Phytoremediation of Physico-chemical Parameters in Wastewater Effluents from Car Wash Bays in Yenagoa Metropolis, Nigeria

Surface water pollution through the discharge of untreated wastewater is on the increase globally. Efforts made using conventional techniques had not yielded the needed results. This study was conducted to determine the effectiveness of some native aquatic plants for the removal of some physico–chemical parameters from car wash wastewater effluents in Yenagoa metropolis. The plants used for this study were lemna minor, nymphaea nouchalli, pistia-stratiotes, eichhornia crassipes and ceratophyllum demersum; while the physico-chemical parameters investigated in this study include pH, DO, COD, BOD5, NO3, PO4 and turbidity. The wastewater samples collected from car wash bays were analysed to determine the level of the physico-chemical parameters concentrations using standard methods. The experiment was conducted in a green house for 42 days retention period. The results indicated that the cultured plants reduced the physico-chemical parameters to a minimum level, except DO, which increased in concentration. Therefore, they are considered good bioremediators of the parameters under review and the bioremediation potentials of the plants are in the order of P. stratiotes > L. minor > E. crassipes > N. nouchalli> C. demersum. It is therefore recommended that these plants should be used to treat wastewater effluents based on the investigated physico-chemical parameters.

Growth of Microcystis strains isolated from environments with the presence and absence of submerged macrophytes in coexistence with Ceratophyllum demersum

Cyanobacterial blooms can cause severe ecological and health problems in drinking water reservoirs. To alleviate this problem, allelopathically active submerged macrophytes can be used to reduce cyanobacterial growth. Accordingly, this study aimed to evaluate the sensitivity of strains of the Microcystis aeruginosa complex isolated from reservoirs with the presence and absence of submerged macrophytes to the allelochemicals of Ceratophyllum demersum. A coexistence experiment was carried out between the submerged macrophyte C. demersum and four Microcystis strains, with two treatments for each strain, one in coexistence with the submerged macrophyte (7 g L-1) and control (in the absence of the macrophyte). Two strains of M. aeruginosa (BMIUFRPE-06 and BMIUFRPE-07) and two of M. panniformis (BMIUFRPE-08 and BMIUFRPE-09) were used, which were isolated from Cajueiro (with submerged macrophytes) and Tapacurá (without submerged macrophytes) reservoirs, respectively. The biomass of Microcystis strains from the reservoir without macrophytes (BMIUFRPE-08 and BMIUFRPE-09) was significantly inhibited in 96% (T-test: p < 0.01) and 74% (T-test: p< 0.05), when compared to the control, respectively, with lower values of growth rates (ANOVA: p < 0.05). The strains isolated from the reservoir with macrophytes (BMIUFRPE-06 and BMIUFRPE-07) showed a growth delay (biomass reductions of 44 and 58%, respectively) in the coexistence treatment but without significant difference from the control on the sixth day of the experiment (biomass - T-test: p > 0.05; growth rate - ANOVA: p > 0.05). These results suggest that strains isolated from environments with submerged macrophytes are less sensitive to allelochemicals of these plants, as these strains may be adapted to the coexistence with submerged macrophytes.

Isolated and combined effects of a submerged macrophyte and a cladoceran on the interactions between Microcystis aeruginosa (Cyanobacteria) and Raphidocelis subcapitata (Chlorophyta)

Introduction: Cyanobacterial blooms in tropical water bodies are increasingly common, because of eutrophication and rising temperatures. Consequently, many freshwater systems are affected, by reducing water quality, biodiversity, and ecosystem services. With the increased frequency of harmful algal blooms, the development of biological tools to improve water quality is an urgent issue. Objective: To evaluate the effects of a submerged macrophyte and a cladoceran on the microcystin-producing cyanobacteria Microcystis aeruginosa (NPLJ-4) and the chlorophyte Raphidocelis subcapitata (BMIUFRPE-02) in mixed cultures. Methods: Two parallel experiments were carried out for ten days to evaluate the effects of the submerged macrophyte Ceratophyllum demersum and the cladoceran Moina micrura on microalgal interactions. Microalgal strains were cultivated in the ASM1 culture medium, under controlled laboratory conditions. The first experiment presented four treatments: M (C. demersum), Z (M. micrura), MZ (C. demersum and M. micrura), and C (control). Meanwhile, the second experiment consisted of five treatments, in which the microalgae were cultivated together at different Microcystis:Raphidocelis ratios: 1:0, 3:1, 1:1, 1:3, and 0:1. Biomass and growth rates of the strains were evaluated every two days, which were statistically treated with three-way or two-way repeated-measures ANOVA. Results: In the first experiment, M. aeruginosa was significantly inhibited in M and MZ treatments from the second day, and Z from the fourth, while R. subcapitata showed no reduction in its biomass in any treatment. On the other hand, R. subcapitata was stimulated from the eighth and tenth days in M treatment and only on the eighth day in Z treatment. In the second experiment, M. aeruginosa was significantly inhibited when cultivated with R. subcapitata in low ratios (Microcystis:Raphidocelis ratio of 1:3) throughout the experiment, while the chlorophyte was stimulated in that treatment. Conclusions: The coexistence of a cyanobacterium with a green alga did not alter the main negative response of M. aeruginosa to the submerged macrophyte and zooplankton but stimulated the green alga. Accordingly, the introduction of submerged macrophytes and cladocerans already adapted to eutrophic conditions, both isolated and combined, proved to be a good method to control cyanobacterial blooms without negatively affecting other coexisting phytoplankton species.

PRELIMINARY STUDY ON AQUACULLURE OF CTENOPHARYNGODON IDELLA VAL.

The classical method of aquaculture in Iraq employed Cyprinus carpio L. (Common carp) as monoculture or as predominat species togather with grass carp and silver carp. In the present study monoculture of grass carp was performed. Three - hundreds fingerlings of grass carp of 1.5 g weight were cultured in about 600 m2 eartheen pond from 20th of June till 9th of November, 1997. For the first two months of the experiment, no additional feed was added to what had been available in the pond. For the rest of the culture period, 1773 kg of five species of plants were utilized. They were included 91 kg of Phargmites australis, 972 kg of Paspalim sp., 423 kg of Medicago sativa, 171 kg of Ceratophyllum demersum and 116 kg of Paspalum Paspaloides. In addition to that a total of 150 kg of manure was used as a fertilizer in three occasions. At the end of the experiment the average weight of the fishes was 498 gm ranged from 370 gm to 980 gm. Further study was commence where 300 fingerlings of grass carp weighting 34 gm as an average were cultured together with 50 fingerlings of silver carp (average weight 92 gm). The experiment January 1998. For the first two months of experiment the fishes didn't consume began in additional food probably due to the low temperature of water during this period.

Improving Wastewater Quality By Using Ceratophyllum Demersum L.

The current study aims to improve the quality of wastewater collected from the secondary sedimentation tank of Hamdan sewage water treatment plant, Basrah, Iraq, using C. demersum L. for phytoremediation potential in the laboratory experiment. The experiments were also designed to establish some toxicological effects of wastewater on plant physiology as a response to wastewater stresses. The selected physio-chemical parameters of wastewater were conducted. Plant analyses were also measured before and after 21st day of exposure. The results showed the efficiency of the plant in improving the water quality in a different ratio. The dilution 1:3 (T3) was the most efficient with a significant difference (p<0.05) between treatment and control for most of the measured parameters. The result showed the efficiency of Ceratophyllum demersum in removing the Total hardness, Ca+2, Mg+2, BOD5, COD, NO3-2, PO4-2, Na+ and Cl- in 1:3 dilution (55.88, 13.27, 89.55, 90, 47.37, 50.65, 48.51, 16.28 and 40.24)% compared with (17.65, 5.42, 27.31, 50, 15.79, 16.30, 13.86, 6.73 and 15.77 )% in control respectively. The Ceratophyllum demersum plant has proven to be effective in improving the quality of wastewater, and therefore it can be considered an effective candidate in phytoremediation technology.

Hydrology-mediated invasive macrophyte impacts on freshwater mussels in a hydropeaking reservoir

Globally-threatened freshwater mussels belonging to the order Unionida (Bivalvia) may be adversely affected by dense beds of submerged macrophytes that modify habitat at the sediment-water interface. Such effects can be particularly pronounced in modified lentic ecosystems such as reservoirs which are subject to hydrological regimes (e.g., hydropeaking) that can exacerbate macrophyte-mediated impacts, including anoxic or hypoxic conditions, the related release of toxic ions (e.g., ammonia), and silt accumulation that inhibits filter-feeding. Accordingly, we compared how population size-structure and biomass of the New Zealand mussel Echyridella menziesii varied inside and outside of dense beds of invasive macrophytes known to have similar impacts on water chemistry (e.g., anoxia) in two northern New Zealand hydroreservoir locations with contrasting hydrology (lacustrine location dominated by Ceratophyllum demersum; and riverine location dominated by Egeria densa). We found adverse sediment-water interface conditions were not always associated with dense submerged macrophyte beds in littoral zones. Nonetheless, where they occurred, adverse sediment-water interface conditions were primary drivers in reduced mussel density and adult skewed size-structure, inferring reduced recruitment. Disentangling direct and indirect effects with structural equation modelling indicated that increased pore-water ammonia did not impact these primarily adult populations of freshwater mussels. Increased sediment organic matter, silt, and previously recorded hypoxia and anoxia were exacerbated in the lacustrine section where variable flows promoting water mixing were not present to reduce their effects. High densities of mussels less than 40 mm in length were associated with favourable sediment-water interface conditions of low silt and sediment organic matter, suggesting that enhanced water exchange in and around macrophyte beds may increase juvenile mussel survival in littoral zones of the riverine lake section. Our findings highlight a potential role for hydropeaking management in mitigating the development of adverse physicochemical conditions, and underscore the context-specific effects that dense non-native macrophyte beds can have on mussel populations.

Comparison of generic and proprietary aquatic herbicides for control of invasive vegetation; part 3 : submersed plants

Herbicide selection is key to efficiently managing nuisance vegetation in our nation’s waterways. After selecting the active ingredient, there still remains multiple proprietary and generic products to choose from. Recent small-scale research has been conducted to compare the efficacy of these herbicides against floating and emergent species. Therefore, a series of mesocosm and growth chamber trials were conducted to evaluate subsurface applications of the following herbicides against submersed plants: diquat versus coontail (Ceratophyllum demersum L.), hydrilla (Hydrilla verticillata L.f. Royle), southern naiad (Najas guadalupensis (Sprengel) Magnus), and Eurasian watermilfoil (Myriophyllum spicatum L.); flumioxazin versus coontail, hydrilla, and Eurasian watermilfoil; and triclopyr against Eurasian watermilfoil. All active ingredients were applied at concentrations commonly used to manage these species in public waters. Visually, all herbicides within a particular active ingredient performed similarly with regard to the onset and severity of injury symptoms throughout the trials. All trials, except diquat versus Eurasian watermilfoil, resulted in no differences in efficacy among the 14 proprietary and generic herbicides tested, and all herbicides provided 43%–100% control, regardless of active ingredient and trial. Under mesocosm and growth chamber conditions, the majority of the generic and proprietary herbicides evaluated against submersed plants provided similar control.