CN-121974525-A - Photovoltaic cell wastewater zero discharge method

Abstract

The invention discloses a zero emission method of photovoltaic cell wastewater, which comprises the steps of dilute acid and dilute alkali wastewater treatment, concentrated acid and concentrated alkali wastewater treatment, comprehensive desilication treatment of the collected concentrated acid and concentrated alkali wastewater, comprehensive softening treatment of the liquid after the comprehensive desilication treatment, ammonia wastewater treatment, denitrification treatment of the collected ammonia-containing wastewater, merging the denitrified liquid into the dilute acid and dilute alkali wastewater treatment, and further ultrafiltration, anti-fouling reverse osmosis purification and recycling. The invention is a novel treatment method which is integrated, low in consumption, high in efficiency and truly realizes resource recovery and zero emission.

Inventors

• MENG FANGFANG
• JIN LIANGHUA
• SHI ZHENGQIAN
• XU HAO
• Kong Menghao
• CHENG HUARUI
• DONG XUBO

Assignees

• 楷德电子工程设计有限公司

Dates

Publication Date

20260505

Application Date

20260311

Claims (7)

1. 1. The zero-emission method for the photovoltaic cell wastewater is characterized by comprising the following steps of: the dilute acid dilute alkali wastewater treatment comprises the steps of carrying out pH adjustment on the collected dilute acid dilute alkali wastewater, and carrying out silicon removal treatment on the wastewater after the pH adjustment; the concentrated acid and concentrated alkali wastewater treatment comprises the steps of carrying out defluorination treatment on the collected concentrated acid and concentrated alkali wastewater, carrying out comprehensive desilication treatment on the liquid after defluorination treatment, and carrying out comprehensive softening treatment on the liquid after the comprehensive desilication treatment; Ammonia wastewater treatment, including denitrification treatment of the collected ammonia-containing wastewater, merging the denitrified liquid into dilute acid and dilute alkali wastewater treatment, and further ultrafiltration, anti-pollution reverse osmosis purification and recycling.
2. 2. The method for zero wastewater discharge of photovoltaic cells according to claim 1, wherein the desilication treatment comprises: carrying out desilication coagulation on the wastewater after pH adjustment by using a comprehensive desilication agent; adding PAC into the liquid after the desilication and coagulation to carry out coagulation reaction; adding a reagent into the liquid after the coagulation reaction is completed to perform flocculation and coagulation reaction; And (3) delivering the liquid after flocculation and coagulation reaction into a reclaimed water tank A, and then carrying out reclaimed water recycling treatment.
3. 3. The method for zero emission of waste water from photovoltaic cells according to claim 2, wherein said reclaimed water recycling treatment comprises: Mixing and primarily regulating the wastewater; Multi-medium filtration treatment; pretreatment pool adjustment; ultrafiltration treatment; Regulating an ultrafiltration water producing pool; Fine filtration pretreatment Reverse osmosis treatment and recycling.
4. 4. The method for zero wastewater discharge of a photovoltaic cell according to claim 1, wherein the defluorination treatment comprises: Mixing concentrated acid wastewater with high fluoride ion content with concentrated alkali wastewater with silicon content; Adding calcium hydroxide and calcium chloride into the mixed wastewater to enable the wastewater to reach pH neutrality, simultaneously precipitating by utilizing Ca 2+ and F - , and adding a medicament to perform coagulation, flocculation and precipitation after generating precipitation; Repeating the steps for a plurality of times until the content of F - in the effluent reaches the set range, and carrying out comprehensive silicon removal treatment on the effluent.
5. 5. The method for zero wastewater discharge of photovoltaic cells according to claim 4, wherein the integrated desilication treatment comprises: Regulating the pH value of the wastewater and making the water quality uniform; adding a comprehensive silicon removing agent into the uniform wastewater to perform a comprehensive silicon removing reaction; carrying out coagulation reaction on the wastewater after the comprehensive desilication reaction; and (3) performing flocculation reaction on the wastewater after coagulation reaction, and performing precipitation separation.
6. 6. The method for zero wastewater discharge of photovoltaic cells according to claim 4, wherein the integrated softening treatment comprises: adjusting the pH value in a comprehensive softening neutralization tank; Then the comprehensive softening reaction tank is utilized, and the chemical agent and the wastewater are fully mixed through a mechanical stirrer to carry out comprehensive softening reaction; Carrying out coagulation reaction on the liquid after the comprehensive softening reaction in a comprehensive softening coagulation tank; carrying out flocculation reaction on the liquid after the coagulation reaction in a comprehensive softening flocculation tank; and (3) carrying out precipitation separation on the liquid after flocculation reaction in a comprehensive softening sedimentation tank, and enabling separated supernatant to enter a filtering system and then enter reclaimed water for recycling treatment.
7. 7. The method for zero wastewater discharge of a photovoltaic cell according to claim 1, wherein the denitrification treatment comprises: Denitrification nitrogen removal; Performing primary nitrification treatment on the liquid subjected to denitrification and nitrogen removal through a primary nitrification tank; And (3) carrying out secondary denitrification treatment on the liquid subjected to the primary nitrification treatment through a secondary denitrification tank.

Description

Photovoltaic cell wastewater zero discharge method Technical Field The invention relates to the field of photovoltaic cell wastewater treatment, in particular to a photovoltaic cell wastewater zero discharge system and a photovoltaic cell wastewater zero discharge method. Background In the photovoltaic cell manufacturing process, the cell shop involves a number of wet process links including texturing, removing BSG (back surface glass layer), polishing, removing PSG (phosphosilicate glass), RC cleaning, graphite boat/quartz boat/basket cleaning, rework cleaning, and exhaust gas treatment units (such as GAS abatement and scrubber systems) and the like. The procedures can generate wastewater with complex components in the running process, and mainly comprise dilute acid, dilute alkali, concentrated acid, concentrated alkali and wastewater containing ammonia and nitrogen. This wastewater is typically collected in a unified collection tank and then enters a subsequent treatment system. However, existing photovoltaic wastewater treatment processes expose the following problems in actual operation: Firstly, dilute acid and dilute alkali wastewater directly enter an Ultrafiltration (UF) and anti-pollution Reverse Osmosis (RO) system after being neutralized, and as the pollutants such as colloid, silicate, metal ions and the like remained in the wastewater are not effectively removed, the pollution and blockage of a membrane assembly are extremely easy to be caused, the continuous reduction of the water yield of the system and the increase of the cleaning frequency are caused, and the recycling efficiency and the service life of equipment are seriously influenced. Secondly, for concentrated acid and concentrated alkali wastewater, conventional pretreatment focuses only on removing fluorine, and the cooperative removal of scaling substances such as silicon, hardness ions (such as Ca2+, mg2+) and the like is ignored. If the process of 'firstly removing silicon and then removing fluorine' is adopted, the consumption of silicon removing agents (such as aluminum salt, magnesium salt and the like) is greatly increased due to large fluctuation of silicon content and difficult precise control of the adding amount of the agents, and the running cost is obviously increased. Thirdly, as the photovoltaic cell process is upgraded, ammonia nitrogen wastewater production continues to increase, but its concentration is generally low (typically <100 mg/L). The traditional stripping method needs to adjust the pH value of the wastewater to be more than 10.5, so that NH 4 < + > is converted into NH 3, and the NH 3 is stripped by aeration and then recycled into ammonia water by an absorption tower. The method has the advantages of high alkali consumption and high operation cost, and has the risk of ammonia gas dissipation in the stripping process, thereby being easy to cause secondary atmospheric pollution and needing to be matched with a complex tail gas absorption system. The other evaporation concentration method can realize ammonia nitrogen separation, but has extremely high evaporation energy consumption due to low salt content and large water quantity of the inlet water, and meanwhile, equipment scaling and corrosion are accelerated in a high-temperature and high-salt environment, so that the maintenance cost is high and the stability is poor. Finally, most of the current systems only adopt first-stage anti-pollution reverse osmosis to recycle the concentrated acid and alkali wastewater, and the generated high-salt concentrated water is directly discharged into an evaporation crystallization unit. The method not only greatly increases the processing load and the steam consumption of the evaporation system, but also obviously reduces the overall water reuse rate, and is difficult to meet the increasingly strict environmental protection requirement of zero emission. Disclosure of Invention Therefore, in order to solve the defects, the invention provides a photovoltaic cell wastewater zero discharge method, which is a novel integrated, low-consumption, high-efficiency and truly realized resource recovery and zero discharge treatment method. Specifically, a photovoltaic cell wastewater zero discharge method comprises the following steps: the dilute acid dilute alkali wastewater treatment comprises the steps of carrying out pH adjustment on the collected dilute acid dilute alkali wastewater, and carrying out silicon removal treatment on the wastewater after the pH adjustment; the concentrated acid and concentrated alkali wastewater treatment comprises the steps of carrying out defluorination treatment on the collected concentrated acid and concentrated alkali wastewater, carrying out comprehensive desilication treatment on the liquid after defluorination treatment, and carrying out comprehensive softening treatment on the liquid after the comprehensive desilication treatment; Ammonia wastewater treatment, including denitrification tre