Water Treatment Plant Sludge Research Articles

Utilization of Drinking Water Treatment Slurry to Produce Aluminum Sulfate Coagulant.

In Egypt, water treatment consumes about 365 000 tons of aluminum sulfate and produces more than 100 million tons of sludge per year. The common disposal system of sludge in Egypt is to discharge it into natural waterways. Toxicity of aluminum, environmental regulations and costs of chemicals used in water treatment and sludge treatment processes led to an evaluation of coagulant recovery and subsequent reuse. The present work aimed at aluminum recovery from sludge of El-Shiekh Zayd water treatment plant (WTP) to produce aluminum sulfate coagulant. Sludge was characterized and the effect of five variables was tested and the process efficiency was evaluated at different operating conditions. Maximum recovery is 94.2% at acid concentration 1.5 N, sludge weight 5 g, mixing speed 60 rpm, temperature 60 °C and leaching time 40 min. Then optimum conditions were applied to get maximum recovery for aluminum sulfate and compared to commercial coagulant on raw water of El-Shiekh Zayd (WTP).

Adsorption of Carbon Dioxide by Reusing Drinking Water Treatment Plant Sludge

Cost effective, easy to use and regenerate could be the desired properties of an adsorbent. Reusing of waste material as CO2 adsorbent can be a good alternative for solving the problem of waste disposal as well. Thus, in this study, aluminium-based drinking water treatment plant sludge as carbon dioxide adsorbent was reused. The sludge collected from a local drinking water treatment plant. It was dried and characterized using scanning electron microscope-energy disperse X-ray (SEM-EDX), Fourier transform infrared spectrometer (FTIR) and thermogravimetric analysis (TGA). Investigations of the effects of temperature, flow rate, concentration of CO2 and adsorbent dosage on CO2 adsorption capacity were performed using a fixed bed column at a pressure of 1 bar. The maximum capacity of 32.56 mg/g was found which was higher than that of some reported adsorbents.

Bioindicators assessing water quality and environmental impacts of water treatment plant sludge

This study had as objectives to assess water quality using macroinvertebrate communities in Gaviao artificial reservoir (Brazil), used to supply potable water to 2.5 million people, and to evaluate how these organisms responded to the discharge of water treatment sludge into a natural wetland. A total of 1,621 specimens across 23 taxa were identified. Mollusca were the dominant and most frequent group while Insecta presented the most richness. Based on feeding mode, there were more predator organisms than scrapers. The Biological Monitoring Working Party (BMWP') method showed to be more sensible to water quality variations than ASPT index, going from polluted to questionable water quality more frequently. The chemical parameters analysed showed no significant variations and were not a sensitive method for assessing water quality. No organisms could be found downstream of the sludge discharge point, indicating a high impact of sludge disposal on local biota.

Bioindicators assessing water quality and environmental impacts of water treatment plant sludge

This study had as objectives to assess water quality using macroinvertebrate communities in Gaviao artificial reservoir (Brazil), used to supply potable water to 2.5 million people, and to evaluate how these organisms responded to the discharge of water treatment sludge into a natural wetland. A total of 1,621 specimens across 23 taxa were identified. Mollusca were the dominant and most frequent group while Insecta presented the most richness. Based on feeding mode, there were more predator organisms than scrapers. The Biological Monitoring Working Party (BMWP') method showed to be more sensible to water quality variations than ASPT index, going from polluted to questionable water quality more frequently. The chemical parameters analysed showed no significant variations and were not a sensitive method for assessing water quality. No organisms could be found downstream of the sludge discharge point, indicating a high impact of sludge disposal on local biota.

Nano-TiO2 enhances biofilm formation in a bacterial isolate from activated sludge of a waste water treatment plant

TiO2 NPs is one of the major components of paints and sunscreens and also acts as a catalyst for waste water treatment. The study demonstrates the toxic effects of TiO2 NPs on an anaerobic bacterium, Macrococcus caseolyticus, isolated from the activated sludge of a waste water treatment facility. The cytotoxicity assessment under UVA, visible light, and dark conditions revealed a dose- and exposure-dependent reduction in viability. The examination of cytotoxicity was performed with membrane permeability assessment through LDH (Lactate dehydrogenase) detection. The formation of exopolymeric substances (EPS) was observed to be dose-dependent, and maximum EPS release was noted under UVA condition. The scanning electron microscopy described the aggregation tendency of biofilm to be more pronounced under UVA condition when treated with TiO2 NPs as compared to the control biofilm. Uptake of TiO2 NPs by the biofilm indicated possible remediation of the NPs in waste water by these organisms.

Fate of cyanobacteria in drinking water treatment plant lagoon supernatant and sludge

In conventional water treatment processes, where the coagulation and flocculation steps are designed to remove particles from drinking water, cyanobacteria are also concentrated into the resultant sludge. As a consequence, cyanobacteria-laden sludge can act as a reservoir for metabolites such as taste and odour compounds and cyanotoxins. This can pose a significant risk to water quality where supernatant from the sludge treatment facility is returned to the inlet to the plant. In this study the complex processes that can take place in a sludge treatment lagoon were investigated. It was shown that cyanobacteria can proliferate in the conditions manifest in a sludge treatment lagoon, and that cyanobacteria can survive and produce metabolites for at least 10days in sludge. The major processes of metabolite release and degradation are very dependent on the physical, chemical and biological environment in the sludge treatment facility and it was not possible to accurately model the net effect. For the first time evidence is provided to suggest that there is a greater risk associated with recycling sludge supernatant than can be estimated from the raw water quality, as metabolite concentrations increased by up to 500% over several days after coagulation, attributed to increased metabolite production and/or cell proliferation in the sludge.

COPPER REMOVAL FROM BIOLOGICAL TREATMENT SYSTEM USING MODIFIED ADSORBENT DERIVED FROM GROUNDWATER TREATMENT PLANT SLUDGE AND RICE HUSK

Copper removal from synthetic wastewater by biomass assisted adsorbents was evaluated in this study. Three different biological reactors of the same size (8.5 L) were aerobically operated at solid retention time (SRT) of 30 days and hydraulic retention time (HRT) of 0.8 day. The first reactor was operated with biomass alone as the control reactor. The second reactor consist of biomass and ground water treatment plant sludge (GWTPS) whilst the third reactor consist of biomass and hybrid adsorbent (HA), which comprises 50% of microwaved incinerated rice husk ash (MIRHA) and 50% of GWTPS. The reactors were operated in eight different phases (Phase 1 – 8). Phases 1 – 2 were operated as acclimation period during which the biomass were allowed to stabilize within the reactor without copper addition. From phase 3 – phase 8, copper was added to the influent of the reactors at various concentrations and the reactor performance was monitored every two days. Results revealed that copper removal with the control reactor (RC) was markedly inferior compared with the reactors supported with GWTPS and HA adsorbents. The copper removal in the control reactor was in the range 0.47 – 2.62 mg/L from phase 5 to phase 8. Copper removal in the GWTPS reactor was in the range 0.19 – 0.83 mg/L from phase 5 to phase 8 whereas copper removal in the HA reactor was in the range 0.27 – 1.09 mg/L at the same conditions. Percentage removal of copper was 85 %, 94 % and 95 % for the control, GWTPS and HA reactors, respectively. The adsorbents, GWTPS and HA reactors removed copper effectively. This study demonstrates that solid waste materials such as GWTPS and HA can be beneficially utilized to improve biomass tolerance towards heavy metal toxicity and yields a significant removal of copper.

A first screening and risk assessment of pharmaceuticals and additives in personal care products in waste water, sludge, recipient water and sediment from Faroe Islands, Iceland and Greenland

A screening of a broad range of pharmaceuticals and additives in personal care products (PPCPs) in sub-arctic locations of the Faroe Islands (FO), Iceland (IS) and Greenland (GL) was conducted. In total 36 pharmaceuticals including some metabolites, and seven additives in personal care products were investigated in influent and effluent waters as well as sludge of waste water treatment plants (WWTPs) and in water and sediment of recipients. Concentrations and distribution patterns for PPCPs discharged via sewage lines (SLs) to the marine environment were assessed. Of the 36 pharmaceuticals or metabolites analysed 33 were found close to or above the limit of detection (LOD) in all or a part of the samples. All of the seven investigated additives in personal care products were detected above the LOD. Some of the analysed PPCPs occurred in every or almost every sample. Among these were diclofenac, ibuprofen, lidocaine, naproxen, metformin, citalopram, venlafaxine, amiloride, furosemide, metoprolol, sodium dodecyl sulphate (SDS) and cetrimonium salt (ATAC-C16). Additionally, the study encompasses ecotoxicological risk assessment of 2/3 of the analysed PPCPs in recipient and diluted effluent waters. For candesartan only a small margin to levels with inacceptable risks was observed in diluted effluent waters at two locations (FO). Chronical risks for aquatic organisms staying and/or living around WWTP effluent pipe-outlets were indicated for 17β-estradiol and estriol in the three countries. Additives in PCPs were found to pose the largest risk to the aquatic environment. The surfactants CAPB and ATAC-C16 were found in concentrations resulting in risk factors up to 375 for CAPB and 165 for ATAC-C16 in recipients for diluted effluents from Iggia, Nuuk (GL) and Torshavn (FO) respectively. These results demonstrates a potentially high ecological risk stemming from discharge of surfactants as used in household and industrial detergents as well as additives in personal care products.

Structural Aspects and Thermal Degradation Kinetics of Water Treatment Plant Sludge of Moroccan Capital

This paper reports a study on the structural characterization, structural transformations with temperature, and non-isothermal degradation kinetics of urban drinking water sludge. Chemical composition analysis by quantitative energy dispersive X-ray fluorescence suggests that the sludge is mainly inorganic in nature with small fraction of organic matter. Structural analysis of the sludge by SEM, XRD, and FTIR reveals structural complexities of the sludge. Thermal treatment of the sludge in the long temperature range shows that the sludge is capable of exhibiting different physico-chemical transitions. The reaction profile of the sludge thermal degradation is evaluated by TGA/DTG analysis which has been found considerably complex comprising many reactions. The thermal degradation kinetics is performed by thermoanalytical data of the sludge obtained by DSC using solid state kinetics approaches. The mechanistic information extracted from kinetic analysis fairly agrees with the structural analysis results. The present study reveals that the analyzed drinking water sludge has significant potential to be employed in the materials of construction.

Characterization of Water Treatment Plant's Sludge and its Safe Disposal Options

Surface water Treatment for potable supplies typically involves coagulation, flocculation, Sedimentation, and filtration processes for removing colloidal as well as suspended solids from raw water. All water treatment plants (WTPs) produce waste/residue known as water treatment sludge (WTS) during the purification of raw water. The sludge produced a WTP at Ghaziabad, India is investigated for physical and chemical characteristics. It consist of about 60% fine sand in grain size range 150-75μ. Silica, alumina, ferric oxide and lime constitute the major percentage of chemical components present in the sludge. Some heavy metals are also found in the sludge. Discharging WTS into river, streams, ponds, lakes, drains etc. or landfilling the dewatered WTS is not environment friendly disposal option. Based on the characteristics, sustainable and profitable disposal through recycling and reuse have been reviewed. Utilization of WTS in brick making, in ceramics making, in the manufacture of cement and cementitious materials and as a substitute to building materials could provide safe disposal route. Reuse in wastewater treatment, in removal of heavy metals from aqueous solutions and in nutrient reduction from laden soils and runoffs are also some of the possible alternatives. It is required to explore suitable option for developing sustainable sludge management strategies under stringent environmental norms.

Study on Influence to Waste Water Treatment Plant’s Sludge by Low-carbon Catalytic Combustion Furnace of Natural Gas

There are two parts in this experiment. One of is about the concentration of Variation of exhaust gas while heating sludge of waste water treatment plant. The other one is about introduce the problems of the traditional incineration processes of sludge of waste water treatment as compared between the sludge heated by natural gas catalytic combustion furnace and the tradition’s. We can see that natural gas low-carbon catalytic combustion furnace realize the near-zero emission of contaminates.

Utilization of water treatment plant sludge in structural ceramics bricks

The main aim of this study is to assess the effect of incorporating water treatment sludges (WTS) of plant Bouregreg on the properties and microstructure of clay used for raw material.This work proposes to test the clays used in the manufacture of a ceramic that could incorporate alumina sludge. The raw materials, alumina sludge and clay, were mixed together in different proportions, were prepared by incorporating from 5 to 30%. Specimens of these mixtures were then fired at 800, 900, and 1000°C. In order to determine the technological properties, such as bulk density, linear shrinkage, water absorption, compressive strength, X-Diffraction, and Scanning Electron Microscopy. The results obtained showed that the samples tested are dense and have high mechanical resistance, without deformation or defects.These clay materials may be used for the production of terracotta products and also for the formulation of low porosity raw material.

Distribution of heavy metals in sediments of a tropical reservoir in Brazil: Sources and fate

Juturnaíba Lake has been utilized for the captation of water to supply over one million people in the Lakes Region, Rio de Janeiro, Brazil. The water treatment plant sludges have been directly disposed in the margins of the lake, constituting a potential threat for the water quality. The aim of the present work was to evaluate the geochemical processes that control concentrations and mobility of metals (Al, Cu, Fe, Mn, Pb and Zn) in the sediments of the Juturnaíba Reservoir, and whether they are affected by the disposal of the water treatment sludges. Sediment samples were collected from thirty-two stations in the Juturnaíba lake, and the total concentration of metals (pseudo-total concentrations), granulometry, total organic carbon, total nitrogen and total phosphorus concentrations were evaluated. Distribution maps and attenuation models were constructed. The results show that the metals concentrations are affected by the presence of large stands of the aquatic macrophyte Egeria sp. (Hydrocharitaceae). The sludges from the water treatment plants do not seem to contribute to the contamination of the sediments, probably because the mobility of the contaminants in the dumping piles is low.

Red ceramics from composites of hazardous sludge with foundry sand, glass waste and acid neutralization salts

This study is aimed at the development of new compositions of municipal water treatment plant sludge with foundry sand, glass waste and acid neutralization salts for red ceramics production. The chemical and mineralogical compositions of the raw materials and structure formation processes of the ceramics made from only industrial wastes were studied using XRF, XRD, SEM, EDS, LAMMA and AAS methods. The initial mixtures of these components were sintered at 900, 950, 1000, 1050 and 1100°C for 6h. The results indicate that the ceramics had flexion resistance strength up to 18.4MPa (sintered at 1050°C), low values of water absorption and linear shrinkage. It was shown that high values of mechanical properties can be attributed mainly to the synthesis of glassy structure formation with small inclusions of new minerals, namely corundum Al2O3, hematite Fe2O3, lazurite Na6Ca2(AlSiO4)6(SO4,S,Cl)2, mullite 3Al2O3·2SiO2, nepheline (Na,K)AlSiO4 and quartz SiO2. The results of leaching and solubility tests by AAS are significantly lower than the requirements of the Brazilian standards, which demonstrates a reliable binding of heavy metals from the waste used as raw materials into insoluble compounds.

The use of water treatment plant sludge ash as a mineral addition

For decades, the sludge produced in water treatment plants (WTP) was dissolved in water and then discharged in watercourses. WTP sludge is rich in pathogens and metals and when discharged in watercourses, it increases the amount of suspended solids, eventually causing the water body to silt up. Existing legislation in Brazil prohibits the discharge of WTP sludge in watercourses, but the practice persists. This study investigated the possibility of using WTP sludge as a mineral addition. First, the pozzolanicity of WTP sludge with Portland cement and the concentration of fixed calcium hydroxide using the Chapelle test were determined after exposing the material to different calcination temperatures and residence times. The samples with the best results were used to investigate the performance of concrete mixes where WTP sludge was substituted for Portland cement in concentrations ranging from 5% to 30% in three different water/binder (w/b) ratios (0.35, 0.50 and 0.65). Results indicate that the use of WTP sludge ash improves the strength of concrete mixes when compared with concrete with rice husk ash or silica fume. By using WTP sludge ash, it is possible to obtain the same strength of a concrete mix with 100% Portland cement and reduce the consumption of cement by 37–200kgm−3 of concrete, depending on the concentration of substitution and the desired strength level.

Biodegradation of multiple microcystins and cylindrospermopsin in clarifier sludge and a drinking water source: Effects of particulate attached bacteria and phycocyanin

The effects of particulate attached bacteria (PAB) and phycocyanin on the simultaneous biodegradation of a mixture of microcystin-LR, YR, LY, LW, LF and cylindrospermopsin (CYN) was assessed in clarifier sludge of a drinking water treatment plant (DWTP) and in a drinking water source. The biomass from lake water and clarifier sludge was able to degrade all microcystins (MCs) at initial concentrations of 10µgL−1 with pseudo-first order reaction half-lives ranging from 2.3 to 8.8 days. CYN was degraded only in the sludge with a biodegradation rate of 1.0×10−1d−1 and a half-life of 6.0 days. This is the first study reporting multiple MCs and CYN biodegradation in the coagulation–flocculation sludge of a DWTP. The removal of PAB from the lake water and the sludge prolonged the lag time substantially, such that no biodegradation of MCLY, LW and LF was observed within 24 days. Biodegradation rates were shown to increase in the presence of C-phycocyanin as a supplementary carbon source for indigenous bacteria, a cyanobacterial product that accompanies cyanotoxins during cyanobacteria blooms. MCs in mixtures degraded more slowly (or not at all) than if they were degraded individually, an important outcome as MCs in the environment are often present in mixtures. The results from this study showed that the majority of the bacterial biomass responsible for the biodegradation of cyanotoxins is associated with particles or biological flocs and there is a potential for extreme accumulation of cyanotoxins within the DWTP during a transient bloom.

Microbial Decolorization and Degradation of Reactive Red 198 Azo Dye by a Newly Isolated Alkaligenes Species

Microbial digestion has the potential to break down complex organic compounds so that they may further degrade it to completely harmless form. The main objective of the present work is to reduce the colour and degradation of the industrial effluent containing extensively used textile dye Reactive Red 198 (RR198) by microbial method. The activated sludge of textile printing waste water treatment plant of Erode, Tamilnadu, India was used as a source of inocula for the isolation of an efficient dye-decolorizing bacterium strain. The isolated bacterial strain was able to use RR198 as sole carbon source for its growth. Gram staining and 16S rDNA gene sequence analysis have identified bacterial strain as Alcaligenes sp. AP04. The isolated strain has decolorized about 90 % of initial dye concentration of Azo dye RR198 within 24 h under aerobic condition at pH 7.0 and temperature 25 °C with 50–200 mg/L dye concentration. A soluble cytosolic enzyme, azoreductase was isolated from it and its molecular mass was found to be 60 kDa. This enzyme has NADH/NADPH-dependent activity and oxygen sensitivity. The thin layer chromatography and gas chromatography–mass spectrometry (GC–MS) analysis of dye decolorized product has confirmed the successful dye degradation by the bacterial activity. Phytotoxicity and inhibition of seed germination of Cicer arietinum and Phaseolus mungo were shown by RR198 treatment while no toxicity and seed germination inhibition was found with the dye degraded products in C. arietinum and P. mungo. Present study might offer valuable implications for the practical application of Alcaligenes sp. for the treatment of azo dyes of industrial effluents.

Vermiremediation of Water Treatment Plant Sludge employing Metaphire posthuma: A soil quality and metal solubility prediction approach

Water Treatment Plant Sludge (WTPS) is formed during sewage treatment and is extremely rich in nutrients (N, P and K) and toxic heavy metals. In this work, efficiency of vermicomposting technology was evaluated using an endogeic earthworm Metaphire posthuma, against aerobic composting in regard to stabilization of WTPS. Different combinations of WTPS and cow dung were utilized as feed stock. Low pH of WTPS changed towards neutrality under both the biocomposting systems. The contents of N (45–61%), P (50–80%) and K (83–88%) increased significantly under Metaphire vermicomposting system accompanied by substantial reduction in total organic C. Interestingly, improvement in soil quality and low accumulation of heavy metal (Cr and Cu) in soil under vermistabilized WTPS treatments was noteworthy. Moreover, the solubility pattern of non metal and metal ions in vermistabilized and crude WTPS was studied to understand their impacts on moist soil environment with the help of MINTEQ geochemical model. The model predicted decrement of metal solubility (Cr, Zn, Cu, and Mn) in WTPS+CD (1:1) and WTPS+CD (2:1) vermicompost as compared to untreated WTPS. The overall results suggest that Metaphire posthuma could be utilized as a successful candidate for bioprocessing toxic WTPS materials.

Manufacturing ceramic bricks with polyaluminum chloride (PAC) sludge from a water treatment plant.

The objective of this research work is to assess the viability of manufacturing ceramic bricks with sludge from a water treatment plant (WTP) for use in real-world applications. Sludge was collected from settling tanks at the Bolonha WTP, which is located in Belém, capital of the state of Pará, Brazil. After dewatering in drainage beds, sludge was added to the clay at a local brickworks at different mass percentages (7.6, 9.0, 11.7, 13.9 and 23.5%). Laboratory tests were performed on the bricks to assess their resistance to compression, water absorption, dimensions and visual aspects. Percentages of 7.6, 9.0, 11.7 and 13.9% (w/w) of WTP sludge presented good results in terms of resistance, which indicates that technically, ceramic bricks can be produced by incorporating up to 13.9% of WTP sludge.

Utilization of Water Treatment Plant Sludge and Coal Fly Ash in Brick Manufacturing

Sludge from a treatment water Brazilian plant station is, frequently, disposed and launched directly in the water bodies, causing a negative impact in the environment. Also, fly ash is produced by burning of coal in coal-fired power stations and is the industrial solid waste most generated in southern Brazil: approximately 4 million tons/y. An efficient disposal of coal fly ash is an issue due to its massive volume and harmful risks to the environment. The main purpose of this study was to evaluate the technical possibilities of incorporating cyclone fly ash (CFA) and sludge from a waste water treatment plant (SWTP) in the production of ecological bricks. The wastes were analyzed for physico-chemical, mineralogical and morphological properties. Various mixtures were prepared by incorporating these industrial wastes in brick production. The effects of wastes incorporation on physical properties such as compressive strength and water absorption have been determined. The best result, in terms of compression strength and water absorption, was reached by the series of bricks produced with 60 % soil, 12 % cement, 8 % coal fly ash and 20 % SWTP by weight. The results showed that SWTP and CFA presented a potential to be used as waste additives in the production of soil-cement bricks.