scholarly journals The Use of Clay-Polymer Nanocomposites in Wastewater Pretreatment

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Giora Rytwo
Keyword(s):  
Colloidal Stability ◽  
Colloidal Suspension ◽  
Sewage Treatment ◽  
Quality Parameters ◽  
Pollutant Removal ◽  
Organic Load ◽  
Rapid Reduction ◽  
Colloidal Matter ◽  
Repulsive Forces ◽  
Treatment Step

Some agricultural effluents are unsuitable for discharge into standard sewage-treatment plants: their pretreatment is necessary to avoid clogging of the filtering devices by colloidal matter. The colloidal stability of the effluents is mainly due to mutual repulsive forces that keep charged particles in suspension. Pretreatment processes are based on two separate stages: (a) neutralization of the charges (“coagulation”) and (b) bridging between several small particles to form larger aggregates that sink, leaving clarified effluent (“flocculation”). The consequent destabilization of the colloidal suspension lowers total suspended solids (TSSs), turbidity, and other environmental quality parameters, making the treatments that follow more efficient. Clay-based materials have been widely used for effluent pretreatment and pollutant removal. This study presents the use of nanocomposites, comprised of an anchoring particle and a polymer, as “coagoflocculants” for the efficient and rapid reduction of TSS and turbidity in wastewater with a high organic load. The use of such particles combines the advantages of coagulant and flocculant by neutralizing the charge of the suspended particles while bridging between them and anchoring them to a denser particle (the clay mineral), enhancing their precipitation. Very rapid and efficient pretreatment is achieved in one single treatment step.

scholarly journals Stability of a colloidal suspension of yacon (Smallanthus sonchifolius) intended for spray drying

2019 ◽  
Vol 72 (2) ◽  
pp. 8863-8871
Author(s):  
Maria Isabel Arango Torres ◽  
Misael Cortés Rodriguez ◽  
Esteban Largo Ávila
Keyword(s):  
Spray Drying ◽  
Colloidal Stability ◽  
Colloidal Suspension ◽  
Added Value ◽  
Quadratic Model ◽  
Independent Variables ◽  
Smallanthus Sonchifolius ◽  
Perishable Product ◽  
Dependent Variables ◽  
Repulsive Forces

Yacon (Smallanthus sonchifolius) is a tuber with a high content of active compounds that offer health benefits, so its productive chain seeks new alternatives to generate yacon products with added value; however, it tends to be a perishable product due to its high aw, chemical composition, and enzymatic activity. The influence of both composition and homogenization in the colloidal stability of yacon suspensions was evaluated for later use in spray drying. Response surface methodology and a central composite design were used, considering three independent variables: homogenization time (TH) (4-6 min), xanthan gum (XG) (0.1-0.2%), and acidity (0.1-0.3%); and the following dependent variables: zeta potential (ζ), color (CIELab), viscosity (μ), stability index by spectral absorption (R), and particle size (D10, D50, and D90). The values of the independent variables that best fit the experimental optimization criteria were: XG=0.16%, acid=0.3%, and TH=4.8 min. The values of the experimental dependent variables and the variables predicted by the quadratic model were ζ=-33.8±4.0 and -37.6 mV, µ=1143.0±93.4 and 1000 cP, R=0.45±0.1 and 0.48, D10=127.8±8.2 and 138.1 µm, D50=251.2±16.3 and 267.7 µm, D90=424.3±28.7 mm and 463.9 µm, L*=41.7±1.4 and 41.8, a*=0.02±0.85 and 1.6, and b*=15.0±1.3 and 14.8, respectively. The colloidal suspension showed adequate physicochemical stability, favored mainly by repulsive forces, homogenization, and rheology of the continuous phase; reaching a content of total solids of 12.5%.

scholarly journals Graphene-Modulated Removal Performance of Nitrogen and Phosphorus Pollutants in a Sequencing Batch Chlorella Reactor

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2181 ◽  
Author(s):  
Gonghan Xia ◽  
Wenlai Xu ◽  
Qinglin Fang ◽  
Zishen Mou ◽  
Zhicheng Pan
Keyword(s):  
Optical Microscopy ◽  
Sewage Treatment ◽  
Ammonia Nitrogen ◽  
Pollutant Removal ◽  
Plate Count ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Practical Support ◽  
Plate Count Method ◽  
The Impact

In this work, the influence of graphene on nitrogen and phosphorus in a batch Chlorella reactor was studied. The impact of graphene on the removal performance of Chlorella was investigated in a home-built sewage treatment system with seven identical sequencing batch Chlorella reactors with graphene contents of 0 mg/L (T1), 0.05 mg/L (T2), 0.1 mg/L (T3), 0.2 mg/L (T4), 0.4 mg/L (T5), 0.8 mg/L (T6) and 10 mg/L (T7). The influence of graphene concentration and reaction time on the pollutant removal performance was studied. The malondialdehyde (MDA) and total superoxide dismutase (SOD) concentrations in each reactor were measured, and optical microscopy and scanning electron microscopy (SEM) characterizations were performed to determine the related mechanism. The results show that after 168 h, the total nitrogen (TN), ammonia nitrogen (AN) and total phosphorus (TP) removal rates of reactors T1–T7 become stable, and the TN, AN and TP removal rates were gradually reduced with increasing graphene concentration. At 96 h, the concentrations of both MDA and SOD in T1–T7 gradually increased as the graphene concentration increased. In optical microscopy and SEM measurements, it was found that graphene was adsorbed on the surface of Chlorella, and entered Chlorella cells, deforming and reducing Chlorella. Through the blood plate count method, we estimated an average Chlorella reduction of 16%. According to the water quality and microscopic experiments, it can be concluded that the addition of graphene causes oxidative damage to microalgae and destruction of the Chlorella cell wall and cell membrane, inhibiting the nitrogen and phosphorus removal in Chlorella reactors. This study provides theoretical and practical support for the safe use of graphene.

In-vessel co-composting – a rapid resource recovery option for septage treatment in Indian cities

2018 ◽  
Vol 8 (4) ◽  
pp. 688-697 ◽  
Author(s):  
Anu Rachel Thomas ◽  
Martin Kranert ◽  
Ligy Philip
Keyword(s):  
Assessment Tool ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Cost Effective ◽  
Organic Load ◽  
Human Waste ◽  
Design Load ◽  
Solids Content ◽  
Chennai City ◽  
Indian Cities

Abstract Septage management is a challenging task across India as more than 44% of the population depends on septic tanks for human waste management. Septage collected from Chennai city, India, was found to be rich in nutrients even though the total solids content (<2%) and C/N are low. The current practice of septage disposal in Chennai city is co-treatment in existing sewage treatment plants. The main drawback of this method is that treatment efficiency could deteriorate if the organic load increased much beyond the design load of the treatment plant and would result in poor treated-water quality. In this context, the present study focused on the potential of in-vessel co-composting as a sustainable treatment option. In order to enhance the co-composting process, suitable co-substrates were identified for making the process efficient and cost-effective. The area under the temperature profile during composting was used as an assessment tool for the identification of the proper mix. Addition of mixed organic waste and coir pith waste (bulking agent) to the dewatered septage gave the highest area among the different combinations. Different waste combinations were investigated in order to assess the suitability for field scale application.

scholarly journals Unfolding Water Quality Status During COVID-19 Lockdown for the Highly Polluted Santiago River in Jalisco, Mexico

2021 ◽  
Author(s):  
Gurusamy Kutralam-Muniasamy ◽  
Fermín Pérez-Guevara ◽  
Ignacio Elizalde Martinez ◽  
Shruti Venkata Chari
Keyword(s):  
Water Quality ◽  
River Water ◽  
Total Nitrogen ◽  
Surface Water Quality ◽  
Quality Parameters ◽  
River Water Quality ◽  
Organic Load ◽  
The Government ◽  
Temporary Closure

Abstract The Santiago River is one of Mexico's most polluted waterways and evaluating its surface water quality during the COVID-19 outbreak is critical to assessing the changes and improvements, if any, from the nationwide lockdown (April-May 2020). Hence, the data for 12 water quality parameters from 13 sampling stations during April-May 2020 (lockdown) were compared with the levels for the same period of 2019 (pre-lockdown) and with the same interval of previous eleven-years (2009-2019). The values of BOD (14%), COD (29%), TSS (7%), f. coli (31%), t. coli (14%) and Pb (20%) declined, while pH, EC, turbidity, total nitrogen and As enhanced by 0.3-21% during the lockdown compared to the pre-lockdown period suggesting decrements of organic load in the river due to the temporary closure of industrial and commercial activities. An eleven-year comparison estimated the reduction of pH, TSS, COD, total nitrogen and Pb by 1-38%. The analysis of water quality index estimates showed short-term improvements of river water quality in the lockdown period, compared to pre-lockdown and eleven-year trend as well as indicated very poor quality of the river. The contamination sources identified by factor analysis were mainly related to untreated domestic sewage, industrial wastewaters and agriculture effluents influencing the river water quality. Overall, our findings demonstrated positive responses of COVID-19 imposed lockdown on water quality of the Santiago River during the study period, providing a foundation for the government policy makers to identify the sources of pollution, to better design environmental policies and plans for water quality improvements.

The fate of detergent surfactants in sewer systems

1995 ◽  
Vol 31 (7) ◽  
pp. 321-328 ◽  
Author(s):  
E. Matthijs ◽  
G. Debaere ◽  
N. Itrich ◽  
P. Masscheleyn ◽  
A. Rottiers ◽  
...  
Keyword(s):  
Fatty Alcohol ◽  
Half Life ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Sewage Treatment ◽  
Field Studies ◽  
Municipal Sewage ◽  
Alcohol Ethoxylate ◽  
Rapid Reduction ◽  
Laboratory Findings

The fate of detergent surfactants in the sewer can be studied both in laboratory tests and in field experiments. The laboratory studies can be used to determine the rate of disappearance of a test molecule as a function of residence time and estimate its half-life in a given habitat. In addition, important information can be obtained on the mechanism of degradation. Field studies can determine the actual environmental concentrations of surfactants in raw sewage which can then be compared with the expected concentration based on consumption volumes. The difference between the measured and predicted concentration provides an estimate for the disappearance of the test chemical during its travel in the sewer and confirms the results of the laboratory tests. This paper focuses on the fate of a number of important representative anionic, nonionic and cationic surfactants, in the sewer. The results of laboratory die-away studies showed that, in general, the half-life for disappearance in the sewer was in the order of hours for Fatty Alcohol Ethoxylate (AE), Fatty Alcohol Ethoxy Sulphate (AES) and Di-Ethyl-Ester Di-methyl-Ammonium Chloride (DEEDMAC). These laboratory findings for AES were confirmed by monitoring actual raw sewage reaching municipal sewage treatment plants. In addition, a field study demonstrated that the concentration of glucose amides (GA) is considerably reduced during its travel in the sewer. These complementary laboratory and field studies provide key information for the safety assessment of surfactants. They demonstrate that the concentration of surfactants can be significantly reduced in the sewer resulting in a rapid reduction of the environmental loading, which is particularly important in environmental situations where inadequate or no sewage treatment exists.

scholarly journals The Improvement of Pollutant Removal in the Ferric-Carbon Micro-Electrolysis Constructed Wetland by Partial Aeration

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 389 ◽  
Author(s):  
Cheng Dong ◽  
Mengting Li ◽  
Lin-Lan Zhuang ◽  
Jian Zhang ◽  
Youhao Shen ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Sewage Treatment ◽  
Pollutant Removal ◽  
Functional Genes ◽  
Subsurface Flow Constructed Wetland ◽  
Removal Efficiencies ◽  
Oxidation Efficiency ◽  
Denitrification Process

Subsurface flow constructed wetland (SSFCW) has been applied for wastewater treatment for several decades. In recent years, the combination of ferric-carbon micro-electrolysis (Fe/C-M/E) and SSFCW was proven to be an effective method of multifarious sewage treatment. However, Ferric substrate created a relatively reductive condition, decreased the oxidation efficiency of NH4+-N, and blocked the following denitrification process, which led to the low removal efficiencies of NH4+-N and total nitrogen (TN). In this study, partial aeration was introduced into the ferric-carbon micro-electrolysis SSFCW (Fe/C-M/E CW) system to solve the problem above. The water quality and nitrogen-related functional genes of bacteria on the surface of substrate were measured for mechanism exploration. The results showed that, the removal efficiencies of NH4+-N and total phosphorus (TP) in an aerated Fe/C-M/E CW system were 96.97% ± 6.06% and 84.62% ± 8.47%, much higher than 43.33% ± 11.27% and 60.16% ± 2.95% in the unaerated Fe/C-M/E CW systems. However, the TN removal in Fe/C-M/E CW system was not enhanced by aeration, which could be optimized by extending more anoxic section for denitrification.

Application of piggery waste to nightsoil plant towards sustainable development

2003 ◽  
Vol 47 (10) ◽  
pp. 147-153 ◽  
Author(s):  
Y. Eum ◽  
S.-W. Oa ◽  
E. Choi
Keyword(s):  
Sustainable Development ◽  
Sewage Treatment ◽  
Organic Load ◽  
Carbon Addition ◽  
Sewage Treatment Plants ◽  
Reactor Temperature ◽  
Nitrification And Denitrification

Organic loads have been significantly reduced in nightsoil plants along with the employment of sewage treatment plants. Nightsoil consisting of 10% septage and showing higher ratios of alkalinity and carbon to nitrogen helped nitrification and denitrification for those combined plants with weak piggery waste. However, alkalinity and carbon addition was necessary with the weak nightsoil consisting of 80% septage when the combined influent was less than 21 g/L COD. The piggery waste could be applied at a rate of 0.5 kgTKN/oxic m3/d, but the organic load should be limited to 0.7 kgCOD/m3/d with strong piggery waste during summer in order not to exceed the reactor temperature higher than 35°C.

The Quality of Marine Water Around a Sewage Outfall

1999 ◽  
Vol 40 (7) ◽  
pp. 11-15 ◽  
Author(s):  
S. Al-Muzaini ◽  
M. Beg ◽  
K. Muslamani ◽  
M. Al-Mutairi
Keyword(s):  
Sewage Treatment ◽  
High Tide ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Coastal Region ◽  
Quality Parameters ◽  
Open Sea ◽  
Foul Smell ◽  
Sea Area ◽  
Physical And Chemical

A major sewage outlet located close to Shuwaikh Harbor discharges raw and treated water from the Al-Ardhiya sewage treatment plant, as well as raw sewage from a pumping station. It also receives input from Kuwait International Airport. The area has been spotted for its characteristic foul smell mainly because of stagnant water at the outlet. Therefore, samples were collected from eleven fixed stations at high tide and six stations at low tide to examine water quality parameters, NO3, NO2, NH3, SO4, S2, PO4, BOD, COD, TOC and heavy metals Pd, V, Cd, Ni, Mn, Cr, Cu, and total fecal coliform. The results of the physical and chemical analyses for both high-and low-tide samples along with microbiological analyses indicate that the Shuwaikh marine area is polluted. The pollution is high near the discharge point and decreases with distance. The data revealed a lower level of chemical pollutants and fecal counts at high tide than at low tide. This is mainly because of the dilution caused by incoming seawater at high tide. Although tidal movement helps reduce pollution in the area, for improvement of the situation to the desired level, biological wastewater treatment is suggested to remove most of the organic matter before discharge. Also, extension of the discharge outfall pipe to the open sea area would help reduce trapping of effluent in the coastal region and check fouling in the area.

Sewage Treatment with a Hybrid Constructed Soil Filter

2015 ◽  
Vol 13 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Mercedes Llorens ◽  
Ana B. Pérez-Marín ◽  
José Sáez ◽  
María I. Aguilar ◽  
Juan F. Ortuño ◽  
...  
Keyword(s):  
Biological Treatment ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Small Towns ◽  
Organic Load ◽  
Activated Sludge Process ◽  
Ecological Process ◽  
Residential Areas ◽  
Conventional Activated Sludge ◽  
Hydraulic Load

Abstract The overall aim of this research was to apply a hybrid constructed soil filter for sewage treatment. A hybrid constructed soil filter is an ecological process used for decentralized sewage treatment in villages, small towns or scattered residential areas. Sewage is firstly treated by conventional physicochemical or biological treatment and then allowed to infiltrate through aerated unsaturated zone wherein it gets purified through processes such as filtration, adsorption, chemical reaction and biodegradation. This system has demonstrated a consistent capacity to remove organic matter and nitrogen. Experimental results have shown that under hydraulic load rates of 0.22 m3/m2 · h and organic load rates ranging from 47 to 156 g COD/m2 · h, mean removal efficiencies of 89% for COD, 99% for BOD5, 86% for suspended solids and 52% for total nitrogen can be achieved using an hybrid constructed soil filter. Compared to the conventional activated sludge process, this technology has many advantages, such as simple construction, low operation and maintenance costs, as well as a simple operation.

scholarly journals Performance evaluation of optimization models in the determination of wastewater treatment efficiencies inside watersheds

RBRH ◽  
2016 ◽  
Vol 21 (4) ◽  
pp. 694-706 ◽  
Author(s):  
Mariana Coelho Santoro ◽  
José Antonio Tosta dos Reis ◽  
Antonio Sérgio Ferreira Mendonça
Keyword(s):  
Complex Analysis ◽  
Sewage Treatment ◽  
Pollutant Removal ◽  
Optimization Models ◽  
Computing Environment ◽  
River Watershed ◽  
Satisfactory Performance ◽  
Wide Range ◽  
Equity Measures

ABSTRACT Determination of sewage treatment plants pollutant removal efficiencies, considering the protection of water resources, is very difficult because it involves complex analysis that must take into account multiple discharges into watercourses presenting different self depuration capacities. The research aimed to evaluate different optimization models for determination of minimum sewage treatment efficiencies for plants located in a watershed. The analyzed optimization models involves minimization of the sum of treatment efficiencies and minimization of inequity between sewage treatment efforts. Water quality mathematical model and Genetic Algorithm were combined in a MatLab software computing environment. The Pardo river watershed is the study area. Pardo river is a tributary of the Itapemirim river, important watercourse located in the southern part of Espirito Santo State, in Brazil. The results indicate that the optimization models that incorporate measurement of equity as a problem restriction did not generate consistent answers, probably because of the wide range of sewage loads values considered in the Pardo river watershed. The models that incorporate equity measures in the objective function showed satisfactory performance and resulted in very close values for minimum sewage treatment efficiencies.

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