In Nederland drijven steeds meer zonnepanelen op het water. Kennis omtrent het effect op de waterkwaliteit van deze zonneparken is echter beperkt. Praktijkmetingen onder de platforms zijn vaak lastig uit te voeren. Er zijn onderwaterdrones ingezet met sensoren en camera’s. Deze praktijkmetingen zijn nodig ter ondersteuning van vergunningverlening en opstellen van richtlijnenvoor ontwerp, implementatie en beheer van drijvende zonnepanelen om een gezond leefmilieu te handhaven en om de duurzame energietransitie te bevorderen. Op de onderzoekslocatie is geen significante impact gemeten op de kwaliteit van het oppervlaktewater.
This paper pioneers the assessment of tourism's total global resource use, including its fossil fuel consumption, associated CO2 emissions, fresh water, land, and food use. As tourism is a dynamic growth system, characterized by rapidly increasing tourist numbers, understanding its past, current, and future contributions to global resource use is a central requirement for sustainable tourism assessments. The paper introduces the concept of resource use intensities (RUIs), which represent tourism's resource needs per unit of consumption (e.g. energy per guest night). Based on estimates of RUIs, a first assessment of tourism's global resource use and emissions is provided for the period 1900–2050, utilizing the Peeters Global Tourism Transport Model. Results indicate that the current (2010) global tourism system may require c.16,700 PJ of energy, 138 km3 of fresh water, 62,000 km2 of land, and 39.4 Mt of food, also causing emissions of 1.12 Gt CO2. Despite efforts to implement more sustainable forms of tourism, analysis indicates that tourism's overall resource consumption may grow by between 92% (water) and 189% (land use) in the period 2010–2050. To maintain the global tourism system consequently requires rapidly growing resource inputs, while the system is simultaneously becoming increasingly vulnerable to disruptions in resource flows.
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Stricter environmental policies, increased energy prices and depletion of resources are forcing industries to look for bio-based and low carbon footprint products. For industries, flax is interesting resource since it is light, strong, environmental friendly and renewable. From flax plant to fiber products involves biochemical and mechanical processes. Moreover, production and processing costs have to compete with other products, like petroleum based materials. This research focusses on sustainable process improvement from flax plant to fiber production. Flax retting is a biological process at which mainly pectin is removed. Without retting, the desired fibre remains attached to the wooden core of the flax stem. As a result, the flax fibres cannot be gained, or have a lows quality. After retting, the fibers are released from the wooden core. Furthermore, machines have been introduced in the flax production process, but the best quality fibers are still produced manually. Due to the high labor intensity the process is too expensive and the process needs to be economical optimized. Since the retting process determines all other downstream processes, retting is the first step to focus on. Lab-scale experiments were performed to investigate the retting process. Factors that were researched were low cost processing conditions like, temperature, pH, dew retting and water retting. The retting rate was low, around three weeks for complete retting. The best retting conditions were at 20°C with water and any addition of chemicals. The process could be shortened to two weeks by recycling the water phase. In a scale-up experiment, a rotating drum was used at the optimal conditions from the lab-experiment (20°C and water). First the flax did not mix with the water content in the rotating drum. The flax was too rigid and did not tumble. Therefore, bundles of flax plants were used. The inner core of the bundle seemed to be protected and the retting rate was less compared to the flax on the surface of the flax bundle. This implies that mechanical impact increased retting in the rotating drum, however heterogeneous retting should be avoided. To overcome the heterogeneous retting problem, a water column was used to improve heterogeneous retting. Retting was performed in a water column and mixing was accomplished by bubbling air. As a result of the mixing, the flax bundle was retted homogenously. And after drying, it was possible to separate the fibers from the wooden flax core. Retting with a bubble column can overcome this problem and seems to be a usable retting process step. Water samples of the lab-scale experiments, the rotating drum and the bubble column showed a chemical oxygen demand (COD) content up to 4 g/L. Overall, 1 kg Flax resulted in 40 g COD. This indicates the possibility to produce biogas that can be used for generating heat and electricity, to make the process sustainable. Around 50% of the weight consists of wooden shives. The shives can be used for pyrolysis and it was possible to produce around 30% coal and 20% oil. These compounds can be used as building blocks, but also to generate heat and electricity. Heat and electricity can be used for the flax processing. Shives were only dried for 1 day at 105°C and slow pyrolysis was used. This indicates that a higher yield can be expected at fast pyrolysis. Overall, the reported implicates that quality fiber production from flax plant can be a feasible, sustainable and a renewable production process. Feasibility of the process can be obtained by, (1) retting at low-cost process conditions of 20°C and using water without any addition of chemicals, (2) with increased flax retting rate by recycling water, (3) with increased flax retting rate by introducing mixing forces, and the ability to lower the energy consumption of the overall process, (4) producing biogas from the COD with anaerobic digestion and (5) producing pyrolysis oil and pyrolysis c
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