Filtration serves as an indispensable core component in water treatment processes, with its effectiveness directly determining the quality of the final effluent. This article systematically introduces the key application points of the filtration process at different stages, based on the actual operational needs of water treatment plants, and provides actionable technical solutions incorporating practical equipment such as bag filters, PP pleated cartridge filters, RO reverse osmosis equipment, self-cleaning filters, and basket filters.
The filtration process removes impurities in water through mechanisms including physical interception and adsorption separation. In actual operation, filtration efficiency is influenced by multiple factors: filter media characteristics determine filtration accuracy, operational parameters such as flow rate and pressure differential affect processing capacity, while inlet water quality directly impacts equipment selection.
Taking a typical multi-stage filtration system as an example, a reasonable process combination can achieve the following removal rates:
This efficient impurity removal not only ensures effluent safety but also significantly reduces chemical dosage in subsequent disinfection units, optimizing operational costs.
Pretreatment is the first line of defense ensuring stable operation of the entire system. At this stage, basket filters and bag filters play critical roles:
Basket filters are typically installed before pumps or at key equipment inlets. Constructed with stainless steel woven mesh, they effectively intercept large particles, aquatic mollusks, and other suspended substances in pipelines, with a general filtration accuracy of 500–3000 micrometers. Their unique basket design offers large dirt-holding capacity and extremely easy cleaning maintenance.
Bag filters use non-woven fabric or polyester filter bags with a filtration accuracy range of 1–200 micrometers, suitable for removing fine suspended particles and some colloidal substances. Their advantage lies in quick filter bag replacement and short system downtime, making them particularly suitable for continuous operation scenarios.
In practical applications, a surface water treatment plant with a daily capacity of 50,000 tons used a combined “basket + bag” pretreatment process to steadily reduce raw water turbidity from 15 NTU to below 3 NTU, significantly reducing the load on subsequent processes.
After pretreatment, water enters the core treatment stage, which mainly includes precision filtration and membrane separation.
The PP pleated cartridge filter, representing precision filtration equipment, uses polypropylene material formed through hot melting, with the cartridge exhibiting regular pleated structures. This design maximizes the filtration area within a limited space. With filtration accuracy reaching 0.1–45 micrometers, it effectively removes fine particles, rust, and other impurities, often serving as a pre-protection device for membrane treatment systems.
RO reverse osmosis equipment is the core of advanced treatment, utilizing the selective permeability of semi-permeable membranes to separate solutes from solvents under pressure drive. Modern RO systems typically include:
An electronics industry ultrapure water project adopted a combined “PP pleated cartridge + RO reverse osmosis” process, achieving stable effluent resistivity above 15 MΩ·cm, fully meeting electronic-grade water standards.
Self-cleaning filters demonstrate unique value in specific scenarios. This equipment automatically initiates cleaning programs through differential pressure control or timing settings, using suction scanning devices or reverse flow to remove contaminants from the filter screen surface.
Its main technical features include:
The application effect of self-cleaning filters is particularly significant in circulating cooling water systems. A petrochemical enterprise’s circulating water field, by installing self-cleaning filters, not only controlled suspended solids concentration below 5 mg/L but also reduced manual cleaning operations by 90%, achieving automated operation.
Correct equipment selection is a prerequisite for ensuring efficient operation of the filtration system. The following key factors need consideration during the selection process:
For basket filters, specifications are primarily determined based on pipeline diameter and expected intercept size; bag filter selection focuses on processing flow rate and filtration accuracy requirements; PP pleated cartridges require attention to chemical compatibility and temperature resistance; core parameters for RO equipment include recovery rate, desalination rate, and energy consumption indicators; self-cleaning filters need special consideration of automatic control methods and cleaning efficiency.
For system integration, a graded configuration model is recommended:
Operational data from a modern water plant shows that systems adopting this graded configuration generally experience a 30% or more extension in the service life of major equipment, with comprehensive system energy consumption reduced by approximately 15%.
Through scientific selection and reasonable configuration, the filtration system can not only meet different water quality requirements but also achieve optimal balance among operational costs, maintenance frequency, and system stability.
