Integrated nanofiltration and upflow anaerobic sludge blanket treatment of textile wastewater for in-plant reuse.

The filtration characteristics of simulated dyeing effluents containing Acid Orange 7, sodium sulfate, and a pH buffer made of acetic acid and sodium acetate is described using a commercially available nanofiltration membrane. The original membrane filtration properties were characterized with deionized water to provide a baseline of membrane performance. At high volumetric concentration of the test solutions, greater than 98% rejection of dye and sodium sulfate were obtained. Rejection of buffering chemicals was approximately 50% in all experiments, giving a permeate water not suitable for reuse in most dyeing operations. The final composite concentrate had a chemical oxygen demand (COD) value > 2000 mg/L. No problems were encountered with anaerobic treatment of the concentrate obtained from the dyeing wastewater. Adjusting the sulfate concentration to give COD-to-sulfate ratios to 2.9, 5.4, and 18.2 in the reactor feed had no significant alterations in the performance of the upflow anaerobic sludge blanket reactor.     

Contaminant Retention Potential of Forested Filter Strips Established as SMZs in the Piedmont of Georgia1

Abstract: It is common practice in the United States and elsewhere to maintain vegetated filter strips adjacent to streams to retain contaminants in surface runoff. Most research has evaluated contaminant retention in managed agricultural field strips, while relatively few studies have quantified retention in forested filter strips, particularly for dissolved contaminants. Plot‐scale overland flow experiments were conducted to evaluate the efficiency of natural forested filter strips established as streamside management zones (SMZs) for retaining phosphorus (P), atrazine, and picloram transported in runoff. Retention was evaluated for five different slope classes: 1‐2, 5‐7, 10‐12, 15‐17, and 20‐22%; two cover conditions: undisturbed forest floor (O horizon intact) and forest floor removed by raking; and two periods with contrasting soil moisture conditions: summer‐dry and winter‐wet season. Surface flow was collected at 0, 2, 4, 6, and 10 m within the filter strip to evaluate changes in solution concentration as it moved through the O horizon and the surface soil horizon mixing zone. On average, a 10 m length of forested SMZ with an undisturbed forest floor reduced initial solution concentration of total dissolved P by 51%, orthophosphate P by 49%, atrazine by 28%, and picloram by 5%. Percentages of mass retention through infiltration of water plus concentration reductions in runoff were 64% for total dissolved P, 62% for orthophosphate P, 47% for atrazine, and 28% for picloram for undisturbed forest floor conditions. Lower retention occurred following forest floor removal, particularly for P. Average dissolved P retention was 16% lower following forest floor removal. For undisturbed sites, differences in retention were more closely related to forest floor depth than to slope or antecedent soil moisture. These results indicate that forested SMZ filter strips provide a significant measure of surface water protection from dissolved P and herbicide delivery to surface water.     

Artificial lakes as a climate change adaptation strategy in drylands: evaluating the trade-off on non-target ecosystem services

Drylands are very susceptible to the effects of climate change due to water stress. One possible climate change adaptation measure is the construction of lakes to increase water availability for drinking and irrigation (food production) and decrease fire risk. These lakes can also increase local biodiversity and human well-being. However, other non-target services such as carbon (C) storage, water purification, and sediment retention might also change. Our main aim was to evaluate the trade-offs on non-targeted ecosystem services due to lakes construction in drylands. This was done using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling tools, comparing a Mediterranean area located in southwest (SW) Europe, with and without artificial lakes. Results showed that the construction of artificial lakes caused an increase of 9.4% in C storage. However, the consequent increase in agricultural area decreased water purification and sediment retention services. This could diminish the life span of the lakes changing the initial beneficial cost-benefit analysis on lakes as adaptation measures to climate change. As a global measure for mitigation and adaptation to climate change strategy, we consider lake construction in drylands to be positive since it can store C in sediments and reduces the vulnerability to water scarcity. However, as a general recommendation and when built to support or increase agriculture in semi-arid landscapes, we consider that lakes should be complemented with additional measures to reduce soil erosion and nutrient leaching such as (i) locate agricultural areas outside the lakes water basin, (ii) afforestation surrounding the lakes, and (iii) adopt the best local agriculture practices to prevent and control soil erosion and nutrient leaching.     

Biogas production from malt bagasse from craft beer industry: kinetic modeling and process simulation

Journal of Material Cycles and Waste Management - In this work, biogas was synthesized from malt enriched-craft beer bagasse with the objective to generate clean energy. Thus, a kinetic model based...