In recent years, the paper industry is industries having strong growth rates in our country. Because the new waves are such as: “Green economy in production” and “Zero Waste” most businesses and people have a great demand for using paper packaging, and recycled paper… Attracting more investment capital from domestic and foreign enterprises.
Facing the breakthroughs, ensuring the quality of output wastewater in paper production is also a challenge for managers. It is necessary to ensure the quality of wastewater, minimize negative impacts on the environment, and save energy, towards the goal of sustainable development. So what are the characteristics of paper wastewater, and how to treat it to achieve the above goals? Let’s follow BioFix Fresh to follow the article below.
1. The origin of paper wastewater.
In the process of paper production, paper wastewater is generated from many different sources. However, the amount of paper wastewater mainly comes from 2 main sources:
• In production: the flow goes through different stages such as cooking, washing after cooking, bleaching, pulping, paper making, etc.
• In daily life: hand washing, personal hygiene, etc.
2. Paper wastewater properties.
And at each stage, the paper wastewater characteristics are constantly changing, making it difficult to control the quality of the output wastewater. With features such as:
High pH (9-11), black flow: Due to the black liquid coming from the cooking process, washing after cooking with mostly dissolved organic substances, chemicals, and a part of the fiber. There is a dry matter concentration from 25% to 35%, accounting for a ratio of 70:30 between organic and inorganic matter. The organic component is lignin dissolved in an alkaline solution, the product decomposes carbohydrates and organic acids. The inorganic components include cooking chemicals such as Na2SO4, NaOH, Na2S, Na2CO3, etc. Therefore, the wastewater will contain a lot of residual alkali and the characteristic smell of sulfur compounds. It may cause cancer and is difficult to decompose in the aquatic environment, due to obtaining highly toxic compounds.
High COD, BOD, TSS content: Due to the process of using chemical or semi-chemical methods is in the bleaching process. It leads to organic compounds, soluble lignin, and toxic detergents causing bioaccumulation such as organochlorine compounds. The COD concentration ranges from 22000-46500 mg/l, and the BOD accounts for about 40-60% of COD. And more than that, the suspended solids content is many times higher than the allowable limit. Pollution of the environment and imbalance of the ecosystem, if not recovered or treated properly.
3. Paper wastewater treatment solution.
To treat the typical components of paper wastewater such as organic matter, chemicals, COD, BOD… We can use some of the following methods:
This is one of the simple, low-cost solutions to effectively remove the components such as solids, residues, paper residues, etc. When combined with the mesh screen device at the tank, the suspended solids will be settled and collected for processing.
b) pH balance:
With high pH, characteristics are in the use of detergents and alkalis. We can use more chemicals to bring the pH value to within the range of 6.5 – 8.5, to increase the efficiency of chemical treatment and organic decomposition before transferring wastewater to the following steps.
d) Biological solutions
This is one of the solutions chosen by many businesses. Especially, in the current period of the green economy, because of its ability to be safe for the environment and effective in controlling components in paper wastewater.
• Anaerobic treatment
As one of the effective biological wastewater treatment solutions for the pulp and paper industry. Because anaerobic microorganisms can process semi-chemical precipitates, sulfites and crafts evaporate from bleaching and mechanical grinding. As well as hydrolyzing carbon chains well is in an anaerobic environment, removing lignin, and fiber components. It avoids high COD in aerobic tanks causing shock load and foaming. Therefore, we can add the probiotic BioFix 114 in this period.
• Aerobic treatment
The aerobic treatment process helps to reduce the high organic matter content in the paper wastewater and ensures the quality of the output wastewater. Because aerobic organisms are capable of decomposing organic matter, so they need a lot of energy to quickly oxidize the waste products and convert them to water and carbon dioxide… Through the amount of oxygen provided by the aerator.
In addition to breaking down organic matter to create new cells, the microorganism performs endogenous respiration to produce energy by the following process:
C5H7NO2 + 5O2 → 5CO2 + 2H20 + NH3 + H
Therefore, we can add BioFix 5E aerobic microorganisms to promote aerobic processing.
- The intermediate tank:
After treating the wastewater, we can use coagulant chemicals to remove the suspended substances in the tank, ensuring the quality of the wastewater. Thanks to the ability to bind small particles into large agglomerates. Thereby, reducing the amount of COD, BOD, turbidity, and odor in wastewater. Because the condensate after forming will settle to the bottom.
And BioFix Poly-Glu products completely meet the above criteria. Moreover, the main ingredient of soybean meal. Therefore, the product is harmless to organisms and has no sterilization effect.