Cement-based solidification/ stabilization of nickel-containing paint sludge using rice hull ash as additive and wastewater effluent from automotive stamping industry as hydrating agent

Date

4-2009

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Amelia E. Parao

Co-adviser

John Meynard M. Tengco

Committee Member

Catalino G. Alfafara, Jewel A. Capunitan

Abstract

Solidification/stabilization technology was used to treat nickel-containing paint sludge using rice hull ash as additive and wastewater effluent as hydrating agent. To determine the effect of varying mass proportions of the raw materials on the compressive strength, leachability and durability of the solidified/stabilized blocks, seven treatments were studied based on the ratio of ordinary Portland cement (OPC); rice hull ash (RHA); sludge. Treatment A served as control with distilled water as hydrating agent (1.0 OPC: 0.0 RHA: 0.0 sludge), Treatment B (1.0:0.0:0.), Treatment C (0.5:0.0:0;5), Treatment D (0.6:0.4:0.0), Treatment E (0.30:0.35:0.35), Treatment F (0.56:0.19:0.25) and Treatment G (0.533:0.233:0.233). Based from the Unconfined Compressive Strength (USC) Test, Treatment C and E failed because the mean USC values were below the standard for landfill use which is 50 psi. Treatment B showed the highest mean USC value to the presence of cement only while Treatment E with high amount of sludge exhibited the lowest. The strength of the blocks decreases with increasing amount of rice hull ash and sludge. For Toxicity Characteristic Leaching Procedure, Treatment E showed the highest amount of nickel in its leachates. Treatment F exhibited the lowest concentration of nickel. All the treatments passed the regulatory limit for sludge leachates which is 5ppm.From the results of Durability Test, Treatment C and E exhibited the highest percent weight loss. These two treatments failed the test since the percent weight loss exceeded the allowable which is 15% of the original sample. The lowest percent weight loss was Treatment A because it contained pure cement. The percent weight loss increase due to increasing amount of sludge and rice hull ash. Based from the results of the different tests and the cost analysis, Treatment F is the best recommended mixture proportions for the raw materials used because it has a lower total projected cost to immobilize the nickel to avoid leaching out into the environment. Also, based on the model, the predicted optimum ratio should be along the yellow, light yellow and light green regions for compressive, leachability and durability tests.

Language

English

Location

UPLB College of Engineering and Agro-Industrial Technology

Document Type

Thesis

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