Effects of sewage sludge amendment and wetting–drying cycles of wastewater irrigation on structural improvement of clay soil

Author(s):  
A. N. Aboubacar Dan Badaou ◽  
U. Sahin

Sewage industry have generated huge amount of sewage sludge. It is found that the amount of sewage sludge generated by Malaysia sewerage companies has reached 5.3 million m3 per year. Sewage sludge (SS) are usually disposed into a landfill or incineration but due to the huge amount of sludge produced and limited availability of lad, it has become an environmental hazard. Thus, this research was conducted to utilize sludge that resulted from the wastewater treatment plant into fired clay brick as well as contributed to other alternative disposal method for the sludge. This research focuses on the investigation of indoor air quality of fired clay brick incorporating with SS. The SS was collected from IWK located at Senggarang and Perwira whilst clay soil was collected at Yong Peng, Johor. The characteristics of SS and clay soil were analyzed using X-ray fluorescence (XRF). From the results, it showed that SS was high with silicon oxide (SiO2 ) and zinc (Zn) that makes it compatible to replace clay soil as raw materials. Next, two types of sewage sludge brick (SSB) which are Senggarang brick (SB) and Perwira brick (PB) were incorporated with 0%, 1%, 5%, 10% and 20% of SS respectively. Then, the compressive strength test was conducted in accordance with the British Standard BS 3921: 1985. Based on the result, it shows that 5% of SS replacements as clay soil into fired clay brick have achieved the optimum strength. As for the indoor air quality (IAQ) test were done in walk-in stability chamber (WiSC) and the gas emission was compared with the Industry Code of Practice on Indoor Air Quality (ICOP-IAQ) through Department of Occupational Safety and Health Malaysia (DOSH, 2010). From the result, IAQ brick for SB and PB showed that up to 5% in fired clay brick were complied with the standard which below the acceptable limit that has provided for wall, column and cube formed. Thus, as a conclusion this method provided an alternative disposal method for the SS whilst producing a new low-cost building material with no negative effect to human as well as benefit to the environment.


1978 ◽  
Vol 58 (3) ◽  
pp. 381-389 ◽  
Author(s):  
A. J. MACLEAN ◽  
A. J. DEKKER

In a pot experiment with additions of Zn, Cu and Ni to a loam soil (pH, 6.3) at rates up to 480 ppm, sewage sludge eliminated the toxic effect of Cu and reduced the toxic effect of Ni on corn, reduced the concentrations of Zn and Ni in the plants, and reduced the amounts of DTPA-extractable metals and of 0.01 M CaCl2-soluble Zn and Ni in the soil. Lettuce grown with the metals and sludges was more susceptible than corn to the toxic effects of the three metals in the loam soil and to Zn in a clay soil (pH 5.9). In the latter soil, Ni was less toxic to lettuce than to corn. The concentrations of metals were considerably higher in lettuce than in corn. Liming of the clay soil to a pH of 6.5 eliminated the toxic effect of Ni on corn and of Zn and Ni on lettuce and reduced the concentrations of the metals in the plants and the amounts of DTPA-extractable and CaCl2-soluble metals in the soil. The order of magnitude of the DTPA-extractable metals was Cu > Zn > Ni whereas the order for CaCl2-soluble metals was Ni > Zn> Cu. Variability in the effect of the metals between crops and soils precluded the use, except as a preliminary guide, of a Zn equivalent concept based on the assumption that Cu is twice as toxic and Ni is eight times as toxic as Zn.


2011 ◽  
Vol 64 (4) ◽  
pp. 871-879 ◽  
Author(s):  
Gonçalo Sousa ◽  
David Fangueiro ◽  
Elizabeth Duarte ◽  
Ernesto Vasconcelos

The objective of the present work was to assess the short term potential of treated wastewater and sewage sludge for ornamental lawn fertilization and irrigation. A field experiment was performed and the following treatments were considered: sewage sludge application + irrigation with public water; sewage sludge application + irrigation with treated wastewater; irrigation with public water; irrigation with treated wastewater (TW). Irrigation with treated wastewater showed a positive effect on lawn installation through higher growth of grass (1,667 cm) and higher dry matter yield (18,147 g m−2). These results represent a significant increase in the grass yield compared with public water irrigation. The grass height (2,606 cm) and dry matter yield (23,177 g m−2) increased even more, when sewage sludge produced in the wastewater treatment plant (WWTP) was applied to soil, which proves once more its benefits as an organic fertilizer. At the end of the experiment, an increase of some soil parameters (pH, electrical conductivity, organic matter, Ca2+, Na+, K+, Mg2+ and NH4+) was observed, indicating that treated wastewater irrigation can cause a soil sodization. This short term study indicated that use of treated wastewater and sewage sludge for ornamental lawn fertilization and irrigation is an environmentally sustainable option for re-use of the WWTP by-products.


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