INCORPORATION OF HYBRID BIOFILTERS IN WATER-SENSITIVE URBAN DESIGN

This paper presents a research study aimed at the development of a hybrid biofilter that can serve for two different applications. This is a unique approach due to the prolonged dry period in Israel covering 7-8 months of the year. The tactic suggested herein is to use the same system for stormwater harvesting/treatment during winter, and for bioremediation of nitrate-contaminated groundwater during summer. Crude cotton and Eucalyptus wood-chips served as alternative carbon sources for denitrification, and both proved to support efficient reduction of nitrate with minimal release of nitrite and organic matter. During the stage of stormwater treatment, two types of biofilter-columns (120 & 70 cm long) were tested, with a minimal saturation zone and no addition of organic carbon. Complete nitrification could be achieved, even under high instantaneous hydraulic loads for both column types. Vegetation on top of the biofilters contributed to improved removal of the nitrate formed, by plant assimilation.

CO₂ budgeting at the regional scale using a Lagrangian experimental strategy and meso-scale modeling

An atmospheric Lagrangian experiment for regional CO2 budgeting with aircraft measurements took place during the CarboEurope Regional Experiment Strategy campaign (CERES) in south-west France, in June 2005. The atmospheric CO2 aircraft measurements taken upstream and downstream of an active and homogeneous pine forest revealed a CO2 depletion in the same air mass, using a Lagrangian strategy. This field experiment was analyzed with a meteorological meso-scale model interactively coupled with a surface scheme, with plant assimilation, ecosystem respiration, anthropogenic CO2 emissions and sea fluxes. First, the model was carefully validated against observations made close to the surface and in the atmospheric boundary layer. Then, the carbon budget was evaluated using the numerous CERES observations, by upscaling the surface fluxes observations, and using the modeling results, in order to estimate the relative contribution of each physical process. A good agreement is found between the two methods which use the same vegetation map: the estimation of the regional CO2 surface flux by the Eulerian meso-scale model budget is close to the budget deduced from the upscaling of the observed surface fluxes, and found a budget between −9.4 and −12.1 μmol.m−2.s−1, depending on the size of the considered area. Nevertheless, the associated uncertainties are rather large for the upscaling method and reach 50%. A third method, using Lagrangian observations of CO2 estimates a regional CO2 budget a few different and more scattered, (−16.8 μmol.m−2.s−1 for the small sub-domain and −8.6 μmol.m−2.s−1 for the larger one). For this budgeting method, we estimate a mean of 31% error, mainly arising from the time of integration between the two measurements of the Lagrangian experiment. The paper describes in details the three methods to assess the regional CO2 budget and the associated errors.

CO₂ budgeting at the regional scale using a Lagrangian experimental strategy and meso-scale modeling

An atmospheric Lagrangian experiment for regional CO2 budgeting with aircraft measurements took place during the CarboEurope Regional Experiment campaign (CERES) in south-western France, in June, 2005. The atmospheric CO2 aircraft measurements taken upstream and downstream of an active and homogeneous pine forest revealed a CO2 depletion in the same air mass. This field experiment is analyzed with a meteorological meso-scale model interactively coupled with a surface scheme, allowing plant assimilation, ecosystem respiration, CO2 anthropogenic emissions and sea fluxes. First, the model is carefully validated against observations close to the surface and in the atmospheric boundary layer. Then, the carbon budget is evaluated using the numerous CERES observations and as well as the modeling results in order to estimate the relative contribution of each physical process. A good agreement is shown in terms of the estimation of the regional CO2 surface flux by the Eulerian meso-scale model budget and by the observations at the surface flux sites. A Lagrangian estimation of regional CO2 surface flux from aircraft observations is more difficult due to several sources of uncertainty. In our case, probable errors are due to the determination of CO2 vertical profile measurements and owing to the difficulties in monitoring the meteorological condition evolution during several hours.

Oxygen flux implications of observed nitrogen removal rates in subsurface-flow treatment wetlands

Nitrification, an oxygen-requiring microbial process, is generally considered the rate-limiting step for N removal in subsurface-flow constructed wetlands treating organic wastewaters. We used a simplified model of sequential N transformations and sinks to infer required rates of oxygen supply at 5 stages along experimental wetland mesocosms supplied with four different organic wastewaters with contrasting ratios of COD: N and forms of N. Mass balances of water-borne organic, ammoniacal and nitrate N, and plant and sediment N uptake showed average net rates of N mineralisation ranging from 0.22-0.53 g m-2 d-1, nitrification 0.56-2.15 g m-2 d-1, denitrification 0.47-1.99 g m-2 d-1 (60-84% of measured N removal) and plant assimilation 0.28-0.47 g m-2 d-1. The nitrogenous oxygen demand (NOD) required to support the observed nitrification rates alone was high compared to expected fluxes from surficial and plant-mediated oxygen transfer. In the presence of high levels of degradable organic matter (COD removal rates up to 66 g m-2 d-1), heterotrophs with significantly higher oxygen affinities and energy yields are expected to out-compete nitrifiers for available oxygen. Problems with commonly held assumptions on the nature of coupled nitrification-denitrification in treatment wetlands are discussed.

Fungi Mikoriza arbuskula (FMA) yang berasosiasi dengan Durio zibethinus di Kabupaten manokwari, Papua Barat, Indonesia

Arbuscular mycorrhizal fungi (AMF) is a symbiosis between fungi and plants. This association is mutualism,AMF contributes to increased plant growth while fungi obtain energy sources from plant assimilation. The purpose of this study was to determine the association of AMF with durian plants (Durio zibethinus) in Manokwari, West Papua. The survey was conducted in 10 villages located in 4 districts known as the center for producing durian. Observation of the presence of AMF spores in the plant's rhizosphere was carried out by the wet sieving method. Furthermore, to find out the association between the two symbionts is done by observing AMF colonization in plant roots. The types of AMF found in the plant's rhizosphere are morphologically identified based on spore characteristics. The results showed that durian was associated with AMF. The percentage of AMF colonization ranged from 39.29 to 80.00%, while the number of spores was 112-336 spores per 100 grams of soil sample. Based on the spore morphological characteristics, AMF found is dominated bythe genus Glomus, Scutellospora, and Acaulospora.

Fungi Mikoriza arbuskula (FMA) yang berasosiasi dengan Durio zibethinus di Kabupaten manokwari, Papua Barat, Indonesia

Arbuscular mycorrhizal fungi (AMF) is a symbiosis between fungi and plants. This association is mutualism, AMF contributes to increased plant growth while fungi obtain energy sources from plant assimilation. The purpose of this study was to determine the association of AMF with durian plants (Durio zibethinus) in Manokwari, West Papua. The survey was conducted in 10 villages located in 4 districts known as the center for producing durian. Observation of the presence of AMF spores in the plant's rhizosphere was carried out by the wet sieving method. Furthermore, to find out the association between the two symbionts is done by observing AMF colonization in plant roots. The types of AMF found in the plant's rhizosphere are morphologically identified based on spore characteristics. The results showed that durian was associated with AMF. The percentage of AMF colonization ranged from 39.29 to 80.00%, while the number of spores was 112-336 spores per 100 grams of soil sample. Based on the spore morphological characteristics, AMF found is dominated by the genus Glomus, Scutellospora, and Acaulospora.