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Chlorine bleaching technology (C process, CEH process, H process and theirs combination), which was identified as a primary formation source of PCDD/Fs, is still widely used by the vast majority of Chinese non-wood pulp and paper mills (non-wood PMs). The purpose of this study was to provide information and data support for further eliminating dioxin for non-wood PMs in China, and especially to evaluate the PCDD/Fs release reduction for those mills converting their pulp bleaching processes from CEH to ECF. The PCDD/Fs concentrations of the bleached pulp and bleaching wastewater with ECF bleaching were in the ranges of 0.13–0.8 ng TEQ kg −1 , and 0.15–1.9 pg TEQ L −1 , respectively, which were far lower than those with CEH process, indicating that the ECF process is an effective alternative bleaching technology to replace CEH in Chinese non-wood PMs to reduce dioxin release. The release factor via flue gas of the alkali recovery boiler in Chinese non-wood PMs was first reported to be 0.092 μg TEQ Ad t −1 in this study. On the assumption that pulp bleaching processes of all Chinese non-wood PMs were converted from CEH to ECF, the annual release of PCDD/Fs via the bleaching wastewater and bleached pulp would be reduced by 79.1%, with a total of 1.60 g TEQ.

Treating and reusing industrial wastewater is one of many means to improve water supply capacity, especially within developing countries. In the past 15 years, remarkable progress has been achieved on the commercial applications of membrane technology in China. The membranes demand in China exceeded 30 billion yuan (US$ 4.8 billion) in 2010, amounting for about 15% of the world total. However, the sate-of-the-art of membrane applications in industrial wastewater treatment is not well understood and documented. This study performs a national survey of membrane plants and membrane manufacturers to investigate the characteristics of membrane technology applications for industrial wastewater treatment to increase water supply in China. The data obtained from the survey of membrane plants were confirmed with the survey of membrane manufacturers. It is aimed to provide comprehensive information of membrane technology applications for industrial wastewater treatment in China to guild the future development of the same kind of applications. The results indicate that 6.7 million m3 of wastewater per day (2.4 billion m3 per year) treatment capacity applies membrane technology. 580 membrane plants have been successfully applied in practice for different industrial wastewater treatment. Petrochemical, power generation, and steel industries account for the majority of membrane technology applications, from both of number of membrane plants and treatment capacity. Northern Chinese provinces which are rich in coal, crude petroleum, and ferrous ore but scarce in water resources have seen the most of membrane practices. Water withdrawal for the power generation industry decreased substantially recently, as water use and reuse efficiency has been improved due to wide applications of advanced wastewater treatment methods such as membrane technology. With increasingly stringent emission standards faced by industry and water resources shortages confronted with China, it is expected membrane technology will play key role to address water quality and quantity issues in China. Membrane market in China is expected to grow at a relative high annual rate of approximate 15% for the next decade. It is worthy to note that environmental impacts due to membrane technology applications for industrial wastewater treatment, including membrane pollution and high salinity water, shall be addressed.

Microwave (MW) hybrid processes are able to disrupt the flocculent structure of complex waste activated sludge, and help promote the recovery of phosphorus as struvite. In this study, to optimize struvite yield, (1) the characteristics of matter released in MW-hybrid treatments were compared, including MW, MW-acid, MW-alkali, MW-H2O2, and MW-H2O2-alkali. The results showed that selective release of carbon, nitrogen, phosphorus, Ca(2+), and Mg(2+) achieved by sludge pretreatment using MW-hybrid processes. MW-H2O2 is the recommended sludge pretreatment process for phosphorus recovery in the form of struvite. The ratio of Mg(2+):NH4(+)-N:PO4(3-)-P was 1.2:2.9:1 in the supernatant. (2) To clarify the effects of organic matter on struvite recovery, the composition and molecular weight distribution of organic matters were analyzed. Low molecular weight COD was found to facilitate the removal rate of NH4(+)-N and PO4(3)-P via crystallization, and the amorphous struvite crystals (

To evaluate the performance of microwave (MW)-chemical hybrid sludge treatment system, a pilot scale MW disintegration unit (treatment capacity of 500 L/d) was constructed. The results showed that organic matter, nitrogen, and phosphorus were effectively released from the MW-pretreated sludge. The values of COD released were 15.91%, 15.07%, 13.83%, 19.35%, and 15.07% for the MW, MW-acid, MW-alkali, MW-H2O2, and MW-H2O2-alkali treatment processes, respectively. Additionally, for a wastewater treatment system with a capacity of 200 m3/d, when coupled with a MW sludge pretreatment unit, the sludge production and sludge yield were greatly reduced by 38.60% and to 0.35 kg VSS/kg CODconsumed, respectively. The total operating cost of the lysis–cryptic growth system was 13.64% lower than that of the CAS system without a MW unit.