1.1 Project Introduction

At present, the experimental wastewater generated by middle school laboratories, especially chemistry and biology laboratories, is mostly discharged directly, which can cause pollution to the environment and harm the health of surrounding residents, especially teachers and students.

By analyzing the sources and water quality characteristics of high school laboratory wastewater, the necessity of treating high school laboratory wastewater is clarified, and effective treatment plans are proposed for this type of wastewater.

1Introduction to Experimental Wastewater in Middle School

According to the teaching syllabus of middle school textbooks,High school experimental wastewaterMainly consisting of chemical laboratory wastewater and a small amount of biological laboratory wastewater, chemical laboratory wastewaterwatermainly includeThe wastewater generated from the experimentExcess samples, standard curves, sample analysis residues, failed or washed solutions, and a large amount of washing water, etc,The specific chemical experiments and main pollutants are as follows:

1) Experimental content

The chemistry laboratory mainly conducts inorganic reactions such as combustion experiments, neutralization reactions, oxidation-reduction reactions, precipitation reactions, as well as combustion, esterification, substitution, color reactions of small amounts of organic matter;

The biology laboratory mainly conducts simple biology teaching, observing the appearance of small animals and a small amount of anatomical observation, observing plant morphology, etc.

The main experimental contents that generate pollution sources are as follows:

Purification of coarse salt, testing of sulfate ions, distillation, extraction, electrolysis of water, preparation of solutions, testing of colloid properties, ion reactions, physical properties of sodium, combustion of sodium, reaction between sodium and water, heating of aluminum foil, reaction between iron powder and water vapor, reaction between aluminum and hydrochloric acid, reaction between sodium hydroxide, reaction between sodium peroxide and water, testing of properties of sodium carbonate and sodium bicarbonate, flame reaction, preparation of aluminum hydroxide, bisexuality of aluminum hydroxide, generation of iron hydroxide and ferrous hydroxide, testing of iron ions, conversion of iron ions and ferrous ions, preparation of silicic acid, combustion of hydrogen in chlorine gas, bleaching of chlorine water, bleaching experiment of dry chlorine gas, testing of chloride ions, solubility of sulfur dioxide in water, absorption of nitrogen dioxide by water Fountain experiment of ammonia dissolved in water The reaction between concentrated sulfuric acid and copper and a small amount of organic experiments.

2) Commonly used drugs (data source:JY/T 0386-2006 and JY/T 0406-2010 Standards for Equipping Science Teaching Instruments in Junior and Senior High Schools

A: Generally inorganic

Aluminum sheet, aluminum foil, zinc granules, iron powder, copper wire, zinc sheet, iodine, aluminum oxide, manganese dioxide, ferric oxide, potassium chloride, sodium chloride, calcium chloride, magnesium chloride, ferric chloride, copper chloride, ammonium chloride, potassium bromide, sodium bromide, copper bromide, potassium iodide, anhydrous sodium sulfite, potassium sulfate, sodium sulfate, aluminum sulfate, iron sulfate, ferrous sulfate, anhydrous copper sulfate, manganese sulfate, ammonium sulfate, zinc sulfate, aluminum potassium sulfate (alum), ferrous ammonium sulfate, ammonium molybdate, potassium carbonate, sodium carbonate, sodium bicarbonate, ammonium bicarbonate, sodium silicate, sodium thiosulfate

B: Generally organic

sodium acetate anhydrous、Ammonium oxalate、paraffin oil、glucose、sucrose、glycerol、soluble starch、vegetable oil、Benzidine

C: Indicator organic dye

phenolphthalein、Methyl Orange、Methylene Blue、magenta、Magnesium reagent、Aluminon、Diphenylthiocyanate, test paper, filter paper

D：Flammable liquid、solid

acetaldehyde、acetone、benzene、toluene、ethyl acetate、absolute ethanol、Sodium, potassium, magnesium strips

E: Oxidants and toxic substances

Sodium peroxide, potassium chlorate, potassium permanganate, ammonium nitrate, potassium dichromate, silver nitrate, sodium nitrite, barium chloride, barium hydroxide, carbon tetrachloride, lead acetate, bromoethane, oxalic acid, benzoic acid

F: Corrosive products

Nitric acid, sulfuric acid, hydrogen peroxide, bromine, aluminum chloride, hydrochloric acid, acetic acid, alkali lime, phenol, formaldehyde, sodium hydroxide, ammonia water, sodium sulfide, sodium hydroxide, calcium hydroxide

3) Investigation results of wastewater and waste liquid generated in junior high school chemistry and biology laboratories (data source: Education Equipment Center)

4) Main pollutants

The main pollutants are common acids, bases, salts, as well as small amounts of heavy metal ions and organic matter.

2.2.1 Inlet waterrequirement

Compliant with《Various types of washing wastewater that are not classified as hazardous waste according to the GB5085-2007 Identification Standards for Hazardous Waste;

Compliant with《Classification criteria for 175 laboratory wastewater in HJ520-2009 Wastewater Classification Code (excluding laboratory waste liquid);

Compliant with《The relevant indicators in the classification table of water pollutants and related indicators in HJ520-2009 Wastewater Classification Code.

2.2.2 Outlet water qualityThe determination

Design effluent quality:According to the characteristics of water quality, the designed effluent quality of this project reachesNeutralization and Discharge Standards for Water Pollutants in Beijing (Local Standards in Beijing)DB11-307-2013）And《GB18466-2005 Discharge Standards for Water Pollutants in Medical Institutions》Table 2 Water pollutant emission limits for comprehensive medical institutions and other medical institutions (Daily average), mainly outputThe water quality standards are shown in the following table: