Observe the color on the tea set or teacup, over the limit will appear lime green.
Water containing heavy metals will appear brown when scrubbed on porcelain or clothing.
Boil the water, then drink it, and feel carefully during the drinking process to see if there is an odor in the water. Whether there is an astringent flavor. If there is it means that the hardness of the water is high.
Use a cup under the tap to catch the water, smell the water whether there is a bleach flavor, if so, your home tap water may contain residual chlorine.
Use a more transparent container, no printed glass, disposable plastic cups can be. Fill a glass with water, leave it for a few hours and then look carefully in a well-lit area to see if there are any suspended particles in the water. If there is, it is recommended to deal with it.
Comparison of three common treatment methods
One, lime and neutralization method
1.1 basic principle
Lime and neutralization reaction method is in the heavy metal ions in the wastewater cast slaked lime C a ( O H ) :, so that it and the heavy metal ions in the water to generate the ionic solubility of the heavy metal hydroxide reaction is very small. Through the dosage to control the water P H value in a certain range, so that the ionic concentration of heavy metal hydroxides in the water is greater than its ionic solubility product and precipitation of heavy metal hydroxides, to achieve the removal of heavy metal ions, purification of wastewater purposes. Collect the wastewater to the wastewater homogenization adjustment tank, through the corrosion-resistant self-priming pump will be mixed wastewater sent to the primary neutralization tank, and in the pipeline add ferrous sulfate solution as arsenic **** precipitant (add Fe / As = 10), at the same time add the milk of lime for full stirring reaction, stirring reaction time of 30 min, the amount of milk of lime dosage by the pH meter automatic control, so that the primary neutralization tank outlet solution In order to oxidize divalent iron into trivalent iron and produce flocculation, an oxidation tank is set up after the primary neutralization tank for aeration and oxidation, and the oxidized wastewater flows to the secondary neutralization tank, and then the milk of lime is added, and the amount of the milk of lime is controlled by a pH meter automatically, so that the pH value of the solution at the outlet of the secondary neutralization tank is 9-11; No. 3 coagulant is added to the outlet of the wastewater from the secondary neutralization tank (the concentration of the coagulant is 10 mg/L). Add coagulant No.3 at the outlet of secondary neutralization tank (dosing concentration is 10mg/L), and the treated wastewater will flow to the thickener for flocculation and sedimentation; the supernatant will flow to the clarifier, and the flow of traditional lime neutralization for heavy metal wastewater treatment is as follows: when lime one-stage neutralization and sodium hydroxide two-stage neutralization, the removal rate of all kinds of heavy metals will be different with the different pH and the effect of sedimentation will be different, and the dissolved product of different metals will be different with the different PH. Different metals have different solubility product with different PH. The same PH, so the precipitation effect on heavy metals is not the same, and the heavy metals in wastewater are usually more than one kind, according to the content of heavy metals in the water when the water is adjusted to the PH corresponding to a certain metal in the lower PH solubility product is the highest. Add milk of lime for neutralization reaction to precipitate most of the metals in the wastewater. Supernatant into the next regulation pool, into the regulation of PH, into the second neutralization reaction pool, to remove the remaining heavy metal ions.
1.2 Advantages and disadvantages of lime neutralization and precipitation
The use of limestone as a neutralizing agent has a strong adaptability, but also has a short wastewater treatment process, simple equipment, lime can be taken in situ, inexpensive, wastewater treatment costs are very low, the slag has a low water content and is easy to dewatering, etc., but, after the lime neutralization treatment of wastewater, the generation of heavy metal hydroxide However, after the lime neutralization treatment of wastewater, the heavy metal hydroxide generated --- alum flower, the specific gravity is small, and easy to break into small particles in the strong mixing or transportation, so its settling speed is slow. Often in the process of settlement and separation with the water overflow, and make the treated wastewater turbidity increases, containing heavy metal ions still exceed the standard. Requirements for wastewater does not contain complexing agents such as C N a, N H . Otherwise, the heavy metal ions in the water will be complexed with the complexing agent complexation reaction occurs, the generation of heavy metal ions as the center of the ion to the complexing agent for the ligand complex complex ion complex and stable, so that the wastewater treatment has become complex and difficult. Has been settled alum flowers and slag sludge water content is very high (up to 99% or more), its filtration and dewatering performance is very poor, coupled with the composition of the complex, containing heavy metals and low grade, which gives the comprehensive recycling and disposal of the difficulties, and even cause secondary pollution. In addition, the large amount of slag is not conducive to the recovery of valuable metals, which is also easy to cause secondary pollution II. Heavy metal wastewater treated with lime water. Since the combination of different heavy metals and OH is different under the same PH, the solubility product of the same metal is different under different PH. Therefore, it is obvious that it is not possible to treat complex wastewater with more heavy metal content by the traditional lime method. Firstly, certain heavy metals cannot be discharged according to the standard, and secondly, the treated wastewater contains more calcium. In smelters, it is difficult to recycle.
Two, sulfide precipitation method
2.1 Basic Principle
Sulfide in the wastewater containing heavy metal ions, so that the heavy metal ions in the water and the reaction of the ionic solubility of the ion generated by a very small sulfide, through the amount of drugs to control the water of heavy metal sulfide ion solubility of the ionic solubility of the ion is greater than that of the heavy metal ions in the wastewater metal ions precipitation or selective precipitation, and then added to the heavy metal ions in the wastewater. Selective precipitation of metal ions in wastewater, and then add polymer trapping agent, and then to the wastewater into a large number of dense micro-bubbles, so that it and the precipitates adhere to each other, the formation of the overall specific gravity of the floating body is smaller than the water, under the action of buoyancy precipitates up to the surface of the water, so that the sulfide in the water to precipitate, to realize the separation of solid-liquid to achieve the effect of removing heavy metals, purification of water purposes. Commonly used sulfiding agents are: Na2S, NaHS, H2S, CaS and FeS.
Three
3.1 Basic principles
Biological agents are high-efficiency biologically active bacterial agents made from advantageous strains of bacteria screened from nature or high-efficiency strains of bacteria produced by gene combination technology, advanced biotechnology and special production processes, the composition of the biological agents can be summarized as microorganisms, enzymes, and some of the substances to maintain the activity of microorganisms. Mainly, the metabolites of the compound functional bacterial group mainly composed of Thiobacillus and other compounds are designed as components, and the biological preparation containing a large number of hydroxyl, sulfhydryl, carboxyl, amino and other functional groups is prepared through the group grafting technology. Firstly, the biological preparation is utilized to realize the depth of heavy metal ions removal from the wastewater and the addition of decalcification and flocculating agents, however, through the separation of the solid-liquid, and the decalcification and calcium ion removal will be carried out. After the removal of heavy metal ions and calcium ions, the clear liquid is processed by the membrane treatment device, and the chlorine ions in the wastewater are removed, so that the treated wastewater meets the water quality requirements for reuse, and the comprehensive reuse of wastewater is realized.
3.2 Advantages of biological agents
The biological agent method of heavy metal wastewater solves the defects of the current chemical agents which are difficult to purify multi-metal ions in depth at the same time. Biological agent depth treatment and reuse technology can simultaneously realize the cadmium, arsenic, lead, zinc, mercury, copper and other heavy metal ions, the concentration of heavy metal ions after treatment is lower than the "lead, zinc industry pollutant emission standards" (GB25466-2010). At the same time, the biological agent has both high efficiency flocculation and synergistic decalcification, calcium ions can be controlled to remove to below 50mg ／L, and the treated low-calcium purified water can be realized for large-scale reuse. The advantages of biological agents are shown in the following: (1) it can shorten the time of microbial culture and domestication, and rapidly increase the concentration of microorganisms in the biological treatment system, so as to improve the working efficiency; (2) the natural microorganisms contained in the biological agents do not contain pathogenic bacteria and pathogenic organisms, and these microorganisms, catalyzed by enzymes, take the organic nutrients in the wastewater as their food, and these microorganisms will gradually decrease with the reduction of pollutants and gradually decrease with the reduction of pollutants, and the microorganisms will gradually decrease with the reduction of pollutants. pollutants and gradually reduce until extinction, will not cause secondary pollution; (3) the use of safe, simple and convenient operation, basically do not need to add equipment or engineering, saving energy, saving capital investment. (4) strong resistance to heavy metal impact load, purification and efficient, stable operation: for the concentration of fluctuations in the wastewater is very large and irregular, the new process after treatment of heavy metals in the purified water is lower than or close to the "drinking water quality standards for domestic drinking water sources"; (5) calcium ions in the wastewater can be controlled to remove, the effect is obvious, it can be controlled to the following 20mg/L, the purification of the water reuse rate of more than 95%; (6) purification of the water COD , SS to reach the (7) good separation of slag and water, clear water, stable water quality, less hydrolysis slag than the neutralization method, high content of heavy metals, conducive to resource utilization; (8) for 100-300mg/L heavy metal wastewater, the cost of biological additives 0.3-0.8 yuan/m3; (9) treatment facilities are conventional facilities, small footprint, low investment and construction costs, and mature technology. For the existing lime neutralization treatment system only need to increase the biological agent storage tanks and pharmaceutical dosing pumps and other systems, low transformation costs.