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In this study, we discussed the advanced treatment process of printing and dyeing wastewater with the patented compounded biological filtration equipment (ZL200610069538.3). The experimental samples were collected from the second effluents of a printing and dyeing wastewater treatment plant. With the experiments of four single factors and the dynamic process under four optimum parameters values, discussions were taken in terms of the effects of PFS dosing quantity, hydraulic loading, filter materials volume ratio, and gas water ratio on COD, chromaticity and ammonia nitrogen respectively. The experimental results indicated that the optimum parameter values were PFS dosing quantity of 25mg/L, hydraulic loading of 0.4m3/ (m2·h), filter materials volume ratio (biological carbon over biological zeolite) of 1.2:1, gas water ratio of 4:1 respectively. When influents values ranges of COD, chromaticity and ammonia nitrogen were 90-110mg/L, 60-80times and 3-8mg/L respectively, the effluents of COD, chromaticity and ammonia nitrogen were less than 46mg/L, 10times and 1 mg/L respectively, which could meet the National Standard of Recycling and Miscellaneous Usages of Municipal Sewage on COD, chromaticity and ammonia nitrogen requirements.

Researching on the feasibility of citrate wastewater recycling treatment, the combined treatment methods of coagulation and filtration were adopted in the recycling treatment process of citrate wastewater from secondary biological treatment effluents. Meanwhile the ferric salt and water treatment processor were used as the coagulant and filtration equipment respectively. The experiments of coagulant addition, hydraulic retention time, the volume ratio of compounded filtering materials, aeration intensity were taken respectively. The final experimental results demonstrated that at the ferric salt addition of 36 mg/L, hydraulic retention time of 40 min, the volume ratio of biological fibred ball / biological carbon and the ratio of water/gas were 1:2 and 1:6 respectively, 81.3% of COD was removed, from179.2mg/L down to33.6 mg/L and 96.7% of SS was removed, from 152.7mg/L down to below 5mg/L. The effluent of the citrate wastewater recycling treatment process with coagulation + water treatment processor could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on COD and SS requirements.

In this study, we presented an approach to coking wastewater advanced treatment process with a patented wastewater treatment equipment. The samples were collected from the effluents of the biological treatment tank in a coking wastewater treatment plant. With the experiments of four static single factors and the continuing dynamic process, the discussions about the effects of pH value, influent loading, reaction time, and volume ratio on chromaticity, COD and NH3-N respectively were conducted. The experimental results identified that the optimum process parameters were pH of 3, influent load of 1m3/m2•h, reaction time of 4h and volume ratio of 2:1 respectively. When influents of chromaticity, COD and NH3-N were 210 times, 249.4mg/L, and 31.7mg/L respectively , the effluent of chromaticity, COD and NH3-N were 16 times, 49.7mg/L, and 9.5mg/L respectively, these values could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on chromaticity, COD and NH3-N requirements.

In this paper, we presented an approach to control on the total hardness over the wastewater treatment recycling process for pulp and paper mill. The main problem, however, is the effects of Ca2+ concentration on the recycling treatment process. The experiments were conducted by using coagulation method with reagents of Ca(OH)2 addition alone and Ca(OH)2 +PAC addition respectively to control on total hardness. The samples were collected from the effluent and the influent of the biological treatment tank respectively of the wastewater treatment plant in a pulp and paper mill. The experimental results identified that the optimum reagent addition position was in the effluent of the biological treatment tank. When addition Ca(OH)2 alone, the optimum Ca(OH)2 addition amount was 2g/L, as a result, 70.1% of total hardness was removed ( from 1088.05mg/L down to 325.16mg/L), pH value was from 7.23 to 8.61, and sludge volume ratio was 9.9%. When addition PAC+ Ca(OH)2 , the optimum Ca(OH)2 addition amount was 1g/L, the optimum PAC addition amount was 300mg/L respectively, as a result, 71% of total hardness was removed( from 1088.05mg/L down to 315.25 mg/L), pH value was from 7.23 to 7.66, and sludge volume ratio was 6.5%. The effluent-quality can meet the National Industrial Wastewater Recycling Standard on the total hardness of 450 mg/L requirement. The reagents of Ca(OH)2 +PAC had many advantages over Ca(OH)2 alone , such as less sludge quantity, high density of sludge, small volume of sludge, and less addition of reagents and so on.