彩涂铝板生产的酸性废水处理技术大分类

彩涂铝板生产中的酸性废水主要来源于酸蚀、中和、氧化、喷淋预处理、除油、酸洗等工序，富含多种有害物质或重金属盐。酸的质量分数差别很大，低含量小于1%，高含量大于10%。碱性废水主要来自氧化车间碱腐蚀、喷淋预处理、碱洗等工序。碱的质量分数大于5%，小于1%。喷染也会产生废水。废水中除了富含酸碱外，往往还富含油脂、油漆、氟化物等无机和有机物。

彩涂铝板酸碱废水具有较强的腐蚀性，经妥善处理后方可排放。酸碱废水管理的一般原则是：1）高浓度酸碱废水优先回收利用，根据水质、水量和不同的技术要求，尽量回用。如果回用困难，或浓度低、水量大，可选择浓缩法回收酸碱。② 酸洗槽清洗水、碱洗槽冲洗水等低浓度酸碱废水应中和。
彩涂铝板在中和处理方面，首先要考虑以废治废的标准。如酸碱废水相互中和，或用废碱（渣）中和酸性废水，用废酸中和碱性废水。在没有这些情况下，可以使用中和剂进行处理。
根据国家标准GB8978-1996《水污染物排放限值》，排放要求为：cod一级≤60mg/L，二级≤120mg/L，悬浮物≤100mg/L，氟离子F-≤10mg/L，pH值6-9。
现代污水处理方法主要分为物理处理、化学处理和生物处理。
1） 物理处理法是分离物理效应，回收不溶性悬浮污染物（包括油膜和油滴）的废水处理方法。一般选用沉淀、过滤、离心分离、气浮、蒸腾结晶、反渗透等方法。从废水中分离出悬浮物、胶体、油脂等污染物，使废水得到净化。
2） 化学处理是通过化学反应和传质作用，将溶解的和胶体的污染物分离去除或转化为无害物质的废水处理方法。一般选择方法有：中和、混凝、氧化回收、萃取、汽提、汽提、吸附、离子交换、电穿透。
3） 生物处理是通过微生物的代谢作用，将废水溶液、胶体、有机物、有毒物质等污染物转化为稳定无害的物质的一种废水处理方法。生物处理分为好氧处理和厌氧处理。目前常用的污泥处理方法有好氧池法、好氧滤池法。厌氧处理法又称生物回收处理法，主要用于处理高浓度有机废水和污泥，采用的处理设备主要为消化池。

The acid wastewater from aluminum plate production mainly comes from the acid etching process, neutralization, oxidation process, spray pretreatment, oil removal, acid washing and other processes, which are rich in various harmful substances or heavy metal salts. The mass fraction of acid is very different, the low content is less than 1%, and the high content is more than 10%. Alkaline wastewater mainly comes from oxidation workshop alkali corrosion, spraying pretreatment, alkali washing and other processes. The mass fraction of alkali is higher than 5% and lower than 1%. Spraying and dyeing also produce waste water. In addition to rich acid and alkali, wastewater is often rich in oil, paint, fluoride and other inorganic and organic substances.

The acid-base wastewater has strong corrosivity and can be discharged only after proper management. The general principles for the management of acid-base wastewater are as follows: 1) high concentration acid-base wastewater should be given priority to recovery and utilization, and should be reused as much as possible according to the water quality, water quantity and different technical requirements. If the reuse is difficult, or the concentration is low and the water volume is large, the concentration method can be selected to recover the acid and alkali. ② Low concentration acid-base wastewater, such as cleaning water of pickling tank and rinsing water of alkali washing tank, should be neutralized.
In terms of neutralization treatment, we should first consider the criterion of treating waste with waste. For example, acid and alkali wastewater neutralize each other, or use waste alkali (slag) to neutralize acid wastewater, and use waste acid to neutralize alkaline wastewater. In the absence of these conditions, neutralizer can be used for disposal.
According to the national standard GB8978-1996 discharge limits of water pollutants, the discharge requirements are as follows: cod class I ≤ 60mg / L, grade II ≤ 120mg / L, suspended solids ≤ 100mg / L, fluorine ion F - ≤ 10mg / L, pH value 6-9.
Modern wastewater treatment methods are mainly divided into physical treatment, chemical treatment and biological treatment.
1) The physical treatment method is a waste water treatment method in which the physical effects are separated and the insoluble suspended pollutants (including oil film and oil droplets) are recovered. Generally, sedimentation, filtration, centrifugal separation, air flotation, transpiration crystallization, reverse osmosis and other methods are selected. The pollutants such as suspended solids, colloids and oil are separated from the wastewater, so that the wastewater can be purified.
2) Chemical treatment is a wastewater treatment method that separates and removes dissolved and colloidal pollutants or converts them into harmless substances through chemical reaction and mass transfer effect. The general selection methods are: neutralization, coagulation, oxidation recovery, extraction, stripping, stripping, adsorption, ion exchange and electric penetration.
3) Biological treatment is a kind of wastewater treatment method which can transform wastewater solution, colloid, organics, toxic substances and other pollutants into stable and harmless substances through the metabolic effect of microorganisms. Biological treatment is divided into aerobic treatment and anaerobic treatment. At present, the commonly used aerobic treatment methods are activated sludge process, biological filter and oxidation pond. Anaerobic treatment method, also known as biological recovery treatment method, is mainly used for the treatment of high concentration organic wastewater and sludge, the use of treatment equipment, mainly for digestion tank.