நீரியல்: தற்போதைய ஆராய்ச்சி

The sewer system of many historical or holy cities is not well associated with the present need. The managing of the sewer system of such cities is very difficult. Karbala, located in central Iraq, is one such city that experiences tremendous pressure on its sewer system due to large visiting population during special religious gathering. As the sewer system of Karbala city is not designed for such high population like many other historic or holy cities, the sewer overflows, inundate the roads, and degrade the environmental due to the polluted sewer during religious gatherings. The problem often becomes critical due to heavy rainfall as the gathering usually happens during monsoon. The modeling of the sewer water quantity with a varying population and rainfall is important for simulating the sewer overflow as well as to manage the sewer system. The modeling of the sewer water quality is also important to understand the possible environmental hazard due to the sewer overflow. In this present study, an attempt has been taken to simulate the spatiotemporal distribution of the sewer water quantity and quality with a varying population and rainfall for the prediction of sewer overflow and possible pollution susceptibility. The Stormwater Management Model (SWMM) will be used in the proposed study. The simulation will be carried out in the city center of the Karbala city where the stormwater network is not fully developed. It is expected that this study will help in the operational management of the sewerage system and mitigate the sewer flooding and related environmental problems.

This document to examine the changes occurred in the flux of nutrients and NEM during dry season and rainy + north wind season in the Caleta system located within the Términos lagoon natural reserve which presents negative impacts caused by discharges of urban wastewater. Salinity, dissolved oxygen, chlorophyll a, nitrogen and phosphorus were monitored during nine months considering the dry, rainy and north wind season. Storms caused sediment disturbances which increased the amount of nutrients into the Caleta system as well as the phytoplankton production (25 mg m-3). The system shows longer times of water renovation during the summer (21 d) unlike (6 d) during the rainy + north wind season. On one hand, the ΔDIP values during dry season (0.0049 μmol m-2 d-1), establishes the system as producer and exporter of DIP into the ocean; on the other hand, the ΔDIP during rainy + north wind seasons (-0.0039 μmol m-2 d-1) suggests the importation of phosphorus from the ocean. Likewise, the system exports DIN (0.0031 μmol m-2 d-1) during the summer and imports DIN (-0.0048 μmol m-2 d-1), during the rainy + north wind seasons. The negative values of fixation-denitrification and NEM during the summer turn the system into a nitrogen sink. Seasonal changes were present in the system, dominated by heterotrophic NEM during summer with higher nitrogen fixation; while an autotrophic NEM dominated during winter.

This research article aims to detect the short term as well as long term significant changes in the surface air temperature time series for Midnapore Weather observation station, West Bengal, India. The temperature time series data has been collected from Indian Meteorological station, Kolkata, for the period from 1941-2010. Fluctuations and trends of annual mean temperature, annual mean maximum temperature and annual mean minimum temperature time series were statistically examined. To identify the abrupt change in trend, the cumulative sum chart (CUSUM) and Bootstrapping were employed on the considered data set. The major change point in the annual mean temperature occurred around 2001 at level 1 (Confidence level 100%). On the other hand, the annual mean maximum temperature and annual mean minimum temperatures have level 1 change points in 2001 and 1969 respectively. The results show that, one can be 100% confident that the annual mean maximum temperature significantly changed between 1998 and 2001. Similarly, annual mean minimum temperature changed between 1963 and 1971 as a confidence level of 98%. Before the change in 2001, annual mean temperature was 27.11°C; while after the level 1 change the temperature becomes 25.1°C. The mean of annual maximum temperature for the period from 1941-2010 has been 34.017°C which reduced to 30.25°C for rest of the period in consideration. For the annual mean minimum temperature, the time series can be divided into two segment taking 1968 as the last point of the first segment for which the average value is 22.38°C, while the second segment, the average value is 18.077°C. The analysis has identified 13 abrupt change points in three temperature time series.

The use of solvents in desalination processes limits the use of certain materials in the construction of the reverse osmosis membranes. Therefore now the research effort has focused on improving new materials. In particular, nanostructured materials will probably form the basis for new reverse osmosis membrane materials. This study makes a review of the new materials used for the construction of reverse osmosis membranes, highlighting the advantages and disadvantages that each of them gives to the desalination process. Firstly inorganic membranes, made mainly from zeolites, offer higher tolerance to a variety of feed waters and harsh cleaning methods. Secondly, two carbonderived materials as carbon nanotubes, exhibit high permeability and high rejection rate, and graphene, with high breaking strength and impermeability to molecules as small standard gases. Finally, a novel concept of membranes called Mixed Matrix Membrane (MMM) which combines organic and inorganic material and the benefits of each one.

Recently one of the most prominent activity focusing in Indian cities is the retrofitting the urban drainage system. Millions of rupees spent on the construction of stormwater drains in towns and cities to prevent flooding during the rains. These drains that extend several kilometers across the town or city are expected to feed all the collected surface runoff into the nearest surface water body such as a lake or a river. Recently a case study was done by Royal HaskoningDHV, a premier engineering and consultancy organization of Netherlands in association with German funding agency - GIZ on improvement of the stormwater management of Raipur city in India. The study suggested that flooding can be prevented in the city by interlinking of stormwater drain with the existing lakes in the city. The lakes can act as the storage reservoirs which dampen the effect of flooding and also reduce the chances of getting lakes dried during summer. Site reconnaissance revealed that most of the drains damaged and the sewage also entering to lakes. The sewerage system in the city observed very poor, creating health and safety issues for the general public. The city municipal corporation is making an effort in restoring these systems. This technical article will try with the following describe and provide with a glimpse into the massive efforts that the Raipur City undertook in order to inspect and clean its drainage and sanitary sewer systems.