Direct drinking water equipment is a specialized device designed to provide purified water for concentrated populations such as campus teachers and students, community residents, hotel guests, etc. Its core is to use multi-stage filtration and deep purification technology to treat tap water or groundwater to meet the direct drinking standards of the “Sanitary Standards for Drinking Water” (GB 5749-2022). The following provides a detailed explanation from both the general structure and working principle, taking into account the characteristics of devices in different scenarios:
1、 Core structure of direct drinking water equipment (universal configuration)
Direct drinking water equipment usually adopts a combination design of “pretreatment+deep purification+terminal sterilization+intelligent control”, with the following specific components:
1. Preprocessing unit (protects the core filter element and extends its lifespan)
PP cotton filter
Construction: Cylindrical filter element (made of polypropylene melt blown) with an accuracy of 5-10 μ m, installed in transparent or stainless steel filter bottles.
Function: Intercept large suspended particles such as sediment, rust, and insect eggs in tap water or groundwater, reduce turbidity, and avoid scratching subsequent precision filters.
Particle activated carbon filter
Construction: 304 stainless steel or fiberglass filter canister filled with coconut shell granular activated carbon (specific surface area ≥ 1000m ²/g).
Function: Absorb residual chlorine (disinfectant residue in tap water), organic matter (such as pesticides, humic acid), odors (earthy smell, disinfectant smell), and pigments in water, improve water quality and taste, and protect subsequent reverse osmosis membranes from oxidation by residual chlorine.
Compressed activated carbon filter (optional)
Construction: A rod-shaped filter element made by pressing activated carbon powder, with an accuracy of 1-5 μ m.
Function: Further adsorb small organic matter and residual chlorine, while intercepting activated carbon powder, improving pretreatment accuracy (suitable for areas with poor water quality).
2. Deep purification unit (core desalination and sterilization process)
Reverse osmosis membrane system (RO system, mainstream technology)
Construction:
Precision filter (security filter, 5 μ m PP filter element, intercepting fine particles remaining from pre-treatment);
High pressure pump (providing 1.0-1.5MPa pressure to drive water molecules through the reverse osmosis membrane);
Reverse osmosis membrane module (roll type composite membrane, pore size 0.0001 μ m, desalination rate ≥ 99.5%);
Automatic flushing valve (flushes the film surface during startup/shutdown to prevent impurity deposition).
Function: Through the selective permeability of reverse osmosis membranes, soluble salts (calcium, magnesium ions, etc.), heavy metals (lead, arsenic), bacteria, viruses, etc. in water are intercepted, producing high-purity direct drinking water (conductivity ≤ 50 μ S/cm).
Ultrafiltration system (UF system, selected in some scenarios)
Construction: Hollow fiber ultrafiltration membrane (pore size 0.01-0.1 μ m), made of PVDF or PES, with strong pollution resistance.
Function: Remove bacteria, viruses, colloids, and large organic molecules, but cannot desalinate (suitable for areas with low TDS in raw water, such as tap water in some southern cities). The produced water can be consumed directly (requires UV sterilization).
3. Terminal processing and storage unit
Post installed antibacterial activated carbon filter
Construction: A small activated carbon filter cartridge (usually sintered activated carbon) installed at the water production end of reverse osmosis/ultrafiltration.
Function: Absorb slight odors that may be generated by reverse osmosis membranes, further improve taste, and inhibit bacterial growth.
UV sterilizer (mandatory)
Construction: Stainless steel chamber, built-in 254nm wavelength UV lamp, irradiation time ≥ 30 seconds.
Function: To kill microorganisms (such as bacteria and viruses) that may remain in the produced water, ensuring the sterility of direct drinking water (sterilization rate ≥ 99.99%).
Pure water tank/storage tank
Construction: Made of 304 stainless steel material (smooth inner wall, easy to clean), equipped with a breathing filter (to prevent bacteria from entering the air).
Function: Store purified drinking water, and use a liquid level sensor to link the front-end equipment to start and stop, ensuring continuous water supply.
4. Transportation and Terminal Equipment
Circulating pipeline network: using food grade 304 stainless steel pipes (polished inner walls) to avoid secondary pollution; Some systems are designed for circulating water supply (continuous flow of water) to prevent the growth of bacteria in stagnant water.
Terminal water dispenser: installed in teaching buildings, community corridors, hotel guest rooms, and other areas, with room temperature, heating, and cooling functions (optional). The water outlet is equipped with a dust cover and a button disinfection device (such as ultraviolet button disinfection).
5. Fully automatic control system
Core components: PLC controller, touch screen, pressure sensor, liquid level sensor, conductivity meter (reverse osmosis system).
Function: Automatically control device start stop (based on water tank level), membrane cleaning (timed or triggered by pressure difference), fault alarm (such as water shortage, membrane fouling), support remote monitoring (optional IoT module), convenient operation and maintenance management.
2、 Working principle (taking the mainstream “reverse osmosis+ultraviolet sterilization” system as an example)
Pre treatment stage: The tap water is first filtered through PP cotton to remove large particle impurities, and then the residual chlorine and organic matter are adsorbed by granular activated carbon. The compressed activated carbon is further purified to ensure that the water quality entering the deep treatment unit meets the standard.
Deep desalination stage: The pre treated water is protected by a precision filter and pressurized by a high-pressure pump into the reverse osmosis membrane module. Water molecules pass through the membrane to form pure water, while salt and impurities are discharged with concentrated water; The membrane surface is regularly washed automatically to maintain filtration efficiency.
Terminal optimization stage: The reverse osmosis produced water is treated with post activated carbon to improve its taste, and then sterilized by ultraviolet sterilizers to ensure sterility; Finally stored in a pure water tank and transported to various terminal water dispensers through a circulating pipeline network.
Intelligent control stage: The system monitors water quality (conductivity), pressure, liquid level and other parameters in real time, automatically adjusts the operating status, alarms in case of water shortage or failure, and ensures stable production of qualified direct drinking water by the equipment.
3、 Equipment characteristics in different scenarios
Typical Configuration of Scene Equipment Characteristics (Core)
Campus water production is large (meeting the needs of thousands of people), terminal water dispensers are widely distributed (in teaching buildings and dormitories), and remote monitoring of reverse osmosis systems, large capacity pure water tanks, circulating pipe networks, and multiple terminals is required
The community covers a large number of households, provides 24-hour water supply, and has high requirements for water quality and safety. It includes dual level reverse osmosis (partial), ultraviolet sterilization, and intelligent inspection system
The hotel/guesthouse has a beautiful appearance, with terminals located on the guest room level/lobby, supporting small reverse osmosis units for hot and cold drinks, and wall mounted terminal water dispensers
Residential buildings with entrance style or centralized building design, compact installation space, silent operation of ultrafiltration/small flow reverse osmosis+kitchen terminal or pipeline direct drinking
summarize
Direct drinking water equipment converts ordinary water sources into pure water that can be consumed directly through the process of “pretreatment → deep purification (reverse osmosis/ultrafiltration) → terminal sterilization → intelligent control”. The core is to remove pollutants, ensure sterility, and improve taste. Selecting appropriate purification technologies (reverse osmosis or ultrafiltration) based on water usage scale and raw water quality in different scenarios, and ensuring convenient and safe drinking water through terminal devices and circulation systems, is an important facility for improving the quality of life in modern campuses, communities, hotels, and other places.
Post time: Jul-24-2025