in a sustainable way.

Continuous Performance Improvement Framework for Sustainable Wastewater Treatment Facilities in Arid Regions: Case of Wadi Rumah in Qassim, Saudi Arabia.

In arid regions such as Saudi Arabia, wastewater treatment (WWT) facilities (meeting promulgated standards) need to adapt their continuous performance improvement (CPI) for long-term sustainability. To achieve this, the facilities need to improve their performance to comply with more strict objectives for broader reuse applications of treated effluent. The present research proposes a CPI framework based on performance benchmarking process for the stepwise improvement of WWT facilities. A grey rational analysis water quality index (GWQI) based on exceedance probability was developed. For weights’ estimation of 11 physical, chemical, and biological water quality parameters, the entropy method effectively accommodated the changes in relative importance of the parameters with including additional future reuse applications. For existing effluent reuse scenarios of restricted and unrestricted irrigation, the GWQI values were found consistent with the modified version of the Canadian WQI (CWQI). The indices’ values (ranged between 0 and 100) greater than 80 showed the efficient operation of four WWT plants in the Qassim Region of Saudi Arabia. Two hypothetical CPI scenarios with future reuse applications (fish, livestock drinking, and recreation) showed an overall decline in the average (of four plants) values of the GWQI (97 to 78) and CWQI (85 to 60). CWQI predicted stricter results for the facilities with parameters’ concentrations exceeding the targets with larger margins and was found applicable for the CPI of WWT facilities in arid regions. For existing scenarios, the assessment results suggest the facilities to control and monitor the chlorination practice. For future targets, tertiary treatment needs to be enhanced for desired nutrients and total dissolved solids removal. The proposed CPI framework provides a platform to initiate the performance benchmarking process for WWT facilities at local or regional levels in Saudi Arabia and elsewhere.

Evaluation of removal of illicit drugs, pharmaceuticals and caffeine in a wastewater reclamation plant and related health risk for non-potable applications

The present study aimed at determining the presence and removal rate achieved through the main treatment stages of a full-scale wastewater reclamation plant for some classes of Organic Micropollutants. Furthermore, the human health risk due to the reuse of the final effluent containing residual concentrations of these pollutants for non-potable applications was assessed.The 8-months monitoring campaign on the influent and effluent of the treatment stages of the plant highlighted that the main removal took place in the bioreactor, reaching median removal of 99 %, 97 %, 60 % 76 %, 71 %, 96 % and 100 %, for benzoylecgonine, cocaine, methamphetamine, trimetoprim, sulfadiazine, ketoprofene and caffeine, respectively. This result was also confirmed by the application of the principal component analysis. A further abatement, although slight, occurred in the tertiary compartment (made up by filtration, UV disinfection and chlorination) for sulfamethoxazole, trimethoprim and ketoprofen, determining a final median removal of 50 %, 94 % and 98 %, respectively. A significant correlation between the removal processes of the investigated organic micropollutants and the traditional water quality parameters was also found out. The human health risk for incidental ingestion and dermal contact resulted to be always below 1 under average and worst scenarios, which indicates that the risk can be considered acceptable.