Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The earthworm Pontoscolex corethrurus (Müller, 1857) is reported for the first time from Punjab, India. This species was first described by German naturalist Fritz Müller in 1857 from Santa Catarina state of Brazil. It is commonly found in gardens, cropland and fallow lands. It tolerates wide range of climatic and edaphic factors due to its endogeic ecological category. P. corethrurus has high efficiency for organic matter assimilation and has ability to live in new habitat due to which it can survive even in very poor soil. The life cycle of this species is well documented and this species has economic importance due to its use in waste management.
This research investigates the spatial and temporal trend analysis of precipitation time series. Precise predictions of precipitation trends can play an imperative role in economic growth of a country. This study examined precipitation inconsistency for 23 stations at Dongting Lake, China, over a 52-year study period (1961-2012). Statistical, nonparametric Mann- Kendall (MK) and Spearman’s rho tests were applied to identify trends within monthly, seasonal, and annual precipitation. The trend-free pre-whitening method was used to exclude sequential correlation in the precipitation time series. The performance of the Mann-Kendall (MK) and Spearman’s rho tests was steady at the tested significance levels. The results showed a fusion of increasing and decreasing trends at different stations within monthly and seasonal time scales. The results obtained with the Mann-Kendall and Spearman’s rho tests showed agreement in their assessments of monthly, seasonal, and annual precipitation trends. The variability of negative and positive trends at various stations points to the need for more detailed studies on the climate change of this region. In the case of whole Dongting basin on the monthly time scale, a significant positive trend is found, while at Yuanjiang River and Xianjiag River both positive and negative significant trends are identified. Only Yuanjiang River has shown a significant trend on the seasonal time scale. No significant trends have been exhibited on the annual time scale in any case. In the case of monthly, Nanxian station exhibited the maximum positive increase in monthly precipitation during the months of July and September. In the case of seasonal, only Tongren station showed a positive trend on the monthly level, and no significant negative trends were detected in both spring and autumn seasons.
Wastewater (WW) volume generated from both domestic and industrial sectors has increased due to rapid industrialization and urbanization. WW is increasingly used on farms because it is cheap and easily available all year, causing various environmental and health implications. In order to evaluate Multan WW, this study characterizes 154 WW samples collected from 11 disposal stations. These samples were analysed for 23 parameters related to organic matter, nutrients, inorganic matter, and pathogens to determine pollution extent distribution, agricultural reuse potential, and WW treatment database. A major contamination concern was found regarding biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total coliform, and E-Coli. The average values of BOD and COD were found to be 2.7 and 3.8 times higher than the permissible limits respectively. The microbiological parameters such as total coliform and E-Coli were found to be 10.6 and 36 times higher than the permissible limits, respectively. However, heavy metals and nutrients were found within the permissible limit except phosphorus. Here, the correlation study on selected WW parameters indicated the direct or indirect relationship among WW constituents and the impact of different sources of pollution on WW characteristics. The present study also presents a critical review of different treatment options according to contamination strength in disposal stations.
The need of wastewater (WW) treatment is increasing along with the production of WW and its disposal without treatment. With a smaller footprint, ease of operation, and relatively less cost, trickling filter (TF) wastewater treatment systems have been considered to be more adoptable for domestic and industrial WW treatment in underdeveloped and/or developing countries – particularly for Asia and Africa. A relatively low-cost and operationally effective TF wastewater treatment system was developed using farm waste cotton sticks as biofilm support media. During the operation of the TF system, flow rates vary from 1.7 to 4.6 m³/hr. The attained removal efficiency for BOD (biological oxygen demand) was 69-78% and for chemical oxygen demand (COD) was 65-80%. The solids removal in TF system was 38-56% for total suspended solids (TSS) and 20-36% for total dissolved solids (TDS). Other aggregates such as turbidity and color removal were 32-54% and 25-42%, respectively. Four to five months of trouble-free operation of the developed TF system indicated the robustness and reliability of the system. Cotton sticks appeared to be a degradation-resistant alternative filter media for the TF system. Moreover, it is useful for reducing potential impacts of WW re-use at the farm level. Treated effluents through the TF system can be re-used as an irrigation water supplement in under-developed and/or developing countries.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.