Phosphorus recovery and recycling from model animal wastewaters using materials prepared from rice straw and corn cobs

Anthropogenic loss of phosphorus to surface waters not only causes environmental problems but depletes valuable phosphorus reserves. In this study, magnesium amended biochars and magnesium silicate, synthesized from corn cobs and rice straw, respectively, were evaluated for phosphorus uptake including the effects of pH and alkalinity. The overall goal was to close the phosphorus loop by recovering phosphorus from animal waste and reusing it as fertilizer. After phosphorus uptake, spent materials were tested for phosphorus release using modified soil tests representing different soil pH and alkalinity conditions. In experiments using model animal wastewaters containing both ammonia and bicarbonate alkalinity, dissolved phosphorus was removed by struvite (MgNH4PO4·6H2O) formation, whereas in deionized water, dissolved phosphorus was removed by adsorption. Alkalinity in the model animal wastewaters competed with phosphate for dissolved or solid-associated magnesium, thereby reducing phosphorus uptake. Spent materials released significant phosphorus in waters with bicarbonate alkalinity. This work shows that abundant agricultural wastes can be used to synthesize solids for phosphorus uptake, with the spent materials having potential application as fertilizers.

Effect of Alkalinity on Catalytic Activity of Iron–Manganese Co-Oxide in Removing Ammonium and Manganese: Performance and Mechanism

In this study, a pilot-scale experimental filter system was used to investigate the effect of bicarbonate alkalinity on the activity of an Fe–Mn co-oxide for ammonium and manganese removal from surface water. The results showed that an increase in alkalinity to 150 mg/L (calculated as CaCO3) by the addition of NaHCO3 significantly promoted the activity of the Fe–Mn co-oxide. The ammonium and manganese removal efficiencies of the Fe–Mn co-oxide increased from 40% to 95% and 85% to 100%, respectively. After NaHCO3 was no longer added, the activity of the filter column remained. Moreover, pH (7.4–8.0) and temperature (12.0–16.0 °C) were not the main factors affecting the activity of the filter, and had no significant effect on the activity of the filter. Further characterization analysis of the Fe–Mn co-oxide filter film showed that after alkalinity was increased, the accumulation of aluminum on the filter media surface decreased from 3.55% to 0.16% and the oxide functional groups changed. This was due to the action of bicarbonate and the residual aluminum salt coagulant in the filter, which caused the loss of Al from the surface of the filter media and weakened the influence of the aluminum salt coagulant on the activity of the Fe–Mn co-oxide; hence, the activity was recovered.

Assessment of Traditional Rice Beer Quality Manufactured by Different Ethnic Tribes of Assam, India

Ethnic communities of North-East India consume various traditional beverages which are mostly prepared by fermentation of rice of their own. Many ethnic communities reside in Assam, India and the consumption of fermented drinks is always considered to be their culture and existence of the ethnic tribes. In present work, eight different rice beer samples are collected from different parts of Assam representing Ahom, Mising and Karbi community. The samples are characterized with respect to various physico-chemical analysis and microbiological parameters. In present work, the methodologies for the process of preparation of rice beers by different ethnic communities are also carefully observed and properly documented. It has been observed that all the samples are acidic in nature and the pH values are ranged from 2.83-5.05, while conductance ranged from 0.028-1.86 ms/cm. The amount of free carbon dioxide varies from 0.105 g/L to 6.81g/L. The amount of hardness varied from 0.012 g/L to 0.38 g/L. The sugar content of various rice beers ranged from below detection limit (BDL) to 4.4 g/100 mL while the percentage of ethanol varies from 2.2 to 5.7 g/100 mL. The correlation matrix study also shows a good positive correlation between conductance and TDS, hardness, free CO2 and bicarbonate alkalinity. In this study, no coliform bacterial contamination appeared while the colony forming unit ranged from 0.3 × 105 to 1.68 × 105 cfu mL-1.

Protection of winter gardens constructions against corrosion caused by aqueous solution of hornbeam ash

The use of coarse-grained concrete (porosity 3-8%) of class B 12.5 15 with water resistance of W 4 and below is widespread in the village buildings in Russia and is associated with poor quality concrete production using manual labor. Since the mid-90s of the 20th century, it has become fashionable to install cottages of greenhouses or winter gardens in the attic space, with fireplaces for heating and using wood ash as fertilizer for plants. According to the survey data, ash moistened during irrigation has bicarbonate alkalinity, slightly aggressive for concrete of this quality. Determination of the pH of the cement stone of the operated column structures was within the range of pH = 11.8-12.6, overlap pH = 9.2-9.4. The studied aqueous solution of hornbeam ash had a bicarbonate alkalinity of 0.81 mEq/dm3 and is a slightly aggressive medium for concrete of this quality. The paper provides measures to protect concrete with Penetron penetrating waterproofing.

Replacement of sodium alginate polymer, urea and sodium bicarbonate in the conventional reactive printing of cellulosic cotton

The objective of this study is to replace sodium alginate (bio composite polymer), urea and sodium bicarbonate (alkalinity) in the conventional reactive printing of cotton with carboxymethyl tamarind plolysaccharide (bio polymer), polyethylene glycol 400 (PEG-400) and trichloroacetic acid respectively. This study was motivated by the goal of coming up with a low-cost, eco-friendly printing process. The results were evaluated on two reactive dyes (color index numbers: Reactive Violet 01 and Reactive Blue 21) at two dose levels (2% and 4% of the printing paste weight). In the conventional recipe, sodium alginate, urea and sodium bicarbonate were added at dose levels of 2%, 15% and 2.5%, respectively; in the modified recipe, the dose levels of the substituted tamarind polysaccharide and trichloroacetic acid were 6% and 4%, respectively. The different dose levels of PEG-400 (0%, 1%, 2%, 3%) were accessed in each modified recipe. Results showed that the Sum K/S and shade strength, dye penetration, staining on white ground of the fabric, rubbing fastness (dry and wet), washing fastness, perspiration fastness (acidic and alkaline), light fastness, sharpness of the edges and fabric softness all improved in the modified recipe with 2% PEG-400. However, the increase in PEG-400 only increased the dye penetration and did not give any significant benefit with the increase in concentration.

Water quality of springs in Badigad Catchment, Western Nepal

Population growth and intense agricultural activities in Nepal has caused substantial increase in demand for fresh water. As there is limited access to surface water in most parts of the country, groundwater and springs are the principal water sources for irrigation and drinking purposes in the Terai and hilly region, respectively. The present study carries out the water quality analysis of 30 spring samples in the Badigad Catchment from Gulmi and Baglung Districts. The study was made to analyse suitability of spring waters of the Badigad Catchment for irrigation and drinking purposes. The physiochemical parameters were analysed using standard methods in the site and laboratory. Average value for pH of the sample was 7.8 with conductivity value ranging from 630 to 1500 micro Siemens/cm. The bicarbonate alkalinity ranges from 140 to 350 mg/L, indicating a medium salinity hazard in the catchment. The water in the catchment was found to be moderately hard with an average of 75mg/L CaCO3 hardness. Nitrate, sulphate, ammonia, chloride, fluoride and sodium absorption ratio were found to be <0.1mg/L, <1mg/L, <1.5mg/L, 3mg/L, 1mg/L and <2, respectively in all samples. Iron content in the water was also below the permissible limits in some samples and not available in some samples. Thus, the spring water in Badigad Catchment is suitable for drinking and irrigation purposes.Bulletin of the Department of Geology, Vol. 18, 2015, pp. 67-74

Start-up of anaerobic reactors for slaughterhouse wastewater treatment

This study aimed to evaluate the start-up of a horizontal anaerobic fixed bed reactor (HAFBR) followed by an upflow anaerobic sludge blanket (UASB) for the slaughterhouse wastewater treatment. HAFBR was filled with bamboo rings and had 1.2 m in length, 0.10 m in diameter and volume of 7.5 L. The UASB had the volume of 15 L. The HAFBR and UASB operated at organic loading rate and hydraulic retention time average of 8.46 and 3.77 kg m-3 d-1 of COD and 0.53 and 0.98 days, respectively. During 150 days of monitoring system it was found pH 6.8, relatively high values of bicarbonate alkalinity (> 1000 mg L-1) and reduced values of volatile acids (70 to 150 mg L-1), which afforded average removal efficiencies of COD total and total suspended solids of the order of 31 and 23% in HAFBR and 79% and 63% in UASB. It can be concluded that the generation and consumption of bicarbonate alkalinity and total volatile acids, thereby maintaining the pH during the study indicated stable operation of the reactors. The COD removal in the reactors was satisfactory especially when it considers that the assessment was conducted in a period of adaptation of organisms to the effluent and also the high organic load applied during this period.

Field Method for Determination of Bicarbonate Alkalinity

Alkalinity is used to calculate the bicarbonate concentrations under various production conditions and the bicarbonate concentration is needed to calculate saturation indices for the prediction of carbonate and sulfide scale formation and also to predict the corrosivity of the produced water during production. Since the saturation index is related to the square of the bicarbonate concentration, the accuracy of alkalinity is vitally important for the prediction of corrosion and scaling indices of all oil and gas production systems. Unfortunately, the total alkalinity remains one of the most difficult parameters to be measured accurately in produced water due to both interferences and the difficulty in preserving the sample during storage. When collected samples de-gas during transport, the dissolved CO2 concentration decreases, pH increases, and brine components start to react with O2 and these reactions cause a reduction in bicarbonate alkalinity. In this study, an experimental method was developed to determine bicarbonate alkalinity in minimal time and operating difficulty. The apparatus consists of four parts: a low pressure sealing vessel, high accuracy pressure gauge, a syringe for acid addition and a thermometer. The changed pressure in this closed vessel, which indicates the amount of CO2 evolved after the addition of a strong acid, is used to determine the bicarbonate alkalinity of the sample. A wide range of synthetic waters and two production water samples were tested. Excellent agreement has been observed between true and calculated concentration. The results enable a more accurate measurement of produced water composition without the error caused by collection and preservation of samples. The field method combined with our automatic titration method enables more accurate prediction of pH, saturation index and corrosion risk at typical conditions of deep water production. This paper provides a reliable and detailed approach for field test of bicarbonate alkalinity with high accuracy and precision and a set of recommendations for field use.