Wastewater degradation test report
1. Water profiles of the water degradation testing
| Resource |
Company |
Environmental service companies |
| contact |
|
|
|
|
|
| Water Ingredient |
Introduction |
Wastewater containing methyl phosphate, dimethyl phosphate and ethyl phosphate |
| COD |
>60000 |
TOC |
|
| Ammonia |
|
Total nitrogen |
|
| pH |
5.34 |
Total phosphorus |
|
| Chloride ion concentration |
|
Salt content |
over 60000 |
| others |
|
| toxicity |
|
| Sample time |
|
| requirement |
COD ≤ 20000 |
| Note |
|
water profile and major pollutants: wastewater sources from an environmental service company, and the major pollutants are methyl phosphate, dimethyl phosphate and ethyl phosphate.
COD value over 60000 mg/L
Ammonia, total nitrogen, and total phosphorus, chloride ion concentration, toxicity and etc, these indicators relevant to nutrient levels and water quality are not traced and recorded during the testing processes.
pH value at 5.34
Salt content at 60000 ppm
Aimed/required COD value of the effluent after electrochemical oxidation testing will be less than 20000 mg/L
2. Experimental principle With Wastewater Degradation Processes
This experiment uses the principle of electrochemical oxidation, with the BDD electrode as the core catalyst material, and finally converts the organic matter in the water sample into CO2 and H2O.
This specific experiment and testing processes could remove methyl phosphate, dimethyl phosphate and ethyl phosphate via direct oxidation at the surface of the boron doped diamond BDD anode, mainly through the electron transfer, major organic compounds such as methyl phosphate, dimethyl phosphate and ethyl phosphate and etc, could be oxidized directly into intermediates, and then inorganic compounds, water, and carbon deoxide via further oxidations.
Indirect oxidation involves oxidation of refractory organic compounds via active oxidizing agents, generated via electrochemical oxidation processes, those oxidizing agents have strong electrochemical oxidation potential, mainly hydroxyl radicals, ozone, hydrogen peroxides, and in other cases, cholride ions and Hclo, and etc,.
Methyl phosphate compounds and variations, once react with hydroxyl radicals, triggering hydrogen abstraction at the alpha-position of the phosphate, hydrogen abstraction is one of the four major pathways of hydroxyl radicals mineralizations processes, the hydrogen abstraction processes primarily generates alpha-phosphatoalkyl radicals, which can then react with other molecules like tetranitromethane (TNM).
Experimental Operation With Wastewater Degradation Processes
Trial test with wastewater degradation processes
Take 900ml of water sample into the electrochemical oxidation beaker trial module, put it into the BDD electrode module, connect the power supply, adjust the current intensity to 8A, and start to degrade. During the degradation process, the water sample is stirred with a magnetic stirrer to make it uniform. Take samples at regular intervals, record current and voltage values, and measure temperature and pH.
3.2 Middle test
Electrolyzer type pilot plant; take 70L water sample, electrode area 0.624㎡, adjust pulse power average current 220A, frequency 12000Hz, duty cycle 60%, average voltage is 13.5V.
4. Experimental phenomenon
Before degradation, the water sample was basically colorless; a very small amount of foam was produced during the degradation process, and almost no precipitation was produced.
5. Results and analysis
| Time/h |
Voltage /V |
Current/A |
BDD area /cm2 |
COD/ mg/L |
| 0 |
4.75 |
220 |
150 |
67932 |
| 10 |
40601 |
| 14 |
32070 |
| 16 |
24840 |
| 18 |
20300 |
Bench Test of Wastewater Degradation via Electrochemical Oxidation Wastewater Treatment Processes
| Time/h |
Voltage
/V |
Current/A |
BDD area
/cm2 |
COD/
mg/L |
| 0 |
13.5 |
220 |
0.624 |
67932 |
| 11 |
44628 |
| 19 |
32153 |
| 27 |
16520 |
| 35 |
2363 |
6. Comparison of experimental results of wastewater degradation
Comparing the energy consumption per ton of water when calculating COD=20,000, considering the pilot test 25h, the pilot test energy consumption is 49.1% of the pilot test, and the efficiency is 2.0364 times that of the pilot test.
To control the stability of the water volume, the accuracy of the comparison experiment is pursued; the temperature of the pilot test water is controlled at about 50℃; if the evaporation of water does not need to be considered, adjusting the higher temperature can further increase the electrolysis efficiency.
