How to Treat Soapy Wastewater With Methanol

Treating wastewater (defined as any water with unwanted organic, solid or chemical materials) is a process that requires patience and exactness to execute successfully, but is nonetheless one that greatly benefits the environment. For example, soapy wastewater -- such as that produced after washing a car -- contains chemicals that can harm marine life if dumped untreated into a drainage system. When planning to discharge water into an enclosed body of water, advanced biological treatments are often necessary. Examples of biological treatments include nitrification and denitrification, the latter method using a source of carbon (such as methanol) that uses bacteria already present in the wastewater to remove nitrates. Several factors in the nitrification and denitrification process -- such as temperature, pH level, and methanol amount -- must be carefully monitored throughout treatment.

Things You'll Need

• Large container
• Wastewater
• Ammonia
• Methanol
• Oxygen sensor
• pH Meter
• Thermometer
• Nitrate meter

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Instructions

• 1

  Measure dissolved oxygen levels in the wastewater using an oxygen sensor or other oxygen probe. Dissolved oxygen levels must be between 2-3mg/L for nitrification to take place, and 4.5 pounds of total dissolved oxygen are required for each pound of ammonia that must be converted to nitrate. Using these parameters, pour the proper amount of ammonia into the wastewater.

• 2

  Monitor the pH levels of the wastewater during the nitrification process using a pH meter. Optimum pH levels must measure between 7.8 and 9.0, though nitrification does occur outside of this range as well. Low alkalinity may be a concern, but avoid using quicklime or other highly reactive materials to stabilize pH levels unless cautionary measures are used and health guidelines followed.

• 3

  Add three to four pounds of methanol to the wastewater for each pound of nitrate. Be careful, for if you use excess methanol, it will be present in the treated water. Because denitrifying bacteria grow slowly and are sensitive to temperature, ensure that the temperature of the wastewater remains at roughly 20 degrees Celsius using a thermometer to monitor it. Also use the pH meter to ensure that pH levels are between 6.0 and 8.0

• 4

  Use a nitrate meter to measure the concentration of nitrates in the wastewater. Although no wastewater should ever be consumed that has not been treated by public health officials, current government standards require that concentrations of nitrate should not be above 45 parts per million (ppm) for drinking water. If nitrate levels are below 45 ppm, the nitrification and denitrification processes can be considered a success.