Intended process water management concept for the mechanical biological treatment of municipal solid waste

Accumulating operational experience in both aerobic and anaerobic mechanical biological waste treatment (MBT) makes it increasingly obvious that controlled water management would substantially reduce the cost of MBT and also enhance resource recovery of the organic and inorganic fraction. The MBT plant at Gescher, Germany, is used as an example in order to determine the quantity and composition of process water and leachates from intensive and subsequent rotting, pressing water from anaerobic digestion and scrubber water from acid exhaust air treatment, and hence prepare an MBT water balance. The potential of, requirements for and limits to internal process water reuse as well as the possibilities of resource recovery from scrubber water are also examined. Finally, an assimilated process water management concept with the purpose of an extensive reduction of wastewater quantity and freshwater demand is presented.

Heavy Metal Remediation in AgoèNyivéLandfill Soils: Enhancing Stability through Organic Amendments

The burial of waste in developing countries, which is often carried out without respect for environmental standards, constitutes a risk of contamination of soils and even groundwater given the toxic elements they contain. The objective of this work is to carry out a study of the retention of heavy metals through the contribution of cattle manure to soil samples from the final Agoè Nyivé landfill in Lomé, Togo. Soil samples from the final landfill were taken from the surface and depth at several locations to form a composite sample. The amendment of the composite sample was carried out with bovine manure on the mock-up in the Laboratory for six months. The determination of the total contents of heavy metals by the atomic absorption spectrophotometer (SAA) on the composite sample showed high contents exceeding the thresholds recommended by the AFNOR NF U 44-041 standard. Sequential extraction on these composite samples showed that the mobile portions of lead, cadmium, copper and zinc are respectively estimated at 78.06%, 50%, 28.89% and 91.59%. The bovine manure used to amend the landfill samples presents physicochemical parameters that can contribute to rendering heavy metals immobile in the soil matrix under natural conditions. The addition of manure initially made it possible to increase the values of pH, electrical conductivity, cation exchange capacity and organic matter, which promote the retention of heavy metals. Secondly, the addition of manure made it possible to reduce the mobile portion of the heavy metals studied;from 78.06% to 14.39% for lead, from 50% to 11.52% for cadmium, from 28.89% to almost 0% for copper and from 91.15% to 80.58% for zinc. The use of cattle manure as an amendment on the composite sample was decisive in reducing the mobility of heavy metals in the polluted soils of the final landfill.

Influence of particle size and salinity on adsorption of basic dyes by agricultural waste: dried Seagrape (Caulerpa lentillifera)

Green macroalga Caulerpa lentillifera was found to have reasonable adsorption capacity for basic dyes, Astrazon Blue FGRL (AB), Astrazon Red GTLN (AR), and Astrazon Golden Yellow GL-E (AY). The initial dye concentration was in the range of 100–1,800 mg/L. The dried algal sorbent was ground and sieved into 3 sizes: S (0.1–0.84 mm), M (0.84–2.0 mm), and L sizes (larger than 2.0 mm). For all conditions examined in this work (at 25°C in batch systems), the adsorption reached equilibrium within the first hour. The kinetic data corresponded well with the pseudo second order kinetic model where the rate constant, k2, decreased as the sorbent size increased for all dyes. The adsorption isotherms followed both Langmuir and Freundlich models. Among three sorbent sizes, S size gave the highest adsorption capacity followed by M and L sizes. A reduction of sorbent size increased the specific surface area for mass transfer, and also increased the total pore volume, thus providing more active sites for adsorption. The adsorption of AB was adversely influenced by the protonation of algal surface at low pH. On the other hand, the adsorption of AR and AY could be due to weak electrostatic interaction, which was not significantly affected by pH. Increasing salinity of the system caused a decrease in adsorption capacity possibly due to the competition between Na+ and the dye cations for the binding sites on algal surface. Moreover, an increase in salinity generated a compressed electrical double layer on the algal surface which exerted repulsive force, retarding the adsorption of positive charged molecules such as the basic dyes.

Size distribution of wet crushed waste printed circuit boards

A wet impact crusher was used to breakdown waste printed circuit boards (PCB's) in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing mechanism was analyzed and the effects of hammerhead style, rotation speed, and inlet water volume on particle size distribution were investigated. The results show that the highest yield of 1 + 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m 3 /h and a smooth hammerhead turning at 1246.15 r/min. Cumulative undersize-product yield curves were fitted to a nonlinear function: the fitting correlation coefficient was greater than 0.998. These research results provide a theoretical basis for the highly effective wet crushing of PCB's.

Effect of sulfate on the methanogenic activity of a bacterial culture from a brewery wastewater during glucose degradation

在葡萄糖的降级上从酿酒厂废水处理植物发源的污泥的最大的特定的 methanogenic 活动(SMA ) 在一个特定的装载基础上在硫酸盐的各种各样的层次被调查。批实验在 pH 在浆液瓶子中被进行 7 和 35 ° C。价值的比较显示当时，这种混合文化的 SMA 被增加并且到达它 0.128 g CH4 煤气的 COD/(g VSS-d ) 的高水平生物资源在与在由重量的 1:0.114 的比率的硫酸盐的接触。

Biodegradability of leachates from Chinese and German municipal solid waste

The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600 000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.

Collimated LaBr_3 detector response function in radioactivity analysis of nuclear waste drums

The properties of a Lanthanum bromide(LaBr3)detector and its response functions were investigated via experiments and simulations in this paper.The LaBr3detector had good relative energy resolution and higher efficiency than a high-purity germanium detector.Monte Carlo and other numerical methods were used to calculate the efficiencies of a LaBr3detector with a square collimation window.A model of the numerical method was established based on a pure geometric model that was consistent with the experimental situation.The results showed that the detector response functions calculated by these methods were in great agreement with experimental results.

Evaluating the treatment of E-waste──a case study of discarded refrigerators

Disassembly and recycling of E-waste creates a series of environmental problems. The selection of a technologically reliable, environmentally friendly, economically affordable and socially acceptable recycling technology for E-waste is a significant question. This study establishes a Monte-Carlo mathematical model of cost minimization, given the constraints of environmentally sound handling of the e-waste, in the context of Crystal Ball risk assessment and evaluation software. By following the streams of the different treatment processes, which consist of various technologies including disassembly, recycling and disposal, the econom-ics of various possibilities were identified and the optimal recycling technology proposed. The key factors of the proposed scenarios were determined by using sensitivity analysis. The results of this study show that, for discarded refrigerators, the operating life span plays the key role. The model supports maintenance and resale of the short lived refrigerators. For the longer lived refrigerators material recycling is recommended by the model. Sensitivity analysis shows that purchase cost, plastic sale price, condenser sale price and disassembly costs are the main effects. This study provides a significant technical support for policy making in E-waste management.

Preparation of Calcium Cross-linked Nano-Fe3O4 Modified Zeolite Microspheres for Cu^2+ Adsorption from Wastewater

Artificial zeolite was modified by nano-Fe3O4 for development of functional adsorbents.Subsequently,adsorbents such as calcium cross-linked nano-Fe3O4 microspheres (Ca-MS),calcium cross-linked nano-Fe3O4 modified zeolite microspheres (Ca-MZS) and iron cross-linked nano-Fe3O4 modified zeolite microspheres (Fe-MZS) were prepared and compared for their adsorption performance.The effects of adsorbent dosage,solution pH,initial concentration and ion content on the removal of Cu^2+ from wastewater are investigated,and the adsorption kinetics and isotherms for the adsorbent materials were analyzed.The experimental results indicate that for the initial concentration of Cu^2+ of 30 mg/L,the adsorption is noted to be most stable.The optimal initial pH for adsorbing Cu^2+ is observed to be 5.5.At an optimal dosage of Ca-MZS of 900 mg/L,the adsorption capacity is measured to be 28.25 mg/g,along with the removal rate of 72.49%.The addition of Na+ and K+ affects the adsorption of Cu^2+.For the Na^+ and K^+ concentration of 0.2 mmol/L,the Cu^2+ removal rate by Ca-MZS drops to 11.94% and 22.12%,respectively.As compared with the adsorbents such as Natural Zeolite (NZ),Ca-MS and Fe-MZS,Ca-MZS demonstrates the best removal effect in solution,where the removal rate reaches 84.27%,with the maximum adsorption capacity of 28.09 mg/g.The Cu^2+ adsorption kinetics of Ca-MZS is observed to follow the Elovich kinetic model,with the adsorption isotherm data fitting the Freundlich isotherm model by using the non-linear method.

A Study on the Radioactivity Level in Raw Materials, Final Products and Wastes of the Phosphate Fertilizer Industries in Bangladesh

A study on the detection of probable radionuclides and their activity concentrations in the raw material (phosphate rock), final product (fertilizer) and waste samples collected from all the phosphate fertilizer factories (total two factories—A Diammonium Phosphate, DAP and a Triple Super Phosphate, TSP factory) in Bangladesh were carried out. A total of seven types of samples (grossly divided into solid and liquid types);liquid waste, waste-mixed river water, normal river water, phosphate rock, phosphate fertilizer, solid waste and normal soil;were analyzed under this study. Raw material samples were collected only from the TSP fertilizer factory. Fertilizer, solid and liquid waste samples were collected from both the factories under study. Moreover, normal soil and natural surface water samples from the suitable areas adjacent to the factories were also collected for the comparison purpose. The samples were analyzed by gamma ray spectrometry technique using a Hyper-Pure Germanium (HPGe) detector of 40% relative efficiency. The analysis of the samples showed that only natural radionuclides such as 226Ra, 232Th and 40K were present in the samples and no traces of artificial radioactivity were found in any of the samples. 40K was found below the detection limit in some samples. The analysis of the samples in the case of TSP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in raw materials were 851.27 ± 7.10, 19.63 ± 6.57 and 54.06 ± 5.93 Bq/kg, respectively, in final product 211.90 ± 4.74, 42.48 ± 10.56 Bq/kg and ND (Not Detected), respectively, in solid waste 187.49 ± 4.88, 70.06 ± 11.76 and 289.27 ± 40.24 Bq/kg, respectively and in liquid waste 6.26 ± 0.63, 10.01 ± 1.39 Bq/L and ND, respectively. The measured results in the case of samples collected from DAP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in the final product were 17.31 ± 3.92, 69.74 ± 9.88 and 48.46 ± 17.22 Bq/kg, respectively, in solid waste 24.47 ± 4.15, 164.62 ± 11.08, 191.52 ± 33.74 Bq/kg, respectively and in liquid waste 3.59 ± 1.05, 37.08 ± 3.30 Bq/L and ND, respectively. Considering the stored raw materials and wastes the part of the ambient environment of the factory, radium equivalent activity, radiation hazard index and external annual effective dose to the workers and public due to these materials were also calculated and compared with world average values.

Indiscriminate Waste Disposal and Its Effects on a Nearby Stream

This research paper was carried out specifically to examine the indiscriminate waste disposal and its effects on water quality of a nearby stream.The study witnessed two seasons(dry and rainy seasons).Field survey as well as laboratory analysis of collected samples were carried out.The results obtained indicated that River Ndongo has an important role in the activities of the inhabitants of Molyko.It is used as disposal site for waste,water is used for household activities and agricultural practices.This provides the inhabitants with the efficient site for waste disposal and a source of water for their activities.However,

Optimization of control parameters for petroleum waste composting

Composting is being widely employed in the treatment of petroleum waste. The purpose of this study was to find the optimum control parameters for petroleum waste in vessel composting. Various physical and chemical parameters were monitored to evaluate their influence on the microbial communities present in composting. The CO 2 evolution and the number of microorganisms were measured as the activity of composting. The results demonstrated that the optimum temperature, pH and moisture content were 56.5-59.5℃, 7.0-8.5 and 55%-60%, respectively. Under the optimum conditions, the removal efficiency of petroleum hydrocarbon reached 83.29% after 30 days composting.

Hollow Fiber Supported Liquid Membrane for Separation and Recovery of ^152+154Eu and ⁹⁰Sr from Aqueous Acidic Wastes

Separation and recovery of 152+154Eu and 90Sr from radioactive waste using tracer concentration from active material from waste tank in the ET-RR1 Egypt via hollow fiber supported liquid membrane (HFSLM) were achieved. The Polypropylene was used as supporter to carrier 0.5M Cyanex301/kerosene (bis(2,4,4-trimethylpentyl)dithiophosphinic acid and 0.1MEDTA as stripping of 152+154Eu and 90Sr ions from nitrate medium at pH ~3.6. The separation factor was found to be ~4 for 152+154Eu over 90Sr. The aqueous feed of mass transfer coefficient (ki) and the organic mass transfer coefficient (km) were calculated to be (1.52 and 4.5) × 10﹣2cm/s, respectively. In addition, the mass transfer modeling was performed and the validity of the developed model from experimental data was found to join in well with the theoretical values when the Cyanex301 concentration is higher than 1% (v/v). The number of cycles evaluated for complete separation of 152+154Eu and 90Sr is five cycles.

Use of Evapotranspiration (ET) Landfill Covers to Reduce Methane Emissions from Municipal Solid Waste Landfills

Solid waste landfills need to have final covers to 1) reduce the infiltration of rainfall into the waste mass and 2) reduce surface greenhouse gas emissions. Most regulations require that such final covers include hydraulic barriers, such as compacted clays with or without geomembrane. Significant research has been undertaken to allow the use of evapotranspiration-based covers (often termed: Evapotranspiration (ET) Cover, Water Balance Covers, or Phyto Covers) as an alternative to the barrier concept covers. ET covers are designed so that they have the capacity to store water by the soil and also have plants or vegetation to remove the stored water. In ET covers, plant roots can enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil. Therefore, biological methane oxidation (a natural process in landfill soils) can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This paper summarizes a study to investigate the capacity of an ET cover to reduce surface greenhouse gas emissions when implemented on a solid waste landfill. This study consisted of using a numerical model to estimate methane emission and oxidation through an ET cover under average climatic conditions in Bennignton, Nebraska, USA. Different simulations were performed using different methane loading flux (5 to 200 gm-2·d-1) as the bottom boundary. For all simulations, surface emissions were the lowest during the growing season and during warmer days of the year. Percent oxidation is the highest during the growing season and during warmer days. The lowest modeled surface emissions were always obtained during the growing season. Finally, correlations between percent oxidation and methane loading into simulated ET covers were proposed to estimate methane emissions and methane oxidation in ET covers.

Sono-Photo Fenton Treatment of Liquid Waste Containing Ethylenediaminetetraacetic Acid (EDTA)

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been used for decontamination purposes in nuclear industry. The presence of EDTA in decontamination wastes can cause complexation of the cations resulting into interferences in their removal by various treatment processes such as chemical precipitation, ion exchange etc. Further, it might also impart elevated leachability of cationic contaminants from the conditioned wastes immobilized in cement or other matrices and can negatively influence the quality of the final form of waste. In the present study, kinetics of degradation of EDTA (20,000 mg/l) by employing either Photo-Fenton process using UV (15 W λmax = 253.7 nm) or Sono-Fenton process using ultrasound at 130 KHz or simultaneous Sono-Photo Fenton process has been investigated. EDTA is effectively degraded by the synergistic effect of both Photo Fenton and Sono Fenton process. All the above mentioned processes were found to follow a first order kinetics reaction. From the observed pH changes during the oxidation processes, it can be concluded that there is a loss of chelating ability of EDTA. Formation of amides was con- firmed during the degradation processes.

The Bioconversion of Municipal Solid Waste in the Biodrying Reactor

The bioconversion process of municipal solid waste was assessed on the basis of the results obtained from the biodrying reactor working at a full industrial scale.The bio-reactor is a part of mechanical-biological installation following mechanical stage.The bio-reactor was equipped with measuring devices allowing the analysis of the parameters like:temperature both inside the waste and also air above the waste and also the humidity of waste during the 14 days of the biodrying process.The kinetics of bioconversion was assessed basing on measured the loss of ignition(LOI)parameter detected during the biodrying process.The LOI value of the samples varied from 17.03%Am.to 30.34%d.m.depending on the location inside the reactor.The estimated kinetic rate constant kT of the bioconversion of biomass in the industrial reactor was kT=0.3141.In analyzed case study the calorific value of product leaving the full-scale bio-reactor is too low to use this product as an alternative fuel.As w'as stated the reason of this is too low a share of the carbon-rich fraction in the feedstock.

Determination of the Occurrence and Elimination of Endocrine Disrupting Compounds (EDCs) in Municipal Wastewater Treatment Plants (WWTP)

In recent years, many research and development activities have focussed on endocrine disrupting compounds (EDCs) in rivers, lakes and surface waters as the potential cause of reproductive disturbances in different aquatic organisms e.g. fish and mollusk. The effluent of wastewater treatment plants was identified as main source for EDCs entering the aquatic environment. The purpose of the present study was to determine the estrogenic activity of wastewater and the elimination efficiency of various WWTPs in the different purification steps using the E-screen assay, an in-vitro test system based on the increasing proliferation of human breast cancer cells (MCF-7) in response to the presence of hormonal active substances. In contrast to expensive and time-intensive targeted instrumental single substance analysis an effect-related biological testing provides a sum parameter for the entirety of compounds contributing to the total estrogenic activity (agonists and antagonists, anti-estrogenic and also toxic compounds) in concentration units of the reference substance 17b-estradiol. The current standard purification methods of biological wastewater treatment in particular the activated sludge process significantly reduce estrogenicity (average 95%). Sorption on activated carbon and subsequent precipitation leads to a further reduction of the overall estrogenic activity up to 99%.

Swine waste as a source of natural products: A carotenoid antioxidant

Development of Environmentally Superior Technologies swine waste management has focused on extraction of products with relatively low unit values. Analyses of the bacterial composition of swine waste lagoon samples confirmed the presence of several purple non-sulfur bacteria (PNSB) species known to produce a variety of carotenoids. We examined a carotenoid naturally abundant in North Carolina swine waste lagoons dominated by PNSB. Analytical methods including high performance liquid chromatography (HPLC), mass spectrometry, and nuclear magnetic resonance (NMR) confirmed the identity of the dominant carotenoid as spirilloxanthin, C42H60O2, with 13 conjugated double bonds. This structure confers antioxidant properties as good as those of carotenoids currently marketed as antioxidants. Visual estimates of the “redness” of swine waste lagoon liquids were highly correlated with carotenoid content. Spirilloxanthin concentrations in a lagoon with a strong PNSB bloom were approximately 0.5 grams·m-3. These results support further investigations into the potential for extracting commercially valuable natural products from swine waste lagoons.

Saturated hydraulic conductivity of compacted bentonite-sand mixtures before and after gas migration in artificial seawater

To understand the self-healing property of an engineered barrier for radioactive waste disposal,the hydraulic conductivity of compacted bentoniteesand mixtures saturated with artificial seawater(SW)before and after gas migration was examined.Na-and Ca-bentonites were mixed with fine sand at a ratio of 70%bentonite in dry weight.Two aspects were considered during the experiment:the hydraulic conductivity of the specimen that was resaturated after gas migration and the distribution of water content immediately after gas migration to study gas migration pathways.The gas migrated through the entire cross-section of the specimen,and gas breakthrough occurred in the equilibrium swelling pressure range approximately.Subsequently,the gas flow rate reached a sufficient large value when the gas pressure was approximately twice the equilibrium axial pressure(the sum of swelling and confining pressures),which excluded the back pressure.Although the gas migration pathway was not visible when the specimen was observed immediately after gas migration,the water content distribution showed that several parts of the specimen with lower water content were connected in the direction of gas migration.After resaturation,the change in permeability was within a limited rangedtwo to three times larger than that before gas migration for each type of bentonite in SW.This slight change suggests that gas migration creates a pore structure that cannot be sealed via crystalline swelling of montmorillonite in SW,even if highly compacted bentonite is used under a constant-volume condition.

A novel method for geometric quality assurance of rock joint replicas in direct shear testing-Part 2:Validation and mechanical replicability

Each rock joint is unique by nature which means that utilization of replicas in direct shear tests is required in experimental parameter studies.However,a method to acquire knowledge about the ability of the replicas to imitate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking.In this study,a novel method is presented for geometric quality assurance of replicas.The aim is to facilitate generation of high-quality direct shear testing data as a prerequisite for reliable subsequent analyses of the results.In Part 1 of this study,two quality assurance parameters,smf and V_(Hp100),are derived and their usefulness for evaluation of geometric deviations,i.e.geometric reproducibility,is shown.In Part 2,the parameters are validated by showing a correlation between the parameters and the shear mechanical behavior,which qualifies the parameters for usage in the quality assurance method.Unique results from direct shear tests presenting comparisons between replicas and the rock joint show that replicas fulfilling proposed threshold values of σ_(mf)<0.06 mm and
|V_(Hp100)|
<0.2 mm have a narrow dispersion and imitate the shear mechanical behavior of the rock joint in all aspects apart from having a slightly lower peak shear strength.The wear in these replicas,which have similar morphology as the rock joint,is in the same areas as in the rock joint.The wear is slightly larger in the rock joint and therefore the discrepancy in peak shear strength derives from differences in material properties,possibly from differences in toughness.It is shown by application of the suggested method that the quality assured replicas manufactured following the process employed in this study phenomenologically capture the shear strength characteristics,which makes them useful in parameter studies.