All kinds of raw water purification process knowledge

one. Well water treatment. Well water treatment

Well water filtration can use the following water purification equipment:
1. Quartz sand filter: This filter can remove sediment, rust, seaweed and other large particles of solid impurities in the water. Under certain pressure, the turbidity is higher
High water is filtered through a certain thickness of granular or non-granular quartz sand, effectively trapping and removing suspended matter, organic matter, colloidal particles and some heavy metal ions in the water, etc.
Finally achieve the effect of reducing water turbidity and purifying water quality.
2. Activated carbon filter: Use the adsorption power of activated carbon to remove chlorine and odor in water.
3. Soft water filtration equipment: Due to the hardness of well water, soft water filtration equipment can reduce the hardness of water quality and absorb calcium and magnesium ions in the water.
4. Ultrafiltration membrane filtration equipment: ultrafiltration membrane can filter out organic matter in water, hydrogen chloride and so on.



If the content of iron and manganese in the well water is high, you can choose to use manganese sand filter. It occurs when the well water containing iron and manganese is aerated or oxidized and the water flows through the manganese sand filter Contact oxidation reaction and biochemical reaction, so that the iron and manganese ions in water precipitate and remove.
Central water purifiers or high-flow pre-filters: These devices are suitable for whole-house water purification and for treating large amounts of water, such as rural groundwater or well water treatment.
Other auxiliary equipment: Depending on the specific water quality situation and needs, other auxiliary equipment such as pumps and disinfection equipment may also be required for more comprehensive water treatment

two. Groundwater treatment. Groundwater treatment

Groundwater treatment mainly has the following ways:
1. Groundwater removal method: by continuously pumping out polluted groundwater, the water quality of polluted areas is gradually restored;
2. Reverse osmosis method: the polluted groundwater is pumped out of the surface well reverse osmosis device for purification treatment, and the treated water is re-injected into the well site;
3. Natural purification method: The residual pollutants undergo ion exchange, precipitation, groundwater dilution, natural hydrodynamic dispersion and molecular expansion with the rocks over a long period of time
Dispersive action, so that the pollution of the solution gradually disappeared naturally;
4. Reduction precipitation method： H2S is injected into the aquifer to reduce and precipitate some harmful elements, including heavy metal elements including uranium.



Some common groundwater treatment methods:
1. Filtration: Through the use of different types of filtration media, such as sand, quartz, activated carbon, etc., can remove particles, suspended matter and organic matter in groundwater;
2. Precipitation and flocculation: the use of flocculants and precipitants can condense suspended matter and particulate matter in groundwater to form larger particles, which is convenient for subsequent filtration and separation;
3. Ion exchange: The use of ion exchange resin to remove ions in groundwater, such as sodium, iron, magnesium, calcium, etc., can effectively reduce the hardness of water and improve water quality;
4. Reverse osmosis: Reverse osmosis is a method of separating dissolved salts and other substances in groundwater from water through a semi-permeable membrane, which is an efficient method of salt removal.
Often used for drinking water and industrial water treatment;
5. Ozone oxidation: The use of ozone to oxidize organic matter in water, so that it decomposes into harmless substances. This method is often used to remove organic pollutants;
6. Biological treatment: The use of microorganisms to degrade and transform pollutants in groundwater, biological treatment includes biological filtration, biological filter and constructed wetland and other methods;
7. Activated carbon adsorption: activated carbon is an excellent adsorbent, which can remove organic matter, color, odor and some dissolved substances in groundwater;
8. Chemical oxidation: The use of chemical oxidants such as hydrogen peroxide, permanganate, etc. to oxidize and decompose pollutants in water to improve water quality;
9. Air float method: Air float method by injecting small bubbles into the water, so that the suspended material rises along the bubble to the surface, and then it is removed by scraper or other methods;
10. Ultrafiltration and microfiltration: Ultrafiltration and microfiltration are filtered through microporous membranes, which can effectively remove microorganisms, bacteria and some smaller suspended substances in water.

These groundwater treatment methods can be used alone or in combination, depending on the specific water quality status and needs to choose the right combination of technologies



According to the different quality of groundwater extracted, it can be divided into the following treatment methods:
1. Physical methods include: adsorption method, gravity separation method, filtration method, reverse osmosis method, air blowing method and incineration method;
2. Chemical methods include: coagulation precipitation method, REDOX method, ion exchange method and neutralization method;
3. Biological methods include: activated sludge method, biofilm method, anaerobic digestion method and soil disposal method.

There are two ways to use groundwater after treatment, one is for direct use, and the other is for recharge. The reason why it is used more for recharge is that recharge can dilute the contamination on the one hand
Water body, flushing aquifers; On the other hand, it can also accelerate the circulation of groundwater and shorten the repair time of groundwater

Three. Tannery wastewater treatment

With the development of leather industry, the pollution of waste water in leather factories is becoming more and more serious. Leather wastewater contains a lot of harmful substances such as organic matter, heavy metals and ammonia nitrogen.This is a potential threat to both the environment and human health.

Overview of leather wastewater
1. Waste water generation and main pollutants: Leather production can be divided into wet operation and dry operation two parts, wet operation is mainly for the preparation section and tanning section, dry operation is mainly For the finishing section

2. Wastewater water quantity and water quality: wastewater water quantity, leather with general leather, processing a cow skin water consumption of one ton, according to the production process, skin
Leather waste water is composed of the following parts, high concentration of C raw skin washing water, containing Ca(OH)2, alkaline hair removal leaching of NazS, containing fat and saponification
Waste water, chromium tanning wastewater and fat dyeing wastewater containing Cr, among which chromium tanning wastewater and hair removal ash leaching wastewater are the most serious pollution;

3. Main characteristics of leather wastewater:
a) Because of the use of a large number of organic raw materials, leather wastewater is a highly concentrated wastewater;
b) Leather wastewater has a high chroma, mainly caused by dyes and tanning preparations and their auxilaries;
c) Leather wastewater has a strong odor, mainly caused by the decomposition of sulfide and protein;
d) Leather wastewater has strong toxicity, mainly due to the use of sulfide and chromium salts
e) The oil content of wastewater in tannery preparation stage is high, and pretreatment is needed.



Leather wastewater treatment process and existing problems:
In the leather production process, most of the water pollutants are produced in the wet processing process (liming, tanning), generally using Ca(OH)2, Na2S hair removal and chromium tanning technology, waste
Because the water contains a high concentration of chromium salts and sulfides and other poisons, it can also be used for enzymatic hair removal and high-absorption chromium tanning technology or plant tanning, which is the treatment of waste water of leather processing enterprises

The Fa generally has two parts:
1). Firstly, the wastewater with different nature and large pollution is divided and pretreated, which is generally a combination of physical and chemical treatment and physical treatment;
2) Comprehensive treatment, which can be summarized as a combination of physical methods, chemical methods, physicochemical methods and biological treatment;



1. Wastewater distribution and pretreatment: Leather wastewater is mainly chromic tanning wastewater, containing Ca(OH)2, NaS strong alkaline hair removal leach wastewater, deashing wastewater contains grease and oil The degreasing wastewater of saponified matter needs to be separated and pretreated.

A. Recycle use of acid leaching solution: Collect the acid leaching and tanning wastewater separately, and recycle the acid leaching solution after pretreatment to reduce the salt usage ratio in addition to sewage discharge Compared with the leaching section that does not use this process, the amount of acid can be reduced by 80% and the amount of acid can be reduced by 25%

B. Direct recycling of tannin with lower concentration: Generally, the first 5 times of low-concentration tannin waste can be reused only after filtration by the filter press

C. Recovery and treatment of tanning solution of high-concentration wastewater:
Recovery process of high-concentration tanning waste liquid after multiple uses, due to Cr(OH); The PH of the completely precipitated liquid is about 8. Lye is added to control the PH of the waste liquid during the reaction process.At this time, 96% of r is precipitated, and then through coagulation treatment or air floating activated carbon adsorption treatment, Cr basically enters the solid waste, tanning and hair removal and liming process part of the water quality The wastewater from tanning section can be fully utilized through the treatment of the above two systems

D. Pretreatment of strong alkaline hair removal and lime leaching wastewater containing Ca(OH)2 and Nazs: Through pretreatment, about 95% of S and 40% of COD in wastewater can be removed

E. Degreasing wastewater pretreatment: degreasing wastewater is a stream of wastewater with high pollution load in tannery industry, mainly containing fats and fatty acids. The main treatment method is acidification pretreatment and fat recovery Fatty acid.

2. Comprehensive wastewater treatment process and problem analysis:
The waste water produced by the leather processing section is properly pretreated first, the comprehensive quality of the waste water is still high, the COD is 2000-3000mg, the mass concentration of Cr is 1.2-15.6mg, and the concentration of Cr is 1.2-15.6mg. The mass concentration is 4.2-18.0mg, therefore, before entering the biochemical treatment system, it is also necessary to carry out pre-treatment, and the pre-treatment process is mainly Coagulation and precipitation or air flotation treatment, after coagulation and precipitation treatment, S, Cr and other biochemical inhibitors in wastewater can be reduced to within the requirements, biodegradability Better.