Efficiency of Treated Domestic Wastewater to Irrigate Two Rice Cultivars, PK 386 and Basmati 515, under a Hydroponic Culture System

The increasing human population continues to exert pressure on the freshwater scarcity. The availability of freshwater for crop irrigation has become challenging. The present study aimed to use domestic wastewater (DWW) for the irrigation of two rice cultivars (CVs) after treatment with the bacterial strain Alcaligenes faecalis MT477813 under a hydroponic culture system. The first part of this study focused on the bioremediation and analysis of the physicochemical parameters of DWW to compare pollutants before and after treatment. The biotreatment of DWW with the bacterial isolate showed more than 90% decolourisation, along with a reduction in contaminants. The next part of the study evaluated the impacts of treated and untreated DWW on the growth of two rice cultivars, i.e., PK 386 and Basmati 515, under a hydroponic culture system which provided nutrients and water to plants with equal and higher yields compared to soil. Growth parameters such as the shoot and root length and the wet and dry weights of the rice plants grown in the treated DWW were considerably higher than those for the plants grown in untreated DWW. Therefore, enhanced growth of both rice cultivars grown in biotreated DWW was observed. These results demonstrate the bioremediation efficiency of the bacterial isolate and the utility of the DWW for rice crop irrigation subsequent to biotreatment

Assessment of ethnopharmacological potential of Cyperus difformis L. in terms of its’ phytochemistry, antibacterial, antioxidant and anticancer attributes

The present research was carried out on Cyperus difformis L., commonly found sedge weed in rice field to evaluate its’ ethnopharmacological potential in terms of phytochemical constituents, antibacterial, antioxidant and anticancer activities. FTIR spectroscopy of powdered material of plant parts, rhizome (with roots), leaves and flowers showed the presence of three main chemical groups, i.e. -OH (alcohol), -C=O (carbonyl) and -CO-O-CO (anhydride). The phytochemical composition of n-Hexane, chloroform and ethanol crude extracts of same parts analysed by GC-MS and n-Hexane extract of various parts indicated 14 compounds with highest (10) in flowers extract followed by six compounds in chloroform and five in ethanol extracts of plant parts. The antibacterial activity was assessed against Salmonella enterica, E. coli and Staphylococcus aureus by using well diffusion method and similar resistance was shown by n-Hexane and ethanol extracts while noticeable inhibition by chloroform extract, especially by leaves showing zone of inhibition, 16.17±0.52mm, comparable with Gentamycin 18±0.11mm. The antioxidant activity in terms of DPPH Scavenging activity was found higher in n-Hexane and chloroform extracts, especially leaves i.e., 54.6±0.43 & 43.45±0.53 as compared to that of ethanol extracts. The percentage activity was increased with an increase of concentration of extracts. Antiproliferative activity checked by SRB proliferative assay and the crude extracts of plant parts of C. difformis showed good activity against A2780 and HCT116 cancer cells in three days. C. difformis having therapeutic action as well as its’ ethnopharmacological history, being used as fodder, it may be recommended good herbal fodder for the dairy animals

Hospital wastewater treated with a novel bacterial consortium (Alcaligenes faecalis and Bacillus paramycoides spp.) for phytotoxicity reduction in Berseem clover and Tomato crops

Hospital wastewaters are produced in large volumes in Pakistan (∼362–745 L/bed.day) and are discharged without proper treatment. They are widely used by farmers for crop irrigation and induce a phytotoxic effect on plant growth. The study was conducted to evaluate the effect of untreated and treated hospital wastewater on seed germination of a fodder crop Trifolium alexandrinum (Berseem clover) and a food crop Solanum lycopersicum (tomato). A bacterial consortium was formed with three bacterial strains, i.e., Alcaligenes faecalis and Bacillus paramycoides spp., which were individually proven efficient in previous studies. The concentrations of untreated and treated hospital wastewater (25, 50, 75 and 100%) were used to irrigate these crop seeds. To assess the efficiency of treatment, the germination percentage, delay index, germination index, stress tolerance indices, seedling vigour index and phytotoxicity index were calculated and were statistically proven significant. The seeds grown in treated wastewater concentrations showed negative values of phytotoxicity indices (tomato: −0.36, −0.47, −0.78 and −1.11; Berseem clover: −0.23) which indicate a stimulatory or non-toxic effect on seedling growth. Our work proposes that this bacterial consortium is efficient for hospital wastewater treatment before crop irrigation

Machine learning approach to predict quality parameters for bacterial consortium-treated hospital wastewater and phytotoxicity assessment on radish, cauliflower, hot pepper, rice and wheat crops

Raw hospital wastewater is a source of excessive heavy metals and pharmaceutical pollutants. In water-stressed countries such as Pakistan, the practice of unsafe reuse by local farmers for crop irrigation is of major concern. In our previous work, we developed a low-cost bacterial consortium wastewater treatment method. Here, in a two-part study, we first aimed to find what physico-chemical parameters were the most important for differentiating consortium-treated and untreated wastewater for its safe reuse. This was achieved using a Kruskal–Wallis test on a suite of physico-chemical measurements to find those parameters which were differentially abundant between consortium-treated and untreated wastewater. The differentially abundant parameters were then input to a Random Forest classifier. The classifier showed that ‘turbidity’ was the most influential parameter for predicting biotreatment. In the second part of our study, we wanted to know if the consortium-treated wastewater was safe for crop irrigation. We therefore carried out a plant growth experiment using a range of popular crop plants in Pakistan (Radish, Cauliflower, Hot pepper, Rice and Wheat), which were grown using irrigation from consortium-treated and untreated hospital wastewater at a range of dilutions (turbidity levels) and performed a phytotoxicity assessment. Our results showed an increasing trend in germination indices and a decreasing one in phytotoxicity indices in plants after irrigation with consortium-treated hospital wastewater (at each dilution/turbidity measure). The comparative study of growth between plants showed the following trend: Cauliflower > Radish > Wheat > Rice > Hot pepper. Cauliflower was the most adaptive plant (PI: −0.28, −0.13, −0.16, −0.06) for the treated hospital wastewater, while hot pepper was susceptible for reuse; hence, we conclude that bacterial consortium-treated hospital wastewater is safe for reuse for the irrigation of cauliflower, radish, wheat and rice. We further conclude that turbidity is the most influential parameter for predicting bio-treatment efficiency prior to water reuse. This method, therefore, could represent a low-cost, low-tech and safe means for farmers to grow crops in water stressed areas

Indigenous Bacillus paramycoides spp. and Alcaligenes faecalis: sustainable solution for bioremediation of hospital wastewater

Farmers near towns and cities are using a wide range of highly polluted wastewaters for crop irrigation in Pakistan due to severe freshwater shortage. The present study aimed to promote indigenous bacterial strains isolated from domestic, hospital, textile, pharmaceutical and mixed wastewaters to remove contaminants and colour and render these wastewaters safer for irrigation. Thirty seven bacterial strains were isolated from five wastewater samples collected from different sites in Lahore, Pakistan. Under optimal growth conditions, three isolates (D6, D7 and P1) showed >93% decolourisation potential in the treatment of hospital wastewater. 16S rDNA sequencing identified two of these isolates (D6 and D7) as showing 100% and 99.86% homology to Bacillus paramycoides spp. – novel strains from B. cereus group. Isolate P1 showed 97.47% homology to Alcaligenes faecalis. GCMS analysis of the untreated hospital wastewater revealed the presence of pharmaceutic pollutants, i.e. Phenol (876 µg/L), Salicylic acid (48 µg/L), Caffeine (7 µg/L), Naproxen (23 µg/L), Octadecene (185 µg/L) and Diazepam (14 µg/L). The analysis of treated hospital wastewaters showed percentage degradation of pharmaceutic pollutants (100%–43%) and significant reduction in the BOD5 (91%–68%), COD (89%–52%) and heavy metals concentrations. These strains therefore can represent a low-cost and low-tech alternative to bioremediate complex matrices of hospital wastewater prior to crop irrigation to support the achievement of clean re-usable water in developing countries like Pakistan