The Characters Of Furniture Painting Waste Water And Study On Pollution Control

Furniture production consists of a very important part of our country’s industrial production. With the improvement of material culture and living standards, the demand for environment-friendly furniture which is not only beautifully designed but also can satisfy the needs of life and work is increasing, which requires the furniture to be embellished and spray-painted. The painting process will produce a certain amount of waste water which contains a lot of pollutants including various kinds of organic solvents and nondegradable organic dyes. The existing municipal wastewater treatment plants cannot effectively deal with this wastewater. What’s more, the quantity of wastewater produced by each painting factory is relatively less, which makes it difficult for the wastewater treatment equipment to work effectively all the time, so with its poor treatment effect, a special wastewater treatment equipment is almost impossible to meet the related emission standards of environmental protection and the requirement of total amount control, especially in towns like Longjiang Town where the furniture production enterprises are mainly in small and medium size. Because of the difficulty to establish an effective wastewater pipe network, the problem of pollution is becoming more and more severe in such places.On the basis of understanding Longjiang River’s pollution status, this study carries out a special investigation to the problem of serious furniture spraying-paint wastewater pollution in Longjiang Town. First, by means of conducting a field research on the source of the furniture spraying-paint wastewater pollution, the study tends to understand the number and distribution of the furniture manufacturing enterprises and find out the existing production of spraying-paint wastewater, the variety and nature of the pollutants and the sewage collection and discharge situation in Longjiang Town, then analyze the rate that the furniture spraying-paint wastewater pollution takes on the river pollution. Second, by looking in details at the spraying-paint wastewater’s quantity, quality and their problems, the study conducts a deep research and investigation into the characteristics of the wastewater. At last, according to the wastewater’s quality, quantity and its collection and discharge characteristics, the study puts forward a combined process:hydrolytic acidification+aerobic biological contact oxidation, which is suitable to spraying-painting wastewater treatment and has been successfully applied in practical use.On this basis, this study analyzes the causes of the furniture spraying-paint wastewater pollution and put forwards corresponding measures to control the pollution:1. Government departments should enhance supervision;2. Set up the frequency standard of the circulating water replacement;3. Reasonably standardize the ways of collecting the spraying-paint wastewater;4. Establish central treatment facilities as soon as possible.By this topical research, we can draw the following conclusions:1. The furniture manufacturing enterprises in Longjiang Town are large in quantity, small in size and wide and scattered in distribution.2. The river going through Longjiang Town is severely polluted. The pollution comes mainly from the rural domestic sewage and industrial wastewater. And the industrial wastewater comes mainly from furniture spraying-painting wastewater. The quantity of the rural domestic sewage COD into the river for each day accounts to2800.3tons. The quantity of the furniture spraying-paint wastewater into the river reaches947.8tons every day, taking almost25%of the total pollution.3. The total quantity of the spraying-paint wastewater is large but the unit amount is small and the fluctuation is great. The average value of wastewater for every furniture enterprise is1.12tons every day. The total amount of wastewater for all furniture enterprises reaches up to1200tons every day.4. The wastewater remains no collection, no treatment and is discharged at will. Most of the enterprises pour their wastewater into the river, and only little of the wastewater is centralized processed by the environmental protection company after door-to door recovery.5. The BODs/CODcr value of the spraying-paint wastewater is smaller than0.3, which makes it difficult to biodegrade. The range of the quality fluctuation is great. The fluctuation range of COD is between6.9to8731mg/L, the fluctuation range of suspended solids is between1to8482mg/L and the range of PH is between5to7. The wastewater’s value of COD and suspended solids for primer spray is higher than for top-coating. The number of days for the circulating water in the water curtain machine to reach saturation state is between10to15days, so the replacement frequency for the circulating water is2to3times a month.6. On the basis of theoretically analyzing the feasibility of the combined process:hydrolytic acidification+aerobic biological contact oxidation, the process is also verified by engineering examples:we take PAM and PFS coagulation and sedimentation combined process to pre-process the furniture spraying-painting wastewater. By this way, the removal rate of COD can get as high as45.1%.If applying the combined process " hydrolytic acidification+aerobic biological contact oxidation" to deal with the spraying-paint wastewater, the removal rate of COD and suspended solids reaches96.3%and82.3%respectively. Effluent COD and SS keep steady at under90mg/L and55mg/L, meeting the Grade One wastewater emission standard in Guangdong Province.