By: Pimluck Kijjanapanich

I Introduction O Objectives S Scope of Study L Literature Review マスタ タイトルの書式設定 M Methodology マスタ タイトルの書式設定 R1R1 Results and Discussion C Conclusions R2R2 Recommendations

the result of oxidation by air and water of metal sulfides contained within mined rock as well as mine wastes. high acidity and high amounts of dissolved heavy metals such as Fe, Zn, Ni, Cu and Pb. extremely toxic to most organisms in both terrestrial and aquatic ecosystems.

The pH modification method - by using lime (CaO), limestone (CaCO 3 ), sodium hydroxide (NaOH) or sodium carbonate (Na 2 CO 3 ) Ion exchange Adsorption treatment Electrochemical treatment Membrane process An interested approach to AMD treatment has been developed that imitate sulfate reduction phenomena occurred in the nature that carry out by sulfate reducing bacteria (SRB) and developed to use for AMD treatment. Disadvantages of the conventional active treatment of AMD (Brown et al., 2002) Relatively high operation and equipment maintenance cost The sludge is chemically complex, unstable, low density and gelatinous resulting large volumes, making difficult and causes long-term problematic disposal

the use of anaerobic sulfate reducing bacteria (SRB), which can reduce sulfate to sulfide by oxidizing an organic carbon source.

an emplacement of reactive materials in the subsurface designed to intercept a contaminant plume, provide a flow path through the reactive media and transform the contaminant(s) into environmentally acceptable forms to attain remediation concentration goals down-gradient of the barrier (Powell and Puls, 1997).

Funnel-and-gate PRB Continuous PRB

No need for expensive above-ground facilities for storage, treatment or transport, other than monitoring wells. After the installation the above-ground can be reused. There are no energy input and limited operational and maintenance costs. The in situ contaminant remediation is more effective than the simple migration control achieved by the impermeable barriers. Contaminants are not brought to the surface so that there is no potential cross media contamination. There no disposal requirements or disposal costs for treated wastes. Avoid the mixing of contaminated and uncontaminated water that occurs with pumping. Advantages of Permeable Reactive Barrier (Powell and Puls, 1997; Puls et al., 1999)

To develop an appropriate PRB system for treating Acid mine drainage (AMD) The specific objectives are: To select the appropriate organic material used as electron donors for treating AMD using PRB. To investigate the reaction rate through batch and continuous studies for evaluation of residence time in PRB To investigate the effect of pH and alkalinity on PRB performance. To investigate the performance of PRB in removing of heavy metal.

Reactivity Stability Availability and cost Hydraulic performance Environmental compatibility Safety Waybrant et al., 1995 the combination of more than one organic source is more successful than the use of solely one material. Gibert et al., 2004 The lower the content of lignin in the organic substrates, the higher its degradability and capacity for developing bacterial activity and sheep manure was the most successful electron donor (sulfate removal level of > 99%)

A group of anaerobic bacteria that can reduce sulfate to form sulfide. The genus Desulfovibrio is one of the most mentioned species in studies of SRB in natural water and wastewater. Gram negative, curved rods and usually having a single polar flagellum.

Anaerobic environment (Eh around -200 mV) pH 5-8 The presence of electron donor and appropriate sulfur species A physical support According to the study of Costa et al. (2007), no SRB activity was observed at pH 2. On the other hand, at pH 5 and 7 SRB growth was observed and this different pH (5 and 7) was not significantly to affect SRB growth.

Literature Review Selection of organic carbon sources Laboratory Analysis Data analysis and Discussion Conclusion and Recommendation Phase I: Batch Test Experiment set-up Investigate appropriate organic carbon sources and optimum residence time. Phase II: Column Test PRB column design Select the two of the best organic carbon. Investigate the effect of pH and alkalinity and heavy metal removal efficiency.

To investigate appropriate organic carbon sources and optimum residence time.

Five organic materials Rice huskCoconut husk chip Bamboo chip Municipal compost (septage) Composted pig manure

valves gas releasing pipe 30 cm 7 cm Organic Material 300 mL (20% by volume) SRB source 100 mL (7% by volume) AMD pH mL (66% by volume) 1.5 L Reaction Bottle

The 3 types of single material were selected: the two of the single materials that have maximum sulfate reducing rate (composted pig manure, rice husk). the single material that has long lasting (coconut husk). PR C

Type of Organic Material Mixture Rice husk Coconut husk chip pig manure Rice husk & Coconut husk (RC) 50:50++- Pig manure & Rice husk (PR) 50:50+-+ Pig manure & Coconut husk (PC) 50:50-++ Pig manure, Rice husk & Coconut husk (PRC) 33:33:33+++ => Mixed Material RCPRPCPRC Remark:+ Have this type of organic material in the formula - No have this type of organic material in the formula

=> Batch ParametersMethods AlkalinityTitration Method Oxidation-reduction potential (Eh) ORP meter pHpH meter SulfateTurbidimetric Method Volatile solid per total solid (VS/TS) Dried at 105 and 550 o C => Sampling Two of the reaction bottles were finished for analyzing at each sampling time.

To investigate the effect of pH and alkalinity and heavy metal removal efficiency.

Log phase Estimation of the Reduction rate and Residence time Slope = -k

NaOH 30 mL/hr (0.155 cm/hr) screen gas releasing pipe  0.4 cm NameA1L1A2L2 Lime adding-+-+ Formula1122

ParametersMethods AlkalinityTitration Method Dissolved Organic Carbon (DOC) High-Temperature Combustion Method Heavy Metal (Fe, Cu, Zn and Mn) Inductively Coupled Plasma (ICP) Oxidation-reduction potential (Eh) ORP meter pHpH meter SulfateTurbidimetric Method => Continuous

ParametersValueStandard*Standard** pH Acidity, mg/L CaCO Total hardness, mg/L CaCO Calcium, mg/L260-- Magnesium, mg/L54-- Sulfate, mg/L623-- Iron, mg/L Manganese, mg/L15.1 not excess 0.5 not excess 1.0 Copper, mg/L0.074 not excess 1.0 not excess 0.1 Lead, mg/L0.005 not excess 0.01 not excess 0.05 Zinc, mg/L1.80 not excess 5.0 not excess 1.0 * Groundwater Quality Standards of Thailand ** Surface Water Quality Standards of Thailand

Type of organic materials Volatile solid/Total solid in 22 days (VS/TS) rice husk Reduced from to coconut husk chip Maintained at bamboo chip Maintained at municipal compost (septage) Reduced from to composted pig manure Reduced from to Volatile solid per Total solid (VS/TS)

=> pH Alkalinity =>

=> Oxidation Reduction Potential (Eh) Sulfate Removal =>

=> Color change in effluent Bamboo chip mediaSeptage mediaComposted pig manure media Coconut husk mediaRice husk media Change of color in effluent of each organic material in 8 days

=> Color change in media composted pig manure media in 16 days bamboo chip media in 16 days

=> Alkalinity Oxidation Reduction Potential (Eh) =>

=> Sulfate Reduction Sulfate Removal =>

Log phase Using % Sulfate removal = 90% From the calculation, HRT = days Safety factor = 1.5, HRT = days Reactor size = 15 L Estimation of the Reduction rate and Residence time

NamePRNPRLPRCNPRCL Lime adding-+-+

=> Alkalinity Oxidation Reduction Potential (Eh) =>

=> Sulfate Reduction Sulfate Removal =>

=> Heavy metal Removal FeCu Zn Mn

Hydroxide Precipitation

=> Dissolved Organic Carbon (DOC)

Composted pig manure and rice husk had maximum sulfate reducing rate and coconut husk had long lasting The suitable hydraulic retention time (HRT) was 16 days. The percentage of sulfate removal was up to 98%, which the residue sulfate concentration was 14.5 mg/L in PRL media. Effluent pH can be maintain in neutral range (6-8) and effluent alkalinity from composted pig manure was the highest. The concentrations of iron reduced from mg/L to around 2 mg/L and copper & zinc concentrations could reach below groundwater quality standards of Thailand. The percentages of iron, copper, zinc, and manganese removal were 93 %, 99 %, 88%, and 96 % respectively in PRL reactor. The column reactors, which added lime into the media, had more efficiency than the reactor that no lime in the media.

Other type of organic materials should be tested. The appropriate ratio of each type of organic material should be defined. The lower pH of AMD should be tested on PRB system. Other type of heavy metal and other concentrations of iron, copper, zinc, and manganese should be tested on PRB system. Plug flow system reactor should be developed to solve the completely mixed problem. AMD from different type of mine should be investigated on PRB system. Performance of pilot should be further investigated.