Water sludge: utilization in the production of construction materials and agriculture Alternative coagulants (a review)

Author(s):  
В.Я. Кофман

При производстве строительных материалов и в сельском хозяйстве могут быть использованы значительные объемы водопроводных осадков, обеспечивая при этом их утилизацию. Следствием применения осадков в строительной промышленности может стать существенная экономия традиционных сырьевых материалов без ухудшения качества продукции. Налаженных поставок водопроводных осадков на предприятия стройиндустрии, однако, пока не происходит, и в качестве основной причины называют непостоянство их состава. Вместе с тем достигнутые результаты свидетельствуют о значительных усилиях, предпринимаемых в этой области. На основе использования водопроводных осадков разработаны технологии производства цемента, строительного раствора, бетона, кирпича, кровельной черепицы, керамических изделий. Сельскохозяйственное применение водопроводных осадков считается наиболее доступным и масштабным вариантом их утилизации. Содержание органики и тяжелых металлов в водопроводных осадках достаточно ограниченно, что выгодно отличает их от осадков сточных вод и позволяет классифицировать как безопасные. К настоящему времени в целом ряде стран проведены многолетние масштабные эксперименты по использованию водопроводных осадков для корректировки содержания растворимого фосфора в почвах, для связывания растворимых форм мышьяка и хрома и корректировки содержания микроэлементов. Кардинальное решение проблемы водопроводных осадков должно быть связано с уменьшением их образования в процессе водоподготовки. В этом направлении ведется поиск альтернативных коагулянтов, прежде всего растительного происхождения. Достигнутые результаты позволили провести опытно-промышленные испытания водного экстракта семян масличного дерева Moringa oleiferaв качестве коагулянта при очистке поверхностной воды. Utilization of water sludge in significant amounts can be provided by using it in the production of construction materials and in agriculture. The use of water sludge in the construction industry can result in significant savings in traditional raw materials without compromising product quality. However, the supply of water sludge to the construction industry enterprises, has not been established so far, and the instability of its composition is posed as the main reason. At the same time, the results achieved evidence significant efforts made in this area. Based on the use of water sludge, technologies have been developed for the production of cement, building mortar, concrete, brick, roofing tiles, and ceramic products. Agricultural use of water sludge is considered as a most affordable and large-scale option of its disposal. The concentration of organics and heavy metals in water sludge is quite limited, which sets it apart from wastewater sludge and allows it being classified as safe. To date, in a number of countries many years of large-scale experiments have been conducted on the use of water sludge for adjusting the concentration of soluble phosphorus in soils; binding soluble forms of arsenic and chromium, and adjusting the concentration of trace elements. A radical solution to the problem of water sludge disposal should be associated with reducing its amount generated during water purification process. In this direction, studies are being conducted on alternative coagulants, primarily of plant origin. The results achieved made it possible to carry out pilot tests of using aqueous extract of Moringa oleifera oil-tree seeds as a coagulant in the purification of surface water.

2010 ◽  
Vol 156-157 ◽  
pp. 939-942 ◽  
Author(s):  
Deng Ling Jiang ◽  
Guo Wei Ni ◽  
Guan Yi Ma

Treatment of municipal wastewater results worldwide in the production of large amounts of sewage sludge. The major part of the dry matter content of this sludge consists of nontoxic organic compounds, in general a combination of primary sludge and secondary (microbiological) sludge. The sludge also contains a substantial amount of inorganic material and a small amount of toxic components. The large volume of wastewater sludge generated requires enormous landfill space for disposal. Diverting the wastewater sludge from landfill would alleviate the shortage of landfill sites. Thus alternative applications have to be considered for the wastewater sludge diverted away from the landfills. The use of wastewater sludge for the production of construction materials is reviewed in this paper. Wastewater sludge can be used as raw materials for making bricks, concrete filler and concrete aggregates. The study reveals that the reuse of wastewater sludge as construction materials offers a technically feasible alternative for sludge disposal.


2004 ◽  
Vol 50 (9) ◽  
pp. 189-196 ◽  
Author(s):  
J.-H. Tay ◽  
K.-Y. Show ◽  
D.-J. Lee ◽  
S.-Y. Hong

The disposal of sludge from wastewater treatment presents highly complex problems to any municipality. Most of the sludge disposal methods have varying degrees of environmental impact. Hence, it is necessary to explore potential areas of reuse in order to alleviate sludge disposal problems and to conserve natural resources. Industrial sludge and marine clay are two forms of high-volume wastes. Using these wastes as a resource of raw materials to produce construction aggregates would enable large-scale sludge reuse. The aggregates were produced at various sludge-clay combinations containing 0, 20, 50, 80 and 100% clay contents, respectively. The pelletized aggregates displayed lower particle densities ranged between 1.48 and 2.25 g/cm3, compared to the density of granite at 2.56 g/cm3. Good 28-day concrete compressive strength of 38.5 N/mm2 achieved by the 100% sludge aggregate was comparable to the value of 38.0 N/mm2 achieved of the granite control specimens. The leachate contamination levels from the aggregates after 150 days were found acceptable when used in concrete, indicating insignificant environmental contamination. The heat flow study showed increases in heat flow at the temperatures of 480°C and between 660°C and 900°C, indicating a need for the extension of heating time around these temperatures.


Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Cheng-An Tao ◽  
Jian-Fang Wang

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.


2021 ◽  
Vol 6 (11) ◽  
pp. 159
Author(s):  
Ricardo Infante Gomes ◽  
David Bastos ◽  
Catarina Brazão Farinha ◽  
Cinthia Maia Pederneiras ◽  
Rosário Veiga ◽  
...  

Construction and demolition wastes (CDW) are generated at a large scale and have a diversified potential in the construction sector. The replacement of natural aggregates (NA) with CDW recycled aggregates (RA) in construction materials, such as mortars, has several environmental benefits, such as the reduction in the natural resources used in these products and simultaneous prevention of waste landfill. Complementarily, CDW have the potential to capture CO2 since some of their components may carbonate, which also contributes to a decrease in global warming potential. The main objective of this research is to evaluate the influence of the exposure of CDW RA to CO2 produced in cement factories and its effect on mortars. Several mortars were developed with a volumetric ratio of 1:4 (cement: aggregate), with NA (reference mortar), CDW RA and CDW RA exposed to high levels of CO2 (CRA). The two types of waste aggregate were incorporated, replacing NA at 50% and 100% (in volume). The mortars with NA and non-carbonated RA and CRA from CDW were analysed, accounting for their performance in the fresh and hardened states in terms of workability, mechanical behaviour and water absorption by capillarity. It was concluded that mortars with CDW (both CRA and non-carbonated RA) generally present a good performance for non-structural purposes, although they suffer a moderate decrease in mechanical performance when NA is replaced with RA. Additionally, small improvements were found in the performance of the aggregates and mortars with CRA subjected to a CO2 curing for a short period (5 h), while a long carbonation period (5 d) led to a decrease in performance, contrary to the results obtained in the literature that indicate a significant increase in such characteristics. This difference could be because the literature focused on made-in-laboratory CDW aggregates, while, in this research, the wastes came from real demolition activities, and were thus older and more heterogeneous.


Author(s):  
Rijk Block ◽  
Barbara Kuit ◽  
Torsten Schröder ◽  
Patrick Teuffel

<p>The structural engineering community has a strong responsibility to contribute to a more efficient use of natural resources. Nowadays the construction industry is by far the most resource intense industry sector, approximately 40-50% of all primary raw materials are used, which raises the question about the architects and engineer’s accountability. In this context and as a result of the Paris Climate agreement the Dutch government defined the program “Nederland Circulair in 2050”, which states the ambition to use 50% less primary materials in 2030 and to have a full circular economy in 2050.</p><p>One possible approach to achieve these ambitious goals is the application of renewable, bio-based materials in the built environment and to replace traditional, typically cement-based, materials. Already in the past natural building materials, such as timber and bamboo have been used widely, but in recent years new materials came up and provide new opportunities to be used in the construction industry. The authors explored various alternatives, such as hemp and flax fibres, mycelium and lignin-based fibres for composite materials, which will be described with various experimental and realised case studies.</p>


2021 ◽  
Vol 36 (2) ◽  
pp. 182-191
Author(s):  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Sabina Dolenec ◽  
Katarina Ster ◽  
Mustafa Hadzalic ◽  
...  

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milici, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
João de Lassio ◽  
Josué França ◽  
Kárida Espirito Santo ◽  
Assed Haddad

The construction industry is increasingly concerned with improving the social, economic, and environmental indicators of sustainability. More than ever, the growing demand for construction materials reflects increased consumption of raw materials and energy, particularly during the phases of extraction, processing, and transportation of materials. This work aims to help decision-makers and to promote life cycle thinking in the construction industry. For this purpose, the life cycle assessment (LCA) methodology was chosen to analyze the environmental impacts of building materials used in the construction of a residence project in São Gonçalo, Rio de Janeiro, Brazil. The LCA methodology, based on ISO 14040 and ISO 14044 guidelines, is applied with available databases and the SimaPro program. As a result, this work shows that there is a substantial waste of nonrenewable energy, increasing global warming and harm to human health in this type of construction. This study also points out that, for this type of Brazilian construction, ceramic materials account for a high percentage of the mass of a total building and are thus responsible for the majority of environmental impacts.


2014 ◽  
Vol 803 ◽  
pp. 99-109 ◽  
Author(s):  
Muhd Fadhil Nuruddin ◽  
Fareed Ahmed Memon

Concrete has been used in the construction industry since long times. It is probably the most widely used construction material in the world, largely due to the abundance of the raw materials for cement manufacture, low relative cost and the versatility and adaptability of concrete in forming various structural shapes. Massive production of concrete and the associated substantial manufacture of cement have however been observed to have a very negative impact. One of the biggest issues of growing concern at the moment faced by concrete industries is the impact of cement production on the environment. The production of cement not only depletes significant amount of natural resources, but also liberates a considerable amount of carbon dioxide (CO2) and other greenhouse gases into the atmosphere as a result of decarbonation of limestone and the combustion of fossil fuels. In addition, cement is among the most energy intensive construction materials, after aluminium and steel [1].


2010 ◽  
Vol 636-637 ◽  
pp. 1286-1291
Author(s):  
M. Luiza Lopes O. Santos ◽  
Antonio Eduardo Martinelli ◽  
M.A.F. Melo ◽  
D.M.A. Melo

One of the major current environmental concerns is the excessive or inefficient consumption of non-renewable natural resources. The construction industry is one of the largest consumers of natural raw materials, playing an important role in the degradation of the environment. Recycling and reusing are concepts that can be effectively applied in the formulation of construction materials, especially mortars. In particular, calcareous quarry can replace, at least to some extent, the cement used in the composition of bricklaying mortars. The objective of this study was to prepare and characterize mortars containing calcareous quarry. The mortars were prepared using Portland CP II F – 32 cement, CH I hydrated lime, river sand and tap water. Different concentrations of residues, ranging from 5 to 30% were used to replace the cement. Mortars with volume ratio of 1:0.5:4.5, commonly used in bricklaying structural masonry, were evaluated. The water to cement ration was set to 1.45. The residue used was fully characterized to determine their specific mass, unitary mass, particle size distribution and morphology, and composition. The mortars were characterized both in their fresh and the results compared to those obtained from a residue-free composition. The results showed that the use of calcareous quarry partially replacing the cement did not significantly affect the performance of the mortars. Compositions containing up to 30% of calcareous quarry can be classified according to NBR 13281 (ABNT, 2005) as bricklaying mortars, and can be used by the construction industry.


1999 ◽  
Vol 40 (11-12) ◽  
pp. 155-162
Author(s):  
Roscoe F. Ward ◽  
Billy Huston

Paper mills are under constant pressure to increase their profits and to reduce their wastewater treatment costs. Champion International Mill in Hamilton, Ohio, is not an exception. The mill produces 340 to 365 tons/day of coated and uncoated printing and writing papers. Prior to 1996, Champion used less than 60 tons/day of secondary fiber. The usage of secondary fiber has increased to 100 to 114 tons/day. In 1996 improvements were made in the mill to reduce fiber losses. At that time the corporation also changed suppliers of polymers. As a result of these changes, the wastewater treatment plant saw its sludge disposal costs increasing. The solids from their screw presses decreased from 55% to 48%. This paper reports the series of options that were examined to improve the dewatering and to lower disposal costs. Included are changes in polymers and polymer applications, changes in the chemical sludge mixing, improved press orifice cleaning, and screw press motor load control systems. The effects of these changes have resulted in improved dewatering and the potential for even higher solids in the sludge cake. The economics of the sludge dewatering system are reviewed.


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