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Wastewater treatment methods are the process of purifying wastewater using physical, chemical, and biological methods, aimed at reducing pollution, achieving wastewater recycling and reuse, and fully utilizing water resources. The following is a detailed explanation of wastewater treatment:
1、 Wastewater type
Wastewater is mainly divided into the following categories:
Domestic wastewater: The wastewater discharged by people in their daily activities is mainly polluted by domestic waste and human excrement. This type of wastewater contains a large amount of bacteria and pathogens, which poses a certain level of harm from a hygiene perspective.
Industrial wastewater: Wastewater generated in industrial production, containing specific and easily identifiable compounds, depending on the nature of the industrial process. Industrial wastewater usually contains pollutants such as heavy metals and organic compounds, which are highly toxic and pose a great threat to human health.
Rainwater and sewage: Rainwater runoff collected from pipeline systems or open channels.
2、 Handling method
Wastewater treatment methods mainly include physical methods, chemical methods, and biological methods.
1. Physical Law
Gravity separation method: using gravity to cause suspended solid particles in wastewater to sink, thereby achieving solid-liquid separation. Common processing equipment includes sedimentation tanks, settling tanks, etc.
Centrifugal separation method: By the action of centrifugal force, suspended particles in wastewater are separated from water. Common processing devices include centrifugal separators and water cyclone separators.
Screening and interception method: using equipment such as grids and sieves to intercept suspended solids in wastewater. In addition, processing methods based on the principle of heat exchange, such as evaporation, crystallization, etc., also belong to physical processing methods.
2. Chemical method
Neutralization method: By adding chemical agents, the pH of wastewater is adjusted to achieve neutrality or near neutrality.
Coagulation method: Adding coagulants to wastewater to aggregate colloidal particles and small suspended solids into coarser flocs, which are then removed through precipitation or filtration.
Redox method: Using oxidants or reducing agents to convert harmful substances in wastewater into harmless substances. For example, using oxidants such as ozone and potassium permanganate to remove organic matter from wastewater.
Ion exchange method: suitable for removing ionic pollutants from water, commonly used for desalination of wastewater.
Electrolysis method: Removing pollutants from wastewater through electrochemical reactions. Especially suitable for high salt wastewater.
3. Biological Law
Activated sludge process: utilizing microorganisms in activated sludge to adsorb and degrade organic matter in wastewater.
Biofilm method: Contact wastewater with biofilms (such as filter media, fillers, etc.), and use microorganisms on the biofilm to degrade organic matter in the wastewater. Biological contact oxidation method belongs to this category, with low sludge volume and simple operation and management, suitable for industries with high requirements for sewage treatment.
Anaerobic biological treatment method: Under anaerobic or low oxygen conditions, anaerobic microorganisms are used to degrade organic matter in wastewater. Suitable for the treatment of high concentration organic wastewater.
