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Free water surface constructed wetlands (FWSCWs) for the treatment of various wastewater types have evolved significantly over the last few decades. With an increasing need and interest in FWSCWs applications worldwide due to their cost-effectiveness and other benefits, this paper reviews recent literature on FWSCWs' ability to remove different types of pollutants such as nutrients (i.e., TN, TP, NH4-N), heavy metals (i.e., Fe, Zn, and Ni), antibiotics (i.e., oxytetracycline, ciprofloxacin, doxycycline, sulfamethazine, and ofloxacin), and pesticides (i.e., Atrazine, S-Metolachlor, imidacloprid, lambda-cyhalothrin, diuron 3,4-dichloroanilin, Simazine, and Atrazine) that may co-exist in wetland inflow, and discusses approaches for simulating hydraulic and pollutant removal processes. A bibliometric analysis of recent literature reveals that China has the highest number of publications, followed by the USA. The collected data show that FWSCWs can remove an average of 61.6%, 67.8%, 54.7%, and 72.85% of inflowing nutrients, heavy metals, antibiotics, and pesticides, respectively. Optimizing each pollutant removal process requires specific design parameters. Removing heavy metal requires the lowest hydraulic retention time (HRT) (average of 4.78 days), removing pesticides requires the lowest water depth (average of 0.34 m), and nutrient removal requires the largest system size. Vegetation, especially Typha spp. and Phragmites spp., play an important role in FWSCWs' system performance, making significant contributions to the removal process. Various modeling approaches (i.e., black-box and process-based) were comprehensively reviewed, revealing the need for including the internal process mechanisms related to the biological processes along with plants spp., that supported by a further research with field study validations. This work presents a state-of-the-art, systematic, and comparative discussion on the efficiency of FWSCWs in removing different pollutants, main design factors, the vegetation, and well-described models for performance prediction. [ABSTRACT FROM AUTHOR]

Surfactants have been widely used in various fields in recent years, but subsequent treatment of their wastewater has always been a problem that needs to be solved. As a new sewage treatment method, algal–bacterial aerobic granule sludge (algal–bacterial AGS) is considered to be one of the potential methods for treating this kind of wastewater. This study investigated the efficiency of using algal–bacterial AGS to treat wastewater containing surfactants and compared it with bacterial AGS. The results indicated that when confronting a high-concentration surfactant, algal–bacterial AGS could keep a relatively high nutrient removal capacity (about 90% dissolved organic carbon, 99% ammonia nitrogen, 52% total phosphorus) and improved the adaptability to sudden changes in high-concentration surfactant environments compared with bacterial AGS. These results illustrated that algal–bacterial AGS is a potential method to process wastewater containing surfactants with superior treatment efficiency and adaption response. [ABSTRACT FROM AUTHOR]

Abstract Chlorella sp. is able to grow and transform inorganic and organic contaminants in wastewater to create biomass. In the present study, Chlorella sp. LH2 isolated from cocoon wastewater was able to thrive in hospital wastewater, then remove nutrients and eliminate E. coli ATCC 8739. The results indicated that optimal cultivation conditions of Chlorella sp. LH2 in hospital wastewater were pH of 8, light:dark cycle of 16:8 at 30oC. The inhibitory effect of chlorination on algae growth was accompanied with the chlorine concentration. BOD5:COD ratio of 0.77 indicated biodegradability of hospital wastewater. The untreated and treated wastewatee samples were collected to investigated the nutrient removal efficiency after 10 days. Untreated and treated results were192 ± 8.62 mg/l 23.91 ± 2.19 mg/l for BOD5; 245 ± 9.15 mg/l and 47.31 ± 5.71 mg/l for COD. The treated value met the required standards for hospital wastewater treatment. The removal efficiency total nitrogen and total phosphorus were 68.64% and 64.44% after 10 days, respectively. Elimination of E. coli ATCC 8739 after 7 days by Chlorella sp. LH2 was 88.92%. The results of this study suggest the nutrients and pathogens removal potential of Chlorella sp. LH2 in hospital wastewater for further practical applications.

Chlorella sp. is able to grow and transform inorganic and organic contaminants in wastewater to create biomass. In the present study, Chlorella sp. LH2 isolated from cocoon wastewater was able to thrive in hospital wastewater, then remove nutrients and eliminate E. coli ATCC 8739. The results indicated that optimal cultivation conditions of Chlorella sp. LH2 in hospital wastewater were pH of 8, light:dark cycle of 16:8 at 30oC. The inhibitory effect of chlorination on algae growth was accompanied with the chlorine concentration. BOD5:COD ratio of 0.77 indicated biodegradability of hospital wastewater. The untreated and treated wastewatee samples were collected to investigated the nutrient removal efficiency after 10 days. Untreated and treated results were192 ± 8.62 mg/l 23.91 ± 2.19 mg/l for BOD5; 245 ± 9.15 mg/l and 47.31 ± 5.71 mg/l for COD. The treated value met the required standards for hospital wastewater treatment. The removal efficiency total nitrogen and total phosphorus were 68.64% and 64.44% after 10 days, respectively. Elimination of E. coli ATCC 8739 after 7 days by Chlorella sp. LH2 was 88.92%. The results of this study suggest the nutrients and pathogens removal potential of Chlorella sp. LH2 in hospital wastewater for further practical applications. [ABSTRACT FROM AUTHOR]

The present study used bench scale columns filled with biochar for phosphorous (P) recovery from real ultrafiltered wastewater. No studies are available about the potentiality of biochar using ultrafiltered real wastewater. Therefore, this study aimed to assess phosphate (PO43−) recovery by biochar-packed columns employing real treated wastewater from an ultrafiltration process. Three flow rates were tested, specifically 0.7, 1.7 and 2.3 L h−1, to gain insights into the optimal working conditions. Results revealed that the maximum amount of PO43− recovery (namely, 3.43 mg g−1 biochar) can be achieved after 7 h by employing the highest tested flow rate. Furthermore, the phosphorus exchange capacity (PEC) was inversely correlated with the feeding flow rate (FFR), with PEC values equal to 35, 25 and 9 % for FFR of 0.67, 1.7 and 2.3 L h−1, respectively. The pseudo-first order model best approximated the adsorption kinetics, thus suggesting that the adsorption of phosphate by biochar depends on its concentrations (i.e. physiosorption mechanism).

The presence of harmful heavy metals (HMs) in the aquatic environment can damage the environment and threaten human health. Traditional remediation techniques can have secondary impacts. Thus, more sustainable approaches must be developed. Microalgae have biological properties (such as high photosynthetic efficiency and growth), which are of great advantage in the HMs removal. In this study, the effect of various concentrations (2×, 4×, and 6×) of copper (Cu), cobalt (Co), and zinc (Zn) on microalgae (C. sorokiniana GEEL-01, P. kessleri GEEL-02, D. asymmetricus GEEL-05) was investigated. The microalgal growth kinetics, HMs removal, total nitrogen (TN), total phosphor (TP), and fatty acids (FAs) compositions were analyzed. The highest growth of 1.474 OD680nm and 1.348 OD680nm was obtained at 2× and 4×, respectively, for P. kessleri GEEL-02. P. kessleri GEEL-02 showed high removal efficiency of Cu, Co, and Zn (38.92–55.44%), (36.27–68.38%), and (32.94–51.71%), respectively. Fatty acids (FAs) analysis showed that saturated FAs in C. sorokiniana GEEL-01 and P. kessleri GEEL-02 increased at 2× and 4× concentrations while decreasing at 6×. For P. kessleri GEEL-02, the properties of biodiesel including the degree of unsaturation (UD) and cetane value (CN) increased at 2×, 4×, and 6× as compared to the control. Thus, this study demonstrated that the three microalgae (particularly P. kessleri GEEL-02) are more suitable for nutrient and HMs removal coupled with biomass/biodiesel production. [ABSTRACT FROM AUTHOR]

In low-middle income countries (LMIC), wastewater treatment using native microalgal-bacterial consortia has emerged as a cost-effective and technologically-accessible remediation strategy. This study evaluated the effectiveness of six microalgal-bacterial consortia (MBC) from the Ecuadorian Amazon in removing organic matter and nutrients from non-sterilized domestic wastewater (NSWW) and sterilized domestic wastewater (SWW) samples. Microalgal-bacterial consortia growth, in NSWW was, on average, six times higher than in SWW. Removal rates (RR) for NH4+- N and PO43−-P were also higher in NSWW, averaging 8.04 ± 1.07 and 6.27 ± 0.66 mg L−1 d−1, respectively. However, the RR for NO3− -N did not significantly differ between SWW and NSWW, and the RR for soluble COD slightly decreased under non-sterilized conditions (NSWW). Our results also show that NSWW and SWW samples were statistically different with respect to their nutrient concentration (NH4+-N and PO43−-P), organic matter content (total and soluble COD and BOD5), and physical-chemical parameters (pH, T, and EC). The enhanced growth performance of MBC in NSWW can be plausibly attributed to differences in nutrient and organic matter composition between NSWW and SWW. Additionally, a potential synergy between the autochthonous consortia present in NSWW and the native microalgal-bacterial consortia may contribute to this efficiency, contrasting with SWW where no active autochthonous consortia were observed. Finally, we also show that MBC from different localities exhibit clear differences in their ability to remove organic matter and nutrients from NSWW and SWW. Future research should focus on elucidating the taxonomic and functional profiles of microbial communities within the consortia, paving the way for a more comprehensive understanding of their potential applications in sustainable wastewater management.

Surfactants have been widely used in various fields in recent years, but subsequent treatment of their wastewater has always been a problem that needs to be solved. As a new sewage treatment method, algal–bacterial aerobic granule sludge (algal–bacterial AGS) is considered to be one of the potential methods for treating this kind of wastewater. This study investigated the efficiency of using algal–bacterial AGS to treat wastewater containing surfactants and compared it with bacterial AGS. The results indicated that when confronting a high-concentration surfactant, algal–bacterial AGS could keep a relatively high nutrient removal capacity (about 90% dissolved organic carbon, 99% ammonia nitrogen, 52% total phosphorus) and improved the adaptability to sudden changes in high-concentration surfactant environments compared with bacterial AGS. These results illustrated that algal–bacterial AGS is a potential method to process wastewater containing surfactants with superior treatment efficiency and adaption response.

In view of the current bottlenecks of low nitrogen and phosphorus removal efficiency and high cathode cost of microbial fuel cells (MFCs), this study constructed single-chamber biocathode MFCs to carry out related research. Single-chamber MFCs with microalgae were fabricated, and nitrogen removal efficiency and greenhouse gas emissions (GHG) were investigated. The results indicated that algae MFCs could significantly reduce GHG (CH4 , CO2 , and N2O) emissions through the competition of electron donor and sequestrating atmospheric CO2. Compared with the control group, the microalgal MFC significantly promoted the removal of total nitrogen (TN) and total phosphorus (TP). The highest open-circuit voltage (0.33 V) and power density (49 mW m−3) were observed in the closed circuit with algae (CC) reactor. Running MFC significantly increased the biomass of algae and produced good quality of biofuel. Quantitative polymerase chain reaction (q-PCR) analysis indicated that mcrA gene copies in the CC reactor (3.2×103 copies mL−1) were significantly higher than those of the no algae (NA) and CC reactors, while the lowest denitrifying gene copies (narG , nirS , and nosZ) were observed in the NA reactor. The Chloroflexi (22%) and Proteobacteria (31%) were the predominant bacterial communities in the CC reactor. Geobacter and Desulfobulbus were the main genera of exoelectrogens. This study can provide reference for nutrients (nitrogen, phosphorus) removal and GHG control in MFC wastewater treatment, but its long-term stability needs to be further studied. [ABSTRACT FROM AUTHOR]

High concentrations of contaminants such as ammonia nitrogen and organic matter in full-strength wastewater severely inhibit the growth of microalgae, contributing to lower biomass accumulation and contaminant removal efficiency. To overcome this limitation, modified biochars prepared from pine sawdust and sugarcane bagasse were used in this study as an adsorbent–desorbent for the pretreatment of wastewater to promote the growth of microalgae. The results showed that the two modification methods (acid/alkaline modification and magnesium salt modification) used in the experiment could increase the abundance of oxygen-containing functional groups. Moreover, magnesium salt modification could effectively improve the pore structure of biochar surfaces and increase the specific surface areas. Compared with the pristine biochars, the adsorption performance of the modified biochar was found to be significantly higher for nutrients in wastewater. The adsorption capacity of the acid/alkaline-modified pine sawdust biochar reached 8.5 and 16.49 mg∙g−1 for ammonia nitrogen and total organic carbon in wastewater, respectively. The magnesium salt modified pine sawdust biochar achieved a more comprehensive nutrients adsorption capacity of 15.68, 14.39, and 3.68 mg∙L−1 for ammonia nitrogen, total organic carbon, and total phosphorus, respectively. The mechanism of ammonia nitrogen adsorption was mainly the complexation of surface -OH functional groups, while the adsorption mechanism for phosphate was mainly the complexation of -OH and Mg-O functional groups and the chemical precipitation of MgO or Mg(OH)2 attached to the surface. [ABSTRACT FROM AUTHOR]

A packed-bed anaerobic-aerobic reactor (PBAOR) with two anaerobic and two aerobic compartments was constructed to treat manure-free piggery wastewater which was characterized by high ammonium (NH4+-N) and low ratio of chemical oxygen demand (COD) to total nitrogen (TN). Performed for 60 days at the normal atmospheric temperature of 25 °C with a constant hydraulic retention time of 32 h and reflux ratio of 2.0, a stable state in pollutants removal was obtained in the PBAOR. Within the next routine operation process, the removal of COD, NH4+-N and TN was above 85.7%, 98.2% and 85.8%, with a residual less than 81.7, 7.2 and 39.9 mg L−1 in effluent, respectively. Twelve veterinary antibiotics classified into tetracyclines (TCs), sulphonamides (SAs) and fluoroquinolones (FQs) were detected from the piggery wastewater. The PBAOR was effective in removing TCs and SAs with an average removal of 74.8% and 93.3%, respectively, but presented a negative removal for FQs. Most COD in the piggery wastewater was mainly removed in the first two anaerobic compartments along with an obvious removal of TCs and SAs, while the TN were mainly removed in the last two aerobic compartments with the negative removal of FQs. [ABSTRACT FROM AUTHOR]

Conventional biological treatment usually cannot achieve the same high water quality as advanced treatment when conducted under varied temperatures. Here, satisfactory wastewater treatment efficiency was observed in a microalgae-bacteria consortia (MBC) over a wide temperature range because of the predominance of microalgae. Microalgae contributed more toward wastewater treatment at low temperature because of the unsatisfactory performance of the accompanying bacteria, which experienced cold stress (e.g., bacterial abundance below 3000 sequences) and executed defensive strategies (e.g., enrichment of cold-shock proteins). A low abundance of amoA-C and hao indicated that conventional nitrogen removal was replaced through the involvement of microalgae. Diverse heterotrophic bacteria for nitrogen removal were identified at medium and high temperatures, implying this microbial niche treatment contained diverse flexible consortia with temperature variation. Additionally, pathogenic bacteria were eliminated through microalgal photosynthesis. After fitting the neutral community model and calculating the ecological niche, microalgae achieved a maximum niche breadth of 5.21 and the lowest niche overlap of 0.38, while the accompanying bacterial community in the consortia were shaped through deterministic processes. Finally, the maximum energy yield of 87.4 kJ L−1 and lipid production of 1.9 g L−1 were achieved at medium temperature. Altogether, this study demonstrates that advanced treatment and energy reclamation can be achieved through microalgae-bacteria niche strategies.

A multistage mesocosm vertical flow constructed wetland system was designed to treat synthetic domestic wastewater with a high nitrogen (N) load. The study aim was to determine the impact of design and operational variables on N removal efficiency in such systems. A tidal flow operational strategy enhanced aeration and was coupled with a step-feeding approach to promote N removal. Over the 420-day running period N removal rates were between 70 and 77 gN/m3/d, for a step-feeding ratio range of 60:40 to 80:20. The system was able to remove 91–95% of chemical oxygen demand, 74–91% of ammonium and 66–81% of total-N. Tidal flow and step-feeding strategies significantly impacted nitrogen removal with the best performance at a step-feeding ratio of 80:20 providing a carbon to nitrogen (COD/N) ratio of 4–5. The bacterial diversity increased at each stage throughout the system with dominating phyla Proteobacteria, Firmicutes, Planctomycetes, Bacteroidetes, Chloroflexi, Verrucomicrobia and Acidobacteria. Dominant bacteria at the genus level were Thiothrix, Planctomyces, Azonexus, Pseudoxanthomonas, Hydrogenophaga, Gemmobacter and other genera suggesting that N removal was accomplished via diverse metabolic pathways, including autotrophic nitrification, heterotrophic denitrification, autotrophic denitrification, and possibly anammox. This study shows benefits of step-feeding strategies in tidal flow constructed wetlands as a cost-effective solution for minimizing external carbon input to achieve effective N removal.

The combination of activated sludge and microalgae in a membrane bioreactor (MBR) is a new promising solution in municipal wastewater treatment to remove nitrate (NO3−) and phosphate (PO43−). Furthermore, municipal wastewater contains a considerable amount of NO3− and PO43− , which is suitable for microalgae growth. It can be concluded from the literature that there is a direct relationship between microalgae biomass production and nutrient removal. Thus, the light cycle and the initial microalgae concentration (as two main factors for microalgae growth) can be optimized. In this study, the biomass productivity in three light-dark (L-D) cycles (h) (24-0, 16-8, and 12-12 h) and initial concentrations (0.5, 1, and 1.5 g·L−1) were measured. The L-D cycle of 24-0 and the initial concentration of 1 g·L−1 was used as the chosen parameter in the membrane photobioreactor (MPBR) containing microalgae. The initial concentration of nitrate, phosphate, chemical oxygen demand (COD), and total dissolved solids (TDS) was investigated. The investigation was performed first on the MBR containing activated sludge and then on the treated wastewater via MBR to MPBR containing microalgae (MBR-MPBR). The duration of the experiment was 133 days. During this period, the removal amount of COD, nitrate, and phosphate was reported at 92.35%, 47.55%, and 36.46% in the MBR, respectively. In MBR-MPBR, the average of nitrate and phosphate removal increased to 93.88% and 88.44%, respectively. However, TDS did not show any notable alterations in both operating systems. According to the findings, the second stage of the treatment process, MBR-MPBR outperformed the MBR system in terms of NO3− and PO43− removal. A membrane bioreactor is a combination of the membrane with microorganisms used in the wastewater treatment process. Due to their simple structure, small size, and high efficiency in removing organic and inorganic substances, membrane bioreactors have been considered for industrial and urban wastewater treatment. Operational parameters in the design of these systems have a significant impact on nutrient removal efficiency. Furthermore, based on the high efficiency of microalgae in removing nutrients, its combination with activated sludge increases the efficiency of the bioreactor. In this work, some operating parameters such as the light-dark cycle and initial concentration of microalgae were optimized in the membrane bioreactor. Then, two various systems, namely a membrane bioreactor (containing activated sludge) and a two-stage membrane bioreactor (containing activated sludge and microalgae), were compared. In this regard, the total dissolved solids, chemical oxygen demand, nitrate, and phosphate removal were investigated. All these values were recorded under optimal conditions of the light-dark cycle and initial concentration of microalgae in two different systems. [ABSTRACT FROM AUTHOR]

The treatment of nutrients and organic contaminants in wastewater using microalgae has drawn significant interest thanks to its advantages of environmental friendliness, low cost, CO2 emission reduction, and recycling of valuable biomass. Among other algae species, Chlorella sp. showed good vitality, simplicity in cultivation, and high nutrient accumulation in harsh conditions of wastewater. In this study, Chlorella vulgaris was inoculated in a membrane photobioreactor (MPBR) with piggery digestate to investigate the C. vulgaris growth rate and the removal efficiency of nutrients and chemical oxygen demand (COD). The results indicated that the cultivation of C. vulgaris in an MPBR system exhibited continuous and simultaneous removal of NH4+, PO43−, and COD from two-fold diluted piggery wastewater. Both the algae growth rate and nutrient removal depended on the liquid hydraulic retention time in the MPBR. The highest removal efficiency of NH4+ (74.55%), PO43− (70.20%), and COD (65.85%) was obtained in the longest HRT of 5 days with the highest microalgae biomass concentration of around 1.1 g/L. The algae washout phenomenon was negligible in the continuous cultivation in the MPBR system. Compared to the cultivation in batch mode, the MPBR could achieve a similar algae growth rate and treatment efficiency with a much shorter hydraulic retention time. [ABSTRACT FROM AUTHOR]

The use of microalgae for the removal of contaminants such as total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD), and other pollutants from palm oil mill effluent (POME) has recently received much attention. This study aimed to investigate the impact of POME as a nutrient on microalgal growth and the rate at which nutrients were removed. Three green microalgae species were isolated from Penang, Malaysia's palm oil mill. The polyphasic approach, which combines morphological and molecular observations, was used for species identification. The three green microalgae were identified as Chlorella sorokiniana, Scenedesmus quadricauda, and Chlorococcum oleofaciens. All three green microalgae were cultivated in 25%, 50%, and 75% (v/v) of lab-scale palm oil mill effluent (LABT-POME) to investigate the growth of these three green microalgae in 100 mL of BBM. Under a light microscope and a scanning electron microscope (SEM), the morphological changes of those three green microalgae (before and after cultivation in 25%, 50%, and 75% dilution of (LABT-POME)) were observed. When cultivated in LABT-POME, C. oleofaciens showed the highest growth rate compared to the other two species of green microalgae. C. oleofaciens was able to remove more than 90% of total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen from LABT-POME, as well as minimise soluble chemical oxygen demand (SCOD) by about 65%. The growth of C. oleofaciens was well fitted to the Verhulst growth kinetic model with an R2 value of 0.99 and a growth rate of 0.3195 day−1 (d−1). The results of this study show the ability of newly isolated green microalgae to remove nutrients (TP, TN, NH3–N, and SCOD) from POME, which could be used as an effective and environmentally friendly method to remove pollutants. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of six plant biofilter designs for urban stormwater quality improvement and reports on their performances. Thirty-six columns were populated with the endemic South African plant Prionium serratum, representing plant biofilter designs that incorporate different pollutant removal mechanisms in the biofiltration process. The experimental biofilter columns were subjected to low, typically observed and high urban nutrient and metal synthetic stormwater pollution for five months. Significant loads of NH3-N and dissolved Cd, Pb and Zn were removed, whereas removal of -N, -P and dissolved Cu was more variable. The most efficient design was found to include standard plant biofiltration techniques with upflow filtration, plenum aeration and a saturated zone supporting anaerobic microbial activity. It was found that the most efficient design removed on average 96% of urban stormwater nutrient and metal loads. HIGHLIGHTS Assessment of various plant biofilter designs (air plenum, different media, geotextile inclusion, saturated zone inclusion).; Inclusion of endemic South African plant Prionium serratum and nationally available materials.; Significant NH3-N and dissolved Cd, Pb and Zn removal.; Varied -N, -P and dissolved Cu removal.;

[Display omitted] • N. oceanica purified tofu wastewater (TFW) and produced eicosapentaenoic acid (EPA) • N. oceanica with fed-batch mode boosted TFW contaminants removal by 86.99 ∼ 98.14 % • TFW - fed N. oceanica accomplished a superior biomass 26.37 g/L and EPA yield 43.5 mg/g. • Eicosapentaenoic acid derived from TFW-fed N. oceanica exerted hypolipidemic effect. Seeking environmentally-friendly and resource-recycling strategies for tofu wastewater (TFW) treatment could effectively mitigate harsh ecological impacts and resource wastage caused by direct discharge. This study investigated the feasibility on the utilization of Nannochloropsis oceanica (N. oceanica) for TFW eutrophication mitigation and eicosapentaenoic acid valorization. The findings demonstrated that employing N. oceanica resulted in significant removal rates for total phosphorus, total nitrogen, ammonia nitrogen, and chemical oxygen demand by 88.60 %, 97.02 %, 94.22 %, and 98.02 % under fed-batch treatment mode. Such nutrients removal efficiency met discharge permit standards while accomplished a superior biomass at 26.37 g/L and EPA yield at 43.5 mg/g by N. oceanica , representing 2.61- and 2.52-fold more than that of batch treatment mode. Furthermore, TFW feeding enhanced the cytomembrane fluidity of N. oceanica and promoted TFW nutrients uptake into cells consequently boosted the nutrients removal efficiency. Simultaneously, TFW feeding upregulated enzymes such as antioxidases, desaturases and elongases responsible for EPA biosynthesis in N. oceanica to collectively protect EPA from oxidation stress and stimulate proactive accumulation. EPA derived from TFW-fed N. oceanica exhibited promising in vitro antihyperlipidaemia efficacy in constructed hyperlipopyte HepG-2 cells. Further, the molecular docking indicated that the hypolipidemic activity partly contributed to that EPA inhibited PPARα signaling to trigger fatty acids β -oxidation and cholesterol transport suppression. The outcomes present a viable route that utilization of microalgae for TFW eutrophication mitigation and EPA valorization to advance carbon neutrality and resource recycling. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate removal efficiency of nitrogen and phosphorus compounds by floating islands with macrophytes and influence of LED lights imitating the photosynthetically active radiation (PAR) on that effectiveness. Improving removal efficiency is crucial, thanks to ever-tightening legal requirements. Main reason for that is growing problem of eutrophication phenomenon. Nowadays, this problem is visible not only in lakes and ponds but also in water courses and coastal water. Study was conducted during time of 15 weeks. In that time, listed parameters were tested: pH, conductivity, total nitrogen, organic nitrogen, ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorus, and phosphates. Each tank was filled with same amount of biologically treated wastewater; ambient temperature and dissolved oxygen concentrations were kept in same range for the time of experiment. Average concentrations of main pollutants in tanks with LED lighting have reached: conductivity, 936 μS/cm; TN, 8.55 mg/dm3; P-PO4, 0.74 mg/dm3; TP, 2.57 mg/dm3. In case of no LED lighting, concentrations of main pollutants have reached: conductivity, 949 μS/cm; TN, 12.85 mg/dm3; P-PO4, 1.28 mg/dm3; TP, 2.54 mg/dm3. Based on observations and analyses, it can be concluded that the use of LED lighting imitating PAR radiation has positive effect on removal efficiency of total nitrogen and phosphates. Data suggests optimal time for treatment with floating islands as 13 weeks, extending that time to 15 weeks leads to degradation of treated wastewater quality instead improving it. Highlights: • Floating islands supported with LED lighting are an alternative solution for nutrients removal. • LED light intensifies nitrogen and phosphorus removal from municipal wastewater. • The use of macrophytes in third stage of wastewater purification may result in increased nutrient removal efficiency. [ABSTRACT FROM AUTHOR]

This study proposes the technology of "runoff storage and seepage utilization" for achieving purification of road rainfall–runoff and presents a multi-level series purification system (PBT-GR) comprising porous asphalt pavement (PAP), a bioretention system (BS), a storage tank (T) and a hydroponic green roof (GR). The operation parameters of each component unit were optimized and the contribution of each unit to pollution was analyzed. The results showed that under typical simulated rainfall, the suspended solids (SS), total nitrogen (TN), total phosphorus (TP), Pb, Zn and Cu removal rates by filtration and interception of porous pavement were 62.26 ± 3.19%, 16.29 ± 1.74%, 29.27 ± 1.37%, 37.61 ± 2.58%, 35.57 ± 4.64% and 31.17 ± 3.27%, respectively. The average concentrations of SS, TN, TP, Pb, Zn and Cu in the effluent of the PBT-GR system were 14.70 ± 2.21 mg/L, 1.52 ± 0.24 mg/L, 0.14 ± 0.04 mg/L, 0.09 ± 0.04 mg/L, 0.11 ± 0.03 mg/L and 0.04 ± 0.01mg/L, respectively, which met the water quality standards recommended in the Chinese guidelines and showed a high adaptability to pollution load. The contents of pesticide residues and heavy metals in cultivated vegetables met the national standards. The period required to recoup the investment in the system was approximately 3 years, indicating its good economic feasibility. The present study can provide a valuable reference of the construction of an efficient, low consumption and sustainable urban stormwater treatment system and can contribute to the improvement in the quality of the urban water environment. [ABSTRACT FROM AUTHOR]

Algae-based membrane bioreactor (AMBR) has shown a potential for simultaneous wastewater treatment and production of algal biomass. However, the effectiveness of AMBR has yet to be further explored for greywater treatment. The present study assessed the algal biomass production, greywater treatment efficiency, and fouling characteristics of a laboratory-scale AMBR. The 12 h dark/12 h light cycle continuous experiments were performed with an AMBR operating at 48 h hydraulic retention time. The average algal biomass and chlorophyll-a production rates were 47.9 mg/L/d and 49.9 μg/L/d, respectively. The distribution of different pigments in the biomass showed an abundance of chlorophyll-a (92.2%) in the reactor. AMBR achieved 96% biological oxygen demand (BOD5) removal and 99% anionic surfactants removal by bacterial oxidation without any external aeration source. Algal assimilation achieved a total nitrogen removal of 52% and total phosphorus removal of 36%. More than 85% of nitrite (NO3-N) in the effluent revealed the absence of nitrification and denitrification processes in the reactor. Further, the reactor accomplished a higher than the 3.5-log reduction of total coliform and E-coli. The greenish cake layer of algal–bacterial biomass primarily caused the membrane fouling and accounted for 80–93% of total fouling resistance. Membrane fouling frequency decreased with the operation time, and physical cleaning effectively recovered the flux. The energy efficiency of AMBR in terms of net energy return (1.04) supported its application for the treatment and recycling of greywater. The present study provides the basis for establishing the guidelines for AMBR design for the treatment of greywater. [ABSTRACT FROM AUTHOR]

With the rapid socio-economic and industrial development, the problem of water shortage is becoming increasingly serious. Seeking alternative water sources to reduce the need for freshwater resources is an increasing concern. Household greywater production is high and accounts for about 50–80% of domestic wastewater. In recent years, the in situ treatment and reuse of greywater have received widespread attention. Treated greywater can be used for non-potable purposes such as toilet flushing and irrigation, which can greatly reduce the pressure of freshwater resource shortage. This paper reviews the sources and characteristics of greywater and analyzes its quantity and quality. In addition, this paper outlines and summarizes various greywater treatment technologies commonly used, including physical, biological, and chemical treatment technologies, as well as combination technologies. Understanding the mechanisms of contaminant removal is essential for effective greywater treatment. While discussing different treatment technologies, we focus on the removal mechanisms of pollutants from greywater, including organics, nutrients, surfactants, and emerging contaminants. Finally, future perspectives on greywater management and reuse are presented. Through a comprehensive review, we expect that this review will help the reader to better understand the characteristics of greywater and to more rationally select the appropriate treatment technology based on the removal mechanism of pollutants. [ABSTRACT FROM AUTHOR]

The bacteria-algae synergistic wastewater treatment process not only efficiently eliminates nutrients and absorbs heavy metals, but also utilizes photosynthesis to convert light energy into chemical energy, generating valuable bioresource. The study systematically explores the formation, algal species, and regulatory strategies of the bacterial-algal symbiosis system. It provides a detailed analysis of various interaction mechanisms, with a particular focus on nutrient exchange, signal transduction, and gene transfer. Additionally, the efficacy of the system in removing nitrogen, phosphorus, and heavy metals, as well as its role in CO 2 reduction and bioresource recycling, is thoroughly elaborated. Potential future research of bacteria-algae cell factory producing bioenergy production, feed or fertilizers are summarized. This paper clearly presents effective strategies for efficiently removing pollutants, reducing carbon emissions, and promoting resource recycling in the field of wastewater treatment. It also provides recommendations for further research on utilizing microbial-algal symbiotic systems to remove novel pollutants from wastewater and extract value-added products from the resulting biomass., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The traditional bioretention systems possess a remarkably low nitrogen and phosphorus removal effect. The removal rate fluctuates greatly, and even appears as negative removal of nitrogen and phosphorus. Four simulated bioretention experimental columns with different bilayer media, packing composition and structure were constructed. Based on the traditional fillers, the modified composite fillers with hydroxy-aluminum and modified vermiculite sludge particle (HAVSP) were added. The traditional filler (C1) and the modified composite filler (C2) were added respectively, moreover saturated zones were set up to enhance the effect of nitrogen and phosphorus removal. Removal of nutrients from experimental columns by simulated runoff efficiency was evaluated and compared. In addition, the effect of media depth on phosphorus retention and denitrifying enzyme activity in bioretention columns was also evaluated. The experimental column #2 filled with C2 had the optimum removal effect on TP (93.70%), however, the removal effect of TP by filling C1 experimental columns was insufficient (57.36%). Designed to remove nitrate (NO3−-N) and total nitrogen, the experimental column #4 showed the best performance (83.54% and 92.15%, respectively). In this study, we propose a fold-flow bioretention system by filling HAVSP in combination with saturated zones. The runoff water quality can be effectively improved, and a new bioretention cell configuration can be provided for efficient stormwater treatment. HIGHLIGHTS Proposing a novel bioretention system by installing a fold-flow board and combining with saturated zones.; Filling hydroxy-aluminum vermiculite sludge particle and setting a bilayer filler inside the structure of the bioretention system.; Evaluating the effect of media depth on phosphorus retention and denitrifying enzyme activity in bioretention columns.;

This research investigates the effect of mixing wavelength light photoperiods (12 h blue, 8 h blue: 4 h green, 4 h blue: 8 h green, and 12 h green) and N/P ratios (1.3 to 8.3) on the growth microalgae–bacteria systems, organic matter, and nutrient removals. The highest microalgae–bacteria growth performance (μ = 0.2 d−1, 481.1 ± 15.3 mg DW L−1) was observed when a 8 h blue: 4 h green mixed wavelength and a low N/P ratio were used. For both N/P ratios, biomass productivity was favored when using the blue light dominated at longer time periods. Mechanisms for nitrogen removal by assimilation depend on the N/P ratio, achieving assimilation between 49 and 65% at a low N/P ratio. High nitrogen removal (>50%) showed a strong relation with alkalinity culture conditions (pH > 8.5). The mixing of wavelength photoperiods seems to be a promising strategy to achieve high biomass productivity and nutrient removal. However, for optimal conditions, N/P ratios in the wastewater should be considered. HIGHLIGHTS Mixing wavelength photoperiods and N/P ratio for microalgae–bacteria grown in wastewater was investigated.; The highest biomass productivities were obtained by mixing blue (8 h) and green (4 h) LED wavelengths.; High nitrogen removal and biomass assimilation was observed at a low N/P ratio.; P limitation affects microalgae–bacteria wastewater treatment performance at the high N/P ratio.;

Purpose: Microalgae show growth and fatty acids (FAs) accumulation up to a certain level which is dependent on species and type of cultivation conditions. Application of abiotic stress on microalgae can induce nutrient uptake and enhance biocomponent accumulation. Methods: In the current study, freshwater microalgae (Chlorella sorokiniana GEEL-01 and Desmodesmus asymmetricus GEEL-05) were investigated for growth, nutrient removal, and FAs composition during cultivation in municipal wastewater under high NaCl concentration (150 to 600 mM) along with control (w/o NaCl addition). Results: The growth of both microalgae declined upon an increase in NaCl concentration in the wastewater. GEEL-05 showed higher growth of 0.572 OD680 nm at 150 mM NaCl, followed by 0.40 and 0.174 OD680 nm in 300 and 450 mM NaCl, respectively. Both microalgae were completely inhibited at 600 mM NaCl. GEEL-01 and GEEL-05 removed 60–80% total nitrogen (TN) up to 450 mM NaCl concentration. Both strains totally removed the total phosphorus (TP) after 8 days of cultivation from wastewater having up to 300 mM NaCl, while 40–80% TP was removed under 450 mM NaCl. FAs profiling of microalgal strains varied under different NaCl concentrations. GEEL-01 had high palmitic acids (33%) at 300 mM NaCl, high oleic acid (28 and 37%) at 300 and 450 mM NaCl and high linoleic acid (23%) at 450 mM NaCl. Whereas, GEEL-05 showed high palmitic acid (51.59%) at 450 mM NaCl and high oleic acid (30%), at 150 mM NaCl. The improved FAs content also resulted in better biodiesel properties. Conclusion: Both microalgae survived under high salinity having NaCl up to 450 mM in wastewater with high nutrient removal and improved FAs profile which indicated their use in wastewater treatment coupled with quality biodiesel production. [ABSTRACT FROM AUTHOR]

Landfill leachates are high-strength complex mixtures containing dissolved organic matter, ammonia, heavy metals, and sulfur species, among others. The problem of leachate treatment has subsisted for some time, but an efficient and cost-effective universal solution capable of ensuring environmental resources protection has not been found. Aerobic granular sludge (AGS) has been considered a promising technology for biological wastewater treatment in recent years. Granules' layered structure, with an aerobic outer layer and an anaerobic/anoxic core, enables the presence of diverse microbial populations without the need for support media, allowing simultaneous removal of different pollutants in a single unit. Besides, its strong and compact arrangement provides higher tolerance to toxic pollutants and the ability to withstand large load fluctuations. Furthermore, its good that settling properties allow high biomass retention and better sludge separation. Nevertheless, AGS-related research has focused on carbon-nitrogen-phosphorus removal, mainly from sanitary sewage. This review aims to summarize and analyze the main findings and problems reported in the literature regarding AGS application to landfill leachate treatment and identify the knowledge gaps for future applications. [ABSTRACT FROM AUTHOR]

This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na2CO3, and NaHCO3) were tested to improve biomass production, metabolites synthesis, and removal of NO3 and PO4. The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO3, and PO4 (80 and 50%, respectively). The addition of NaHCO3 as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO3 and PO4 in both strains. [ABSTRACT FROM AUTHOR]

The purpose of current study was to investigate the effects of sediment desiccation on nutrient dynamics and eutrophication in wetlands during the presence or absence of wiry and sturdy rooted emergent macrophytes, based on the hypothesis that sediment desiccation negatively correlated with plants nutrient uptake abilities and positively with nutrients fluxes at sediment-water interface. Growth of four emergent macrophytes, including two wiry rooted plants, i.e., Alocasia cucullata and Aglaonema commutatum, and two sturdy rooted plants, i.e., Cannabis indica and Acorus calamus, were grown and investigated in dried-rewetted sediments (DS) and constantly wet sediments (WS), respectively, for 6 months. The findings revealed that sediment drying and rewetting process significantly decreased the diffusion of overlying nutrient into sediment and the particle size density, porosity, and nutrients' repository ability in DS treatments, while the sediment bulk density and mineralization of organic macronutrients increased. Compared to WS treatments, the DS treatments impaired plant growth, root biomass, shoot biomass, and stimulated higher fluxes of ammonium nitrogen ( NH 4 + –N, 0.042−0.081 mg m – 2 d – 1) and phosphate (P O 4 3 – – P , 0.009−0.030 mg m–2 d–1) at sediment-water interface upon rewetting. The higher internal release of macronutrients and dissolved organic carbon (DOC) from DS led to the higher chlorophyll-a (Chl-a) concentrations (34.47−21.28 to 41.76−33.36 μg L–1) in their water column than in the water column of WS. The wiry rooted plants with higher root biomass displayed lower internal release of NH 4 + –N, PO43–P and DOC and water column Chl-a concentrations than the sturdy rooted plants in two sediment types. Root biomass of plants correlated positively with TN (63−87%) and TP (56−78%) removal percentages from WS and DS. These results demonstrated that sediment desiccation process reduced plant growth and enhanced internal loading of nutrients and consequently accelerated eutrophication in these wetlands. [ABSTRACT FROM AUTHOR]

Real field demonstrations to assess the removal efficiency of nutrients and organic matter from domestic wastewater were carried out using algal-bacterial photobioreactors. The reactors which consisted of three basins of 200 L were fed with secondary effluent of domestic wastewater and operated under natural day light/dark cycles. The results demonstrated that reaction time (RT) has a substantial role on the whole process performance. Whereas inoculation with nitrifiers affected the process only in some aspects. The enhancement in the dissolved oxygen production rate (1.15 mg O2. L−1.h−1) was in alignment with growing higher algal biomass concentrations due to the increase in RT. COD removal rates were significantly increased (p

The potential of microalgae as a source of renewable energy based on wastewater has received increasing interest worldwide in recent decades. A freshwater microalga Chlorella vulgaris was investigated for its ability to remove both nitrogen and phosphorus from three industrial wastewaters which were diluted in microalgae in two different proportions (namely, 50% and 75%). C. vulgaris grew fastest under 75% palm oil mill, and showed an maximum cell density (0.408 ± 0.012 g/L) for Palm Oil Mill Effluent (POME) wastewater, followed by riboflavin manufacturing wastewater (0.402 ± 0.083 g/L), and fertilizer industrial wastewater (0.320 ± 0.074 g/L), indicating the levels of nitrogen and phosphorus greatly influenced algal growth. Low removal efficiency for total nitrogen (TN) (11.35 ± 0.07% – 51.31 ± 0.03%) and total phosphorus (TP) (31.25 ± 0.24% – 93.62 ± 0.16%) was observed. C. vulgaris grew well when TP concentration was very low, indicating that this might be not the limiting factor to algal growth. The results suggest the potential of removing nutrient from wastewater by microalgae cultivation as production feedstock.

[Display omitted] Biochar utilization for adsorption seems to be the most cost-effective, easy/fast approach for pollutants removal from water and wastewater. Due to the high adsorption properties, magnetic biochar proved to be efficient in the sorption of heavy metals and nutrients. Although there are several studies on development of magnetic biochars, there is a lack of research on development of high-performance magnetic biochar from food waste for removal applications. This study aimed at preparing new classes of magnetic biochar derived from tea waste (TBC) for removal of heavy metals (Ni2+, Co2+), and nutrients (NH 4 + and PO 4 3−) from water and effective fertilizer (source of NH 4 + and PO 4 3−). Standard carbonization process and ultrafast microwave have been used for fabrication of TBCs. The removal of nickel, cobalt as the representatives of heavy metals, and over-enriched nutrients (NH 4 + and PO 4 3−) from water were tested and the removal kinetics, mechanism, and the effect of pH, dissolved organic matter and ionic strength were studied. Simultaneously, possible fertilizing effect of TBC for controlled release of nutrients (NH 4 + and PO 4 3−) in soil was investigated. Up to 147.84 mg g−1 of Ni2+ and 160.00 mg g−1 of Co2+ were adsorbed onto tested biochars. The process of co-adsorption was also efficient (at least 131.68 mg g−1 of Co2+ and 160.00 mg g−1 of Ni2+). The highest adsorbed amount of NH 4 + was 49.43 mg g−1, and the highest amount of PO 4 3− was 112.61 mg g−1. The increase of the solution ionic strength and the presence of natural organic matter affected both the amount of adsorbed Ni2++Co2+ and the reaction mechanism. The results revealed that magnetic nanoparticle impregnated onto tea biochar, can be a very promising alternative for wastewater treatment especially considering removal of heavy metals and nutrients and slow-release fertilizer to improve the composition of soil elements. [ABSTRACT FROM AUTHOR]

Porous asphalt pavement (PAP) system is a widely used treatment measure in sustainable stormwater management and groundwater recharge, but their variable performance in nitrogen (N) and phosphorus (P) removal requires further reinforcement prior to widespread uptake. Two laboratory-scale PAP systems were developed by comparing limestone bedding and zeolite incorporated into modified zeolite powder porous microsphere (MZP-PM) as a filter column under a typical rainfall. The PAP system of zeolite bedding incorporated into MZP-PM (a weight less than 5% of zeolite) removed 74.5% to 90.6% of ammonium (NH4+-N) and 72.9% to 92.4% of total phosphate (TP) from the influent, as compared with 25.7% to 62.7% of NH4+-N and 32.6% to 56.4% of TP by that of the limestone as bed material. This improvement was presumably due to MZP-PM's high adsorption capacity and surface complexation. The formation of ≡(La)(OH)PO2 was verified to be the dominant pathway for selective phosphate adsorption by MZP-PM and ion-exchange was proved to be the main removal process for ammonium. This study provides promising results for improving N and P removal by modifying a porous asphalt pavement system to include an MZP-PM adsorbent column as a post-treatment. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.

ABSTRACT Phytoremediation, as the implementation of microalgae in the treatment of effluents, is used to remove nitrogen compounds and phosphorus that can cause eutrophication in receiving water bodies. The present study evaluated the phytoremediation of urban and fish farming wastewater and growth performance of Litopenaeus vannamei using microalgae Chlorella vulgaris. Microalgae were cultivated stationary with three treatments: T1 sewage treatment station effluent (STS), T2 fish farming effluent (FF) and T3 with standard medium (SM) Guillard f/2), conducted in quintuplicate for each culture medium, using a 20 L carboy for eight days. 5.0 L inoculum (25%) plus 15 L culture medium, T1 STS, T2 FF and T3 SM (75% of each) were used to start the experiment. The shrimp experiment was realized with three treatments in quintuplicates, completely randomized design, during 15 days. The animals were maintained in tanks of 100 L under constantly aerated, resulting in a concentration above 5.0 mg L− 1 of dissolved oxygen, in a density of 70 animals m-3, fed four times per day (8:00, 11:00, 14:00 and 16:00 h) offering to T1 commercial feed (C-Feed) with 35% crude protein, T2 and T3 with commercial feed plus addition of 5.0% dry biomass of C. vulgaris. The best result for algal perfomance, lipid biomass and nutrient removal was with Fish farm wastewater. The additive with the highest performance was FF-Feed. C. vulgaris has a high potential for removing nutrients from wastewater, producing biomass and lipids, in addition to increasing shrimp productivity.

The present study used bench scale columns filled with biochar for phosphorous (P) recovery from real ultrafiltered wastewater. No studies are available about the potentiality of biochar using ultrafiltered real wastewater. Therefore, this study aimed to assess phosphate (PO 4 3- ) recovery by biochar-packed columns employing real treated wastewater from an ultrafiltration process. Three flow rates were tested, specifically 0.7, 1.7 and 2.3 L h -1 , to gain insights into the optimal working conditions. Results revealed that the maximum amount of PO 4 3- recovery (namely, 3.43 mg g -1 biochar) can be achieved after 7 h by employing the highest tested flow rate. Furthermore, the phosphorus exchange capacity (PEC) was inversely correlated with the feeding flow rate (FFR), with PEC values equal to 35, 25 and 9 % for FFR of 0.67, 1.7 and 2.3 L h -1 , respectively. The pseudo-first order model best approximated the adsorption kinetics, thus suggesting that the adsorption of phosphate by biochar depends on its concentrations (i.e. physiosorption mechanism)., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

The use of microalgae for the removal of contaminants such as total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD), and other pollutants from palm oil mill effluent (POME) has recently received much attention. This study aimed to investigate the impact of POME as a nutrient on microalgal growth and the rate at which nutrients were removed. Three green microalgae species were isolated from Penang, Malaysia’s palm oil mill. The polyphasic approach, which combines morphological and molecular observations, was used for species identification. The three green microalgae were identified as Chlorella sorokiniana, Scenedesmus quadricauda, and Chlorococcum oleofaciens. All three green microalgae were cultivated in 25%, 50%, and 75% (v/v) of lab-scale palm oil mill effluent (LABT-POME) to investigate the growth of these three green microalgae in 100 mL of BBM. Under a light microscope and a scanning electron microscope (SEM), the morphological changes of those three green microalgae (before and after cultivation in 25%, 50%, and 75% dilution of (LABT-POME)) were observed. When cultivated in LABT-POME, C. oleofaciens showed the highest growth rate compared to the other two species of green microalgae. C. oleofaciens was able to remove more than 90% of total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen from LABT-POME, as well as minimise soluble chemical oxygen demand (SCOD) by about 65%. The growth of C. oleofaciens was well fitted to the Verhulst growth kinetic model with an R2 value of 0.99 and a growth rate of 0.3195 day−1 (d−1). The results of this study show the ability of newly isolated green microalgae to remove nutrients (TP, TN, NH3–N, and SCOD) from POME, which could be used as an effective and environmentally friendly method to remove pollutants.

The treatment of nutrients and organic contaminants in wastewater using microalgae has drawn significant interest thanks to its advantages of environmental friendliness, low cost, CO2 emission reduction, and recycling of valuable biomass. Among other algae species, Chlorella sp. showed good vitality, simplicity in cultivation, and high nutrient accumulation in harsh conditions of wastewater. In this study, Chlorella vulgaris was inoculated in a membrane photobioreactor (MPBR) with piggery digestate to investigate the C. vulgaris growth rate and the removal efficiency of nutrients and chemical oxygen demand (COD). The results indicated that the cultivation of C. vulgaris in an MPBR system exhibited continuous and simultaneous removal of NH4+, PO43−, and COD from two-fold diluted piggery wastewater. Both the algae growth rate and nutrient removal depended on the liquid hydraulic retention time in the MPBR. The highest removal efficiency of NH4+ (74.55%), PO43− (70.20%), and COD (65.85%) was obtained in the longest HRT of 5 days with the highest microalgae biomass concentration of around 1.1 g/L. The algae washout phenomenon was negligible in the continuous cultivation in the MPBR system. Compared to the cultivation in batch mode, the MPBR could achieve a similar algae growth rate and treatment efficiency with a much shorter hydraulic retention time.

The rhizobacteria of genus Azospirillum and Bacillus are effective at fixing atmospheric nitrogen, promote plant growth and can largely contribute to beneficial recovery from degraded pastures. This study aimed to evaluate the development and nutritional status of Urochloa brizantha cv. Marandu in response to nitrogen doses along with inoculation of Azospirillum brasilense and Bacillus subtilis. The experiment was carried in a completely randomized design in a greenhouse with four replications and in factorial scheme 4 × 5. The treatments were consisted of seeds inoculation (without inoculation, A. brasilense (strains Ab-V5, Ab-V6), B. subtilis (strain CCTB04) and co-inoculation with strains of A. brasilense + strain of B. subtilis, and nitrogen doses (0, 50, 100, 150 and 200 kg ha−1, equivalent to 0, 25, 50, 75 and 100 mg dm−3 N) from urea. The sole inoculation of A. brasilense and B. subitilis promoted plant height of Marandu grass along with nitrogen fertilization. The co-inoculation of these bacteria increased potassium accumulation in Marandu grass along with nitrogen doses. Regardless of bacterial inoculation, number of tillers, leaves, dry matter accumulation, crude protein and accumulations of N, P, Ca, S and Mg were increased with increasing nitrogen doses in the first forage cycle. [ABSTRACT FROM AUTHOR]

In this study, the three biofilm-anoxic-oxic-MBR systems were operated in parallel using different carbon source feed types. The three systems were operated with complete sludge retention to compare microbial community composition and system efficiency. High average removal of ammonia and COD was obtained in the three reactors. However, total nitrogen and total phosphorus removal efficiency were significantly higher in the VFAs feed systems when compared with the glucose feed system. The highest and most stable BNR efficiency was observed when acetate was used as a carbon source. The qPCR analysis revealed that ammonium oxidizing bacteria, denitrifiers and total bacteria were all highest in the acetate feed system followed by the propionate feed system. Moreover, among all carbon source types, the PUS-biofilm could maintain a higher degree of abundance of total bacteria than the sludge biomass. Meanwhile, ammonium oxidizing bacteria and denitrifiers were enriched in the sludge biomass rather than in the PUS-biofilm. The results of illumina sequencing revealed that acetate followed by propionate were favourable to the growth of microorganisms that were associated with the BNR process, which was the main reason for the high efficiency of nutrient removal in the acetate and propionate feed systems. [ABSTRACT FROM AUTHOR]

In this study, the effects of different operating conditions on excess sludge minimization in an oxic-settling-anaerobic (OSA) process were evaluated. The experiment involved two systems operating in parallel, one implementing the OSA process and a conventional activated sludge (CAS) system as control, both configured according to a pre-denitrification scheme. Five periods (P1–P5) were studied, during which the OSA was operated under different layouts, which differed from the returned sludge to the anoxic (A) or aerobic (B) mainstream reactors and the hydraulic retention time in the anaerobic reactor of the OSA system (8–12 h). The excess sludge production in the OSA plant was lower in all the investigated configurations, indicating that successful sludge minimization was achieved. Specifically, the sludge production was lowered by approximately 12% (P1), 29% (P2), 40% (P3), 26% (P4) and 41% (P5). Scheme A enabled the establishment of the uncoupling metabolism and the extracellular polymeric substance (EPS) destructuration. In contrast, scheme B enabled the establishment of the maintenance metabolism in addition to the uncoupling metabolisms, whereas cell lysis and EPS destruction were minimized. This allowed for obtaining higher sludge reduction yield (26–40%) without compromising the effluent quality.

This study proposes the technology of “runoff storage and seepage utilization” for achieving purification of road rainfall–runoff and presents a multi-level series purification system (PBT-GR) comprising porous asphalt pavement (PAP), a bioretention system (BS), a storage tank (T) and a hydroponic green roof (GR). The operation parameters of each component unit were optimized and the contribution of each unit to pollution was analyzed. The results showed that under typical simulated rainfall, the suspended solids (SS), total nitrogen (TN), total phosphorus (TP), Pb, Zn and Cu removal rates by filtration and interception of porous pavement were 62.26 ± 3.19%, 16.29 ± 1.74%, 29.27 ± 1.37%, 37.61 ± 2.58%, 35.57 ± 4.64% and 31.17 ± 3.27%, respectively. The average concentrations of SS, TN, TP, Pb, Zn and Cu in the effluent of the PBT-GR system were 14.70 ± 2.21 mg/L, 1.52 ± 0.24 mg/L, 0.14 ± 0.04 mg/L, 0.09 ± 0.04 mg/L, 0.11 ± 0.03 mg/L and 0.04 ± 0.01mg/L, respectively, which met the water quality standards recommended in the Chinese guidelines and showed a high adaptability to pollution load. The contents of pesticide residues and heavy metals in cultivated vegetables met the national standards. The period required to recoup the investment in the system was approximately 3 years, indicating its good economic feasibility. The present study can provide a valuable reference of the construction of an efficient, low consumption and sustainable urban stormwater treatment system and can contribute to the improvement in the quality of the urban water environment.