Can the treated wastewater be used to supply vegetables?As we all know, we are in the age of population explosion. People need more and more food to eat, and more water to grow food and vegetables. At the same time, clean water is increasingly limited. Someone is thinking we should treat the waste water to supply the vegetables! Nowadays, the production mode of agricultural water after wastewater treatment has been popularized. AzumaDr metering pump is used to improve the accuracy and efficiency of wastewater treatment.
In fact, a study in 2004 found that in Israel, recycled water (treated wastewater) already accounts for half of the water used for agricultural irrigation; In Spain, 17% of the water used for irrigation is recycled. In California, the figure is 6%.
So what kind of water are these vegetables grown from?The researchers carried out a series of studies.
Drug pollution
First it came the Israeli scientists, who studied the drug carbamazepine, which remains in vegetables fed with wastewater. The drug is commonly found in regenerated water, remains in the soil for a long time, and can be absorbed by plants.
In a oneweek experiment, the researchers convened 34 volunteers, randomly feeding some people with vegetables irrigated with reclaimed water, and the other with vegetables irrigated with clean water, and continuously monitoring carbamazepine in the urine of volunteers. The content of its metabolites was also tested for vegetables under different irrigation methods.
Among the vegetables involved in the experiment, cucumber, lettuce, parsley, pepper and tomato were all victims of reclaimed water irrigation. The content of carbamazepine in the vegetables irrigated with reclaimed water was significantly higher than that of pure water irrigation. Only carrots are barely qualified.
The researchers also found that although some volunteers had carbamazepine in the urine at the beginning of the experiment (due to personal health reasons), volunteers who consumed water to irrigate vegetables in the urine of carbamazepine The amount has not changed. That is to say, among these volunteers, the person who had carbamazepine in the urine at the beginning of the experiment did not increase the level of urinary carbamazepine at the end of the experiment. There was no carbamazepine in the urine at the beginning of the experiment. The person did not have carbamazepine in the urine at the end of the experiment. Volunteers who used reclaimed water to irrigate vegetables, regardless of whether carbamazepine appeared in the urine at the beginning of the experiment, found carbamazepine in the urine test without exception at the end of the experiment. Of course, the amount of drugs found in the urine due to the consumption of reclaimed water to irrigate vegetables is much lower than that at the time of dosing, but this still reflects the fact that reclaimed water irrigation exposes consumers to drug contamination.
Virus infection
Then there are us virus scientists - who used mathematical models to assess the risk of exposure to enterovirus in different populations after irrigating vegetables (cauliflower, cabbage, cucumber and lettuce) with reclaimed water. They found that different groups of people had very different vegetable eating habits: Asians ate the most vegetables, native Americans significantly less cabbage and lettuce, and blacks ate fewer cucumbers.
Despite this, the risk of infection of enteroviruses by eating vegetables is small, but Asians do have the greatest risk of eating the most. Since this study did not take into account the treatment of vegetables, it was eaten by default. So in theory, Asians can pull back a game because of good cooking habits.
Heavy metal pollution
Next is the heavy metal researchers in Asia and Africa. Ingestion of heavy metals can have serious consequences for the human body. In addition to the well-known carcinogenicity, it can also cause damage to nerves, bones, circulatory system, endocrine and immune system, and may destroy Normal function of liver, kidney and lung.
In Sika of Kenya, scientists tested heavy metal ions (copper, zinc, cadmium, nickel, and lead) on reclaimed water-irrigated vegetables in the Makongeni market, along with silt and reclaimed water. The kale, spinach and parsley that participated in the test were all qualified and met the heavy metal content recommended by the World Health Organization. However, scientists have emphasized that regular cleaning of sludge is important to prevent heavy metal ions from enriching and causing crop contamination.
The study in Bangladesh was similar to the case of Sika, which detected 27 samples and 9 levels of lead, nickel and arsenic in reclaimed water irrigated crops, all of which were qualified. Scientists have found that the highest lead content is amaranth leaves, and the other vegetables with the highest levels of heavy metals are jute leaves. The crop with the lowest heavy metal content and the safest is green papaya.
In many parts of Algeria, untreated sewage flows into rivers and is directly used by local farms to irrigate various raw vegetables such as lettuce and carrots. Therefore, government legislation mandates sewage treatment, and reclaimed water can be irrigated to reduce agricultural products. And pathogens and contaminants in the environment.
The researchers chose a city with a sewage treatment plant to measure the levels of copper, zinc, lead, and cadmium in reclaimed water-irrigated crops (potatoes, tomatoes, and cucumbers) and compare them to crops in other parts of Algeria. The result was unexpected: the heavy metal content of reclaimed water irrigated vegetables was lower than elsewhere, and eating this vegetable can reduce the daily intake of heavy metals by up to 85%. This is probably "as long as the treatment is done well, the wastewater can also become a treasure"? AzumaDr metering pump has been committed to water treatment for many years, and the waste water is no longer empty talk.
Nutrients and chemicals in vegetables
There is also a waste water that may not be treated, such as beer wastewater. In theory, it contains not only toxic substances, but also many organic substances and nutrients needed for plant growth.
In the vicinity of a brewery in Shandong, researchers set up three experimental fields: clear water irrigation, wastewater irrigation and stripping mixed irrigation. They planted six crops of leeks, green onions, cabbage, lettuce, potatoes and cabbage.
During the harvest season, the researchers examined the levels of vitamin C, nitrate and nitrite in three crop fields and found that beer wastewater irrigation significantly increased the vitamin C content of lettuce, potatoes and cabbage, which seemed to be good. Message. On the other hand, wastewater increases the amount of nitrate in cabbage, lettuce and cabbage, and increases the nitrite content of amaranth and potatoes. Only the green onions firmly say: no matter how much water you pour, how long I should grow.
In general, today's humans are difficult to bypass the waste water treatment and become a production mode for agricultural water. Many research findings have shown that reclaimed water irrigation has advantages and disadvantages. It cannot be simply generalized. The key issues are also clear: how to treat sewage? Can the treated reclaimed water reach the irrigation standard? China's Shenyang, Tianjin, and silver have all been affected by sewage irrigation. The pain of heavy metal pollution, such as the use of unpolluted or contaminated agricultural water that has not been treated even after treatment, is tantamount to quenching thirst. The examples show that Japan's AzumaDr metering pump assists in the proper treatment of reclaimed water, and only corrects the pressure of the earth's water resources slightly under the premise of ensuring human health.
Contact person : Melissa Tel：0086-571-86705853 Mobile Phone/Wechat: +86 18100194854 Wechat/Whatsapp: +86 17857981418 Email address: melissaliu@azumadr.com |
