Follow-up treatment for reverse osmosis concentrate water

This post was last edited by slll611 on 2016-6-14 at 22:11. The reverse osmosis concentrate stream is generally used for concentration purposes, as well as for zero-discharge systems

With a COD level of only 120 ppm, is it still necessary to use an ozone BAF? . It’s just that the TDS level is high; it goes straight into an MVR concentration and desalination process. The condensate water has its TDS reduced to 50 ppm, meeting the discharge standards. As for the resulting salt, it needs to be determined whether it is a mixed salt or a single-component salt – mixed salts are treated as waste, while single-component salts can be recycled.

Firstly, it’s no problem to feed normal wastewater with a TDS of 6000 into the biological treatment process; even wastewater with a total salt content of 20,000 can be fed directly into this process. There are just more precautions to take during operation. There are many manufacturers of salt-tolerant strains nowadays, so this concentration is no longer a problem. Secondly, since the original poster wants to explain ozone and BAF, this water is intended to be reused or discharged after meeting certain criteria. Regarding the concentrated water resulting from reverse osmosis, if it is the concentrated water obtained after desalination of industrial water, it is possible to reduce the COD to around 60 through ozone and BAF treatment; however, this depends on the effectiveness of the ozone treatment process and the performance of the BAF system. It is recommended that the original poster conduct a simple test; nowadays, small-scale ozone generators as well as compact biochemical equipment are available for purchase, and the test results will be clear at a glance. When finalizing the design, take the amplification effect into account; by choosing appropriate equipment and process parameters, there should be no major issues.

Classification: Based on the different uses and protection objectives of marine areas, seawater quality is divided into four categories. Category 1 is suitable for marine fisheries areas, marine nature reserves, and reserves for rare and endangered marine species. The second category applies to aquaculture areas, sea bathing beaches, marine sports or recreational areas where humans have direct contact with seawater, as well as industrial water use areas directly related to human consumption. Category 3 is suitable for general industrial water use areas and coastal scenic tourism areas. The fourth category is applicable to marine port waters and marine development operation areas. Standards: The various standards for seawater quality are listed in Table 1. Table 1: Seawater Quality Standards (mg/L) | Sequence | Parameter | Category 1 | Category 2 | Category 3 | Category 4 | 1 | Suspended matter | No oil films, foam, or other suspended substances on the sea surface | No visible oil films, foam, or other suspended substances on the sea surface | 2 | Color, odor, taste | Seawater shall have no abnormal color, odor, or taste | Seawater shall not have any unpleasant or offensive color, odor, or taste | 3 | Suspended matter | Amount artificially added ≤10 | Amount artificially added ≤10 | Amount artificially added ≤100 | Amount artificially added ≤150 | 4 | E. coli ≤ (cells/L) | 10,000 | Water quality for shellfish farming intended for human consumption ≤700 | – | 5 | Fecal coliforms ≤ (cells/L) | 2,000 | Water quality for shellfish farming intended for human consumption ≤140 | – | 6 | Pathogens | Water used for shellfish farming intended for human consumption must be free of pathogens. 7 Water temperature (°C): The temperature increase in seawater caused by human activities shall not exceed 1°C in summer and 2°C in other seasons. The temperature increase caused by humans shall not exceed 4°C in that area at that time. 8 pH: 7.8–8.5, without exceeding 0.2 pH units beyond the normal range for that sea area; 6.8–8.8, without exceeding 0.5 pH units beyond the normal range for that sea area. 9 Dissolved oxygen: >6, 5, 4, 3. 10 Chemical oxygen demand (COD) ≤: 2, 3, 4, 5. 11 Biological oxygen demand (BOD5) ≤: 1, 3, 4, 5. 12 Inorganic nitrogen ≤ (in terms of N): 0.20, 0.30, 0.40, 0.50. 13 Non-ionic ammonia ≤ (in terms of N): 0.020. Continued from Table 1: Serial number, Parameter, Category 1, Category 2, Category 3, Category 4. 14 Active phosphates ≤ (in terms of P): 0.015, 0.030, 0.045. 15 Mercury ≤: 0.00005, 0.0002, 0.0005. 16 Cadmium ≤: 0.001, 0.005, 0.010. 17 Lead ≤: 0.001, 0.005, 0.010, 0.050. 18 Hexavalent chromium ≤: 0.005, 0.010, 0.020, 0.050. 19 Total chromium ≤: 0.05, 0.10, 0.20, 0.50. 20 Arsenic ≤: 0.020, 0.030, 0.050. 21 Copper ≤: 0.005, 0.010, 0.050. 22 Zinc ≤: 0.020, 0.050, 0.10, 0.50. 23 Selenium ≤: 0.010, 0.020, 0.050. 24 Nickel ≤: 0.005, 0.010, 0.020, 0.050. 25 ** ≤: 0.005, 0.10, 0.20. 26 Sulfides ≤ (in terms of S): 0.02, 0.05, 0.10, 0.25. 27 Volatile phenols ≤: 0.005, 0.010, 0.050. 28 Petroleum substances ≤: 0.05, 0.30, 0.50. 29 BHC ≤: 0.001, 0.002, 0.003, 0.005. 30 DDT ≤: 0.00005, 0.0001. 31 Malathion ≤: 0.0005, 0.001. 32 Methyl parathion ≤: 0.0005, 0.001. 33 Benzo(a)pyrene ≤ (μg/L): 0.0025. 34 Anionic surfactants (in terms of LAS): 0.03, 0.10. 35 *Radioactive nuclei (Bq/L): 60Co: 0.03; 90Sr: 4; 106Rn: 0.2; 134Cs: 0.6; 137Cs: 0.7. Standard-setting process: ① Based on existing experimental research and field investigations, and using the quantitative causal relationships between various water quality parameters (including pollutants) and their impacts on target systems (such as humans, ecosystems, or biological resources) as the main basis, seawater quality standards are first established. ② Using these seawater quality standards as a foundation, and taking into account the natural and social conditions of the designated protected sea areas, standards are further formulated based on cost-benefit or cost-risk analysis results. “\"Benchmark\" and \"standard\" are two related concepts that should not be confused. “A “benchmark” is the scientific basis for determining and assessing whether an environment is suitable for its intended use; it has no legal binding force on its own ； The “standards” have a legal character in relation to specific waters or sewage discharges, and once approved by the competent authorities, they must be enforced.

4 Monitoring of seawater quality 4.1 The collection, storage, transportation, and pre-treatment of samples for seawater quality monitoring shall be carried out in accordance with the relevant provisions of GB12763.4－91 and HY003－91. 4.2 The monitoring of each item in this standard shall be carried out according to the analysis methods in Table 2. Table 2 Methods for Analyzing Seawater Quality Sequence Number Parameter Analysis Method Detection Limit, mg/l Reference Standards 1 Suspended solids Visual inspection method N/A 2 Color, odor, taste Colorimetric method, sensory method GB12763.2-91, HY003.4-91 3 Suspended solids Gravimetric method 2, HY003.4-91 4 Coliforms (1) Fermentation method, (2) Filter membrane method HY003.9-91 5 Fecal coliforms (1) Fermentation method, (2) Filter membrane method HY003.9-91 6 Pathogens (1) Microfiltration adsorption method 1.a, (2) Precipitation virus concentration method 1.a, (3) Dialysis method 1.a 7 Water temperature (1) Vertical continuous monitoring of water temperature, (2) Monitoring of water temperature at standard layers GB12763.2-91, GB12763.2-91 8 pH (1) Electrical measurement using a pH meter, (2) Colorimetric pH method GB12763.4-91, HY003.4-91 9 Dissolved oxygen Iodometric titration method 0.042, GB12763.4-91 10 Chemical oxygen demand (COD) Alkaline potassium permanganate method 0.15, HY003.4-91 11 Biological oxygen demand (BOD5) Five-day incubation method HY003.4-91 12 Inorganic nitrogen (expressed as N) Nitrogen: (1) Indophenol blue method 0.7, GB12763.4-91, (2) Sodium hypobromite oxidation method 0.4, GB12763.4-91 Ammonium ions: Diazotization-azo method 0.3, GB12763.4-91 Nitrate ions: (1) Zinc-cadmium reduction method 0.7, GB12763.4-91, (2) Copper-cadmium column reduction method 0.6, GB12763.4-91 13 Non-ionized ammonia (expressed as N) Calculated according to Appendix B 14 Active phosphates (expressed as P) (1) Phosphomolybdic blue method using ascorbic acid reduction, (2) Phosphomolybdic blue extraction spectrophotometry 0.62, 1.4, GB12763.4-91, HY003.4-91 15 Mercury (1) Cold atomic absorption spectrophotometry, (2) Gold-collected cold atomic absorption spectrophotometry 0.0086, 0.002, HY003.4-91, HY003.4-91 16 Cadmium (1) Flameless atomic absorption spectrophotometry, (2) Flame atomic absorption spectrophotometry, (3) Anodic stripping voltammetry, (4) Dithizone spectrophotometry 0.014, 0.34, 0.7, 1.1, HY003.4-91, HY003.4-91, HY003.4-91, HY003.4-91 17 Lead (1) Flameless atomic absorption spectrophotometry, (2) Anodic stripping voltammetry, (3) Dithizone spectrophotometry 0.19, 4.0, 2.6, HY003.4-91, HY003.4-91, HY003.4-91 18 Hexavalent chromium Diphenylcarbazide spectrophotometry 4.0, GB7467-87 19 Total chromium (1) Diphenylcarbazide spectrophotometry, (2) Flameless atomic absorption spectrophotometry 1.2, 0.91, HY003.4-91, HY003.4-91 20 Arsenic (1) Hydrogen arsenide–

The treatment methods include evaporation crystallization and mixing it into wastewater, depending on the actual conditions of your entire process as well as your budget. . . . . .