scholarly journals Removal of Phosphorus from Synthetic Wastewater Using Recycled Concrete Aggregates as a Filter Medium

2018 ◽  
Vol 9 (1) ◽  
pp. 13-26 ◽  
Author(s):  
S. H. Adnan ◽  
R. Hamdan ◽  
N. A. Roni

These days, sustainability has become a primary concern as the large amount of natural resources are being used to produce materials such as concrete. Concrete from the construction industry constitutes the major proportion of construction waste. This could bring negative impact including depletion of natural resources, pollution, increasing landfill space, and high cost of waste disposal. All of these negative impacts are the sustainability issues that should be concentrated on. Hence, alternative methods have been introduced in order to reduce waste by recycling concrete waste. One of the alternative methods that can be used is by reusing recycled concrete aggregates (RCA) from discarded waste cubes. RCA can be used to produce new concrete but it will generally have a lower performance compared to normal concrete. Thus, the present study introduces an alternative method which is by reusing the RCA as a water filter medium to remove phosphorus from wastewater. Phosphorus is one of the inorganic compounds found in wastewater that can lead to environmental problems such as eutrophication. Based on previous studies, many types of materials with various chemical compositions have been used for phosphorus removal from wastewater. Therefore, this study demonstrates the ability of RCA as an alternative method for phosphorus removal from wastewater. In addition, three different factors have been considered in the removal of phosphorus namely, different initial concentration of phosphorus, different sizes of RCA and dosage of RCA used during the treatment process. Based on the experiments conducted, the lowest initial concentration of phosphorus of 10 mg/L, the smallest RCA size ranging between 0mm to 5mm and the highest RCA dosage of 50g resulted in the highest percentage of phosphorus removal in wastewater.

2018 ◽  
Vol 7 (4.30) ◽  
pp. 116
Author(s):  
Norwardatun Abd Roni ◽  
Suraya Hani Adnan ◽  
Rafidah Hamdan

This paper assesses of recycled concrete aggregates as a filter for removal of phosphorus in synthetic wastewater. Recycled concrete aggregate used as a filter system emerged as an alternative technology for phosphorus removal. This can overcome the problem of construction site waste by converting the waste into something valuable products. Thus, this study aim to determine the percentage of Phosphorus removal by using two different size of Recycled Concrete Aggregate which is (5 mm to 10 mm) and (25 mm to 30 mm). A total of five vertical recycled concrete aggregate filter laboratory scale was design using recycled concrete aggregate and five different concentration of synthetic wastewater which is 10 – 50 mg/L was prepared. Samples were taken from the influent and effluent filters to be tested once a week, and analyzed to determine the value of pH and the percentage of Phosphorus removal (%). RCA was analyzed using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) testing to determine chemical composition. Results shows that RCA is highly contained with Aluminium, Calcium and Magnesium elements that enhanced the phosphorus adsorption. The RCA with size 5 mm to 10 mm  and synthetic wastewater 10 mg/L display high potential in removing Phosphorus with 99.54% removal at pH 9.77. The lower concentration of synthetic wastewater, smaller size of RCA and higher pH have slightly better Phosphorus removal efficiency. Thus, RCA has a potential in removing Phosphorus from synthetic wastewater.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 695
Author(s):  
Natt Makul ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Abdullah M. Zeyad ◽  
Sergey Klyuev ◽  
...  

Currently, a number of disadvantages hampers the use of recycled concrete aggregates (RCA). The current review proves that concretes made with complete replacement of natural aggregate with RCA allow the production of high-quality concrete. One of the possibilities for improving concrete properties with RCA is the use of extended curing and pozzolanic materials with varying cement ratios. The potential use of RCA concretes is in the production of high-value materials that increase environmental and financial benefits. RCA have strong potential in the development of a new generation of concrete and stimulate economic activity in many countries in addition to optimizing natural resources. Economic benefits include minimal travel costs; cheaper sources of concrete than newly mined aggregates; reduction of the landfill area required for the placement of concrete waste; the use of RCA minimizes the need for gravel extraction, etc. The proposed strategy could be to sequentially separate demolition waste such as roof finishes, waterproof materials, interior and exterior materials, etc. Closing life cycles is the main approach used for efficient structures for the recycling and reuse of construction and demolition waste in the production and recovery of materials, especially when recycling and reusing materials. In the life cycle, the recycling of recovered materials allows them to be used for new construction purposes, avoiding the use of natural concrete aggregates. Government, design institutes, construction departments and project managers should be involved in the creation and use of RCA. In demolition and construction, the main players are the project owners. Their obligations, expectations and responsibilities must be properly aligned. For the past 20 years, recycled concrete aggregate from demolition and construction waste has been considered as an alternative to pure concrete in structural concrete to minimize the environmental impact of construction waste and demolition waste and the conversion of natural aggregate resources. It is now recognized that the use of RCA for the generations of concrete is a promising and very attractive technology for reducing the environmental impact of the construction sector and conserving natural resources. In the market, the selling price is not an obstacle for market applications of RCA, as there are scenarios in which their cost is lower than the cost of products made from conventional building materials. This is more of an acceptance factor in the market for recycled concrete aggregates. In this sector, the lack of identification, accreditation and uniform quality certification systems and their narrow application cause some marketing problems. With proper RCA preparation, concrete with standard physical and mechanical properties and performance characteristics can be obtained.


Author(s):  
Norwardatun Abd Roni ◽  
◽  
Suraya Hani Adnan ◽  
Nuramidah Hamidon ◽  
Tuan Noor Hasanah Tuan Ismail ◽  
...  

The removal of phosphorus from wastewater is a common procedure. Improving water quality is the aim of wastewater treatment. There are many types of conventional methods that have been used for the removal of phosphorus. Phosphorus reaction with chemicals can be removed immediately from water. However, the use of chemicals often increases the cost of wastewater treatment. This study aims to investigate the physical and chemical characteristics of RCA that influence the removal of phosphorus, as well as the percentage of phosphorus removal using RCA of two different sizes namely, 5 mm to 10 mm and 25 mm to 30 mm. The samples taken from the influent and effluent filters were tested and analysed in terms of the uptake capacity of phosphorus (q) and the percentage of phosphorus removal (%). The highest percentage of phosphorus removal achieved was 99.54% in the initial concentration of 10 mg/L by RCA measuring between 5 mm to 10 mm while the lowest percentage of phosphorus removal was 66.25% in the initial concentration of 50 mg/L for RCAs measuring between 25 mm to 30 mm. Furthermore, RCA achieved the highest uptake capacity (q) of 3.45 mg/L in the initial wastewater concentration of 50 mg/L. In conclusion, RCA has the potential to remove phosphorus, particularly in low concentrations of synthetic wastewater and high pH conditions.


Author(s):  
Gifty E ◽  
Harini Devi N ◽  
Meena P ◽  
Gunasekar S

With increase in population and urbanization, demand of raw materials such as cement and aggregate has increased in the construction industries. Further it has been recognized that waste from construction &demolition sectors are of large volume and this volume is increasing every year. Utilization of demolished waste offers not only the solution of disposal problems but also helps to conserve natural resources for meeting increased demand of aggregates and save energy. This study deals with the fabrication of concrete paver blocks using construction and demolition (C&D) waste as a replacement of natural aggregates.


2018 ◽  
Author(s):  
Driton R. Kryeziu ◽  
Armend Muja ◽  
Fisnik Kadiu ◽  
Visar Krelani ◽  
Besian Sinani ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 209
Author(s):  
Adilson C. Paula Junior ◽  
Cláudia Jacinto ◽  
Thaís M. Oliveira ◽  
Antonio E. Polisseni ◽  
Fabio M. Brum ◽  
...  

The search for environmental preservation and conservation of natural resources gives rise to new concepts and viable technical solutions on the path to sustainable development. In this context, this study’s main objective is to analyse the influence of recycled concrete aggregates (RCAs) on the development of pervious concrete, whose use as a floor covering represents an excellent device to mitigate the urban soil sealing phenomena. For this, mechanical and hydraulic tests were carried out, in addition to microstructural analyses and the assessment of its environmental performance. The results obtained were compared to reference studies also involving the incorporation of recycled aggregates. A pilot-scale case study was conducted, involving a parking space lined with pervious concrete moulded “in situ”. In laboratory tests, permeability coefficients and mechanical strengths compatible with the literature and above the normative limit for light traffic were found. The case study demonstrated higher permeability than in the laboratory, but the flexural strength was lower, being indicated only for pedestrian traffic. The environmental assessment showed that the RCA represents a positive contribution to the environmental performance of pervious concrete. Still, attention should be given to the recycled aggregate transport distance between the concrete plant and the RCA treatment plant.


2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.


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