Water Treatment Sludge Research Articles

Drinking water treatment sludge as an effective additive for biogas production from food waste; kinetic evaluation and biomethane potential test

The effect of drinking water treatment sludge (DWTS) as a mixture additive, on biogas and methane production from food waste was studied. Mesophilic anaerobic digestion of food waste with 5 concentrations of DWTS (0, 2, 6, 12, and 18 ppm) was carried out. It was found that DWTS can significantly enhance biogas and methane yield. The highest biogas (671 Nml/g VS) as well as methane yield (522 Nml/g VS) was observed when 6 mg/kg DWTS was added. This is equal to 65 and 58 percent increase in comparison with the control digester. The calculated lag time for methane was found to be in between 3.3 and 4.7 days. The DWTS also reduced the lag phase and retention time. The biogas experimental data was fitted with the modified Gompertz and the first-order kinetic models with R2 higher than 0.994 and 0.949, respectively. The ratio of the experimental biogas production to the theoretical biogas production (ɛ) for control sample was 0.53 while for other samples containing additive were higher than 0.78.

Optimizing dewaterability of drinking water treatment sludge by ultrasound treatment: Correlations to sludge physicochemical properties

Sludge dewatering has proven to be an effective method to reduce the volume of sludge. In this study, drinking water treatment sludge (DWTS) was treated by ultra-sonication under variable conditions comparing two sonoreactor types (bath and probe), four frequencies (25, 40, 68, 160 kHz) and four energy density levels (0.03, 1, 3, 5 W/mL). The effects of these conditions were studied using specific resistance to filtration and capillary suction time as measures of dewaterability, and floc size, the Brunauer, Emmett and Teller (BET) specific surface area and Zeta potential to determine treated sludge characteristics. The results indicated that the dewaterability of sonicated sludge improved at relatively low energy densities of 0.03 and 1.0 W/mL, while an optimum for sonication duration (within 10 min) was also identified. Higher frequencies (tested up to 160 kHz) with acoustic energy density of 0.03 W/mL also reduced the dewatering property. At higher energy densities of 3.0 and 5.0 W/mL, dewaterability of sludge deteriorated regardless of ultra-sonication time, with an increase of solubilized organic matter content and severely changed floc characteristics. The deterioration of the dewatering capacity was closely related to the considerably reduced floc sizes, dissolution of proteins and polysaccharides, and to the Zeta potential of sonicated sludge flocs. The dewaterability was not correlated with BET specific surface area. Mechanistic explanations for the observations were discussed by analyzing corrosion patterns of aluminum foil as a measure for cavitation field distribution.

Trace analysis of parabens preservatives in drinking water treatment sludge, treated, and mineral water samples.

Parabens have been widely used as antimicrobial agents, mainly in food products, pharmaceuticals, and cosmetics. Although they are known as safe preservatives, they also cause some harm to human health, which has been discussed lately. Therefore, the aim of this study was to evaluate the occurrence of nine parabens (including isomers) in mineral and drinking waters, besides in drinking water treatment sludge (DWTS) samples with determination by liquid chromatography tandem mass spectrometry (LC-MS/MS). Both methods solid phase extraction (SPE) and QuEChERS were validated. Calibration curves showed a correlation coefficient of 0.99 for all compounds. LOQ values ranged from 0.04 to 4μgL-1 in aqueous matrices and from 5 to 500ngg-1 in DWTS. Recoveries between 70 and 115% were reached with RSD below 20% for all compounds in SPE whereas recoveries between 62 and 119% were found with RSD below 20% for almost all compounds in QuEChERS. Matrix effect had low values (< 20%); it was only above 20% for methylparaben in the SPE and for pentylparaben in the QuEChERS. Using a quick and simple extraction procedures with SPE, QuEChERS, and LC-MS/MS analyses, these methods proved to be selective and sensitive. They were successfully applied to real samples (treated water, mineral water, and sludge), and methylparaben was detected at concentration levels below 0.242μgL-1 in mineral and treated water samples and 10ngg-1 in DWTS samples.

Detoxification of polluted marine sediments using water treatment sludge

ABSTRACTThe purpose of this study was development of the optimal conditions for the inertization of the polluted marine sediments using groundwater treatment sludge highly enriched in iron and aluminum. For that purpose fine-grained sediment (>85% clay and silt fraction) highly enriched in copper and zinc was amended with the waste sludge (from 10% to 50%). The sample with the optimum percentage of the waste sludge was further subjected the thermal treatment at 200–800°C. The efficiency of the treatment was determined by the leaching tests and toxicity testing using Hordeum vulgare L. as biosystem. The percentage of the seed germination, the root elongation, and the germination index before and following the treatment were determined. Untreated sediment leachate caused significant arrest in the percentage of the seed germination (6.7 ± 6.7%), the root elongation (1.9 ± 2.2%), and the germination index (0.2 ± 0.3%) with EC50 of 24.9%, suggesting a significant toxic potential of the sediments. After amendment with 30% of the waste sludge the concentrations of the considered micropollutants decreased below regulated values while all three toxicological parameters showed no significant difference compared to the negative control. The toxicity of the sediment was completely removed following the thermal treatment at 400°C.

Aerosol exposure and risk assessment for green jobs involved in biomethanization

Anaerobic digestion is a consolidated biotechnology able to produce renewable energy from biomasses. In the European countries, quick growth of biogas production from different organic matrices including wastes has been observed. In relation to the characteristics and quantity of the anaerobic digestion of feedstock, there are different technologies, advantages and criticisms. An accurate occupational risk assessment and development of management tools for green jobs involved in the anaerobic digestion plants are due. The aim of this work is to assess the aerosol exposure for such workers, focusing on the bioaerosol risk. Full scale plants for the treatment of organic municipal waste, waste water treatment sludge, agro zootechnical and food producing byproducts were involved for this purpose. The bioaerosol levels were monitored during activities through culturing and biomolecular methods; moreover, the sub-fractionated PM10 and carried endotoxins were measured in different plant areas. Global microbial contamination is higher (>5000 UFC/m3) in the area where organic wastes are handled and pretreated, both for organic municipal waste plants - with a bacterial prevalence - and agro zootechnical plants - with a fungi prevalence. Moreover, the microbial contamination is higher where organic municipal waste is present in respect to other biomasses (ANOVA p < 0.01). Numerous pathogens are carried by the aerosol. HAdV-4 presence is lower than LOQ (50 gene copies/m3) in all the samples. Environmental PM10 reached the 280 μg/m3 level including PM3 for 78%. Endotoxin pollution overtakes the 90 EU/m3 limit sporadically. Personal PM4.5 reached 10 mg/m3 only for maintenance technicians in the pretreatment area for organic municipal waste. The risk can be evaluated under a quantitative and qualitative point of view highlighting risk management improvement for anaerobic digestion plants.

Evaluation of Fresh Properties of Controlled Low-Strength Material Produced from Water Treatment Sludge-Fly Ash-Slag Mixture Using Alkaline Activation

This study used a sodium hydroxide (NaOH) solution to activate a mixture of water treatment sludge, fly ash, and slag, in order to produce a new alkali-activated controlled low-strength material (CLSM). Fresh properties of this new CLSM were investigated through the tests of workability, setting time, and ball drop time. Test results show that the addition of water treatment sludge (WTS) decreased workability. In addition, the addition of such WTS increased initial setting time and ball drop time, whereas the alkali equivalent (AE) shortened the initial setting time and ball drop time. At a liquid-to-solid ratio (L/S) of 0.9, a WTS content of 10%, and an alkali equivalent of 9%, the fresh properties for the CLSM conforms to the design principles and provisions of the Public Works Department, Taipei City Government, and is ideal for road construction in order to reduce traffic impact.

The beneficial usage of water treatment sludge as pottery product

The disposal of sludge from water treatment operations has become a major problem in Malaysia. The problem becomes acute because of scarcity of space for installation of sludge treatment facilities and disposal of treated sludge. Traditionally, treated sludge from water treatment plant will be sent to landfill for disposal. This method does not benefit anybody besides creating other problems. Instead of considering it as a waste, sludge must be considered as a quality by-product that can be changed into beneficial product for consumer. As a pilot study, this research only emphasize on characterization of water treatment sludge and its behaviour when mixed with clay. Mineralogical compositions were determined using XRD, XRF for chemical composition and physical testing including Atterberg limit test and particles size distribution. Identification of beneficial usage is based on the characteristics of water treatment sludge. Keywords : chemical composition; mineral composition; physical characteristics; pottery product; water sludge.

Use of flyash to improve soil properties of drinking water treatment sludge

Improvement of soft soil using cementitious additives is a widely practiced technique in the construction industry. However, cement mixing is considered to be an expensive technique and this research has attempted to study the use of an industrial waste; flyash to improve a drinking water treatment sludge. Flyash is a fine, glass powder recovered from the gases of burning coal during the production of electricity at Norochchole, thermal power plant in Sri Lanka. The larger amount of drinking water treatment sludge which is a very soft clayey soil, is disposed into the environment without acquiring any benefit. Use of flyash in improving soft soils such as sludge with a low maximum dry density and low CBR will solve few burning issues such as dumping of flyash and sludge, health issues due to disposal of flyash and sludge, difficulties to find soils with better properties for road constructions and other construction related applications. Identifying the characteristics of the sludge, studying the variation of maximum dry density and optimum moisture content with flyash content, strength gain with time, and the applicability of the improved soil in the industry are the key findings and observations of this study. It was observed that the optimum proportion of the flyash to be added to the sludge to achieve a remarkable gain in its properties is around 30% of its dry weight. Acceptable CBR value was achieved after 7 days curing followed by standard 4 days soaking period.

Removal of methylene blue from aqueous solutions using alum Sludge: Sorption optimization by response surface methodology

A sorption process on low cost sorbents is one the promising methods for removing of these pollutants from aqueous solutions. This report describes use of drinking water treatment sludge which is abundantly available from drinking water treatment plants, to remove methylene blue (MB) dye from aqueous solutions. The main objective of this work is to determine the optimum conditions for removal of MB dye, a common compound that is used as a model for organic chemicals. Response surface methodology (RSM) is used in the optimization of the sorption process. Six independent important factors which are temperature of treatment, pH of solution, dosage of sorbent, initial dye concentration, contact period and temperature of sorption were investigated using batch sorption technique with a 26 half factorial faced centered central composite design

Characterization and acid resistance test of one-part geopolymer from fly ash and water treatment sludge

Development of geopolymers from wastes or by-products introduces a sustainable approach to replace ordinary Portland cement (OPC)-based concrete with an eco-material of lower green-house gases emissions. However, safety concerns related to the conventional two-part geopolymer has limited large-scale applications of the product. In this context, a novel one-part geopolymer from coal fly ash and water treatment sludge has been presented. The transformation of raw materials to geopolymer was observed by FTIR, SEM and XRD analyses. Acid resistance test has proved that the new binder had great durability against sulphuric acid attack. After 28 days immersion in 5% H2SO4 solution, weight of all samples was hardly changed. Compressive strength, on the other hand, has not decreased but significantly increased as curing time increased. The properties were also compared to those of control samples cured in water. It was demonstrated that strong acid immersion did not create any noticeable effect on the weight and strength of one-part geopolymer system developed from coal fly ash and water treatment sludge.

Use of a water treatment sludge in a sewage sludge dewatering process

The objective of the research study was to determine whether a sewage sludge conditioning had any impact on sludge dewaterability. As a conditioning agent a water treatment sludge was used, which was mixed with a sewage sludge before a digestion process. The capillary suction time (CST) and the specific filtration resistance (SRF) were the measures used to determine the effects of a water sludge addition on a dewatering process. Based on the CST curves the water sludge dose of 0.3 g total volatile solids (TVS) per 1.0 g TVS of a sewage sludge was selected. Once the water treatment sludge dose was accepted, disintegration of the water treatment sludge was performed and its dewaterability was determined. The studies have shown that sludge dewaterability was much better after its conditioning with a water sludge as well as after disintegration and conditioning, if comparing to sludge with no conditioning. Nevertheless, these findings are of preliminary nature and future studies will be needed to investigate this topic.

Investigation on mixture design of one-part geopolymer from fly ash and water treatment sludge

This study presents a one-part geopolymer system from coal fly ash and water treatment sludge. Geopolymer is typically produced from two parts namely the aluminosilicate solids, which is typically sourced out from industrial by-product, and an alkali activator solution which reacts with aluminosilicate solids to form an inorganic polymeric network. For a one-part geopolymer system, the solid binder with activators will just be added with water to address the drawback of corrosive and viscous alkali activator solution. Formulation of the proportion of geopolymer precursors with the two solid alkali activators namely sodium hydroxide and sodium aluminate was conducted using statistical mixture design. Effects of each components as well as interactions between them were evaluated by step-wise regression analysis. It was found that high alkali content decreased the compressive strength of binder. Meanwhile, the incorporation of sludge in this system helps reduce the unit weight of samples. Multiple response surface analysis that maximized compressive strength and minimized unit weight resulted in the optimal combination of 18.9% sludge, 76.1% fly ash and 5.0% NaOH.

"The Application of Dynamic Up – Flow Sand Filtration in Water Sludge Treatment"

"The Application of Dynamic Up – Flow Sand Filtration in Water Sludge Treatment"

WATER TREATMENT SLUDGE AS POTENTIAL SOIL AMENDMENT FOR NATIVE PLANTS OF THE BRAZILIAN CERRADO

This work evaluates the effect of 5 mixtures of water treatment sludge, soil from the Cerrado region (Brazil) and a commercial substrate on the growth of 4 species of native plants (Copaifera langsdorffii, Astronium fraxinifolium, Peltophorum dubium and Tabebuia roseo-alba) from the Brazilian Cerrado. A randomized design was setup with four repetitions and WTS loading rates of 0, 204, 417, 638 and 869 g/kg. Plant sampling for analysis was performed at 30, 60, 90, 120 and 150 days after planting, totalling 400 experiments. The results on morphological parameters and foliar analysis showed good results for the sludge loading rates of 204 and 417 g/kg (18,75 and 37,5% of sludge, respectively), for the Copaifera langsdorffii, Astronium fraxinifolium and Tabebuia roseo-alba growth, which presented the highest values for plant diameter, height and total dry matter weight at the 90th and 120th day of experiments. These loading rates seem to provide suitable buffer conditions and nutrients for plant growth. For sludge loading rates of 638 and 869 g/kg the development of all species was reduced, suggesting that plant growth was probably affected by both the higher concentration of Al and the poor mixture structure due to excess of sludge.

Use of water treatment sludge in ceramic matrix for manufacturing bricks

Use of water treatment sludge in ceramic matrix for manufacturing bricks

Effect of ultrasonic and thermal disintegration of water treatment sludge

This research was conducted to evaluate the effects of thermal and ultrasound disintegration on the disintegration degree (DD) of water treatment sludge from a municipal water treatment plant. A disintegration process was used to (i) improve subsequent coagulation efficiencies and dewatering processes (ii) reduce sludge production, and (iii) obtain both economic and enviromental benefits. The results show that using the disintegration process has an influence on DD values. It is also worth emphasising that the main parameter determining the efficiency of ultrasonic and thermal disintegration was the time of the applied process. Other parameters such as ultrasound intensity and temperature had a reduced impact on DD values.

Performance of waste-based amendments to reduce metal release from mine tailings: One-year leaching behaviour

A one-year leaching experiment has been conducted in order to assess the effectiveness of several amendments on metal immobilization in mine tailings from an old Pb/Zn mining area of Central Spain (San Quintín mine). Demineralized water was used as leaching solution, selecting doses equivalent to the annual rainfall conditions of the studied area. Columns with mine tailings without any amendment and others treated with 10% of sugar foam (SF), 15% of drinking water treatment sludge (DWS), 30% of paper mill sludge (PMS) and 15% of olive mill waste (OMW) were used. SF, DWS and PMS amendments increased the pH of leachates from values of approximately 4 to around neutrality. Additionally, the release of sulfate ions from the oxidation of pyritic residues was decreased in some extent by SF and DWS amendments. Metal leaching was effectively reduced by the amendments reaching overall decreases with respect to the unamended columns of 79–96% for Pb, 36–100% for Zn, 50–99% for Cu and 44–100% for Cd. The effect of the amendments in leachate pH, sulfate concentration and metal release from mine tailings was kept throughout the whole experimental period. Our results showed that the application of different organic and inorganic amendments based on by-products and waste materials may be a feasible alternative for the restoration of soils around abandoned metal mines.

Eco-efficient recycling of drinking water treatment sludge and glass waste: development of ceramic bricks

Current management for drinking water treatment sludge and glass waste is insufficient, and a new method is needed. We sought to develop a new approach for effective management. This work analyses the application possibilities of drinking water treatment sludge (DWTS) and windows glass waste (GW) to be used for the production of ceramic products. DWTS and GW are renewable, ecological and economical waste additives which save raw materials. Ceramic body with (40–60) of DWTS and (10–40) of GW additives have been burnt at 900 and 1000 °C temperatures. It is determined that DWTS and GW have an impact on physical–mechanical properties of ceramic body (density, compressive strength, water absorption, porosity) and change macro- and microstructure. DWTS additive also acts as natural colouring pigment. The work proposes eco-efficient application way of drinking water treatment sludge and windows glass waste, it solves exportation of DWTS and GW to landfills problems and positively affects regional ecological balance.

Arıtma çamurlarının su verme özelliklerinin iyileştirilmesinde biyokütle ve kömür külü ilavesinin etkilerinin incelenmesi

Diminishing the amount of water in sewage sludges is the most determinant factor in terms of increasing the options of removing and being reduced the number of sludges to remove. In the current situation, the most preferred methods are the mechanic methods for sludge dewatering. But, the quenching features of the sludge must be improved and the conditioning procedures need to be actualized by adding polyelectrolyte into the sludge to enhance the productivity of the mechanical methods. As an alternative to the use of polyelectrolyte in sludge conditioning procedure, the effects of the use of biomass and coal ash on the quenching features are analyzed in this research. For this purpose, the biomass and the coal ash were mixed with the sewage sludges in different ratios. The 1/1000 cationic polyelectrolyte solution was used as the control application. According to the results obtained from the study, as the ash content in the mixtures increases, the specific resistance to filtration (SRF) and the filter cake moisture content (FCM), which are the most important indicators of water quenching properties, have been significantly reduced. The closest results to the polyelectrolyte application (SRF 2,8.1011 m.kg-1, FCM: % 58,96) used as the control were obtained from the BC6 application (SRF: 29.1011 m.kg-1, FCM: % 65,92) where the highest ratio of biomass ash used. Moreover, the results of the implementations of biomass and coal ash are determined as statistically similar (R2=0,99). In the content of biomass and coal ash heavy metals, it is seen that the ratios of heavy metal of biomass ash are lower for all values other than Zn. It is thought according to these results that the biomass and coal ash can be used to improve the dewatering features of domestic waste water treatment sludges. However, considering the heavy metal level of the sludge, it can be said that the best alternative is the use of biomass ash for increasing the disposal options after dewatering.

Utilisation of drinking water treatment sludge for the manufacturing of ceramic products

The influence of the additive of drinking water treatment sludge on the physical and mechanical properties, structural parameters, microstructure of the ceramic products is analysed in the research. Drinking water treatment sludge is renewable, environmentally-friendly, economical additive saving expensive natural raw materials when introduced into the ceramic products. The main drinking water treatment sludge component is amorphous Fe2O3 (70%). Formation masses are prepared by incorporating from 5 % to 60 % of drinking water treatment additive and by burning out at the temperature 1000 °C. Investigation showed that the physical and mechanical properties, microstructure of the ceramic bodies vary depending on the amount of drinking water treatment additive incorporated. In addition, drinking water treatment additive affects the ceramic body as a pigment that dyes the ceramic body in darker red colour.