Metagenomic community composition and resistome analysis in a full-scale cold climate wastewater treatment plant

Background Wastewater treatment plants are an essential part of maintaining the health and safety of the general public. However, they are also an anthropogenic source of antibiotic resistance genes. In this study, we characterized the resistome, the distribution of classes 1–3 integron-integrase genes (intI1, intI2, and intI3) as mobile genetic element biomarkers, and the bacterial and phage community compositions in the North End Sewage Treatment Plant in Winnipeg, Manitoba. Samples were collected from raw sewage, returned activated sludge, final effluent, and dewatered sludge. A total of 28 bacterial and viral metagenomes were sequenced over two seasons, fall and winter. Integron-integrase genes, the 16S rRNA gene, and the coliform beta-glucuronidase gene were also quantified during this time period. Results Bacterial classes observed above 1% relative abundance in all treatments were Actinobacteria (39.24% ± 0.25%), Beta-proteobacteria (23.99% ± 0.16%), Gamma-proteobacteria (11.06% ± 0.09%), and Alpha-proteobacteria (9.18 ± 0.04%). Families within the Caudovirales order: Siphoviridae (48.69% ± 0.10%), Podoviridae (23.99% ± 0.07%), and Myoviridae (19.94% ± 0.09%) were the dominant phage observed throughout the NESTP. The most abundant bacterial genera (in terms of average percent relative abundance) in influent, returned activated sludge, final effluent, and sludge, respectively, includes Mycobacterium (37.4%, 18.3%, 46.1%, and 7.7%), Acidovorax (8.9%, 10.8%, 5.4%, and 1.3%), and Polaromonas (2.5%, 3.3%, 1.4%, and 0.4%). The most abundant class of antibiotic resistance in bacterial samples was tetracycline resistance (17.86% ± 0.03%) followed by peptide antibiotics (14.24% ± 0.03%), and macrolides (10.63% ± 0.02%). Similarly, the phage samples contained a higher prevalence of macrolide (30.12% ± 0.30%), peptide antibiotic (10.78% ± 0.13%), and tetracycline (8.69% ± 0.11%) resistance. In addition, intI1 was the most abundant integron-integrase gene throughout treatment (1.14 × 104 gene copies/mL) followed by intI3 (4.97 × 103 gene copies/mL) while intI2 abundance remained low (6.4 × 101 gene copies/mL). Conclusions Wastewater treatment successfully reduced the abundance of bacteria, DNA phage and antibiotic resistance genes although many antibiotic resistance genes remained in effluent and biosolids. The presence of integron-integrase genes throughout treatment and in effluent suggests that antibiotic resistance genes could be actively disseminating resistance between both environmental and pathogenic bacteria.

Nitric Acid-Potassium Hydroxide Fractionation of Rice Straw: an Integrated Biorefinery Initiative

Rice straw was fractionated with nitric acid in order to avoid the cooking liquor recovery in pulp production from agricultural residue (rice straw). The rice straw treated with 11.03% nitric acid at 90 ℃ for 3hr yields 53.09% pulp. The nitric acid treated rice straw pulp had high amount of lignin and minerals. However, further treatment of nitric acid pulp with low potassium hydroxide reduced the lignin and ash sufficiently as well as the pulp yield. Pulp yield reduced from 53.09 to 34.27%. The papermaking properties of the nitric acid followed by KOH treated pulp showed better quality than the nitric acid pulp. Nitric acid liquor was used several times. Pulp yield decreased in every step of reusing of the nitric acid spent liquor although residual lignin content increased. The final effluent liquor was rich with potassium, nitrogen and biomass that can be used as soil nutrient for cultivation.

Washing Machine Filters Reduce Microfiber Emissions: Evidence From a Community-Scale Pilot in Parry Sound, Ontario

Washing clothing is a known pathway for microfibers to reach the environment. Previous research has investigated microfiber capture close to the source (i.e., the washing machine), and demonstrated washing machine filters as a potential mitigation strategy. Widespread deployment into homes may be an effective solution to prevent microfiber emissions. Here, we investigated the effectiveness of washing machine filters at the level of a community. We installed filters in 97 homes in a small town, representing approximately 10% of households connected to the municipal wastewater treatment plant (WWTP). We evaluated treated final effluent and found a significant reduction in microfibers after filter installation. Furthermore, lint samples from filters revealed an average weekly lint capture of 6.4 g, equivalent to 179,200–2,707,200 microfibers. This research shows that microfiber filters on washing machines are effective at scale, and this result can help inform policy decisions to reduce microfiber emissions from laundering textiles.

Metagenomic Community Composition and Resistome Analysis in a Full-scale Cold Climate Wastewater Treatment Plant

Background: Wastewater treatment plants are an essential part of maintaining the health and safety of the general public. However, they are also an anthropogenic source of antibiotic resistance genes. In this study, we characterized the resistome, the distribution of classes 1-3 integron-integrase genes (intI1, intI2, and intI3) as mobile genetic element biomarkers, and the bacterial and phage community compositions in the North End Sewage Treatment Plant in Winnipeg, Manitoba. Samples were collected from raw sewage, returned activated sludge, final effluent, and dewatered sludge. A total of 28 bacterial and viral metagenomes were sequenced over two seasons, fall and winter. Integron-integrase genes, the 16S rRNA gene, and the coliform beta-glucuronidase gene were also quantified during this time period. Results: Bacterial classes observed above 1% relative abundance in all treatments were Actinobacteria (39.24% ± 0.25%), Beta-proteobacteria (23.99% ± 0.16%), Gamma-proteobacteria (11.06% ± 0.09%), and Alpha-proteobacteria (9.18 ± 0.04%). Families within the Caudovirales order: Siphoviridae (48.69% ± 0.10%), Podoviridae (23.99% ± 0.07%), and Myoviridae (19.94% ± 0.09%) were the dominant phage observed throughout the NESTP. The most abundant bacterial genera (in terms of average percent relative abundance) in influent, returned activated sludge, final effluent, and sludge, respectively, includes Mycobacterium (37.4%, 18.3%, 46.1%, and 7.7%), Acidovorax (8.9%, 10.8%, 5.4%, and 1.3%), and Polaromonas (2.5%, 3.3%, 1.4%, and 0.4%).The most abundant class of antibiotic resistance in bacterial samples was tetracycline resistance (17.86% ± 0.03%) followed by peptide antibiotics (14.24% ± 0.03%), and macrolides (10.63% ± 0.02%). Similarly, the phage samples contained a higher prevalence of macrolide (30.12% ± 0.30%), peptide antibiotic (10.78% ± 0.13%), and tetracycline (8.69% ± 0.11%) resistance. In addition, intI1 was the most abundant integron-integrase gene throughout treatment (1.14x104 gene copies/mL) followed by intI3 (4.97x103 gene copies/mL) while intI2 abundance remained low (6.4x101 gene copies/mL).Conclusions: The wastewater treatment plant successfully reduced the abundance of bacteria, DNA bacteriophages, and antibiotic resistance genes although many of them still remained in effluent and biosolids. The presence of integron-integrase genes throughout treatment and in effluent suggests that antibiotic resistance genes could be actively disseminating resistance between both environmental and pathogenic bacteria.

Existence, Fate And Risk Assessment of Pharmaceuticals During Treatment of Domestic Wastewater: Mass Flow And Consumption Calculation

In Egypt, pharmaceuticals consumption is dramatically increasing, owing to the population growth and the unrestricted sale manner. Therefore, the occurrence and fate of nine pharmaceutical compounds (PhCs) were scrutinized at the different stages of sewage treatment plant (STP) in Giza, Egypt. Levels of these PhCs were assessed in wastewater and sludge phases by a high-performance liquid chromatography coupled. Nine PhCs were detected in both wastewater and sludge. Average concentration of the total PhCs detected in influent, primary sedimentation effluent and final effluent were 227, 155 and 89 µg/L, respectively. The overall removal efficiency of the individual PhCs ranged from 18 % to 72 % removal. The occurrence trend revealed that biodegradation and sorption are the concurrently removal mechanisms of the studied PhCs. As well, the calculated total mass load of individual PhCs were in the range 328 – 42256, 152 – 26180, and 257 – 6625 g d-1 for influent, effluent and sludge. Meanwhile, the calculated range of personal mass load of the individual PhCs was 193 – 15274, 120 – 10864 and 34 - 265 µg d-1 Pe-1, for the influent, the final effluent and the sludge, respectively. The overall personal pharmaceutical consumption per day in West of Greater Cairo was estimated based on influent concentration of STP. Sulfamethoxazole, paracetamol and diclofenac were identified with the highest levels in the influent of STP, PSE and FE as well as in the dewatered sludge. Furthermore, the high concentrations of these compounds in the sludge confirms the sorption pathway removal of PhCs. Generally, the average daily and annual consumption per capita of the most dominant PhCs in wastewater; sulfamethazole, paracetamol and diclofenac are 60.09, 34.79, and 26.69 mg d-1 Pe-1 and 22, 12.52, and 12.52 g y-1 Pe-1, respectively. Moreover, risk assessment (RQ) for the detected PhCs in FE is greatly higher than the predicted non-effect concentration (PNEC). Conclusively, the FE of STP is considered a risky source for PhCs in adjacent surface water.

Influence of Ammonium Sulphate from anaerobic pasteurization digester latrines (APDLs) effluent on soil pH

Improper disposal of human waste is one of the most serious health problems in developing countries due to pollution of the environment. The use of chemical fertilizers for agriculture increase the plant growth to meet the food security of the world, but also causes environmental problems including lowering of soil pH. On the other hand, anaerobic pasteurization digester systems enable the recovery of nutrients from human faces and urine for the benefit of agriculture, thus helping to preserve soil fertility. Therefore, the present work aims to assess the potential of using ammonium sulphate processed from anaerobic pasteurization digesters latrines (APDLS) effluent to stabilize soil pH. The experiment was laid out in a completely randomized design with four treatments replicated four times. The treatments were Ammonium sulphate, Compost manure, Di-ammonium Phosphate (DAP) and control. The results showed that soil pH increased significantly (p<0.05) from 4.7 -4.9 before planting to 5.6 - 5.7 after planting. The organic and inorganic fertilizers as well as the interaction between the fertilizer and time did not have significant effect on soil pH (p > 0.05). The Ammonium sulphate recovered from APDLs final effluent could act as effective as a chemical fertilizer without significant reduction in the yield.

A Study on the Control of Attached Algae by Installing the Drainage Cover Device for the Final Sedimentation of Sewage Treatment Plant

Objectives : Adherent algae which are generated in the final sedimentation weir of the sewage treatment plant and the drainage channel, affect the quality of the final effluent water, and it has bad aesthetic effect due to fomation of flcok floating in the sedimentation tank. Therefore, the purpose of this study is prevention of the growth of adherent algae in advance by installing circular cover on the final sedimentation weir and drainage channels.Methods : In this study, we compared the growth pattern of adhered algae on weir and drainage channels before and after installation of circular cover at the final sedimentation weir and drainage channel of the sewage treatment plant. In addition, to identity species of attached algaem microscopic observation was applied, and ch-a concentration was analyzed to confirm the quality of the final effluent water.Results and Discussion : Then, we compared the results before and after installation of cover to check adhesion status of algae on the surface of final sedimentation drain. In case without cover, it was confirmed by observing the growth of attached algae under normal condition with air and photosynthetic reaction, and in case with cover, it was compared with opening after a certain period of time after installation of the drainage cover. As a result of the comparison, it was confirmed that a lot of attached algae occurred in the sedimentary weir and the drain. From the above results, the occurrence of final sedimentation algae is not only affected by the material and season of the drainage, but also after the formation a cluster by algae that have strong adhesion force, and then the microbial species contained in the effluent build secondary attachment and forms colony.Conclusions : In order to prevent the growth of adherent algae, a method of suppression of the growth of adherent algae by inhibition of photosynthesis was studied by installing a cover device on the weir and drain channels. As a result of installing a cover (34,000 thousand won) and reviewing economic feasibility, it can be recovered in 2.6 years, and stainless steel was selected in the view of mechanical stability and facility aging. The final sedimentation water quality increased 99.8% of Ch-a concentration treatment efficiency and 15% of SS sedimentation efficiency by installing a cover.

Optimizing water and resource recovery facilities (WRRF) for energy generation without compromising effluent quality

The primary separation unit (PSU) splits the organic load on the water and resource recovery facility (WRRF) between the primary sludge (PS) anaerobic digester (AD), where energy can be generated, and the biological nutrient removal (BNR) activated sludge (AS) reactor, where energy is consumed. With a CHONP element mass-balanced plant-wide stoichiometric and kinetic steady-state model, this paper explores quantitatively the impact of four cases of increasing organics removal efficiencies in the PSU on (i) settled wastewater characteristics, (ii) balanced solids retention time (SRT) of the Modified Ludzack-Ettinger (MLE) and University of Cape Town/Johannesburg (UCT/JHB) systems for lowest economical effluent N and P concentrations, (iii) reactor volume, (iv) energy consumption for aeration, pumping and mixing, (v) energy generation by AD of PS and waste activated sludge (WAS), (vi) N&P content of the PS and WAS AD dewatering liquor (DWL) and (vii) final effluent N and P concentrations with and without enhanced biological P removal (EBPR), and looks for an optimum WRRF layout for maximum energy recovery without compromising effluent quality. For the low biogas yield from the WAS AD, decreasing as the SRT of the BNRAS system gets longer and with the added complexity of N&P removal from the digested sludge DWL, makes AD of WAS undesirable unless P recovery is required. Because the wastewater biodegradable particulate organics (BPO) have a low N&P content, it is better to divert more biodegradable particulate organics to the PSAD with enhanced primary separation than digest WAS – the PSAD DWL can be returned to the influent with relatively small impact on final effluent N and P concentration.

Treatment of Marigold Flower Processing Wastewater Using a Sequential Biological- Electrochemical Process

Agriculture is the mainstay of the Indian economy. The agro-based industries produce high volumes of highstrength wastewaters that need to be treated and reused to prevent environmental pollution and water wastage. This study evaluated the performances of a sequential biological-electrochemical process for treating an anaerobically digested effluent of a Marigold flower processing agro-industry. The uniqueness of this wastewater possess a major challenge to its treatment since not many studies have been conducted on this wastewater. The biological treatment was carried out in a Sequential Batch Reactor (SBR). The treated water was further polished in a Continuous Bipolar-mode Electrochemical Reactor (ECR) to remove the residual organics. The anaerobically digested effluent Chemical Oxygen Demand (COD), Dissolved Organic Carbon (DOC), Total Nitrogen (TN), Total Phosphorus (TP) and Total Suspended Solids (TSS) were 5750 ± 991 mg/L, 980 ± 120 mg/L, 692 ± 60 mg/L, 9.7 ± 1.1 mg/L, and 1144 ± 166 mg/L, respectively. A significant level of treatment was achieved in the SBR. The combined system was able to remove 79% of COD, 85% of DOC, 53% of TN, and almost 100% of TP, TSS, and Volatile Suspended Solids (VSS). Several organic compounds belonging to the category of natural plants compound, pesticide, fungicide, etc. were detected in the raw wastewater. Most of the compounds were almost completely removed by the treatment system. The final effluent was almost colorless and free from suspended solids. However, for reuse, the water needs to be further treated in an advanced oxidation process.