Application of response surface methodology in process parameters optimization for phenol mineralization using Fenton’s peroxidation

Adverse effect of the highly biorecalcitrant compound phenol to the environment is well established and its concentrations in industrial effluents vary greatly from 2.8 to 6,800 mg/l depending on the source. Fenton process effectively mineralises to CO2 and H2O but reported works consumed more reagents and require longer reaction times. Due to the strong interaction between the several predictor variables in the Fenton oxidation, response surface methodology was used to optimise the mineralization treatment. Efficient, faster and economical operating conditions for phenol removal were explored by investigating four parameters namely the concentration ratio of hydrogen peroxide to phenol - ((H2O2):(Phenol)), mass ratio of hydrogen peroxide to ferrous ions - ((H2O2):(Fe2+)), initial phenol concentration - ([Phenol]o) and reaction time - (tr). The optimal TOC % reduction obtained were 35 and 88% for initial phenol concentrations of 100 and 5 mg/l, respectively. Reaction conditions corresponding to this phenol mineralization a reaction time of 20 min at ratios of 6 and 15 for [H2O2]:[Phenol] and [H2O2]:[Fe2+], respectively. For mineralisation at 52.5 mg/l phenol concentration, the optimal conditions were 20 min, ratios 10 and 15 for the reaction time, [H2O2]:[Phenol] and [H2O2]:[Fe2+], respectively. The soluble iron content of the analysed supernatant was found to be below the 15 mg/l (the maximum limit allowable for total iron discharges required by common regulative subscribed). This indicated that, the Fenton reagents were utilised during the peroxidation reaction evident from the almost near consumption of all Fe2+ introduced in about 85% of the samples, thus, negating the need for immobilising the Fe2+ catalyst or its removal by post treatment. The work proves that the optimized Fenton process can be potentially used for treatment of any phenol containing wastewater.Key words: Fenton process, phenol mineralization, response surface methodology

Composition and diversity of larval fish in the mangrove estuarine area of Marudu Bay, Sabah, Malaysia

The composition of fish larvae and their diversity in different habitats are very important for fisheries management. Larval fishes were investigated in a mangrove estuary of Marudu Bay, Sabah, Malaysia from October 2012 to September 2013 at five different sites. Monthly samples of fish larvae were collected at five sampling sites by a plankton net with a mouth opening of 40.5 cm in diameter. In total, 3879 larval fish were caught in the investigated area. The mean density of ichthyoplankton at this area was 118 larvae/100 m(3). The fish larval assemblage comprised of 20 families whereas 13 families occurred at St1, 16 at St2, 16 at St3, 12 at St4 and 16 at St5. The top major families were Sillaginidae, Engraulidae, Mugilidae and Sparidae with Sillaginidae consisted 44% of total larval composition. St3 with 143 larvae/100 m(3) had the highest density amongst the stations which was due to higher abundance of Sillaginidae. Shannon-Wiener diversity index represented significant variation during monsoon and inter-monsoon seasons, peaking in the months December-January and May-June. However, Shannon-Wiener index, evenness and family richness showed significant differences among stations and months (p < 0.05)

Growth and survival of the tropical sea urchin, Salmacis sphaeroides fed with different macroalgae in captive rearing condition

An experiment was undertaken to develop appropriate culture techniques for high-valued tropical sea urchin, Salmacis sphaeroides under captive aqua-rearing conditions. Three-month-old juveniles produced through induced breeding, larval rearing and metamorphic induction were stocked with 20 juveniles in each of nine well-aerated glass aquaria (46 x 30 x 30 cm).? Juveniles fed with red alga (Amphiroa fragilissima) were designated as Treatment-1 (T1), brown alga (Sargassum polysystum) as Treatment-2 (T(2)) and sea grass (Enhalus acoroides) as Treatment-3 (T(3)). At the time of stocking, juveniles were under the same age group and batch-reared with a mean length and weight of 9.98 ? 0.56 mm and 0.49 ? 0.11 g, respectively. The juveniles were fed ad libitum, and the seawater in each rearing aquarium was changed at bi-monthly intervals. The culture was carried out for one year during which time the juveniles attained sexual maturity. Growth performances (viz., final weight, weight gain, final length, length gain, specific growth rate and daily growth rate) and survival of adults were significantly higher (P < 0.05) in T(1) than those in T(2) and T(3), respectively. Gonad production, in terms of wet gonad weight and gonad index, also followed the same trend as that for growth. Hence, of the three algal feed evaluated, red alga appeared to be the most suitable food for rearing of S. sphaeroides under captive conditions. The present study is the first demonstration of successful culturing of S. sphaeroides in a static aquarium system, the findings of which could be helpful towards the commercial sea urchin aquaculture

Single Incision Laparoscopic Surgery for Acute Appendicitis: Feasibility in Pediatric Patients

Background. Laparoscopic appendicectomy is accepted by many as the gold standard approach for the treatment of acute appendicitis. The use of Single Incision Laparoscopic Surgery (SILS) has the potential of further reducing postoperative port site complications as well as improving cosmesis and patient satisfaction. Method. In this paper we report our experience and assess the feasibility of SILS appendicectomy in the pediatric setting. Results. Five pediatric patients with uncomplicated appendicitis underwent SILS appendicectomy. There were no significant intraoperative or postoperative complications. All patients were discharged within 24 hours. Conclusions. The use of Single Incision Laparoscopic Surgery appears to be a feasible and safe technique for the treatment of uncomplicated appendicitis in the pediatric setting. Further studies are warranted to fully investigate the potential advantages of this new technique

Development of breeding and fingerling production techniques for endangered long-whiskered catfish Sperata aor in captivity

An experiment was undertaken to develop a suitable seed production technique for Sperata aor in captivity. Naturally produced fry of aor was reared at different densities in nine nursery ponds 0.012 ha in size with an average depth of 0.8 m each. Three stocking densities tested, each of which was triplicated. Fry of aor stocked at 100,000/ha was designated as treatment-1 (T1), 150,000/ha as treatment-2 (T2) and 200,000/ha as treatment-3 (T3). All stocked fry were from the same age group with mean length and weight of 1.78 ± 0.28 cm and 0.24 ± 0.05 g, respectively. Fry in all the treatments were fed with SABINCO nursery feed (32.06% crude protein) for the first 14 days and starter-I (31.53% crude protein) for days 15 to 56. Physico-chemical parameters and plankton population of pond water were within the optimal level being better in T1 than those in T2 and T3. Growth in terms of final weight and length, weight and length gain, specific growth rate, daily growth rate, and survival of fingerlings were significantly higher in T1 followed by T2 and T3. Food conversion rate was significantly lower in T1 than in T2 and T3. Significantly higher number of fingerlings was produced in T3 than those in T2 and T1. Despite this, consistently higher net benefits were achieved from T1 than from T2 and T3. This is the first time report that stocking of 100,000 fry/ha appears to be the most suitable density for rearing of aor fingerlings in nursery ponds

Environment and diversity of ichthyoplankton in the seagrass beds of Sungai Pulai Estuary, Johor, Peninsular Malaysia.

Larval fish composition, seasonal diversity and their abundance influenced by environmental parameters were investigated between October 2007 and September 2008 in the Sungai Pulai seagrass beds of Johor, Malaysia. Fish larvae were collected monthly by a bongo net through 30 min surface tows in the seagrass beds. In situ environmental variables were recorded during the sampling cruises. Habitat temperatures of fish larvae ranged from 26.92-30.83°C (Mean ± SE, 29.11 ± 0.34°C); dissolved oxygen ranged from 4.73 to 7.19 mgL-1 (5.96 ± 0.19 mgL-1) and the salinity fluctuation was between 27.38 and 33.67 ppt (30.64 ± 0.50 ppt). In total 2,801 larvae, belonging to 20 families were recorded, with a mean abundance of 79 individuals/100 m3. Top six families (Clupeidae, Terapontidae, Nemipteridae, Sillaginidae, Blenniidae and Gobiidae) occurred consistently around the year. Larvae belonging to family Clupeidae (47.94%) and Terapontidae (17.35%) were most abundant in the study area. The density of total larval fishes varied significantly (P<0.05) among the different months. The highest diversity index (1.99) was observed in July while the lowest (1.20) was observed in September. Mean body length of larval fishes was 3.34 ± 0.51 mm (Mean ± SE) and ranged from 1.20 to 15.52 mm. It is revealed that 45% of the individuals were less than 4 mm and 99% were less than 6 mm (TL). The abundance of dominant families was found to have correlation (positive or negative) with the water parameters. Regular occurrence of larvae of different size range confirms the continuous spawning activity in this seagrass area

Food and feeding habits of Omobranchus sp. (Blenniidae: Omobranchini) larvae in the seagrass-mangrove ecosystem of Johor Strait, Malaysia

The stomach contents of Omobranchus sp. (family Blenniidae) larvae were investigated in a seagrass-mangrove based ecosystem in Johor Strait, Malaysia from October 2007 to September 2008. Specimens of larval fish were collected through subsurface towing of a Bongo net from five different stations. The stomach sacs of 267 Omobranchus sp. larvae were separated and observed, which comprised of 24 significant food stuffs belonging to 6 main groups viz. phytoplankton (62.45%), zooplankton (18.24%), algae (5.56%), plant-like particles (5.75%), debris (4.22%) and unidentified particles (2.03%). In situ water parameters were also measured throughout the sampling cruises. There was a strong and significant positive correlation between stomach phytoplankton and salinity (r = 0.658, p < 0.05).? Canonical correlation analysis indicated a weak relationship (29.8%) between stomach contents and physico-chemical parameters. Only salinity appeared to be the controlling factor for the stomach contents of Omobranchus sp. larvae in the investigated area. Based on the stomach content analysis, it could be concluded that Omobranchus sp. were mainly herbivorous during the larval stages

Development of digestive tract of hilsa shad, Tenualosa ilisha (Hamilton 1822) fry in the lower Meghna estuary, Bangladesh

This study was designed to describe the morphological development of the gut of Hilsa, Tenualosa ilisha from yolk sac to early juvenile stage. Samples were collected from the lower Meghna River, Bangladesh and laboratory analysis was conducted at Universiti Putra Malaysia, Malaysia. Digestive tract was transparent and straight tube in structure at yolk sac stage. After yolk sac absorption, the digestive tract was differentiated into mouth opening, buccopharyngeal cavity, esophagus, stomach, intestines and rectum. Development of digestive tract was almost completed during pre-flexion stage. Gut loop was clearly observed at post flexion stage. Digestive tract was equal to more than three-quarter of standard length during larval development. The percentage of gut length compared with the standard length were 84.87 ± 4.87 %, 85.64 ± 4.47 %, 82.29 ± 6.18 %, 77.99 ± 4.98 %, 74.02 ± 3.27 % at yolk sac, preflexion, flexion, post- flexion and juvenile stages, respectively. There was a strong linear relationship between the gut length and standard length (R2 = 0.97). This is the first report on morphological changes of gut and its development of T. ilisha larvae, which might be very useful information for aquaculture development of T. ilisha

Development of captive breeding and seed production techniques for Giant River Catfish Sperata seenghala

The Giant River Catfish Sperata seenghala, locally known as “Guizza Air” (and hereafter referred to as just Guizza), has significant aquacultural and conservational values, but closer monitoring of the fish is now badly needed. To protect the species from extinction, an experiment was undertaken to breed and produce seed of Guizza in a captive-rearing system. In our study, Guizza were successfully bred and the naturally produced fry were reared at different stocking densities in nine earthen nursery ponds having an area of 0.012 ha each with an average depth of 0.8 m. Three stocking densities were evaluated in three replicates each. Fry produced from natural propagation that were stocked at 100,000/ha were defined as treatment 1 (T1), those stocked at 150,000/ha as treatment 2 (T2), and those stocked at 200,000/ha as treatment 3 (T3). At stocking, all reared fry were of the same age-group with a mean±SD length and weight of 1.74±0.27 cm and 0.20±0.03 g, respectively. Fry in all the experimental ponds were reared with commercial Saudi Bangla (SABINCO) nursery feed (32.06% crude protein) for the first 14 d and starter-I (31.53% crude protein) for days 15–56. Growth (final weight, final length, weight gain, length gain, and specific growth rate) and survival of the fingerlings were significantly higher in T1 than in T2 and T3. Feed conversion rate was significantly lower in T1 than in T2 and T3. Moreover, the physicochemical measurements and plankton population of the pond water were within the optimal level for fish culture, with plankton abundance being higher in T1 than in T2 and T3. Consistently higher net benefits were obtained from T1 than from T2 and T3. Hence, of the three stocking densities, 100,000 fry/ha was the most suitable density for rearing Guizza fingerlings in nursery ponds