Remediation of gold smelting wastewater using biogenic hydrogen sulfide

Date

4-2010

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Rex B. Demafelis

Co-adviser

Lorele Trinidad

Restrictions

Restricted: Not available to the general public. Access is available only after consultation with author/thesis adviser and only to those bound by the confidentiality agreement.

Abstract

Goldsmelting and jewelry-making are considered to be two of the main sources of livelihood in Bulacan. But the same industry that brought development to the towns was the same one that killed the river system. . A study released by EMB last April 2007 stated that these industries generally do not have wastewater treatment facilities and are expectedly discharging wastes into the Marilao- Meycauayan- Obando (MMO) river system. The general objective of the study is to evaluate the feasibility of using biogenic H2S produced by a local bacterial isolate to remove Cu2+ from gold smelting wastewater. Gold smelting wastewater was treated with hydrogen sulfide produced by a local bacterial isolate to precipitate out copper as copper sulfide. Wastewater was characterized and was found to have 7025 ppm copper, COD of 387.45 mg/L, pH of 0.81, and conductivity of 91.7 mS/cm. A comparative analysis of the three sulfate reducing media showed that Calcium Sulfate ? Egg Media (CEM) was the most efficient in terms of copper removal efficiency. The optimum pH and temperature for CEM to produce maximum amount of H2S was found to be pH 10 at 36°C. The wastewater needed to be purged every 8 hours for 20 minutes to avoid accumulation of toxic hydrogen sulfide that is fatal to the bacteria. Maximum copper removal at a single purging was attained at initial copper concentration of 5000 ppm. Copper content of gold smelting wastewater was reduced below DENR standards of 1.2 ppm. The results of the study showed that copper removal using biogenic hydrogen sulfide is feasible for gold smelting wastewater.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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