Sukanta Rana

Use of human urine in phytoplankton production as a tool for ecological sanitation

Measurements of primary productivity of phytoplankton and enumeration of the counts of coliform and heterotrophic bacteria (HB) were made in the water of 12 experimental tanks used for 3 treatments and control in triplicate as follows: (a) fresh human urine (0.02%), (b) stored human urine (0.02%), (c) mixed urine of fresh and stored human urine (0.02%) and (d) control without input of urine. The gross primary productivity of phytoplankton was highest in the stored urine treated tanks (508 mg C m(-2) h(-1)) followed by fresh urine (353 mg C m(-2) h(-1)), mixed urine (303 mg C m(-2) h(-1)) and control (215 mg C m(-2) h(-1)). Similar was the response of net primary production of phytoplankton. The mean count of HB observed in stored urine fed tanks was significantly higher (59-184%) than the remaining urine fed treatments. The mean count of Escherichia coli did not differ from urine treated tanks to control implying the good quality of water. The concentration of dissolved oxygen of water (7.6 to 12.8 mg L(-1)) in these tanks remained satisfactory for aquaculture. The mean concentration of ammonium-N observed in fresh urine treated tanks was more than 10 times higher than the remaining treatments employed. In contrast, the level of phosphate and electrical conductivity in the stored urine treated tanks were significantly higher than the remaining treatments. It is proposed that stored urine with a significantly reduced load of E. coli might be an effective low cost liquid fertilizer for algal biomass production.

Evaluation of the fertilizer values of stored and fresh human urine in experimental mixed culture of fish and prawn

With a view to closing the nutrient loop between sanitation and fish culture, advanced fry of different species of fish (rohu, bata, mrigal, common carp, tilapia, punti) and larvae of freshwater prawn were reared in twelve experimental tanks in a mixed culture system for 120 days using three treatments (fresh urine, stored urine and mix of fresh and stored human urine) and control in triplicate. The total weight for all the species of fish and prawn in the stored urine (420.0 g) was 18 and 27% higher compared to fresh (356.0 g) and mixed urine (332.0 g) treatments, respectively. Likewise, primary productivity of phytoplankton and heterotrophic bacterial load related to phosphate level of water were also highest and lowest in the stored urine (GPP—508 ± 39.87 mg C m–2 h–1; heterotrophic bacteria—38.38 cfu × 103 mL–1) and control system (GPP—214 ± 38.09 mg C m–2 h–1; heterotrophic bacteria—13.53 cfu × 103 mL–1), respectively. The mean count of E. coli, on the other hand, did not differ between urine fed treatment and control. As a possible mechanism, it is suggested that stored urine upon transfer to aquaculture pond underwent degradation and mineralization that induced the autotrophic and heterotrophic food webs conducive to fish growth.

Current status of arsenic contamination in drinking water and treatment practice in some rural areas of West Bengal, India

The aim of the present investigation was to draw the current scenario of arsenic (As) contamination in drinking water of community tube well and drinking water treated by tube wells installed with different adsorbent media-based treatment plants in districts Nadia, Hooghly and North 24-Parganas districts, West Bengal, India. As removal efficiencies of different treatment plants varied from 23 to 71%, which is largely governed by adsorption capacity of adsorbent and influencing environmental factors. Though investigated treatment plants removed substantial amount of As from tube well water, high As concentration in treated drinking water was retained after passing through the treatment plants. This high level of As concentration in tube well water and retention of high As concentration in treated drinking water were severe for the consumers which therefore, indicating the improvement of removal efficiency of treatment plant by meticulously considering favorable influencing factors or/and application of other high capacity treatment alternatives to adsorb the excess As retained in drinking water and regular monitoring of As concentration in the treated drinking water are indispensable.

Treatment Wetlands as Ecotechnological Tools for Regenerative Reclamation of Wastewater: Experiences from Working with Kalyani Model

Presently world is facing mounting water stress, both in quantity and quality, which has prompted many municipalities for a more efficient use of the water resources, including a widespread acceptance of water reuse practices. Treatment technology encompasses a vast variety of options. As a low-cost, eco-friendly approach constructed wetlands are recently promoted for wastewater treatment and end use applications of reclaimed water. The present study was conducted to assess the performance of a series of treatment wetlands (waste stabilization ponds) in wastewater purification in Kalyani, West Bengal, India in the perspective of reclamation and bioregenerative reuse of reclaimed wastewater. The waste stabilization ponds have been proved very efficient and cost-effective nature-based system for increasing the ecological value of wastewater in culturing aqua-crops and thus converting organic wastes into fish biomass.