Effects of Paper Mill Sludge on Potassium, Sodium, Calcium, and Magnesium Concentrations in Different Soybean Cultivars

A field experiment was conducted on a sandy loam soil at an Experimental Farm in Taejon, South Korea, to determine the effects of paper mill sludge compost application rates on K, Na, Ca and Mg concentrations of soybean (Glycine max (L.) Merr.) aboveground tissues and the genotypic effects on the concentrations of these elements. Sludge compost treatments of 0, 75, and 150 t ha-1 were applied to 30 diverse soybean cultivars. Concentrations of K, Na, Ca, and Mg in aboveground tissues harvested 69 days after …

Properties of paper mill sludge–wood fiber–HDPE composites after exposure to xenon-arc weathering

We used paper mill sludge（PMS） to substitute for part of the wood fibers（WF） used to reinforce high density polyethylene（HDPE）.The resulting composites were subjected to xenon-arc weathering.The composite filled with limited PMS（under 10 %） had mechanical properties and aging resistance similar to those without PMS.The composites containing more PMS faded and cracked more readily than those without PMS.Based on the carbonyl index,crystallinity,and wood index,PMS appeared to accelerate the degradation of composites during weathering.Adding PMS to WF–HDPE composites reduced the weathering resistance,and this reduction was not significant if the PMS content did not exceed 20 % of the wood fibers.Therefore,PMS could be used as a reinforcement in wood-plastic composites at levels less than20 % of the wood fiber content.

Aerobic composting of paper mill sludge and the reuse of compost in agriculture

Paper mill sludge （PMS） is a kind of bio-solid waste. The technology of aerobic composting of PMS was investigated. The ratio of the material components was as follows, sludge：chicken dung：spill=6kg：2kg：4kg, which could attain 55% moisture content （MC） and 25 the ration of carbon to nitrogen （C/N）. The aeration rule of fan was controlled by single chip microcomputer （SCM）. During composting, the system temperature more than 55℃ lasted for 3 days, pH changed in the range of 6.5-8.5 and MC changed between 53% to 60%. PMS became mature on the 20th day. The germination index （GI） of compost attained 95% or so and coliform was 23/100 ml volatile solid （VS） and organic carbon （OC） were stable at the content of 60% and 30%, respectively. The result showed that this technology could make the sludge stable and innocuous. A pot experiment with latosolic red soil mixed with paper mill sludge compost （PMSC） was carried on. The result showed that PMSC could increase the crop biomass, the soil nutrients and the physical characteristics of the soil, such as OC, total nitrogen （TN）, total phosphorus （TP）. The total amount of heavy metals in the soil was measured to be lower than the Environmental standard for soil in China （GB15618-1995）. So PMSC was a good and safe soil amendment.

Effects of amendments of paper mill sludge and nutrients on soil surface CO2 flux in northern hardwood forests

Safe and economical disposal of paper mill sludge is a key consideration for forest products industry. A study was conducted to examine the effects of amendments of sludge and nutrients on soil surface CO2 flux （Rs） in northern hardwood forests and to quantify the relationship among Rs, soil temperature, and moisture in these stands. The experiment was a randomized complete block design that included sludge-amended, fertilized, and control treatments in sugar maple （Acer saccharum Marsh） dominated hardwood forests in the Upper Peninsula of Michigan, USA. Results showed that Rs was positively correlated to soil temperature （R^2 = 0.80, p 〈 0.001）, but was poorly correlated to soil moisture. Soil moisture positively affected the Rs only in the sludge-amended treatment. The Rs was significantly greater in the sludge-amended treatment than in the fertilized （p = 0.033） and the control （p = 0.048） treatments. The maximum Rs in the sludge-amended treatment was 8.8 μmol CO2 · m^ 2. s^-1, 91% and 126% greater than those in the fertilized （4.6 μmol CO2 · m^-2· s^-1） and control （3.9 μmol CO2· m^- 2· s^-1） treatments, respectively. The Rs did not differ significantly between the fertilized and control treatments. The difference in Rs between sludge-amended and the other treatments decreased with time following treatment.

Fenton-like degradation of Methylene Blue using paper mill sludge-derived magnetically separable heterogeneous catalyst:Characterization and mechanism

For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst（PMS-Fe-380） was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue（MB）. The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover,leaching tests indicated that the leached iron is negligible（〈0.5 mg/L）. This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.

Emission and drying kinetics of paper mill sludge during contact drying process

The emission and contact drying kinetics of the paper mill sludge (PMS) were studied through experiments carried out in a paddle dryer. To get a better understanding of its drying mechanism, a penetration model developed by Tsotsas and Schlünder (1986) was used to simulate the drying kinetics of the PMS. The result indicated that this kinetics could be divided into three phases: pasty, lumpy and granular phases, and could be successfully simulated by the penetration model as the related sludge parameters were integrated into the model. The emission rate curves of the volatile compounds (VCs) were interrelated to the drying rate curve of the PMS, especially for volatile fatty acids (VFAs) and ammonia in this study.