Using Chitosan as a Coagulant in Recovery of Organic Matters from the Mash and Lauter Wastewater of Brewery

Chitosan is a natural biopolymer which can be used to replace aluminum salts and chemical polymers as a coagulant to avoid the human health problems caused by the residual of aluminum and chemical polymers in water. Chitin is a major component in shrimp and crab shells, and chitosan can be produced from chitin via a deacetylated process. Since the biodegradation of chitin is very slow, large amount of discards from the processing of crustaceans has become a major concern in seafood industry. Therefore, more works are need to find the possible applications of chitin, chitosan and their derivatives. This research used chitosan as a coagulant to recover wheat dregs in the wastewater from washing the mash and the lauter unit in a brewery, and regards this study as an example to understand the influences of the characters of the wastewater on the treatment plant of brewery. The result shows that the␣wastewater from the mash and the lauter units can have the best treatment efficiency at the coagulant dosage of 120 mg/L in the original pH 4.5. Increasing the solution pH decreased the turbidity removal efficiency. The dominant mechanisms for chitosan to remove colloids in the␣wastewater are charge bridging and neutralization, and the later becomes less significant in␣the high pH. The coagulant of chitosan removed most of the colloidal form organic matter in the wastewater, but it has only little effect on the removal of dissolving organic matter. Chitosan is a natural material, after coagulation the sludge from the mash and lauter wastewater can serve directly as an animal husbandry fodder after been dehydrated. Therefore, the loading to wastewater treatment plant and the cost of treatment could be reduced.     

Chitin and Chitosan Extracted from Shrimp Waste Using Fish Proteases Aided Process: Efficiency of Chitosan in the Treatment of Unhairing Effluents

Extraction and depolymerisation of chitin and chitosan from shrimp waste material was carried out using fish proteases aided process. A high deproteinization level (80 %) was recorded with an Enzyme/Substrate ratio of 10 U/mg. The demineralization of shrimp waste was completely achieved within 6 h at room temperature in HCl 1.25 M, and the residual content of calcium in chitin was below 0.01 %. The degree of N-acetylation, calculated from the ¹³C CP/MAS-NMR spectrum, was 85 %. The chitin obtained was converted to chitosan by N-deacetylation. X-ray diffraction patterns also indicated two characteristics crystalline peaks approximately at 10° and 20° (2θ). Chitosan was then evaluated in the treatment of unhairing effluents from the tanning industry. A result showed that chitosan as a coagulant has good performance in alkaline pH and at concentration of 0.5 g/L. Within these conditions, chitosan could decrease turbidity value, total suspended solids (89 % at 1.5 g/L), biological oxygen demand (33.3 % at 1.5 g/L) and chemical oxygen demand (58.7 % at 1.5 g/L).     

Revegetating industrial waste disposal sites

Short-rotation tree plantations were established at seven industrial waste disposal sites in southern Finland. Altogether 31,500 willow cuttings were planted between 1984 and 1989. Neutralized residue from a titanium dioxide pigment process had an unfavourable influence on growth. Biological sludges from a municipal sewage treatment plant, and pulp and paper mills were too compact to be used alone as substrate, but gave a good supply of nutrients. Sand, bark and de-inking waste were sufficiently porous, but were low in nutrients. A mixture of different waste materials is therefore recommended as a substrate for willow stands. Replacement of a natural soil cover with waste material allows disposal of a greater volume of refuse and diminishes the costs of revegetation. The landfill characteristics have to be taken into account. The high temperature of bark also disturbed the growth of willow stands. Ferrous sulphate in the landfill limits the possibility of irrigating the stand. The highest biomass production of the stands exceeded that of normal Finnish forest. Willow stands can be used for landscaping industrial waste disposal sites, for increasing evapotranspiration and minimizing leachate discharge.     

Assessment and analysis of industrial liquid waste and sludge disposal at unlined landfill sites in arid climate

Municipal solid waste disposal sites in arid countries such as Kuwait receive various types of waste materials like sewage sludge, chemical waste and other debris. Large amounts of leachate are expected to be generated due to the improper disposal of industrial wastewater, sewage sludge and chemical wastes with municipal solid waste at landfill sites even though the rainwater is scarce. Almost 95% of all solid waste generated in Kuwait during the last 10 years was dumped in five unlined landfills. The sites accepting liquid waste consist of old sand quarries that do not follow any specific engineering guidelines. With the current practice, contamination of the ground water table is possible due to the close location of the water table beneath the bottom of the waste disposal sites. This study determined the percentage of industrial liquid waste and sludge of the total waste dumped at the landfill sites, analyzed the chemical characteristics of liquid waste stream and contaminated water at disposal sites, and finally evaluated the possible risk posed by the continuous dumping of such wastes at the unlined landfills. Statistical analysis has been performed on the disposal and characterization of industrial wastewater and sludge at five active landfill sites. The chemical analysis shows that all the industrial wastes and sludge have high concentrations of COD, suspended solids, and heavy metals. Results show that from 1993 to 2000, 5.14+/-1.13 million t of total wastes were disposed per year in all active landfill sites in Kuwait. The share of industrial liquid and sludge waste was 1.85+/-0.19 million t representing 37.22+/-6.85% of total waste disposed in all landfill sites. Such wastes contribute to landfill leachate which pollutes groundwater and may enter the food chain causing adverse health effects. Lined evaporation ponds are suggested as an economical and safe solution for industrial wastewater and sludge disposal in the arid climate of Kuwait.     

Quaternized Chitosan for Ecological Treatment of Bauxite Mining Effluents

One of the major concerns of mining companies is the safety of their tailing dams. Among the cares required to operate such a dam, a proper treatment of the effluent composing its waste stands out, since that, waste must be treated before returned to the environment. In the process of bauxite beneficiation, the effluent level of turbidity is the discard parameter that deserves attention. In this work, quaternized chitosan (TMC_Cl^?) derivative with cationic charge was synthetized and investigated to be used as coagulant in bauxite treatment for tailing dam effluent. The chitosan (CHT) was quaternized by methylation reaction. The quaternized chitosan structure was characterized by the following techniques: FTIR Spectroscopy and ¹H nuclear magnetic resonance (NMR). Its thermal stability was analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis. After quaternized chitosan was obtained, analysis with aluminum sulfate, protonated and quaternized chitosan were executed in jar-test apparatus. The tests were conducted in order to find the optimum pH, velocity gradient, coagulant and alkalizer dosages, as well as coagulation, flocculation and decantation time. The studied coagulants showed good results and reduced the effluent turbidity to levels below determined by legislation. By comparing the coagulants, it was possible to state that quaternized chitosan presented higher reduction of effluent turbidity levels; the tests were performed in the same conditions.     

改性粉煤灰混凝剂处理工业混合废水的试验研究

通过混合酸、氯化钠制备改性粉煤灰混凝剂,探讨粉煤灰粒度、酸用量、加热时间、反应温度等对废水处理效果的影响,得出制备混凝剂最佳工艺方案。通过正交试验,用最佳混凝剂处理工业混合废水,找出混凝剂投量、废水pH值、搅拌时间及静置时间等最佳参数,探索一条以废治废的可行方法。     

Managing petroleum refining wastes by thermal desorption

The U.S. Environmental Protection Agency has developed regulations under the Hazardous and Solid Waste Amendments (HSWA) of 1984 to restrict the land disposal of hazardous wastes. As a result of the regulations, all hazardous wastes to be placed on the land must meet treatment standards based on the performance of the best demonstrated available technology (BDAT) identified for individual waste classifications. The Marathon Oil Company is currently evaluating innovative technologies for managing listed waste materials, with a focus on waste minimization and recycling. Remediation Technologies, Inc. (ReTeC) has conducted testing on wastewater treatment sludges from three Marathon refineries using a proprietary thermal desorption technology. The results from these tests have demonstrated that the technology has the ability to consistently meet BDAT treatment standards, while preferentially separating and condensing residual moisture and oils from the material.     

Recycled blocks with improved sound and fire insulation containing construction and demolition waste

The environmental problem posed by construction and demolition waste (C&D waste) is derived not only from the high volume produced, but also from its treatment and disposal. Treatment plants receive C&D waste which is then transformed into a recycled mixed aggregate. The byproduct is mainly used for low-value-added applications such as land escape restoration, despite the high quality of the aggregate. In the present work, the chemical composition properties and grading curve properties of these aggregates are defined. Furthermore, the resulting recycled concrete with a high proportion of recycled composition, from 20% to 100% replacement of fine and coarse aggregate, is characterized physically and mechanically. An environmental study of the new construction material when all aggregates are substituted by C&D waste shows a low toxicity level, similar to that of other construction materials. The new material also has improved properties with respect to standard concrete such as high fire resistance, good heat insulation, and acoustic insulation.     

壳聚糖吸附重金属离子的研究进展

综述了,我国近几年来壳聚糖处理含重金属离子废水的研究进展。壳聚糖及其改性产品的吸附性能主要体现在对各种金属离子的吸附上,为了有选择性地吸附某种或某些金属离子,人们通过修饰、交联、接枝等方法对壳聚糖进行了各种改性研究。     

Comparison of selected aerobic and anaerobic procedures for MSW treatment

This paper considers selected efficiency rates and process data of aerobic and anaerobic procedures for the treatment of municipal solid waste and residual waste. Data are exclusively related to mechanical-biological treatment (MBT) procedures for generating waste appropriate for landfilling. The following aspects are regarded: general framework conditions for the application of MBT, efficiency of decomposition and of stabilisation, air and water emissions and energy balances. The presented data can be used for more efficient planning. In comparison to aerobic processes, anaerobic digestion can be ecologically advantageous, particularly with regard to exhaust emissions and energy balances. On the other hand, the wastewater emissions and the wastewater treatment required must be regarded as disadvantageous. Due to the relatively short period of operational history of most anaerobic processes for mechanical-biological waste treatment and thus limited experiences, operational reliability of anaerobic processes is slightly lower. Extensive biological stability of the treated waste for low-emission disposal cannot be reached by anaerobic digestion alone, but only in combination with additional aerobic post-treatment. In connection with the utilisation of renewable energies and the rising relevancy of climate protection, it can be affirmed that anaerobic digestion for the treatment of municipal solid waste has a high potential for further development.     

A Review Of The Management Of Radioactive Wastes In Medical Institutes

Amongst the waste from health care institutions, radioactive waste represents a special category since it cannot be modified or neutralized by any available conventional means. Accordingly, disposal of radioactive waste can mean only its transfer from a place where it represents some hazard to somewhere else where it can be retained without undue risk. Radioactive waste arises in health care institutes as a result of diagnostic, therapeutical or research uses of unsealed radioactive substances. Sometimes, sealed sources withdrawn from further use might also be subject to disposal. Most radionuclides used in medicine are short-lived beta-, or beta-gamma emitters and represent a low risk, if properly handled, that is if due care is taken to prevent significant contamination of the workplace and personnel. Low-activity gaseous and liquid waste can usually be discharged to the environment directly; medium-activity or high-activity waste should be stored for variable periods to allow natural decay before specialized disposal.This paper presents a review of the different types of radioactive wastes produced in hospitals, and introduces many of the sources of generation and subsequent disposal options. An example is given of the wide range of guidance available, both by national bodies in Hungary and international agencies, such as the International Atomic Energy Agency (IAEA), World Health Organisation (WHO) and International Committee on Radiological Protection (ICRP).     

Land disposal of mixed human and animal wastes: A review

Combining septic tank effluent and animal wastes (mixed wastes) for eventual application to land is being proposed as an alternative wastewater disposal system. Both types of waste are spread on land separately, and private practice may be to mix and spread them together, but in most of the United States mixing of these wastes for land disposal is illegal. No research has been done to assess the hazards associated with spreading mixed wastes on land. The concern is with the impact on public health of adding septic tank effluent to animal wastes for disposal as animal wastes. The effects of pathogens already present in animal waste are presumably allowed for in current U.S. regulations.Pathogens in mixed wastes include viruses, bacteria and parasites. Viruses are not always present in on-site waste disposal systems, but when present are in high numbers. Most viral particles will pass through the septic tank and will remain viable. Transmission will be prevented if these particles are retained in soil or other solids until any of several factors deprive them of infectivity. As animals are the chief reservoir of most enteric bacteria that are pathogenic to man, no additional hazards from bacteria are expected in a mixed waste system. Some parasite eggs and cysts will settle into the bottom of the septic tank, but significant numbers will pass through and will remain viable. Retention with solids will minimize transmission through food and water. In all instances it is important to match land use and waste disposal carefully.     

Papermill industrial waste as a sustainable source for high efficiency absorbent production

Papermill sludge (PMS) is generated during the wastewater treatment process of paper production. Its handling and disposal techniques are of great concern for the environment. It can be landfilled as a waste, or it can be recycled and converted into useful products of high value. It has a very promising application as an absorbing agent for the cleaning of water surfaces polluted with hydrophobic substances (vegetable, synthetic and mineral oils, animal fats, fuels, organic chemicals and even coal dust). Here, we present the pretreatment procedure (hydrophobation, mechanical and thermal treatments) of PMS that produces a lightweight absorbent material (HAWSC - high efficiency absorbent for water surface cleaning), which floats on the water surface and binds hydrophobic pollutants with considerably higher efficiency than commercially available mineral and synthetic absorbents. After its application, it can be incinerated, due to its high caloric value, to produce energy. The incineration residues can then be formed into granules that can be used as an efficient absorbent for fluids spilled onto solid surfaces.     

甲壳素和壳聚糖在水处理中的应用

介绍了天然有机高分子化合物——甲壳素和壳聚糖的制备、化学结构和特性，阐述了其在水处理中的应用及发展前景。甲壳素和壳聚糖的来源广泛，其性能优良、无毒、无公害、可生物降解，可用作吸附剂、絮凝剂、分离膜材料、离子交换剂和杀菌剂，是一类非常有开发利用前景的新型水处理材料。     

Generation of solid wastes in typhoon disasters and their emergent cleaning and treatment means

In Taiwan, typhoons usually result in a large amount of waste that needs to be removed in a short time from July to October. This study reviewed the relevant regulations on the clean-up of typhoon waste, including emergency response regulations, organizations and information systems; and we also discuss different typhoon waste clean-up and disposal methods. The results indicate that the parameters other than the maximum wind speed, such as the maximum accumulated rainfall, flooded area, waste output, sludge output, disinfected area and government dispatched attendance reached statistical significance (p < 0.05). Waste, tree branches and bird carcasses were primarily incinerated, while silt and building materials were buried, and pig and cattle carcasses were placed in a landfill with the tertiary treatment of wastewater. This study also reports on the relevant regulations for prevention of epidemics among personnel working in disaster areas. The results can provide important references for the disposal of typhoon waste in developing countries. As Asian countries have similar life styles and are often attacked by typhoons, the results of this study provide Asian countries with the operating experience of Taiwan in emergency treatment of solid waste resulting from typhoons as a reference for them to plan response systems and operation.     

Effect of aluminum sulfate and cationic polyelectrolytes on the destabilization of emulsified wastes

Emulsified oil in wastewater constitutes a severe problem in the different treatment stages. Aluminum salts have been traditionally used as coagulants in wastewater treatments. Polyelectrolytes are used to coagulate and flocculate colloidal systems. The performance of aluminum sulfate in comparison to polyelectrolytes (chitosan and polyacrylamide) as conditioning chemicals for an emulsion waste was tested, and the predominant mechanisms acting in each case were analyzed. Turbidimetry, jar test, colloidal titration and microscopy were used to test emulsion destabilization. Both charge neutralization and bridge formation were identified and confirmed as mechanisms of interaction of polyelectrolytes with waste constitutents. Charge neutralization would be more important for chitosan than for polyacrylamide treatment. A coincidence between the doses necessary to reach zero colloidal charge and minimum turbidity was observed for polyelectrolytes. The time necessary to produce system clarification was larger for aluminum sulfate than for polyelectrolytes; this time was shortened for higher aluminum sulfate concentration. The pH showed a marked effect on aluminum sulfate performance with the optimum at pH 6; polyelectrolyte action was practically not affected by pH. Polyelectrolyte addition produced the minimum turbidity for the same doses that zero colloidal charge; at higher doses, emulsion was restabilized and became turbid again. However, aluminum sulfate treatment did not produce emulsion restabilization.     

An LCA model for waste incineration enhanced with new technologies for metal recovery and application to the case of Switzerland

A process model of municipal solid waste incinerators (MSWIs) and new technologies for metal recovery from combustion residues was developed. The environmental impact is modeled as a function of waste composition as well as waste treatment and material recovery technologies. The model includes combustion with a grate incinerator, several flue gas treatment technologies, electricity and steam production from waste heat recovery, metal recovery from slag and fly ash, and landfilling of residues and can be tailored to specific plants and sites (software tools can be downloaded free of charge). Application of the model to Switzerland shows that the treatment of one tonne of municipal solid waste results on average in 425 kg CO₂-eq. generated in the incineration process, and 54 kg CO₂-eq. accrue in upstream processes such as waste transport and the production of operating materials. Downstream processes, i.e. residue disposal, generates 5 kg CO₂-eq. Savings from energy recovery are in the range of 67 to 752 kg CO₂-eq. depending on the assumptions regarding the substituted energy production, while the recovery of metals from slag and fly ash currently results in a net saving of approximately 35 kg CO₂-eq. A similar impact pattern is observed when assessing the MSWI model for aggregated environmental impacts (ReCiPe) and for non-renewable resource consumption (cumulative exergy demand), except that direct emissions have less and no relevance, respectively, on the total score. The study illustrates that MSWI plants can be an important element of industrial ecology as they provide waste disposal services and can help to close material and energetic cycles.     

混凝技术在印染废水处理中的应用及研究进展

概括了混凝技术在印染废水的预处理和深度处理以及印染废水回用工艺的预处理等领域的应用情况。介绍了目前用于印染废水处理的无机混凝剂、有机絮凝剂及复合混凝剂等的应用发展现状。复合混凝剂因各组分之间的协同作用提高了混凝性能,减少了投药量,进而降低了混凝污泥的产量。应对有机组分进行阳离子化,以减少无机组分的用量,并通过接枝反应等制备出具有多支链、含较多具有吸附功能的官能团结构的有机高分子,以提高混凝效果。应进一步针对实际印染废水,考察其他污染物以及实际操作条件对混凝效果的影响,以优化改良复合混凝剂。     

Report: biomedical waste management practices at Balrampur Hospital, Lucknow, India.

Biomedical waste has become a serious health hazard in many countries, including India. Careless and indiscriminate disposal of this waste by healthcare establishments and research institutions can contribute to the spread of serious diseases such as hepatitis and AIDS (HIV) among those who handle it and also among the general public. The present study pertains to the biomedical waste management practices at Balrampur Hospital, a premier healthcare establishment in Lucknow, in North India. The study shows that infectious and non-infectious wastes are dumped together within the hospital premises, resulting in a mixing of the two, which are then disposed of with municipal waste at the dumping sites in the city. All types of wastes are collected in common bins placed outside the patients wards. For disposal of this waste the hospital depends on the generosity of the Lucknow Municipal Corporation, whose employees generally collect it every 2 or 3 days. The hospital does not have any treatment facility for infectious waste. The laboratory waste materials, which are disposed of directly into the municipal sewer without proper disinfection of pathogens, ultimately reach the Gomti River. All disposable plastic items are segregated by the rag pickers from the hospital as well as municipal bins and dumps. The waste is deposited either inside the hospital grounds, or outside in the community bin for further transportation and disposal along with municipal solid waste. The open dumping of the waste makes it freely accessible to rag pickers who become exposed to serious health hazards due to injuries from sharps, needles and other types of material used when giving injections. The results of the study demonstrate the need for strict enforcement of legal provisions and a better environmental management system for the disposal of biomedical waste in the Balrampur Hospital, as well as other healthcare establishments in Lucknow.     

Removal of ammonium and phosphates from aqueous solutions by biochar produced from agricultural waste

The concern about protecting water quantity and quality is one of the most severe challenges of the twenty-first century since the demand for water resources grows as the population and its needs grow. Additionally, and as expected, most human activities produce wastewater containing undesirable contaminants. On the other hand, the generation of agricultural waste and its inappropriate disposal causes further problems. Current wastewater treatment methods involve a combination of physical and chemical processes, technologies, and operations to remove pollutants from effluents; adsorption is an excellent example of an effective method for wastewater treatment, and biochar is currently one of the most valuable adsorbents. This review focuses on new research about applying biochar produced from agricultural waste as a low-cost and environmentally friendly method for removing ammonium and phosphates from aqueous solutions.