A mixed culture, prepared by acclimatising Chlorella vulgaris (C. vulgaris) to municipal wastewater (MWW), was used in two reactors: one was inoculated with activated sludge (AS), and the other was not (NAS). Under 12:12 h light: dark, mixing, and a hydraulic retention time of 1.17 d, both systems removed ∼92 % of 270 mg-COD/L, 57 % of 70 mg-N/L, and 27 % of PO43--P, while achieving a sludge volume index of 42 mL/g. C. vulgaris disappeared and was replaced by other algae, including cyanobacteria, indicating that inoculation is not necessary. Higher dissolved oxygen production, IC uptake, and nitrification occurred in the NAS reactor than in the AS reactor, supported by a higher abundance of the autotrophic/aerobic community in the NAS reactor. Genomic data revealed latent mechanisms (denitrification, N-fixation, nitrate/nitrite reduction, multiple phosphorus pathways) than mass balance. Pure algae seeding is not essential, but activated sludge seeding could affect performance.

Breakpoint chlorination ("burn") is a common practice to recover chloramine from nitrification. It, however, leads to the formation of a high amount of toxic disinfection by-products and is operationally complex. This study evaluated the effectiveness of repeated (daily) rechloramination at a Cl/N mass ratio of 4.5:1 in a continuously flowing reactor system where nitrification (nitrite, 0.187 mg-N L-1 and chloramine, 0.55 mg-Cl-2 L-1) occurred. Repeated (daily) rechloramination with 3 mg-Cl-2 L-1 was more effective than with 2 mg-Cl-2 L-1 in suppressing nitrification (nitrite 0.016 mg-N L-1) and bacterial populations (ATP 5 pg.mu L-1), thus recovering chloramine residuals (1.5 mg L-1). This effect was noted within three days of rechloramination and remained stable for the next seven days, after which rechloramination was stopped. Chloramine gradually decreased, and in about ten more days, nitrite started to increase. Chloramine drop was triggered by the incoming water quality -chloramine (1.7 mg-Cl-2 L-1), chloramine decaying proteins and microorganisms contributing to the decay coefficient of 0.0143 h(-1). Nitrite in incoming water was < 0.007 mg-N L-1. Nitrite appeared when the chloramine concentration decreased below the biostable residual concentration (BRC), but it contributed < 15 % to the decay. Therefore, the necessary conditions for successful recovery by repeated rechloramination are: a) ensuring upstream water quality is suitable to maintain chloramine above the BRC after stopping rechloramination, b) selecting a dose that could consistently keep the chloramine above the BRC, and c) a minimal biofilm-affected tank (e.g., surface to volume ratio <1 m(-1)). If a tank or pipe is biofilm-affected, chloramine should be kept above 1.7 mg-Cl-2 L-1.

Municipal wastewater (MWW) was treated using a microalgal-bacterial consortium without mechanical aeration. An inoculum for the reactor was prepared by acclimatizing Chlorella vulgaris to MWW and supplementing with a small amount of activated sludge. The hydraulic retention time (HRT) and solids retention time (SRT) were progressively reduced from 6.67 to 1.17 d and from 10 to 6.67 d, respectively, to test the process robustness under realistic MWW operation. The COD removal efficiency was 88% at 0.23 kg-COD/m3/d. Mass balance suggested the major nitrogen and phosphorus removal mechanism as assimilation. A high percentage (80%) of oxidized nitrogen indicated an efficient nitrification at all HRTs. Inorganic carbon (IC) balance calculation explained the observed IC dynamics. The chlorophyll a-to-mixed liquor volatile suspended solids (MLVSS) ratio and percentage of nitrite responded to IC limitation and supplementation. The mixed liquor exhibited excellent settleability (sludge volume index: 42 mL/g) with dense algal-bacterial flocs. An increased organic loading rate, however, reduced daytime dissolved oxygen, suggesting limitation under non-aerated conditions. These findings demonstrate the potential of microalgal-bacterial systems to achieve efficient COD removal and nitrification at realistic HRTs without aeration while emphasizing the importance of IC management.

Using a laboratory-scale system, consisting of a primary disinfection tank (PDT) and three intermittently mixed reactors (R1–R3) in series, bulk water and biofilm contributions to chlorine decay were quantified. The reactors (surface-to-volume ratio: 23.7 m−1; retention time in each reactor: 42.6 ± 1.18 h) were fed with plant-filtered water (PFW). Secondary disinfection was carried out in R1. Free chlorine concentration decreased with travel time (R1: 1.2 mg/L; R2: 0.6 mg/L; and R3: 0.12 mg/L). The bacterial number (ATP) decreased from 67 pg/mL in PFW and remained at ~2–3 pg/mL in R1 and R2 but increased back to 68 pg/mL in R3. First-order chlorine decay rate coefficients decreased from R1 to R2, as expected, but increased by five-fold from R2 to R3. The increased bacterial number (ATP) in R3 and batch chlorine decay tests confirmed that bulk water (soluble compounds, microbes, and sediments) contributed approximately 40% of the decay, and the biofilm contributed 60% in R3. When ATP levels in the reactors were combined with literature data, the bacterial number increased significantly when free chlorine decreased below 0.2 mg/L, but data between 0.2 and 0.5 mg/L are limited. More investigation is needed in the future for chlorine < 0.5 mg/L regarding bacterial regrowth and its effect on bulk water chlorine decay.

Street trees provide valuable ecological and social benefits to urban environments; however, their root systems can compromise nearby infrastructure, reducing structural integrity and service life. This investigation quantifies the extent of these impacts, underscoring the significant asset damage and financial challenges posed by tree root intrusion into stormwater and sewer systems. Data collected from Orange City Council suggests that tree roots affect approximately 23.8% of stormwater lines, 20% of sewer reticulation mains, and 26.1% of sewer trunk mains, with Asbestos Cement (AC) pipes found to be the most negatively impacted. Financial modelling indicates that the current Council budget for asset renewal and replacement is severely underfunded, with stormwater and sewer allocations falling short by factors of 5.6 to 11.2 and 2.4 to 4.8, respectively, depending on damage severity. The study ranks commonly planted urban tree species based on their potential to damage infrastructure. The findings demonstrate the need for targeted preventive measures, such as the strategic selection of less invasive species, to mitigate infrastructure damage, reduce long-term costs and increase asset lifecycle. This study also outlines several potential solutions such as tree removal, root barrier installation, appropriate species selection, chemical treatments, and inspection programs evaluated in terms of cost, environmental impact, and feasibility based on existing literature. By integrating these strategies, local governments can better balance urban greenery with essential infrastructure durability, ensuring that the ecological benefits of urban forestry do not come at an unsustainable economic cost.

Over the past decade, escalating extreme weather events have significantly affected New South Wales (NSW), Australia, with unprecedented droughts and intense fires. Yet, the impact on water quality and purification processes remains insufficiently studied. This research focuses on the immediate changes in NSW's environmental water quality and issues in water purification unit operations following the 2019 bushfires. Water samples and maintenance records from affected catchments, intakes, purification units, and reservoirs were analysed. Compared to control samples, post-bushfire water exhibited high turbidity. Sediment and ash shock loads posed significant threats to aquatic ecosystems. Elevated turbidity, suspended sediments, pH, and alkalinity were major concerns for water purification. Raw water samples showed turbidity exceeding 195 NTU, with flocculation and sedimentation most impacted. Immediate measures included sediment traps, aeration, pre-chlorination, and inline monitoring. These findings inform strategies to mitigate bushfire impacts on water quality and optimise water purification in fire-prone regions.

This work comprehensively demonstrates the ability of heterotrophic bacteria, isolated from a chloraminated system, to decay chloramine. This study non-selectively isolated 62 cultures of heterotrophic bacteria from a water sample (0.002 mg-N/L nitrite and 1.42 mg/L total chlorine) collected from a laboratory-scale reactor system; most of the isolates (93.3%) were Mycobacterium sp. Three species of Mycobacterium and one species of Micrococcus were inoculated to a basal inorganic medium with initial concentrations of acetate (from 0 to 24 mg-C/L) and 1.5 mg/L chloramine. Bacterial growth coincided with declines in the concentrations of chloramine, acetate, and ammonium. Detailed experiments with one of the Mycobacterium sp. isolates suggest that the common mechanism of chloramine loss is auto-decomposition likely mediated by chloramine-decaying proteins. The ability of the isolates to grow and decay chloramine underscores the important role of heterotrophic bacteria in the stability of chloramine in water-distribution systems. Existing strategies based on controlling nitrification should be augmented to include minimising heterotrophic bacteria.

This study reports the importance of maintaining a high pH and/or chloramine concentrations in water distri-bution system to supress the growth of nontuberculous mycobacteria (NTM) -a group containing some oppor-tunistic pathogens. Four sets of reactor systems, each containing three reactors connected in series, were operated at three different feed water pH values (7.6, 8.4, and 9.0) and two different chloramine concentrations (2.6 and 3.8 mg/L). Altogether, 44 operational taxonomic units of NTM were identified. The NTM species Mycobacterium chelonae, M. europaeum, M. gordonae, M. stephanolepidis, M. llatzerense, M. lentiflavum, and M. kyorinense were detected in the majority of the samples. Among them, M. chelonae was highly dominant NTM species in majority of the tested samples. The NTM populations were in the range of 8.83E+ 01-6.30E+ 05 gene copies/mL. Higher relative abundances of NTM were noted in reactors containing higher chloramine residuals, but the number of NTM and total bacterial population increased with the decreasing chloramine concentration, under low pH (<8.4) and under nitrifying conditions. This study underscores the benefits of maintaining high pH in the feed as it not only increases the chloramine stability, but also suppresses the bacterial growth including NTM.

This paper highlights the potential to effectively inhibit nitrification and restore chloramine levels using a low copper concentration in a biofilm-affected (surface-to-volume ratio 16 m−1) continuous-flow laboratory-scale chloraminated system. High nitrite and low chloramine containing tanks are always recovered with chlorine “burn” by water utilities. The “burn” is not only costly and operationally complex, but also compromises the water quality, public health, and customer relations. A laboratory system comprising five reactors connected in series was operated. Each reactor simulated conditions typically encountered in full-scale systems. Low amount of copper (0.1–0.2 mg-Cu L−1) was dosed once per day into nitrified reactors. At any given time, only one reactor was dosed with copper. Not only inhibition of nitrification, chloramine decay associated with bulk water, biofilm and sediments also improved. However, the improvement was quicker and more significant when the influent to the reactor contained a high chloramine and a low nitrite concentration. Ammonia oxidising microbes exhibited resilience when exposed to low copper and chloramine concentrations for an extended period. Chloramine decay due to planktonic microbes and chemical reactions in bulk water decreased more rapidly than decay attributed to biofilm and sediments. The concept “biostable residual chlorine” explained how copper and chloramine can inhibit nitrification. Once nitrification was inhibited, the chloramine supplied from upstream effectively continued to suppress downstream nitrification, and this effect lasted more than 50 days even at 22 °C. The findings could be used to develop short-term copper dosing strategies and prevent negative impacts of nitrification and breakpoint chlorination.

The present research was conducted to examine different parameters of variability, correlations, and path coefficients associated with yield and yield-related traits in aerobic rice. The analysis of variance indicated noteworthy variations among the genotypes for all the traits investigated. Among them, flag leaf area and alkali spreading value showed high PCV and GCV. Except for days to fifty per cent flowering, days to maturity, and amylose content, the remaining traits demonstrated substantial heritability combined with high genetic advance as percentage of mean. The correlation analysis revealed significant positive association between grain yield per plant and several traits, namely effective tillers per plant, test weight, chlorophyll content, and length breadth ratio. Traits such as test weight, effective tillers per plant, and flag leaf area showed a positive direct effect on grain yield per plant. Therefore, it is crucial to give priority to traits that exhibit significant positive correlations and substantial direct effects during selection process. This approach will yield rewarding results in the development of high-yielding cultivars suitable for aerobic conditions. Keywords: Aerobic rice, PCV, GCV, Heritability, Correlation coefficient, Path analysis

Salinity, along with drought, is one of the key abiotic stressors that has posed a danger to the advancement and evolution of cereal crops like rice and wheat. Water shortage and a lack of irrigation water availability are the main causes of salty soil formation. Rice is salt sensitive and glycophyte, wheat is moderately salt tolerant. Wild tolerant cultivars like Oryza coarctata and Oryza alta are more tolerant than traditional cultivars such as Pokkali and Nona Bokra in rice. Salt stress affects crop plants’ processes like ionic imbalance, osmotic and oxidative stress. Na+ should be low in the shoots of the plant which is restricted by various transporters in the cell membrane of the roots in soil. High K+ & Na+/K+ homeostasis should be maintained. Many RILs and NILs have been developed which acts as a donor for salinity tolerant genes. FL478 is a recombinant inbred line in which candidate genes are situated in the Saltol region of chromosome 1 region which is obtained by a cross between Pokkali x IR29. Increase in world’s population, rice output must be increased by at least 25% by 2030 and 50% by 2050.Salinity stress is a polygenic character which involves several genes works in harmony. For evolution of salinity tolerant cultivars, we need to access the physiological, biochemical genetic responses of the crop plant which helps in transfer of candidate genes from donor parents to elite high yielding salt sensitive cultivars. Especially in rice salt tolerant mechanisms like, Ion equilibrium regulation, Adjustment of osmotic potential, Reduction of ROS, Nutrient disequilibrium, and Regulation of PGRs. Conventional, MABC, MAS and direct gene transfer by transgenic methods. This review paper's main objective is to understand the mechanisms of the crop plants to salinity effects and development of salt tolerant cultivars by modern approaches which fulfill the food scarcity of staple food crops with increasing population.

The urgent issue facing the world in the 21st century is food security due to the ever-increasing population. Globally, Green Revolution increases the intensive use of chemical fertilizers and agrochemicals. Several attempts have been made over the years to improve agricultural crop productivity, primarily through pesticides and inorganic fertilizers, which cause the accumulation of agrochemicals in soil, adversely affected the soil dynamics, and disrupt soil biodiversity. Additionally, these substances can pile up in the soil-plant-animal-continuum systems and result in major health concerns. Sustainable agricultural practices make use of natural processes to increase production as well as quality while reducing harmful environmental effects. Numerous soil fertility factors contribute to the sustainability of agricultural production systems by influencing plant tolerance to biotic and abiotic stress, as well as increased soil microbial activity, which increases soil fertility. Utilizing plant growth–promoting microorganisms reduces the use of chemical fertilizers and improved crop production in an ecofriendly and sustainable manner. Thus, ecofriendly biofertilizers must, therefore, undergo a paradigm shift. The present chapter addresses the use of bioengineering to pandering the process of biological nitrogen fixation, phosphorus uptake, and potassium solubilization in a variety of microorganisms to resilience soil fertility and crop productivity in sustainable modes.

The escalating threat of climate change is a major challenge to global food security. One of the ways to mitigate its impact is by developing crops that can withstand environmental stresses such as drought, heat, and salinity. Plant breeders have been employing conventional and modern approaches to achieve climate-resilient crops. Climate-resilient crops refer to both crop and crop varieties that exhibit improved tolerance towards biotic and abiotic stresses. These crops possess the capacity to maintain or even increase their yields when exposed to various stress conditions, such as drought, flood, heat, chilling, freezing and salinity. Conventional breeding entails selecting and crossing plants with desirable traits, while modern breeding deploys molecular techniques to identify and transfer specific genes associated with stress tolerance. However, the effectiveness of both methods is contingent on the crop species and the targeted stress. Advancements in gene editing, such as CRISPER-cas9 and genomics-assisted breeding, offer new opportunities to hasten the development of climate-resilient crops. These new technologies include Marker Assisted Selection, Genome-Wide Association Studies, Mutation breeding, Transcriptomics, Genomics, and more. The review concludes that these cutting-edge techniques have the potential to enhance the speed and precision of developing crops that can endure the challenges posed by climate change.

The two most commonly adopted strategies, rechlorination (addition of chlorine) and rechloramination (addition of chlorine and ammonia), to recover and stabilise chloramine from nitrification were comprehensively evaluated in laboratory- and full-scale systems. Laboratory-scale batch experiments were conducted in a nitrifying sample (~0.05 mg-N/L). In the full-scale service reservoir, repeated rechlorination was ineffective in suppressing nitrification and microbial chloramine decay during warmer months (>20 °C), even when rechlorination was started at nitrite <0.005 mg-N/L. Measurement of decay rates through microbial chloramine decay factor method provides a deeper understanding of a water sample than traditional nitrification indicators. The method has the ability to provide an early warning (one month in advance), show the presence of microbial chloramine decay in non-nitrified water and that of chloramine decaying proteins in any samples. In the batch sample, nitrification and the production of chloramine-decaying proteins and bacterial regrowth had to be suppressed to recover chloramine. Rechloramination (~2.5 mg/L) outperformed rechlorination, as it maintained a relatively higher chloramine concentration. Microbes were killed within 30 min of dosing chlor(am)ine, likely due to shock or compounds formed during chloramine formation reactions; however, microbes regrew (or survive) to a different degree in all samples despite the prolonged presence of chloramine (large CxT), defying the CxT concept. The key to the recovery of chloramine appears to be consistently maintaining chloramine >1.7 mg/L and shocking with a high chloramine dose. The findings will assist water utilities in designing and assessing the effectiveness of nitrification remediation strategies in chloraminated water supply systems.

A better alternative to breakpoint chlorination (BPC) or “chlorine burn” to recover from nitrification is proposed. The BPC involves adding chlorine to achieve Cl/N mass ratios more than 7.5 g-Cl2/g-NH4+-N to convert to free chlorinated system. Thus, it is operationally complex and increases the chance of the formation of regulated disinfection by-products (DBPs). Reverting the system back to (mono)chloraminated system is also operationally complex. All these processes require informing public and disruption to service. We tested three Cl/N mass ratios (5.5:1, 7.5:1, 10:1) and three predetermined reaction times (breakpoint reaction time). After the breakpoint reaction time, the samples were rechloraminated (2.5 mg/L at a Cl/N mass ratio of 4.5:1) twice. The second rechloramination was carried out when chloramine had reached 1.0 mg/L. The improvement was evaluated based on the ability of the method to improve chloramine stability, suppress nitrification, and reduce active bacterial cells. Results showed a Cl/N ratio of 5.5:1 (a new method) followed by two rechloramination doses achieved the same improvement as the traditional Cl/N ratio of 10:1 and one rechloramination. Major factor controlling the effectiveness of the new method relies on the ability of the disinfectant to deactivate chloramine-decaying proteins present in nitrified water. The new method does not need the conversion to a free chlorinated system and thus significantly minimises the operational complexity, disruption to service and potential to form DBPs. It offers a potentially novel solution but needs optimisation and testing in a continuous flow system.

The historic usage and discharge of per- and polyfluoroalkyl substances (PFAS) containing chemicals have produced many contaminated sites and PFAS contamination has become a global concern due to their persistence, widespread distribution, and potential adverse impacts for human and environmental health. However, there have been limited investigations on the specific behavior of bacterial communities in PFAS contaminated soils. In this study, a quantitative PCR assay and Illumina MiSeq sequencing were used to investigate the variations of bacterial communities in a regional Australian airport contaminated with PFAS. The dominate PFAS detected in soil samples was Perfluorooctanesulfonic acid (PFOS), which accounted for 82% of total PFAS and the maximum PFOS level was noted (20,947±1824 ng.PFOS/mg.Soil) at the top soil. Irrespective of the degree of PFAS contamination at different depths, the comparable percentile contribution of each PFAS was observed in soil samples. Significantly higher bacteria amplicon sequence variant (ASV) and diversity were noted in uncontaminated soil than PFAS contaminated soil. Bacterial genera Rhodanobacter and Chujaibacter were dominant in the PFAS contaminated soil. Three different bacterial genera of Alphaproteobacteria, Ambiguous taxa of Acidobacteriia, and genus Chujaibacter of Gammaproteobacteria showed a significant positive correlation and RB41, Gaiella showed a significant negative correlation with 11 different PFAS concentrations. Overall, the results presented in this study suggest that the counts and species diversity of soil microorganisms are adversely influenced by PFAS contamination.

This study shows if biologically activated carbon (BAC) is backwashed at the correct frequency, a number of benefits can be derived in addition to aiding the subsequent coagulation process. Previous studies have shown that the BAC improves the removal of dissolved organic carbon (DOC) by subsequent coagulation by decreasing non-coagulable dissolved organic carbon (NC-DOC). However, the actual mechanism of such observation or optimising strategies of NC-DOC removal is unknown. The impact of backwashing on BAC reactor performance in terms of NC-DOC removal and microbial community structure was investigated. A laboratory scale BAC column was operated for more than five months with backwashing at once every five days, but in one cycle it was operated without backwashing for 14 days and the effluent collected at different times from the last backwash was subjected to enhanced coagulation (EC). All the effluent of BAC collected at different days depicted better floc forming characteristics than the feed water which is raw surface water. The effluent collected on day three from the last backwash (BAC-3d) contained the least amount (1.64 mg/L) of NC-DOC despite the highest DOC (3.89 mg/L) of all effluents. The coagulant requirement (5 mg-Fe3+/mg-DOC) was minimal for BAC-3d effluent among raw water and all other BAC effluent water samples. This is remarkable given the raw water contained 2.76 mg/L of NC-DOC. The microbial community on BAC granules on day three contained a higher abundance of biodegradable organic matter (BOM) removing microorganisms and low abundance of opportunistic pathogens. Similar performance in terms of DOC removal with the backwash was also observed in the continuous operation of other BAC columns. Possible backwash frequency that optimises the BAC/EC and derives many other benefits is proposed. The BAC/EC combination could help solve many emerging issues cost-effectively hence, needs further investigation.

Thirteen inbred lines, three testers, thirteen nine hybrids, and two checks were tested in an RBD design with three replications at the Irrigation Research Station Farm, Araria, Bihar during the season of kharif 2020. The goal was to assess the direct and indirect impacts of characteristics on grain yield in maize and to establish the phenotypic and genotypic connection between traits. Character association studies will aid in assessing the link between the yield and its components in order to improve the selection's effectiveness. In light of this, the current study used twelve quantitative parameters to analyze the correlation coefficient and path analysis among 39 F1s, 13 inbred, three testers, and two check of maize. Correlation studies indicated that plant height (cm), ear height (cm), ear length (cm), ear diameter (cm), 1000 kernels weight, kernel rows per ear, number of kernels per row showed significant positive association with grain yield (Kg/ha) as well as among themselves at phenotypic and genotypic level. As a result, selecting for any one of these characters would result in improvements in the other characters as well as an increase in grain yield (kg/ha). Path coefficient analysis revealed that the highest positive direct effects on grain yield was exhibited by ear length, ear diameter, kernel rows per ear, kernels per row, 1000 kernels weight, ear height, days to 50% silking. As a result, the current study could aid in the trustworthy selection of parental lines based on the features listed above, as well as the development of high yielding varieties for future breeding programs.