Domestic Wastewater Treatment Process Research Articles

Measures for Achieving Carbon Neutrality in Domestic Wastewater Treatment Plants

Objectives : In modern society, domestic wastewater treatment plants are essential infrastructure. However these facilities are also major sources of significant greenhouse gas emissions. To mitigate the climate crisis and move towards a sustainable society, reducing greenhouse gas emissions from domestic wastewater treatment plants is an urgent task. Achieving this requires the integrated application of technological improvements and institutional measures.Methods : Fundamental strategies for reducing greenhouse gas emissions from domestic wastewater treatment plants include detailed categorization and quantification of emission sources, the implementation of greenhouse gas reduction facilities, and the enforcement of water usage reduction policies. This study uses modeling software to estimate the detailed emissions of greenhouse gases generated during the domestic wastewater treatment process. Additionally, it establishes the baseline treatment process of the domestic wastewater treatment plant and analyzes the greenhouse gas reduction effects of each facility by incorporating technological methods such as anaerobic digesters and combined heat and power (CHP) systems. Furthermore, it evaluates the impact of reducing water usage through water footprint (WF) labeling on greenhouse gas emissions from the domestic wastewater treatment plant as an institutional approach.Results and Discussion : In scenario analysis, the implementation of anaerobic digesters results in a 6.7% reduction in greenhouse gas emissions compared to the baseline, while the addition of CHP systems to anaerobic digestion is predicted to reduce emissions by 29.1%. By integrating CHP systems with anaerobic digesters and applying WF labeling, a reduction of 38.3% in greenhouse gas emissions from the domestic wastewater treatment plant compared to the baseline is anticipated. These results demonstrate the significant role of implementing anaerobic digesters, CHP systems, and WF labeling in achieving the carbon neutrality goal of domestic wastewater treatment plants.Conclusion : The integrated application of technological methods, institutional approaches, and detailed emission calculations through process modeling can be considered crucial for reducing greenhouse gas emissions from domestic wastewater treatment plants.

Domestic Wastewater Treatment Using Natural Filtration and Solar Distillation Processes

Fresh water is most important daily requirement for human survival. On one hand many regions/countries are facing challenges related to availability of potable water for drinking and daily needs, on other hand water is wasted daily from different domestic applications. Processing and reuse of domestic waste water can help bridge gap between demand and supply. Present study describes a domestic waste water treatment process using combined natural filtration and solar distillation methods. In natural filtration process husk fibre, activated carbon and coconut husk fibre were used as filters. For solar distillation a pyramid shaped distillation unit is used. The samples of domestic waste water were collected from laundry, kitchen and house cleaning applications. The pH, TDS (total dissolved solids) and DO (dissolved oxygen) values of domestic waste water samples and water after treatment were tested. The results after treatment reveal that the values of TDS, pH, and dissolved oxygen are close to the standard values required for potable water which can be further used in different applications.

Comparative Analysis of Greenhouse Gas Emissions from Domestic Wastewater Treatment Processes by Modeling: Existing Estimation Methods vs Modeling

This study examined the existing methodologies and the applicability of process modeling concerning the estimation of nitrous oxide (N<sub>2</sub>O) emissions from wastewater treatment processes. The method of extimating N<sub>2</sub>O emissions from wastewater occurring during biological nitrification and denitrification processes can be divided into those before and after legal nitrogen effluent quality enhancement for domestic wastewater treatment plant. Initial IPCC guidelines such as IPCC 1996 GL, GPG 2000, and IPCC 2006 GL, provided methods for estimating N<sub>2</sub>O emissions throughout domestic wastewater, while the revised version, IPCC 2019 RF, proposed methods for estimating each N<sub>2</sub>O emission by distinguishing wastewater treatment and effluent after the advancement of wastewater treatment plants. The National Greenhouse Gas Inventory Report (NIR) in Korea adopted the methodology of GPG 2000, and the Emissions Trading System (ETS) applies the estimation method of IPCC 2006 GL in the wastewater treatment plants. This study utilized process modeling to consider the process characteristics and operating conditions of wastewater treatment plants. IPCC, NIR, and ETS estimate N<sub>2</sub>O emissions based on nitrogen behavior activity data and emissions factors. On the other hand, process modeling estimates N<sub>2</sub>O emissions in each unit process of the wastewater treatment plant using a 4-step AOB nitrification/4-step denitrification model and a liquid/gas transfer model. The estimation results of N<sub>2</sub>O emissions from modeling method were compared with the estimation results of IPCC, NIR, and ETS to analyze the suitability of the estimation method. Through this, it was evaluated how appropriate process modeling is for estimating N<sub>2</sub>O emissions in domestic wastewater treatment plants.

N2O Emission from Partial Nitrification and Full Nitrification in Domestic Wastewater Treatment Process

Using actual domestic wastewater as the research object, nitrogen compounds and their combinations were added to different nitrification (partial nitrification, full nitrification) processes to investigate nitrous oxide (N2O) emission and its nitrification mechanisms. The presence of influent NH4+ was the driving force of N2O emission during nitrification. Compared with full nitrification, NO2− in partial nitrification more readily generated N2O by denitrification. Under the proportional gradient of NH4+-N:NO2−-N/NO3−-N, 30:0, 20:10, 10:20, and 0:30, total N2O emissions during partial nitrification were 2.81, 11.30, 65.20, and 11.67 times greater than the total N2O emissions during full nitrification. Full nitrification was more beneficial to N2O emission reduction. This provides a control strategy for N2O emission reduction in wastewater treatment processes under the background of reducing the production of greenhouse gases.

Anaerobic membrane bioreactor model for design and prediction of domestic wastewater treatment process performance

Anaerobic treatment of municipal wastewater that produces energy and low levels of biosolids for disposal has the potential to replace conventional aerobic processes. Here we propose a generic model for anaerobic membrane bioreactors (AnMBRs) that incorporates hydrolysis and dispersed growth microbial metabolism of particulate and soluble substrates, including a size-exclusion constraint based upon the pore size of submerged membranes. The model can be expanded to include attached growth systems, such as anaerobic fluidized bed reactors (AFBRs) within the staged anaerobic fluidized membrane bioreactor (SAF-MBR) system. Model development entailed: (1) acquisition of key kinetic metabolic parameters based on independent batch studies, (2) creation of a matrix of metabolic processes, and (3) development of a model that describes the relevant mass balances in the system. The utility of the model is demonstrated for dynamic simulations of a pilot-scale second generation SAF-MBR treating municipal wastewater (SAF-MBR 2.0). System outputs include the COD of the system effluent (= permeate), recirculated bulk COD and MLSS, gas production rate and composition, and dissolved methane concentration. These parameters are critical for system design and assessment. Predictions of performance by a pilot-scale system agreed well with monitored values, typically with less than 10% error, indicating that the developed model and independent batch assays for model calibration can enable reliable systems-level performance simulations.

The Energy Efficiency of Domestic Wastewater Treatment Processes: Case Analysis

The Energy Efficiency of Domestic Wastewater Treatment Processes: Case Analysis

Efektivitas Pengolahan Air Limbah Domestik Grey Water Dengan Proses Biofilter Anaerob dan Biofilter Aerob (Studi Kasus: IPAL INBIS Permata Bunda, Bontang)

Domestic wastewater from non toilets is referred to as grey wastewater, domestic wastewater from bathing, washing and from the kitchen. Incubator Bisnis (INBIS) Permata Bunda is a forum for the application of entrepreneurial skills (apprenticeship) for people with disabilities residing in Kampung Aren, Bontang City, East Kalimantan. Grey wastewater treatment at INBIS Permata Bunda with a grease trap, filtration, sedimentation, anaerobic biofilter, aerobic biofilter, sedimentation and control. The research objective was to determine the effectiveness of INBIS Domestic WWTP to reduce organic pollutant loads based on the quality standard parameters of domestic wastewater from the Minister of Environment and Forestry Regulation No.P.68 of 2016 those are the parameters of pH, BOD, COD, TSS, fatty oil, ammonia, and total coliform. The domestic wastewater treatment process for grey wastewater has a reduced effectiveness ranging from 56.73% - 97.65% and has met the quality standards for the parameters, pH, BOD, COD, ammonia, fatty oil, and total coliform, but for TSS parameters and total coliform needs operational evaluation. Grey waterwater from the INBIS domestic wastewater treatment plant has the potential to become an alternative water source for watering plants (afforestation) if the processing results are in accordance with quality standards.

Ammonia harvesting via membrane gas extraction at moderately alkaline pH: A step toward net-profitable nitrogen recovery from domestic wastewater

Membrane gas extraction technique enables recovery of high-purity ammonia from waste streams through gas-phase mass transfer across hydrophobic membranes. This study demonstrates the potential of ammonia recovery with gas permeable membrane, operated at moderately alkaline feed pH, as a substitute for the current approach of biological nitrogen removal in domestic wastewater treatment process. The measured apparent ammonia mass transfer coefficient in 3-h operation at a feed pH of 9.2 was 0.0713 cm/min, which, despite being 1.53-fold smaller than that at a feed pH of 11, was excellent for application to domestic wastewater. Application of lower feed pH prevented inorganic fouling of membrane. A notable advantage of the moderately alkaline feed pH condition is that the consumption of alkaline agents added for deprotonating bicarbonate instead of ammonium can be minimized. Calculation shows an opportunity that the monetary value of recovered ammonia exceeds the cost of the base consumed when moderately alkaline feed pH is applied. This study substantially extends current knowledge of the membrane gas extraction technique for ammonia recovery by investigating the process kinetics, fouling propensity, and chemical requirements as functions of pH, thereby verifying the potential of this technique to contribute to improving the sustainability of the global nitrogen cycle.

Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors

Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4+ and P-PO43− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4+ and P-PO43− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4+ and P-PO43-, respectively.

Effect of blending landfill leachate with activated sludge on the domestic wastewater treatment process

A sludge contact is proposed to form high-level free ammonia exposure for co-treatment of landfill leachate with domestic wastewater.

Effect of COD and HRT Changes in Submerged Microbial Fuel Cells on Nitrogen Removal at the Level of Domestic Wastewater

Submerged-type microbial fuel cells (MFCs) have been developed to cost-effectively treat organics in wastewater. However, evaluation of nitrogen removal in MFCs is still limited to apply MFCs for domestic wastewater treatment. This study developed submerged MFC system consisting of 4 units and evaluated COD and TN removal efficiencies and energy recovery according to substrate type and concentration and HRT. The organic removal efficiencies were 78% (500 mg-COD/L), 89% (150 mg-COD/L of acetate) and 76% (150 mg-COD/L of glucose) at the optimal HRT of 6 h. Submerged MFC system for removal of low-strength nitrogen (40 mg-N/L) could satisfy the TN discharge limit (<20 mg-N/L) and the nitrogen removal rates of 72-192 g-N/m3 /d at the optimal HRTs of 3 h (acetate) and 8 h (glucose). Because additional energy for nitrogen removal is not required, despite low energy recoveries (<0.004 kW/kg-COD), it is expected that the submerged MFC system can be applied as the energyneutral domestic wastewater treatment process. Key words: Submerged Microbial Fuel Cell, Nitrification And Denitrification, Hydraulic Retention Time, Energy-Neutral Domestic Wastewater Treatment

Performance Efficiency of the Zeolite Synthesized from Fly Ash in Wastewater Treatment

In the present study we are exploring the possibility of using fly ash to produce zeolite. In this synthesis process, class F fly ash from Neyveli Thermal Power Plant, Cuddalore district, Tamil Nadu, India was utilized. The fly ash was subjected to fusion process with sodium hydroxide for an hour. The synthesized material was characterized to obtain the mineral composition. The resulting zeolite is competitive with commercially available materials which are used as ion exchangers in wastewater treatment and soil decontamination. In this study, the synthesized zeolite was analyzed for the performance removal efficiency of pollutants from domestic wastewater. The batch method was adopted to study the influential parameters, such as initial pH value of the solution, and dosage of zeolite, in the domestic wastewater treatment process.

Performance and microbial community of a novel non-aeration-based up-flow bioelectrochemical filter (UBEF) treating real domestic wastewater

Domestic wastewater treatment process via the activated sludge is complicated, energy-negative and potentially harmful. In this study, an up-flow bioelectrochemical filter reactor (UBEF) was designed without positive aeration in-priority for treating real domestic wastewater under different hydraulic retention times (HRTs). The removal of chemical oxygen demand (COD), ammonia and total nitrogen was attained at a high efficiency of 89%, 99% and 99% respectively, when HRT was set at h1 of ∼2.53 d. However, with the decreased of HRT from 2.53 to 0.28 d, the removal efficiency of nitrogen and COD decreased to 50% and 40% respectively, but the maximum power density increased from 3.01 to 98.90 mW/m3 with a low Coulombic efficiency of 0.25–1.51%. The results demonstrated that the UBEF can remove COD and ammonia from real domestic wastewater in an aeration-free energy sustainable process, although its power output was low. Moreover, the functional bacteria were detected using 16S rRNA gene-based pyrosequencing analysis, which showed that the microbial communities were different under varied HRT conditions. The Thauera-dominated consortium was inoculated in order to enhance the removal of pollutants and the generation of electricity from domestic wastewater, it was kept at a relative abundance when continuously feeding the real wastewater. In particular, nitrogen removing bacteria (NRB) including Nitrosomonas, Ignavibacterium, Thiobacillus, Dokdonella, Comamonas, Sterolibacterium and Flavobacterium were enriched on the anode and the cathode of the UBEF, which contributed to nitrogen removal by nitrification and denitrification. Therefore, this study demonstrated that the UBEF configuration had great potential applicability for energy sustainable wastewater treatment.

Removal of Estrogenic Effect by Typical Domestic Wastewater Treatment Processes

Targeting at the characteristics of low concentration but high risk of endocrine disrupting compounds in the aquatic environment, the current study investigated the distribution of estrogenicity and E2 level using recombinant yeast estrogen screen (YES) and enzyme linked immunosorbent assay (ELSIA) during domestic wastewater treatment processes. The results showed that the levels of estrogenicity and E2 in influents of wastewater treatment plants were 4.35-7.58 ng·L-1 and 36.95-83.43 ng·L-1, respectively. It was found that biological treatment processes played a crucial role in the removal of estrogenicity and E2, such as oxidation ditch, A2/O and A2/O followed by MBR, where the removal of estrogenicity and E2 was 71.10%-75.54% and 75.88%-80.72%, respectively. The activated sludge, with an estrogencity level of 1.84-2.43 ng·g-1 and an E2 level of 8.45-12.84 ng·g-1, had the function of eliminating estrogenic effect to a certain extent by adsorption. The estrogenic activity in the effluent of domestic wastewater was 1.06-2.19 ng·L-1, which will pose potential risk to the aquatic life in the environment. Last but not least, ELISA had a good correlation with YES assay, which provides a new method for rapid screening and assessment of water environmental estrogen.

Use of thermal water as a natural coagulant for domestic wastewater sustainable treatment

In the last several years, the interest on domestic wastewater treatment has increased due to the rise of water consumption resulted from the world population growth. The excessive use of inorganic coagulants, such as aluminum sulphate, in domestic wastewater treatment processes contributes to generate high negative environmental impacts and risks to living organisms. Besides its low biodegradability, as aluminum sulphate increases metal content in discharged effluents rises, generating toxic sludge. Therefore, searching for clean and sustainable processes for domestic wastewater treatment is important in order to reduce the pollutant discharges into fresh water bodies. In this paper, the potential use of thermal water as a natural coagulant for the domestic wastewater treatment from Manizales city (department of Caldas, Colombia), was studied. The effect of coagulant dose was analyzed and compared with the results of the conventional coagulants. Applying different doses of coagulants in domestic wastewater showed that the best coagulation activity was achieved by adding 35 ml/l of thermal water, and 140 mg/l of aluminum sulphate. In both cases, high turbidity removal efficiency (98.1 %) was achieved. The removal efficiency of Chemical Oxygen Demand (COD) using aluminum sulphate was 81.5 %, and using thermal water was 75.4 %. In conclusion, thermal water has positive coagulation properties; therefore, it is a promising alternative to aluminum sulphate as a natural coagulant on the treatment of domestic wastewater.

Minimization of nitrous oxide emission from CASS process treating low carbon source domestic wastewater: Effect of feeding strategy and aeration rate

Nitrous oxide (N2O) emission during wastewater treatment can be mitigated by improving operational conditions, e.g., organic carbon supply and dissolved oxygen. To evaluate the control parameters for N2O emission in the low carbon source domestic wastewater treatment process, N2O emissions from Cyclic Activated Sludge System (CASS) under different feeding strategies and aeration rates were investigated. Results showed that continuous feeding enhanced nitrogen removal and reduced N2O emission compared to batch feeding, while a higher aeration rate led to less N2O emission. N2O was mainly produced during non-aeration phases in batch feeding CASS and the amount of N2O generated from denitrification decreased under continuous feeding, indicating that carbon source in the continuous influent relieved the electron competition between denitrification reductases during non-aeration phase. Moreover, taxonomic analysis based on high-throughput 16S rRNA gene sequencing revealed higher abundance of denitrifying bacteria, especially N2O-reducing bacteria in continuous feeding CASS.

Platforms for energy and nutrient recovery from domestic wastewater: A review

Alternative domestic wastewater treatment processes that recover energy and nutrients while achieving acceptable nutrient limits (<5mgNL−1) are a key challenge. Major drivers are value and availability of phosphorous, nitrogen, and potassium, and increasing energy costs. The two major platforms that can achieve this are (a) low energy mainline (LEM), with low strength anaerobic treatment, followed by mainline anaerobic nitrogen removal and chemical or adsorptive phosphorous removal and (b) partition–release–recover (PRR), in which carbon and nutrients are partitioned to solids through either heterotrophic or phototrophic microbes, followed by anaerobic digestion of these solids and recovery from the digestate. This paper reviews practical application of these processes, with a focus on energy costs. Compared to conventional processes which require 0.5kWhkL−1 electricity (500mgCODL−1 influent concentration), PRR requires only 0.05kWhkL−1 electricity. LEM offers the possibility to recover 0.1kWhkL−1 as electricity with net energy generation above 400mgCODL−1influent, while PRR becomes energy generating at >650mgCODL−1. PRR offers the possibility for recovery of nitrogen and other nutrients (including potassium) through assimilative recovery. However, the energetic overhead of this is substantial, requiring 5kWhkgN−1 as electricity, which compares to ammonia fixation costs. The lower energy costs, and near to market status of LEM treatment make it likely as a recovery platform in the shorter term, while ability to recover other elements such as nitrogen and potassium, as well as enhance favourability on concentrated wastewaters may enhance the desirability of partitioning in the longer term.

혐기성 막 생물반응조를 이용한 하수처리의 최근 동향

【With the increasing concern on climate changes and energy shortage, anaerobic membrane bioreactors (AnMBR) become a promising alternative to aerobic processes for domestic wastewater treatment. Two major advantages of AnMBRs are energy production and sludge reduction. Recently, several different configurations of AnMBRs have been proved to produce high quality effluent at reasonable hydraulic retention time and ambient temperature. One of the major problems of the AnMBR is membrane fouling control, and some solutions are already suggested. Other problems to be solved before the full application of the AnMBR are recovery of dissolved methane, management of residual nutrients and sulfide. Considering the potential advantages and future technology development, AnMBR will become major domestic wastewater treatment process in near future.】

Decrease of antiandrogenic activity in gray water and domestic wastewater treated by the MBR process

In order to figure out the variation of the androgens/antiandrogens in wastewater treatment, androgenic/antiandrogenic activities were investigated in two membrane bioreactors (MBR) treating gray water and domestic wastewater, respectively, in Beijing city, China. The androgens and antiandrogens were extracted from water and solid samples by a solid phase extraction (SPE) method and the androgenic/antiandrogenic activities were detected with a recombined androgen receptor (AR) yeast assay. The results showed that there were no androgenic induction activities either in water or in solid samples, but all samples exhibited obvious antiandrogenic activities. The antiandrogenic activities in the suspended solids contributed to 27.4% of the total antiandrogenic activities in gray water and 37.7% in domestic wastewater. Although the concentration of flutamide equivalent (FEQ) of the domestic wastewater (3.1 mg L(-1)) was about three times higher than that of the gray water (1.1 mg L-(1)) in the liquid phase, the effluent FEQ of the two processes was comparable, and the concentrations were 53.7 ± 2.4 μg L(-1) and 68.9 ± 6.0 μg L(-1), respectively. By mass balance analysis, a total of 1825.2 mg FEQ antiandrogens flowed into the gray water and 4914.1 mg flowed into the domestic wastewater treatment process every day. More than 95% of the influent antiandrogens in the liquid phase was removed in both systems. And only 64.5 mg and 69.0 mg FEQ antiandrogens flowed out of gray water and domestic wastewater treatment processes every day. Biodegradation was considered to be the crucial antiandrogen removal mechanism in MBR, which contributed to 98% of the antiandrogen removal in the gray water treatment plant, and 91% in the domestic wastewater treatment plant.

Factor analysis of H2S emission at a wastewater lift station: a case study

Odor and corrosion are common problems in domestic wastewater collection, transportation, pumping, and treatment processes. Based on the comparison among odorous compounds and onsite observations at a wastewater lift station, H2S is more likely to have caused the odor and corrosion problems than methanethiol and other organic sulfides. The field data from both air and wastewater quality monitoring demonstrated that more H2S (1 ppmv) was formed at a more negative redox potential, lower pH, and a higher temperature of wastewater. Since the lower detection level of most current analytical techniques is much greater than human's smell and the reference concentration for adverse health effects, automatic monitoring on the threshold of H2S formation provides a mechanism to trigger control techniques only when necessary for cost saving purposes. Based on Gibbs free energy, a more negative redox potential is required to form H2S with an increase in pH and a decrease in temperature and SO 4(2-) concentration. However, pH effect is more significant than both temperature and SO 4(2-) concentration for H2S formation. It is recommended that H2S control techniques be started when the redox potential is below -44mV, the pH is lower than 5.6, and the temperature is higher than 11.5°C to control H2S below the reference concentration. Corroded concrete particles were examined by X-ray diffraction, which showed that the dominant crystal form was quartz.