Biological phenol removal can be carried out by biosorption and various suspended and attached growth processes. Use of waste material for biosorption is widely investigated area of research. Use of low cost biosorbents serves twin purposes. It can minimize waste disposal problem and also helps in phenol removal from wastewater.
Hydrolysis of oil is essential and important step in synthesis of various compounds. Investigations are reported on oil hydrolysis and factors affecting it. Second topic includes hydrolysis and its applications. Various compounds are synthesized from different types of raw materials. Different type of oils such as palm kernel oil, crude oil, fats, andirobas oil, crambe oil, animal extracted oil etc. are promising raw materials. Compounds such as palmitic, oleic and stearic acids can be synthesized from these types of raw materials. Next chapter is about vermicomposting. Vermicomposting is one of the most practiced methods for domestic and household solid waste. In this, earthworms feed on anything that is biodegradable. Extra care is needed to prevent plant damage as high plant nutrients and plant growth stimulators can inhibit seed germination and growth to some degree. Investigations indicated increase in the parameters like total nitrogen (%), Available phosphorus (%) and Exchangeable potassium (%).Vermicomposting may supply an opportunity for employment. Fourth review discusses various aspects of wood preservations. The failure to control wood-destroying insects and fungi causes additional forest cutting. Wood preservation allows us to increase the service life of wood. Investigations by some researchers reveal that performance of wood preservation techniques can be changed by chemical modification of wood structure through the formation of adducts and the treatment with nano-materials.
Compounds such as Acid Copper Chromate (ACC), Alkaline Copper Quaternary (ACQ), is-(N-cyclohexyldiazeniumdioxy)-copper (Cu-HDO), Borates, Chromated Copper Arsenate (CCA), Chromium, Copper Azole (CA), Creosote are used as wood preservatives. This topic on wood preservation is followed by reviews of mosquito repellents. Places such as tree holes that periodically hold water, tide water pools in salt marshes, sewage effluent ponds, irrigated pastures, rain water ponds provide favorable conditions for mosquito growth. The problem of mosquitoes becomes severe due to the diseases such as malaria, which can be fatal. There is need to develop public mosquito programs. Chemical, physical, mechanical and biological methods for mosquito repelling are reported in literature. Various plant essential oils are used for mosquito repelling from ancient ages. Studies and research on mosquito repellent is generally aimed at cost reduction and increasing effectivity. Sixth chapter discusses various aspects of aerobic decomposition. Aerobic method needs diffusion of air through waste. Also sizeable amount of sludge is produced in aerobic method. Aerobic methods are most common in the waste treatment because of simplicity and effective treatment. Aerobic and anaerobic digestion methods have their own advantages and disadvantages. Seventh topic talks about research carried out by various investigators on anaerobic waste treatment and generation of biogas. The increase in population in developing countries has two major effects on economy in addition to food crises, the generation of waste and increase in energy requirement. The waste treatment is important aspect because of its odor, its effect on soil and ground water. The domestic, kitchen, vegetable, poultry, canteen and hotel waste causes major disposal problems. The use of this waste for biogas production is very attractive alternative. It serves twin purposes, waste treatment and energy generation. The waste after biogas production can be used as fertilizer. Ninth review in the book summarizes research and studies on enzyme immobilization. Enzyme catalyzed reactions provide huge boost to the efforts concentrated on cost effective and environment friendly technology. Immobilization of enzyme has advantages such as high thermal and operational stability, improved pH stability. Various investigators have carried out investigations to study effect of immobilization on enzyme activities. It is followed by review on downstream processing.
About 80 % cost of synthesis is for downstream processing. Ethanol, citric acid, lactic acid, amino acids, proteins and many other compounds are produced by biochemical pathways. Various methods for downstream processing include centrifugation, filtration, extraction, membrane separation. Requirement of high purity products with low production cost calls for efficient and cost effective downstream processing. There is potential to reduce the cost by increasing fermentation efficiency and reducing biomass and enzyme costs in case of fermentation. Biochemical reactions are utilized in wastewater treatment and synthesis of many compounds. Eleventh review in the sequence talks about kinetics. The biochemical reactions used in wastewater treatment are characterized by substrate concentration, biomass concentration, retention time, cell mass concentration and growth rate. The rate of substrate utilization and cell growth defines the effectiveness and kinetics of biological reactions. Monod growth kinetics is often used for explaining kinetics of substrate utilization. The last review in the sequence is about anaerobic treatments by UASB reactors. These treatments can be carried out to minimize chemical and biological oxygen demand. Anaerobic treatments are effective treatment methods with high treatment efficiencies. Upflow anaerobic sludge blanket (UASB) reactors are gaining importance because of high conversions and cost effectiveness.