scholarly journals Wastewater sludge disposal in the claydite construction product

Author(s):  
Ekaterina Koroleva ◽  
Victor Bazhenov
2002 ◽  
Vol 46 (10) ◽  
pp. 295-303 ◽  
Author(s):  
H. Ødegaard ◽  
B. Paulsrud ◽  
I. Karlsson

The paper discusses different strategies for the disposal of wastewater sludge, particularly the “use on land” strategy and the “productification” strategy. In the “use on land” strategy the new regulations in Europe call for stabilization as well as disinfection of sludge to be used on land. The paper discusses the design and operation experiences with stabilization/disinfection methods in Norway where such treatment has been compulsory since 1995. In the “productification” strategy it is differentiated between the production of “bio-soils” and production of specific products (energy, nutrients, coagulants etc) and the “marketability” of these products is evaluated. An example of a sludge treatment concept aimed at recycling - the KREPRO process - is presented.


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.


2007 ◽  
Vol 2 (4) ◽  
Author(s):  
Heidi G. Snyman

This paper deals with the trends, legislative framework and current sludge management practices in southern Africa. Recognising that a large percentage of the Southern African population is not serviced with full waterborne systems, a paper on the management of sludge in the region would not be complete without discussing the management of faecal sludge (FS) from on-site sanitation systems as well. The first half of the paper focuses on the management of wastewater sludge from waterborne sewage systems. The research papers from the region focus primarily on the impact of sludge application on land and agricultural use. The wastewater sludge disposal practices and legislative trends in South Africa are discussed in detail including an overview of the technologies that are used to stabilise, dewater and dry the wastewater sludge. The majority of plants in South Africa do not treat the sludge further than the traditional anaerobic digestion and activated sludge extended aeration. Final disposal methods are still dominated by on-site disposal methods including direct land application (dedicated land disposal) and stockpiling of the sludge on site. The second half of the paper focuses on the management of FS from on site sanitation systems. The FS, which is often contaminated with domestic waste, originating from these on-site sanitation systems requires responsible handling and disposal. The problems and challenges in FS management are highlighted as well as the recommended legislative trends.


2000 ◽  
Vol 42 (9) ◽  
pp. 1-5 ◽  
Author(s):  
P. A. Vesilind

The United State Environmental Protection Agency (U.S. EPA) attempted to set health-based regulations for sludge disposal and used worst-case scenarios to estimate the detrimental health effect. In the absence of adequate information, this exercise led them to err so much on the conservative side that the regulations became unrealistic and would not have been accepted by the public. So the US EPA decided to do what was expedient – to establish regulations that allow most wastewater treatment plants to dispose of their sludges, knowing that these regulations are better than none at all. Such regulatory decision-making has ethical ramifications because it involves distributing costs and benefits between affected citizens. The principle of expediency as articulated by Earle Phelps calls for a regulator to optimize the benefits of health protection while minimizing costs within the constraints of technical feasibility. Phelps' expediency principle, proposed over fifty years ago, is still a useful application of ethics using scientific knowledge to set dynamic and yet enforceable environmental regulations. In the case of sludge disposal, the US EPA made an ethical decision based on the principle of expediency, weighing the moral good of human health protection versus the moral harm of taking wealth by requiring costly wastewater sludge treatment and disposal.


Author(s):  
А.Н. Григорьева ◽  
Р.Ш. Абиев ◽  
Ф.И. Лобанов ◽  
О.Ю. Тарарыков

Проблема утилизации осадка сточных вод в последние годы становится все более актуальной для коммунального хозяйства. Приведены результаты исследования процесса суспендирования осадка известьсодержащим реагентом Дезолак, определены размеры твердых включений, что позволило рассчитать необходимую скорость вращения перемешивающего устройства: средний заутеровский диаметр частиц составил 55 мкм, плотность твердой фазы – 2211 кг/м3. Для эффективного суспендирования реагента необходимо обеспечить угловую скорость мешалки не менее 0,03 м/с. Исследованы основные критерии подобия для масштабирования аппаратов, определено, что при выборе мешалки следует учитывать критерий Фруда Fr, так как именно этот показатель для трех исследованных реакторов практически постоянен. На основании проделанной работы определено, что отношение мощности к объему перемешиваемой жидкости не может являться критерием для расчета аппаратов, оснащенных перемешивающими устройствами GMS: для данных мешалок справедливо снижение мощности на перемешивание с увеличением размеров аппарата. In recent years the problem of wastewater sludge disposal has become more and more urgent for the municipal economy. The results of a study of the process of sludge suspending with Dezolak, a lime-containing agent, are presented; the size of solid inclusions is determined to provide for calculating the required rotation speed of the mixing device: the average Sauter particle diameter was 55 μm, the density of the solid phase was 2211 kg/m3. For effective chemical suspending the angular velocity of the mixer should be more than 0.03 m/s. The main similarity criteria for scaling the apparatus were investigated; it was determined that while choosing a mixer, the Froude criterion Fr should be taken into account, since that very indicator was practically constant for the three investigated reactors. Based on the work done, it was determined that the ratio of power to the volume of the mixed liquid cannot be a criterion for calculating devices equipped with GMS mixing devices: for these mixers, a decrease in the mixing power with an increase in the size of the device is valid.


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.


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.


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.


1996 ◽  
Vol 34 (7-8) ◽  
pp. 179-186 ◽  
Author(s):  
C. J. Hu ◽  
R. A. Gibbs ◽  
N. R. Mort ◽  
H. T. Hofstede ◽  
G. E. Ho ◽  
...  

The beneficial use of wastewater sludge is to some extent restricted by the presence of human pathogens. Following a risk assessment and monitoring programme it was found that the pathogen which posed the highest potential risk of infection in treated sludge was Giardia. Giardia cyst concentrations were found to be approximately 900/g wet weight of sludge following anaerobic digestion, although not all of the cysts may have been infective. In further studies three methods of wastewater sludge disposal or treatment were investigated. Anaerobically digested and mechanically dewatered sludge was stored for up to 60 weeks, incorporated into sandy soil and composted on a laboratory scale. Giardia cysts remained at levels which could be considered a public health concern after storage of sludge for over one year and after composting. However, cysts appeared to be destroyed within 12 weeks following soil amendment. The implications of the presence of Giardia for sludge disposal are discussed.


1989 ◽  
Vol 65 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yvon Grenier ◽  
Denis Couillard

A literature review brings some evidences that wastewater sludge disposal in the forest is technically feasible since specialized machines have been designed for this purpose. Sludge utilization could be a part of a forest management plan where this particular form of fertilization would take place during silviculture operations. Additional height yields of 350% after 4 months growth with seedlings and 250% after 3 years with young plants have been observed showing that forest fertilization with wastewater sludge is beneficial. The use of agricultural land only for disposal of the sludge production of a municipality may be inadequate; wooded areas can be used as complementary surfaces to maximize the recycling of this new resource, the sludge. Key words: forest fertilization, forest management, spreading machinery, wastewater, sludge.


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