Deposition Of Sludge Research Articles

Graphene Oxide as a Dye Effluent Adsorbent: Adsorbed Graphene Oxide as an Efficient Supercapacitor Electrode Material

Graphene oxide (GO) has been used as an effective dye effluent adsorbent and it is used for an effective application as a supercapacitor electrode material. The conventional dye effluent treatment utilizes a series of complex processes with results in a huge deposition of sludge. The adsorbent based dye effluent treatment is an option to treat dye effluent due to the highly turbid nature of dye effluent. Instead of using a series of chemicals to treat dye effluent, the GO can be a sensible entrant owing to its exceptional surface area and its scalable retreatment approach, whereas the former chemicals leave undesirable sludge.

Magnetic Imaging of Sludge Outside Steam Generator Tube With Array Magnetoresistance Sensors

The water impurities and corrosion products of the nuclear power plant structure form sludge outside the steam generator tube (SGT), which decreases the energy exchange efficiency resulting in tremendous economic loss and may lead to serious defects posing a threat to the safe operation. Thus, it is critical to efficiently inspect the deposition of sludge outside SGT. This work reveals that the sludge sample of a nuclear power plant has little conductivity and relative permeability about 2.88. Based on the electromagnetic properties of the sludge, we proposed a novel probe with array tunnel magnetoresistance (TMR) sensors for inspection of magnetic field disturbed by the presence of sludge outside the SGT. The principle of the method and the parameters of the probe were studied using a 3D finite element method (FEM) model. It is seen that the signal amplitude of the offset sensor configuration is stronger than that of the probe with non-offset sensor setup and the offset design avoids the disadvantage of non-sensitive to symmetry sludge. Further, it is observed that the sludge inspection performance is better at a lower excitation frequency, i.e. 1 kHz. The TMR sensors provide superior image quality at the low excitation frequency. A prototype probe is manufactured and tested. Sludge samples prepared according to the realistic fouling scenarios in steam generator were tested by the probe. The experimental results validate the feasibility of the probe and demonstrate the advantage of enhancing signal to noise ratio (SNR) of imaging by suppressing the background signal of tube support plate structure under the low excitation frequency.

Quantitative evaluation of non-active land input ofmicroplastics: A case of PET polymer

Microplastics (MPs) are plastics with size less than 5 mm. In recent years, microplastics have attracted more attention due to their ubiquitous environmental distribution, especially in water environment. Little is known about the pollution of microplastics in the terrestrial environment, especially in areas where there is no active input of MPs. It has been documented that MPs are widely detected in atmospheric dustfall and sewage sludge. However, there are few studies on the input fluxes of MPs to terrestrial environment, such as dust deposition and land-application of sludge. Polyethylene terephthalate (PET) is a thermally stable and chemically inert polyester and can be used to produce polyester fabrics, beverage bottles, plastic films, etc. PET accounts for one-third of total plastics in China, with an annual consumption of 37.5 million tons. In this study, we optimized an alkali-assisted chemical depolymerization method coupled with liquid chromatography-mass spectrometry to detect PET polymers in the environmental samples. The limits of quantification for PET MPs in atmospheric dustfall and sewage sludge were 195 ng (per 50 mg dustfall) and 180 ng (per 100 mg sludge), respectively. The method was applied to quantify PET polymers in atmospheric dustfall and sewage sludge samples collected in Tianjin, China. The results showed that PET could be detected in all dustfall samples with concentrations ranging from 776 to 5399 μg/g. The input fluxes of PET MPs via dust deposition were calculated as 100–586 μg m–2 d–1 in Tianjin. Additionally, region- and season-related fluxes were estimated. High deposition fluxes were observed in the upper and lower directions of the prevailing wind in Tianjin. There was a significant difference in the deposition flux of PET polymers between dry season and rainy season. The annual settlement of PET MPs in Tianjin was estimated to be 4.8−28 t. The concentrations of PET polymers in sewage sludge were 296−519 μg/g. The laundry water of polyester fabric clothing may be the main source of PET polymer in sewage treatment system. The total amounts of PET MPs discharged with sludge were calculated to be 186−326 t/a in Tianjin and 2370−4150 t/a in China. This accounts for roughly 0.006%− 0.011% of its total annual consumption in China. Assuming that 15% of the sewage sludge is applied as fertilizer, the estimated annual input of PET MPs to farmland is 28−49 t in Tianjin and 356−622 t in China. Besides, concentrations of PET polymers were found as high as 73−944 μg/g in the mineralized garbage soil from a landfill. This indicates an estimated input of ~20000 tons of PET MPs to terrestrial environment, through the utilization of mineralized garbage soil for municipal application. Atmospheric deposition is an important way for microplastics to enter the terrestrial environment, and the spatial and temporal distribution of the input flux is relatively uniform. The utilization of sludge and mineralized garbage soil may lead to the intensive investment of microplastics in farmland and urban environment, and its ecological risk is worthy of attention.

Influence of phosphorus on ash fouling deposition of hydrothermal carbonization sewage sludge fuel via drop tube furnace combustion experiments

Phosphorus effect on ash fouling deposition produced during combustion process of sewage sludge solid fuel is a very important factor. Previous studies have only focused on decrease of the ash melting temperature and increase of slagging and sintering by phosphorus content. Therefore, research regarding combustion fouling formation and its effect on temperature reduction of deposit surface by phosphorus content is insufficient. Ash fouling is an important factor, because ash in the combustion boiler process deposits on the surface of heat exchanger and interferes with heat exchange efficiency. In particular, temperature reduction of heat exchanger surface via fouling should be considered together with fouling deposition, because this is related to the heat exchanger efficiency. Synthetic ash, phosphorus vaporization, and drop tube furnace experiments were performed to investigate effect of phosphorus on ash fouling formation and temperature reduction of deposit surface under combustion condition. Phosphorus was highly reactive and reacted with ash minerals to produce mineral phosphate, which promoted ash fouling deposition during the combustion experiments. In contrast, the occurrence of sintering on deposited fouling resulted in formation of a large hollow structure, which alleviated the temperature reduction on the deposit surface. Phosphorus content had a substantial correlation with fouling deposition behavior and influenced reduction in the surface temperature of the heat exchanger, because it led to generating low temperature mineral phases.

Ultrasound differential diagnosis of hepatic hilar cystic lesions in neonates and infants

Objective To explore the value of ultrasound in differential diagnosis of hepatic hilar cyst in neonates and infants. Methods The ultrasonographic characteristics of 93 children with hilar cysts under 6 months of age admitted to the General Surgery Department of Beijing Children′s Hospital.Affiliated to Capital Medical University from January 2014 to December 2018 were retrospectively analyzed.According to the surgical results, they were divided into two groups: cystic biliary atresia (CBA) group and congenital choledochal cyst (CC) group, 21 cases in the CBA group and 72 cases in the CC group.The size of cyst in hepatic portal area, the shape of gallbladder in empty stomach, the expansion of intrahepatic and extrahepatic bile ducts, the deposition of biliary sludge and the communication between cyst and intrahepatic bile duct were observed by ultrasound. Results The cyst volume of CBA group was 0.4(0.1, 1.3)cm3, and that of CC group was 18.3(5.4, 50.3)cm3.The cyst volume of CBA group was significantly smaller than that of CC group (P<0.01); 19 cases had abnormal gallbladder morphology in CBA group and 4 cases in CC group (P<0.01); 1 case had biliary sludge in hilar cyst in CBA group and 51 cases had biliary sludge in cyst in CC group (P<0.01); no intrahepatic bile duct dilatation was observed in CBA group, and 54 cases had intrahepatic bile duct dilatation in CC group (P<0.01); no cyst communicated with intrahepatic bile duct in CBA group, and all cysts communicated with intrahepatic bile duct in CC group (P<0.01). Conclusion Gallbladder shape, cyst size, biliary sludge deposition, intrahepatic bile duct dilatation and the communication between cyst and intrahepatic bile duct can be used as sonographic features to differentiate CBA from CC. Key words: Ultrasound; Cystic biliary atresia; Choledochal cyst

Scale Prevention Technique to Minimized Scaling on Re-Injection Pipes in Dieng Geothermal Field, Central Java Province, Indonesia

DOI: 10.17014/ijog.5.2.129-136Dieng geothermal field including its volcanic geothermal system is dominated by hot water. Brine water is characterized by high salinity, content of chloride (Cl-), amorphous silica (SiO2), Na+, and K+. The condition of brine water has potential for the formation of amorphous silica scale in the re-injection pipeline which is one of the obstacle in the electrical energy production. The scale prevention on re-injection pipes was performed with non-acid re-injection system. Nevertheless, the scale formed in the re-injection pipe is still relatively thick due to the non-optimal sludge. This research is focused in optimizing the deposition of sludge. The research aim is to apply scale prevention technique on re-injection pipeline by involving engineering technology. The study was conducted through laboratory experiments with factorial design method 23 (two levels of three factors). Those three factors are pH, concentrations of coagulants and flocculants concentrations which act as the independent variables. The indicator is the volume of sludge deposition and turbidity of brine water which act as the dependent variables. The result showed that the most significant factor is pH, whereas the concentrations of coagulant and flocculant are preserved to accelerate and stabilize the sludge deposition. The optimal condition is achieved at the level of pH 8, the concentration of 10 ppm coagulant (PAC), and 1 ppm flocculants (Polyamide). These parameters are then used for the preparation of scaling process technology on the prevention of re-injection pipeline by adding some equipments on settling ponds. Therefore, in addition to reduce environmental degradation, it also produces sludge that has potential to be used as raw materials for other industries.

Assessing clogging of laminated hydrophobic membrane during fecal sludge drying

A new sanitation technology has been proposed in which a laminated hydrophobic membrane contains and enhances drying of fecal sludge in a toilet, with particular focus on application to urban regions of low-income countries. The proposed technology uses a laminated hydrophobic membrane liner as an integral component of container-based sanitation systems. The focus of this study is to quantitatively evaluate the laminate's clogging after repeated use, which will affect replacement interval and might limit the laminate's application in container-based toilets. The membrane of the laminated hydrophobic membrane used in this process is hydrophobic and only allows vapor transport. Drying of water vapor using the laminated hydrophobic membrane occurs due to moderate temperature or humidity gradients, while other constituents such as aqueous dissolved solutes of fecal sludge are retained. Controlled laboratory experiments evaluated repeated use of a laminated hydrophobic membrane for fecal sludge drying, with mild brushing/rinsing of the laminate between each application. Drying occurred at a constant rate as long as the fecal sludge moisture content exceeded 11.6 (g/g), below which water activity <1. Over five drying cycles, at a significance level of α = 0.05 the dimensionless drying rate in the constant-rate period was not reduced. While scanning electron microscopy and energy dispersive X-ray analyses of used laminated hydrophobic membrane showed deposition of fecal sludge on the inner fabric of the laminate, particulate accumulation was never sufficient to alter the fecal sludge drying rate. Experiments with only water indicated that the fecal sludge increased the effective diffusion length through the laminate by 10–30%. These data demonstrate that clogging of the laminated hydrophobic membrane is minor over five cycles of fecal sludge drying with mild rinsing between cycles, indicating that use of the laminate may be feasible in many field applications.

Technical problems of wastewater treatment plant in crude palm oil industry A case study in PT Socfin Indonesia-Kebun Sungai Liput, Nang groe Aceh Darussalam Province

Crude palm oil produced in Indonesia has already been known as the largest in the world. Unfortunately many of palm oil factories (CPOF) spread out in Indonesia have not good wastewater treatments (WWTP) yet. PT Socfin Indonesia, as an example, which is located in Aceh Tamiang Regency, still has BOD contained in its final effluent of the waswater treatment plant more than 150 ppm. In fact, the capability and capacity of WWTP in PT Socfin are 192 m3per day. Because of improper operational and maintenance of the WWTP, the technical prob lem are accumulated, such as, increasing the deposition of sludge and decreasing the retention time. The following affect is the treatment process is not going well and the quality of effluent is getting worse. The objective of this paper is to solve the technical problems by means remov ing the deposition of sludge periodically and fixing floating aeration in the aerobic pond. Method using for this paper is survey and wastewater sampling. A recommendation of the was tewater treatment system has been proposed after average BOD from WWTP outlet is defined 158 mg/L. The recommendation has seven procesess including oil separation, neutralization, closed tank anaerobic digester equipped with gas holder, extended aeration, settling tank, sand drying bed and land application.

하천의 물리 환경성 평가체계의 적용 - 도시하천을 중심으로 -

The purpose of this study is to present the basic data for restoration of physical stream environment by analyzing habitat variables because habitat environment is changed due to the construction of waterfront space in urban streams. Assessment results of 10 habitat variables(three divisions) were almost same as optimal condition, in the reach of reference stream where there are no stream crossing structures and channel alteration. Assessment results of reaches in urban rivers, where streams were improved on water-friendly recreation activities, appeared to be marginal condition. Because habitat environment got worse due to stream improvement works such as construction of weir for water landscape, stepping stones for walking, low water revetment and high water revetment, and high water channel. In addition, in the case of mid gradient stream, the frequency of riffles was small or not existed because the intervals of the river crossing structures was short. In the case of mild stream types, the diversity of the pool was damaged due to the deposition of sludge in the upstream pool of weir and the installation of low water revetment.

Tuning the surface chemistry of lubricant-derived phosphate thermal films: The effect of boron

Understanding the interactions among the various additives in a lubricant is important because they can have a major influence on the performance of blends under tribological conditions. The present investigation is focused on the interactions occurring between ZnDTP and dispersant molecules in an oil formulation, and on their reactivity under purely thermal conditions in the presence of air-oxidized iron surfaces. Nuclear magnetic resonance spectroscopy (NMR) was performed on undiluted blends at different temperatures, while angle-resolved X-ray photoelectron spectroscopy (ARXPS) was exploited to investigate the surface reactivity on oxidized iron surfaces. The results indicate that the dispersant, generally added to blends for preventing the deposition of sludge, varnish and soot on the surface, might also inhibit the reaction of all other additives with the steel surface.

Performance of submerged anaerobic membrane bioreactor for thermomechanical pulping wastewater treatment

A hollow fiber submerged anaerobic membrane bioreactor (SAnMBR) was operated for 160 days for thermo-mechanical pulping pressate treatment. A COD removal efficiency of 83±4% was achieved under all tested conditions, although the residual COD in permeate increased slightly with an increase in influent COD. The biogas yield slightly decreased with a higher feed concentration. The EPS production increased with an increase in organic loading rate. Membrane performance was affected by both the influent COD concentration and biogas sparging rate. The fouling layer samples were characterized using various analytical tools. The results suggest that it is feasible and attractive to treat thermomechanical pulping wastewater by a hollow fiber SAnMBR. Cake layer formation was the dominant mechanism of membrane fouling. An increase in biogas sparging rate actively mitigated the accumulation and deposition of sludge on/in membrane module, thus favored the enhancement of membrane flux and an efficient long-term operation.

Agricultural utilisation of municipal sludge in willow plantation

This paper presents the results of analyses of the monitoring selected energetic willow plantations (30 ha) located in Podkarpackie Province (Poland), which have been fertilised using a prototype trailer for land-applying municipal sludge. The fertilisation of the willow plantation is undertaken using this prototype for the subsurface application of municipal sewage sludge into soil. The presented prototype is a component of technology of energetic plant production that has been developed at the Rzeszow University of Technology. The results of soil investigations allow to us conclude that the deposition of sewage sludge using the presented prototype of the agricultural trailer is conducted in accordance with legal regulations and does not cause significant perturbation of the natural trophic chain.

In-situ integration of microbial fuel cell with hollow-fiber membrane bioreactor for wastewater treatment and membrane fouling mitigation

A hollow-fiber membrane bioreactor was integrated with a microbial fuel cell to develop a novel system of MFC–MBR based on the utilization of electricity recovered by the MFC for wastewater treatment improvement and membrane fouling mitigation in the MBR. In this system, a maximum power density of 2.18W/m3 and an average voltage output of 0.15V were achieved at an external resistance of 50Ω. The removal efficiencies of COD, ammonia nitrogen (NH4+-N) and total nitrogen (TN) in the MFC–MBR were improved by 4.4%, 1.2% and 10.3%, respectively. It is worth noting that, in addition to reducing the deposition of sludge on the membrane surface by the electric field force, the MFC–MBR also alleviated the membrane fouling by sludge modification. Compared with the control MBR (C-MBR), less loosely bound extracellular polymeric substances (LB-EPS), lower SMPp/SMPc ratio, more homogenized sludge flocs and less filamentous bacteria were obtained in the MFC–MBR, which improved the dewaterability and filterability of the sludge. The cake layer on the membrane formed by the modified sludge was more porous with lower compressibility, significantly enhancing the membrane filterability. A proof of concept of an MFC–MBR was provided and shown to be effective in membrane fouling mitigation with efficient wastewater treatment and energy recovery, demonstrating the feasibility of the minute electricity generated by the MFC for membrane fouling alleviation in the MBR.

Laboratory Test Study on Rapid Chemical Deposition of Fresh Dredger Fill

After hydraulic reclamation of the dredger fill, as the deposition of surface sludge requires a relatively long time, the consolidation treatment cannot be immediately performed until the sludge-water separation is completed and the separated water is drained. The laboratory test makes a research on the effects of chemical agents and drainage condition on the sludge deposition process. The research shows that the early-stage deposition velocity of sludge is increased obviously and the sludge-water separation time is shortened after water hydrophobing agents and polymeric flocculants are added. However, the later-stage deposition velocity is slow and the deposition strength is low. Thus, certain drainage conditions are required to increase the later-stage deposition velocity and deposition strength of sludge.

In-situ utilization of generated electricity in an electrochemical membrane bioreactor to mitigate membrane fouling

How to mitigate membrane fouling remains a critical challenge for widespread application of membrane bioreactors. Herein, an antifouling electrochemical membrane bioreactor (EMBR) was developed based on in-situ utilization of the generated electricity for fouling control. In this system, a maximum power density of 1.43 W/m3 and a current density of 18.49 A/m3 were obtained. The results demonstrate that the formed electric field reduced the deposition of sludge on membrane surface by enhancing the electrostatic repulsive force between them. The produced H2O2 at the cathode also contributed to the fouling mitigation by in-situ removing the membrane foulants. In addition, 93.7% chemical oxygen demand (COD) removal and 96.5% NH4+-N removal in average as well as a low effluent turbidity of below 2 NTU were achieved, indicating a good wastewater treatment performance of the EMBR. This work provides a proof-of-concept study of an antifouling MBR with high wastewater treatment efficiency and electricity recovery, and implies that electrochemical control might provide another promising avenue to in-situ suppress the membrane fouling in MBRs.

Application of waterworks sludge in wastewater treatment plants

The potential for reuse of iron-rich sludge from waterworks as a replacement for commercial iron salts in wastewater treatment was investigated using acidic and anaerobic dissolution. The acidic dissolution of waterworks sludge both in sulphuric acid and acidic products such as flue gas washing water and commercial iron solution was successful in dissolving the iron from waterworks sludge. The anaerobic dissolution of waterworks sludge due to co- digestion with biological sludge (primary and biological activated sludge) resulted in reduction of iron, increase in dissolved iron(II), increase in pH due to the produced alkalinity from dissolution of iron(III)hydroxides from waterworks sludge, lower internal recirculation of phos- phate concentration in the reject water and reduced sul- phide in the digested liquid. However, recirculation of the produced soluble iron(II) as an iron source for removal of phosphate in the wastewater treatment was limited, because the dissolved iron in the digester liquid was limited by siderite (FeCO3) precipitation. It is concluded that both acidic and anaerobic dissolution of iron-rich waterworks sludge can be achieved at the wastewater treatment plant, and are economically and environmentally more favour- able compared to deposition of the waterworks sludge in controlled landfills.

A STUDY ON THE IMPACT OF SLUDGE ON WATER QUALITY OF HORI RIVER

The effect of sludge on water quality has big problems in Hori River, Nagoya, Japan. An observation is carried out to find out the relationship between the sludge and water quality at Naka Bridge of Hori River. Observations have done in the spring and neap tides using salinity, dissolved oxygen, turbidity, water temperature and ph as indicators. Moreover, experiment on the chemical parameters of water quality such as TN (inorganic form i.e. NH4-N, NO3-N, NO2-N) and TP were done in order to find out the impacts of sludge on the water for the improvement of better habitants of Hori River. Overall, TP and TN for the different two tides did not show any large variations and were fairly comparable. The pattern of water quality changed with the tides. For example, during spring tide, high DO levels were recorded and vice versa. At spring tide, the DO levels increased due to wave action and sea water intrusion. The sludge flushed into the river during spring tide of high velocity and exposure in the middle layers. Therefore, it noted that the water quality of the Hori River was greatly influenced by the tidal changes and the deposition of sludge.

Bait-lamina assay as a tool to assess the effects of metal contamination in the feeding activity of soil invertebrates within a uranium mine area

As part of the tier 2 of a site-specific risk assessment, this study was the first reporting an intensive in situ application of the bait-lamina assay; two exposure periods (7 and 14 days) were tested during four seasons in ten different sites, within a uranium mine area and at two different depths. The most contaminated sites (by deposition of sludge from the effluent treatment pond) were discriminated after 14 days of exposure because extremely low percentages of feeding activity were recorded. Previous sub-lethal ecotoxicological assays, already had demonstrated that the habitat function of these soils is compromised. Nevertheless, seasonality has proved to have a significant influence on responses. Thus to strength conclusions about the impact of contaminants, the in situ bait-lamina assay should be performed on different annual seasons, at least for temperate regions. It was also found that some environmental parameters (e.g. soil moisture and litter) can act as confounding factors in the bait-lamina assay.

Contribution for tier 1 of the ecological risk assessment of Cunha Baixa uranium mine (Central Portugal): I Soil chemical characterization

Within the tier 1 of a site specific risk assessment, the pseudo-total concentrations (extracted with aqua regia) and the potential mobile fractions of metals were determined to perform a preliminary evaluation of risks posed by contaminated soils from an abandoned uranium mine (Mangualde, Central Portugal). Considering the mobile fractions of metals, extracted with artificial rain water, aluminium and uranium were the most concerning elements, since their concentrations were above soil quality criteria values (SQGVs) established for both elements. However, according to the evaluation based on potential mobile fractions of elements, rather than on pseudo-total metal concentrations the risks were limited to sites within the exploitation area, where contamination derives mainly from past in-situ leaching activities of pore ore as well as from the deposition of sludge from the effluent pond. The exclusion of other sites under evaluation, from the risk assessment process, requires additional data provided by soil screening ecotoxicological assays.

Performance of newly developed hollow fiber module with spacer in integrated anaerobic–aerobic fungi reactor treating textile wastewater

A submerged microfiltration membrane bioreactor implementing the white-rot fungus Coriolus versicolor was developed for effective treatment of textile dye wastewater [1]. In that system membrane fouling was precluded by placing a bundle of hollow fibers within a pre-filtration assembly, so as to avoid direct deposition of sludge onto it, together with its periodic high-pressure back-washing and low-dose chemical back-flushing. However, the extreme vulnerability of the bare membrane used in that study to inter-fibral deposition of sludge leading to merging of fibers indicated necessity of development of an appropriate module so that the proposed system may enjoy more flexibility in terms of precluding fouling. This study reports superior performance, in terms of avoiding fouling, of newly developed hollow fiber module with spacer over that of usual hollow fiber bundles under severe operating conditions induced by high strength industrial wastewater with concomitant biofouling.